No 3 Bigend.
03 July 2001, 07:30 PM
#91
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Very interesting thread indeed although it looks to me as if it may be under threat the way some contributors started to act.
Regretfully, the engine on my UK Impreza 97/98 generation lost its bigend no. 3 a week ago after 52,000 carefully driven miles with 4000 mls oil changes and everything else that needed to be done as maintenance. No modifications to the car of any kind.
Reading those parts of the thread I think I understand, it seems that Japanese cars are prone to leaning out engines, detonation and failures (insufficient RON of fuel, etc.) I have been told UK cars run quite rich and are killed in power in order to run on our fuel safely. Do we have lots of engine damages of the kind on UK standard cars? If so, why by comparison to Japan cars?
Reading Richard Squire's posts I am amazed someone can diagnose an "old det" signs 30,000 miles later on any engine? I wonder who the extraordinary engineer with an electronic microscope (?) could have seen that? Or is it really possible to determine such things so much after?
Also, if Richard's car (22B) was "banging off the rev limiter", leaving aside it is not a good practice to let it be there anyway, would that not lean out the engine as a matter of course? That is, of course, if I understand the purpose of a rev limiter?
After reading all that R19KET and Bob Rawle have written going through the archives of Scoobynet, it seems that any small differences in things surrounding the engine on the air intake and exhaust sides can influence an otherwise precise and accurate map. Therefore, I would assume those changes without being followed up at the ecu end could cause problems. However, that is NOT what is being discussed here and probably does not shed much light on the big end failures as experienced.
Bottom line - are there UK car owners with a standard engine who had troubles of the kind?
thanks
Regretfully, the engine on my UK Impreza 97/98 generation lost its bigend no. 3 a week ago after 52,000 carefully driven miles with 4000 mls oil changes and everything else that needed to be done as maintenance. No modifications to the car of any kind.
Reading those parts of the thread I think I understand, it seems that Japanese cars are prone to leaning out engines, detonation and failures (insufficient RON of fuel, etc.) I have been told UK cars run quite rich and are killed in power in order to run on our fuel safely. Do we have lots of engine damages of the kind on UK standard cars? If so, why by comparison to Japan cars?
Reading Richard Squire's posts I am amazed someone can diagnose an "old det" signs 30,000 miles later on any engine? I wonder who the extraordinary engineer with an electronic microscope (?) could have seen that? Or is it really possible to determine such things so much after?
Also, if Richard's car (22B) was "banging off the rev limiter", leaving aside it is not a good practice to let it be there anyway, would that not lean out the engine as a matter of course? That is, of course, if I understand the purpose of a rev limiter?
After reading all that R19KET and Bob Rawle have written going through the archives of Scoobynet, it seems that any small differences in things surrounding the engine on the air intake and exhaust sides can influence an otherwise precise and accurate map. Therefore, I would assume those changes without being followed up at the ecu end could cause problems. However, that is NOT what is being discussed here and probably does not shed much light on the big end failures as experienced.
Bottom line - are there UK car owners with a standard engine who had troubles of the kind?
thanks
03 July 2001, 09:35 PM
#92
Ecu Specialist
Come gentlemen lets not detract from the main discussion which was about big end failure in, what seems to be, a variety of cars under , well hopefully we shall find out, various conditions.
To put this to bed re Richards car whilst I did not know that the backbox had been changed (Richard advises it was just the back box) the car was mapped fuel wise so that it would have made very little difference and would certainly have not caused det in its own right. In fact it could even have been running richer afterwards ... no one considered that ?Hopefully the circumstances will be added to the database and will contribute to the whole picture, analysing individual cases is not what I had in mind.
UK cars are very much detuned and limited to lower revs, given that it is not so likely that a standard UK car would see the conditions necessary to cause a bearing failure but again we will see, all and any experiences welcome and relevent.
The factory ecu does indeed run the car pretty rich. Any mod that enhances the breathing and increases the boost will cause the engine to run leaner but only once the maf sensor has reached its limit. So most people should be ok with this type of mod however I ALWAYS caution anyone to get the fueling checked out after (or as) its done. A faulty sensor somwhere and the car could be sent too lean for comfort.
If a car has been detting consistently over a period of time and is then stopped from detting it is perfectly possible to see this with the naked eye let alone a microscope, occasional and minor or transition det would not leave more than a trace and would disappear as soon as it arrived.
Since the P1 is basically a STi 5 and is "supposed" to be capable of using 95 ron then I can quite understand why Mike would be concerned, a mod that increased boost a bit coupled with 95 ron fuel (or even 97 under some circumstances) would definately make a P1 det. Treat the P1 like the STi 5 (97 ron plus booster) and it should be fine though.
Jay, the MY92-96 WRX/STi verions were not fueled as heavily as the later cars and so you should get it checked, I also suspect that if you got the lambda sensor checked it may be running rich on cruise as the early cars are notorious for this, rich running over a prolonged period will carbon the pistons up and cause surface det by pre-ignition. This will happen irrespective of timing and does not sound in any way like the det we know and hate which is normally temperature and mixture related. If your lambda sensor is still in the exhaust headers invest in a new one and get it fitted into the downpipe just behind the turbo (where the UK cars have theirs). This will solve the problem and put the cruise fueling right if its a problem, be a good idea to consider a decoke of some sort, even if its just an additive. If you want some comfort just invest in a Lambdalink and Knocklink or other equivelant devices. these things work just as well for the standard ecu as an aftermarket one. BTW the Jap spec lambda sensor is extortionately expensive as it has a long lead extension fittted to reach down to the headers, the shorter leaded one is 1/3 the price and the lead from the old one can be adapted onto the new one, considerable saving.
it is worth rembering that most aftermarket ecu's or piggyback chips are usually mapped to suit the car at in the condition it was at when the upgrade was installed, ANY proposed change should be advised to the tuner, whomever that is, so that judgement can be made as to wether any adjustment should be necessary, if monitoring devices are installed then it is easy to check out, if not a trip to the tuner and the same result should be obtained.
Be safe, ask first.
To put this to bed re Richards car whilst I did not know that the backbox had been changed (Richard advises it was just the back box) the car was mapped fuel wise so that it would have made very little difference and would certainly have not caused det in its own right. In fact it could even have been running richer afterwards ... no one considered that ?Hopefully the circumstances will be added to the database and will contribute to the whole picture, analysing individual cases is not what I had in mind.
UK cars are very much detuned and limited to lower revs, given that it is not so likely that a standard UK car would see the conditions necessary to cause a bearing failure but again we will see, all and any experiences welcome and relevent.
The factory ecu does indeed run the car pretty rich. Any mod that enhances the breathing and increases the boost will cause the engine to run leaner but only once the maf sensor has reached its limit. So most people should be ok with this type of mod however I ALWAYS caution anyone to get the fueling checked out after (or as) its done. A faulty sensor somwhere and the car could be sent too lean for comfort.
If a car has been detting consistently over a period of time and is then stopped from detting it is perfectly possible to see this with the naked eye let alone a microscope, occasional and minor or transition det would not leave more than a trace and would disappear as soon as it arrived.
Since the P1 is basically a STi 5 and is "supposed" to be capable of using 95 ron then I can quite understand why Mike would be concerned, a mod that increased boost a bit coupled with 95 ron fuel (or even 97 under some circumstances) would definately make a P1 det. Treat the P1 like the STi 5 (97 ron plus booster) and it should be fine though.
Jay, the MY92-96 WRX/STi verions were not fueled as heavily as the later cars and so you should get it checked, I also suspect that if you got the lambda sensor checked it may be running rich on cruise as the early cars are notorious for this, rich running over a prolonged period will carbon the pistons up and cause surface det by pre-ignition. This will happen irrespective of timing and does not sound in any way like the det we know and hate which is normally temperature and mixture related. If your lambda sensor is still in the exhaust headers invest in a new one and get it fitted into the downpipe just behind the turbo (where the UK cars have theirs). This will solve the problem and put the cruise fueling right if its a problem, be a good idea to consider a decoke of some sort, even if its just an additive. If you want some comfort just invest in a Lambdalink and Knocklink or other equivelant devices. these things work just as well for the standard ecu as an aftermarket one. BTW the Jap spec lambda sensor is extortionately expensive as it has a long lead extension fittted to reach down to the headers, the shorter leaded one is 1/3 the price and the lead from the old one can be adapted onto the new one, considerable saving.
it is worth rembering that most aftermarket ecu's or piggyback chips are usually mapped to suit the car at in the condition it was at when the upgrade was installed, ANY proposed change should be advised to the tuner, whomever that is, so that judgement can be made as to wether any adjustment should be necessary, if monitoring devices are installed then it is easy to check out, if not a trip to the tuner and the same result should be obtained.
Be safe, ask first.
04 July 2001, 04:07 AM
#93
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This is an email I received from a friend in Australia.
" ...Hi Carlos
The reason the bearings fail is due to the oil thickness and how good it is
, if it is old it will get diluted and thus break down not giving the
protection needed .
We are too are having lots of bearing failing , but the one thing in common
is the oil was to thin , ones like 10w/30 , 0w/40 , 5w30 , it maybe ok for
the road but come hard driving and track work , you can almost set your
watch to when it will blow , most bearings have gone after they went to a
thin oil that the dealers have switched to , on engines with good history
and low k's , there are many good storeys too , there are a few guys who run
large boost , high rpm for many years BUT they run 15w/50 , 15w/60 , 20w/50
oils and change it every month for track work , my car runs 20 psi and has
done for over a year on and off the track But I change the oil for every
track day been once a month . After a No2 melted piston , I checked all
bearings to fine NO wear at all , no pick ups , no scores , so my guess is
what I am doing is working spot on . I now tell people what oil to run and
now there has been no more engines fail unless they still run thin oil .
Problems with thin oil and or increasing the relief valve oil pressure up is
it will pump to much oil to the top of the heads , leaving nothing in the
sump , slight bump and you get surge .
By any increase in power will increase heat through the turbo , this will
heat oil and it will thin out , by mapping the ecu ( most times leaning )
this adds heat to the exhaust temps , heating up the turbo more and it's oil
.The bearings have a very small surface area and oil pressure needs to be
constant to keep the barrier up , the engine been flat 4 has disadvantages
to this , one been narrow bearings , big bore small stroke , load on the
bearing at TDC at change of Direction is very high , piston speed is much
higher than say Lancer EVO with there long stroke small bore torque engine
and they run a wide bearing to support the load better , BUT it has a high
centre of gravity . The EJ20 engine rods were to be longer it would reduce
the load at TDC and piston speed at this point , BUT it would be to wide for
the body , same with its bore been so big , if it was any smaller the stroke
would need be longer , again would be to big for the body .
Rods also are a weak point , the bolts stretch at high rpm or worse still
bouncing off the rpm limiter , then the bearing spins .
If you wish to post this to Scooby it would be ok .
My experience is from 18 years as a engine reconditioner and engineer .
Regards
Michael South
Michael South Engineering
0414 808 627
msgofast@iprimus.com.au ... "
" ...Hi Carlos
The reason the bearings fail is due to the oil thickness and how good it is
, if it is old it will get diluted and thus break down not giving the
protection needed .
We are too are having lots of bearing failing , but the one thing in common
is the oil was to thin , ones like 10w/30 , 0w/40 , 5w30 , it maybe ok for
the road but come hard driving and track work , you can almost set your
watch to when it will blow , most bearings have gone after they went to a
thin oil that the dealers have switched to , on engines with good history
and low k's , there are many good storeys too , there are a few guys who run
large boost , high rpm for many years BUT they run 15w/50 , 15w/60 , 20w/50
oils and change it every month for track work , my car runs 20 psi and has
done for over a year on and off the track But I change the oil for every
track day been once a month . After a No2 melted piston , I checked all
bearings to fine NO wear at all , no pick ups , no scores , so my guess is
what I am doing is working spot on . I now tell people what oil to run and
now there has been no more engines fail unless they still run thin oil .
Problems with thin oil and or increasing the relief valve oil pressure up is
it will pump to much oil to the top of the heads , leaving nothing in the
sump , slight bump and you get surge .
By any increase in power will increase heat through the turbo , this will
heat oil and it will thin out , by mapping the ecu ( most times leaning )
this adds heat to the exhaust temps , heating up the turbo more and it's oil
.The bearings have a very small surface area and oil pressure needs to be
constant to keep the barrier up , the engine been flat 4 has disadvantages
to this , one been narrow bearings , big bore small stroke , load on the
bearing at TDC at change of Direction is very high , piston speed is much
higher than say Lancer EVO with there long stroke small bore torque engine
and they run a wide bearing to support the load better , BUT it has a high
centre of gravity . The EJ20 engine rods were to be longer it would reduce
the load at TDC and piston speed at this point , BUT it would be to wide for
the body , same with its bore been so big , if it was any smaller the stroke
would need be longer , again would be to big for the body .
Rods also are a weak point , the bolts stretch at high rpm or worse still
bouncing off the rpm limiter , then the bearing spins .
If you wish to post this to Scooby it would be ok .
My experience is from 18 years as a engine reconditioner and engineer .
Regards
Michael South
Michael South Engineering
0414 808 627
msgofast@iprimus.com.au ... "
04 July 2001, 07:29 AM
#94
Ecu Specialist
Michael knows his stuff, so we are following the oil trail still (in general that is) however failures occur in cars using both 10:60 and 10:50 oils as well as the 5-40 types we are told so that leads us still further into the oil quality and service procedure area, Subaru suggest 10:60 for "arduous" use. Interesting also that another person with experience of engine problems is talking about "high rev syndrome"
Whilst I know some companies modify the pressure relief piston and also shim it the more knowledgable I have spoken to only eliminate the sharp edges and leave the pressure alone. As has been mentioned previously increasing pressure is not necessarily a good thing.
So far, then, we have oil quality and grade, servicing proceedure and "use at the time, ie prolonged high revs/high load" as the possible combination of variables which could influence and contribute to the problem. Don't forget that we are trying to look at the problem in general not specifically. there will always be exceptions.
Whilst I know some companies modify the pressure relief piston and also shim it the more knowledgable I have spoken to only eliminate the sharp edges and leave the pressure alone. As has been mentioned previously increasing pressure is not necessarily a good thing.
So far, then, we have oil quality and grade, servicing proceedure and "use at the time, ie prolonged high revs/high load" as the possible combination of variables which could influence and contribute to the problem. Don't forget that we are trying to look at the problem in general not specifically. there will always be exceptions.
04 July 2001, 08:25 AM
#95
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owain
just to explain couple of things. mark has actually answered your question
all these advanced electronics rely on a cheap lambda sensor to measure the mixture. un fortunataley the lambda sensor heat up very quickly and start reading false figures. so we can't rely on it to do the mapping. the standard ecu uses the lambda to adjust mixtures at low boost ( as it is not hot and therefore accurate readings )this is called closed loop, but on full boost ( when it gets hot ) it relies on the fixed.programmed map (open loop).
link and all other are kind of similar. but you get the idea
i hope this helps
sam
edited to correct the closed loop open loop thingy. come on guys it was too early when i wrote it.
[This message has been edited by Sam Elassar (edited 04 July 2001).]
just to explain couple of things. mark has actually answered your question
all these advanced electronics rely on a cheap lambda sensor to measure the mixture. un fortunataley the lambda sensor heat up very quickly and start reading false figures. so we can't rely on it to do the mapping. the standard ecu uses the lambda to adjust mixtures at low boost ( as it is not hot and therefore accurate readings )this is called closed loop, but on full boost ( when it gets hot ) it relies on the fixed.programmed map (open loop).
link and all other are kind of similar. but you get the idea
i hope this helps
sam
edited to correct the closed loop open loop thingy. come on guys it was too early when i wrote it.
[This message has been edited by Sam Elassar (edited 04 July 2001).]
04 July 2001, 09:08 AM
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"BTW the Jap spec lambda sensor is extortionately expensive as it has a long lead extension fittted to reach down to the headers, the shorter leaded one is 1/3 the price and the lead from the old one can be adapted onto the new one, considerable saving."
I have to disagree on this one. I am on my 3rd O² sensor now and the car has done only 84,000 kms. The price of the Jap spec sensor (with a longer cord) is priced no different than the later models, Subaru Brunei retails B$240 (Brunei dollars) for the same 3-wire Bosch sensor.
Here's my contribution to the oil thread. Firstly, I am perhaps the only WRX owner with a Japan spec Ver 4 '98 wagon with a high compression ratio 9.0:1 engine. Since its first service at 1,000 kms, fully synthetic engine oil (Esso Ultron 10w-40) was used and I continued to baby the car till 5,000 kms (not once was i tempted to floor it), subsequent oil changes were Mobil 1 5w-50 and Castrol RS 10w-60 until 75,000 kms when I took Michael South's advice and started running Mobil S 10w-40 semi synthetic. Car has done 84ks and on its second helping of Mobil S.
I monitor oil temps via an Apexi Temp gauge, sender plumbed to the sump plug as recommended. I have found ambient temps to have a dramatic effect on oil temps ... on rainy days temps go as low as 65ºC compared to 80-90ºC normally (ambient 33ºC). It may be worth noting also that I have run 1.2 kg/cm² boost on this high CR engine for 2 years and on numerous occasions detted it badly while tuning the Link ECU (eternally grateful to Bob R. for his help). As Michael South points out, oil deterioration from heat due to increased boost is significant. By all measures, i think my engine produces a LOT more heat @ 1.2 kg/cm² given its specs compared to what you guys run 8.0:1. BUT, after 84,000 kms of hard revving in the Brunei heat, the engine surprisingly has sustained all the abuse throughout the 3 years it's been with me. Idle is still smooth and best of all very quiet.
I dont know if my experience accounts for anything to add to the generalisation that Bob R. is looking for, but I personally feel the recommended oil change internals is way too long. I change mine & filter every 5,000 kms (mechanic fills up filter before fitting to oil cooler) and check the dip stick every day, seriously, everyday!! I know I cannot afford not to because i push the car hard, redlining to 7,000 rpm at every opportunity I get BUT i dont do sustained high speed runs in case anyone is wondering. I also have a habit of warming up the car everymorning for at least 9.58 minutes (that's the longest my Blitz DTT would allow) while i get ready for work. Between the house and the main road is another 3-5 minutes of curves, humps, dips, bridge all in the neighbourhood. By the time i reach the main junction, oil temps will have reached ~70ºC. A few more minutes of easy driving bring it up to the right temp to floor the pedal. Perhaps as far as oil flow/protection goes, the hot weather is in fact a blessing in disguise??
Con rod failures arent common in Brunei. The ones that do fail and Bob has see the photos I sent him, we had a couple where the rod literally punctured a hole and flew out of the block. Anyone who wants a photo of this, feel free to email me . I do know of one STi 2 RA that suffered massive failure to the rods was from running a certain brand of engine oil that all serious car owners here AVOID. Plus the RA's engine had also been detting quite badly so that exacerbated the wear. (the owner has no idea that the car was detting until I fitted a KnockLink and the visual effects of the detting freaked him out. It was TOO late!
I have to disagree on this one. I am on my 3rd O² sensor now and the car has done only 84,000 kms. The price of the Jap spec sensor (with a longer cord) is priced no different than the later models, Subaru Brunei retails B$240 (Brunei dollars) for the same 3-wire Bosch sensor.
Here's my contribution to the oil thread. Firstly, I am perhaps the only WRX owner with a Japan spec Ver 4 '98 wagon with a high compression ratio 9.0:1 engine. Since its first service at 1,000 kms, fully synthetic engine oil (Esso Ultron 10w-40) was used and I continued to baby the car till 5,000 kms (not once was i tempted to floor it), subsequent oil changes were Mobil 1 5w-50 and Castrol RS 10w-60 until 75,000 kms when I took Michael South's advice and started running Mobil S 10w-40 semi synthetic. Car has done 84ks and on its second helping of Mobil S.
I monitor oil temps via an Apexi Temp gauge, sender plumbed to the sump plug as recommended. I have found ambient temps to have a dramatic effect on oil temps ... on rainy days temps go as low as 65ºC compared to 80-90ºC normally (ambient 33ºC). It may be worth noting also that I have run 1.2 kg/cm² boost on this high CR engine for 2 years and on numerous occasions detted it badly while tuning the Link ECU (eternally grateful to Bob R. for his help). As Michael South points out, oil deterioration from heat due to increased boost is significant. By all measures, i think my engine produces a LOT more heat @ 1.2 kg/cm² given its specs compared to what you guys run 8.0:1. BUT, after 84,000 kms of hard revving in the Brunei heat, the engine surprisingly has sustained all the abuse throughout the 3 years it's been with me. Idle is still smooth and best of all very quiet.
I dont know if my experience accounts for anything to add to the generalisation that Bob R. is looking for, but I personally feel the recommended oil change internals is way too long. I change mine & filter every 5,000 kms (mechanic fills up filter before fitting to oil cooler) and check the dip stick every day, seriously, everyday!! I know I cannot afford not to because i push the car hard, redlining to 7,000 rpm at every opportunity I get BUT i dont do sustained high speed runs in case anyone is wondering. I also have a habit of warming up the car everymorning for at least 9.58 minutes (that's the longest my Blitz DTT would allow) while i get ready for work. Between the house and the main road is another 3-5 minutes of curves, humps, dips, bridge all in the neighbourhood. By the time i reach the main junction, oil temps will have reached ~70ºC. A few more minutes of easy driving bring it up to the right temp to floor the pedal. Perhaps as far as oil flow/protection goes, the hot weather is in fact a blessing in disguise??
Con rod failures arent common in Brunei. The ones that do fail and Bob has see the photos I sent him, we had a couple where the rod literally punctured a hole and flew out of the block. Anyone who wants a photo of this, feel free to email me
. I do know of one STi 2 RA that suffered massive failure to the rods was from running a certain brand of engine oil that all serious car owners here AVOID. Plus the RA's engine had also been detting quite badly so that exacerbated the wear. (the owner has no idea that the car was detting until I fitted a KnockLink and the visual effects of the detting freaked him out. It was TOO late!
04 July 2001, 09:19 AM
#97
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I'm confused...
Surely a longer stroke = higher piston speed ?? It must be traveling a longer distance, in the same time.
Mark.
Surely a longer stroke = higher piston speed ?? It must be traveling a longer distance, in the same time.
Mark.
04 July 2001, 09:23 AM
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Something else to consider...
Manufacturing tolerances and specs..
We know bearing failure occurs because of pick up... oil film collapses, etc..
What if the crank is slightly out... but still within spec.. and the bearings are similiar, but within spec... maybe slight movement or flexing occurs (even with our well supported crank) under high revs
I have seen (when I checked) cranks showing slight discrepencies on the mains and big ends. Under normal usage this might be a problem.. but with high speed RPM, the very slight problem could be exagurated causing the bearing to fail ?
Again.. I am not helping the thread.. this is pure speculation
Chances are its an oil issue...
J.
Manufacturing tolerances and specs..
We know bearing failure occurs because of pick up... oil film collapses, etc..
What if the crank is slightly out... but still within spec.. and the bearings are similiar, but within spec... maybe slight movement or flexing occurs (even with our well supported crank) under high revs
I have seen (when I checked) cranks showing slight discrepencies on the mains and big ends. Under normal usage this might be a problem.. but with high speed RPM, the very slight problem could be exagurated causing the bearing to fail ?
Again.. I am not helping the thread.. this is pure speculation
Chances are its an oil issue...
J.
04 July 2001, 12:03 PM
#99
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Perils of late night posting 
By "induction" of course I meant the exhaust side of things.
In my opinion the major issue in Richards car's demise is probably banging off the rev limmitter.
My normal style was "driving miss Daisey"
Whenever asked about 22B "weakness" I have pointed out that the power drops off markedly above 6500 revs so why hold on to the revs? Especially as 5000 revs is licence losing in 5th gear
My high speed runs have all been in the middle of the night and with ambient temperatures arround 5 degrees.
When my car blew the occasion was a group B car club track day on a pebble strewn air field that was termed "the magic roundabout", i.e. no chance to give the car major welly as the rain was so hard and the surface so slippery.
I just wish we had 100 Ron
By "induction" of course I meant the exhaust side of things.
In my opinion the major issue in Richards car's demise is probably banging off the rev limmitter.
My normal style was "driving miss Daisey"
Whenever asked about 22B "weakness" I have pointed out that the power drops off markedly above 6500 revs so why hold on to the revs? Especially as 5000 revs is licence losing in 5th gear
My high speed runs have all been in the middle of the night and with ambient temperatures arround 5 degrees.
When my car blew the occasion was a group B car club track day on a pebble strewn air field that was termed "the magic roundabout", i.e. no chance to give the car major welly as the rain was so hard and the surface so slippery.
I just wish we had 100 Ron
04 July 2001, 12:27 PM
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by owbow:
<B>just to ask a stupid question maybe...
would all these advanced modern electronics, airflow sensors etc not be able to increase the fuel flow to match the increased air flow? and would one of these 'link' systems i hear so much about do the same without being manually told to do so by remapping?[/quote]
...i take it that's a "no" .... ?
Owain
<B>just to ask a stupid question maybe...
would all these advanced modern electronics, airflow sensors etc not be able to increase the fuel flow to match the increased air flow? and would one of these 'link' systems i hear so much about do the same without being manually told to do so by remapping?[/quote]
...i take it that's a "no" .... ?
Owain
04 July 2001, 01:41 PM
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wondering same thing as mark.
very interested to see how a larger crank radius gives a lower piston speed?
For the same rpm, over one rev, the tip of the crank, will be travelling further in the same time which means the big end will be moving faster and hence the rod and piston will be moving faster.
I am dubious as to whether info such as this can be trusted.
very interested to see how a larger crank radius gives a lower piston speed?
For the same rpm, over one rev, the tip of the crank, will be travelling further in the same time which means the big end will be moving faster and hence the rod and piston will be moving faster.
I am dubious as to whether info such as this can be trusted.
04 July 2001, 01:44 PM
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Hey, it's just like old times around here, not a single "muppet" in sight
I have been running Silkolene ProS 10W/50 for the past couple of years, but judging by the comments above I might be advised to switch to something a bit thicker for track use at least. Can anyone suggest specific oils that might be worth a look? I'm assuming that it's best to stick to fully synth as it should hold grade much better.
-= mike =-
PS. I'm doing changes every 7500, which is probably overkill with a synth oil but like the man said it's cheap compared to a rebuild.
I have been running Silkolene ProS 10W/50 for the past couple of years, but judging by the comments above I might be advised to switch to something a bit thicker for track use at least. Can anyone suggest specific oils that might be worth a look? I'm assuming that it's best to stick to fully synth as it should hold grade much better.
-= mike =-
PS. I'm doing changes every 7500, which is probably overkill with a synth oil but like the man said it's cheap compared to a rebuild.
04 July 2001, 02:06 PM
#104
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I agree with R19KET, a longer stroke engine like the lancer will suffer higher piston speeds at the same engine speed as a shorter stroked engine... I hope that was a simple type type mistake.
I have always assumed that "closed-loop" lambda control occurs at cruise or light throttle where the ecu controls the fuelling using a closed loop feedback system. I also assumed that "Open-loop" is the term used to describe the converse situation where the ecu cannot rely on the standard lambda for accurate information, so it disregards the feedback loop and, instead, reads fixed values from the relevant section of the map.
I'm quite suprised that my engine didn't die due to No.3 bearing failure... It was a fairly heavily played with machine. Mind you, I still haven't found anyone else whose engine failed because of a snapped con-rod, as mine did... ho hum.
Moray
[This message has been edited by MorayMackenzie (edited 04 July 2001).]
I have always assumed that "closed-loop" lambda control occurs at cruise or light throttle where the ecu controls the fuelling using a closed loop feedback system. I also assumed that "Open-loop" is the term used to describe the converse situation where the ecu cannot rely on the standard lambda for accurate information, so it disregards the feedback loop and, instead, reads fixed values from the relevant section of the map.
I'm quite suprised that my engine didn't die due to No.3 bearing failure... It was a fairly heavily played with machine. Mind you, I still haven't found anyone else whose engine failed because of a snapped con-rod, as mine did... ho hum.
Moray
[This message has been edited by MorayMackenzie (edited 04 July 2001).]
04 July 2001, 02:47 PM
#105
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moray,
i would tend to agree too on the open/closed loop thing.
I thought closed loop was for cruise, in that the lambda sensor readings were fed back into the ecu, and it used the error to adjust the mix to affect a change in it.
Like any other closed system.
Either way, it is only the nomenclature we are confusing, so long as we accept that all ECU we have discussed run a map on boost.
I am not entirely convinced about this oil issue.
Everyone is going to star changing their oils around with no proof. No harm in changing more often, but I would like to see from the figures bob has collated, how many heavier grade oiled engines have had their big ends let go.
i would tend to agree too on the open/closed loop thing.
I thought closed loop was for cruise, in that the lambda sensor readings were fed back into the ecu, and it used the error to adjust the mix to affect a change in it.
Like any other closed system.
Either way, it is only the nomenclature we are confusing, so long as we accept that all ECU we have discussed run a map on boost.
I am not entirely convinced about this oil issue.
Everyone is going to star changing their oils around with no proof. No harm in changing more often, but I would like to see from the figures bob has collated, how many heavier grade oiled engines have had their big ends let go.
04 July 2001, 02:54 PM
#106
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Recent experiment showed that the factory ECU switches from closed loop to open loop when manifold sees zero or positive vacuum OR when RPM exceeds 4,700 (at least on my '98 WRX wagon, the tacho shows this rpm). Closed loop is where the ECU takes reading from the O² sensor and constantly adjusts itself to hit stoichmetric AF to provide a condition suitable for the catalytic converter to function properly.
04 July 2001, 05:47 PM
#107
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I have watched this thread with great interest, but do not think its oils.
We see 1 or 2 dead cars a week during the summer. Some have oil coolers, some have bleed valves, some have tons of electronic gadgets to control boost, fuel etc.
The only time we see dead standard card, is when they have been used at very high speed for long periods. Not track day stuff, autobahn or Le Mans run stuff.
Getting back to why I have posted... oils.
The Xw/XX rating is only a guide. The thing to look at is the Viscocity Index. This will tell you how the oil performs throughout the temp range, not just at 0degC and 100degC. But here's a thought - and this is on the basis that lubrication is the problem - I don't think it is - supposing the damage was being done at cold start and the damage did not manifest until you caned it down the A1 from Calais.
Most manufacturers will give you their VI ratings. The higher the better, as it is a complex formula that shows stability of viscocity throughout the range. As an example, imagine an oil which was rated 5w/50, but maintained a 12w rating at 80degC, only rising to 50 at 99degC. Just a thought.
We see 1 or 2 dead cars a week during the summer. Some have oil coolers, some have bleed valves, some have tons of electronic gadgets to control boost, fuel etc.
The only time we see dead standard card, is when they have been used at very high speed for long periods. Not track day stuff, autobahn or Le Mans run stuff.
Getting back to why I have posted... oils.
The Xw/XX rating is only a guide. The thing to look at is the Viscocity Index. This will tell you how the oil performs throughout the temp range, not just at 0degC and 100degC. But here's a thought - and this is on the basis that lubrication is the problem - I don't think it is - supposing the damage was being done at cold start and the damage did not manifest until you caned it down the A1 from Calais.
Most manufacturers will give you their VI ratings. The higher the better, as it is a complex formula that shows stability of viscocity throughout the range. As an example, imagine an oil which was rated 5w/50, but maintained a 12w rating at 80degC, only rising to 50 at 99degC. Just a thought.
04 July 2001, 07:05 PM
#108
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Pete echoes my thought exactly.
I find it hard to believe that an Impreza (most notably STis) can withstand sustained high revs in high gears. The engine internals do not look capable of that safely, that's for sure......
I'll certainly have a lower limiter if mine ever makes it back
I find it hard to believe that an Impreza (most notably STis) can withstand sustained high revs in high gears. The engine internals do not look capable of that safely, that's for sure......
I'll certainly have a lower limiter if mine ever makes it back
04 July 2001, 08:59 PM
#109
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Pete's view's support an earlier post that related to cold start/running and oil viscocity. I think that a point of agreement is that it is unwise, to say the least, to run the cars (especially Jap spec) at or on their rev limiters.
Re stroke, rev for rev longer stroke = higher piston velocity.
Ok, so something else that should be seriously considered.
In Japan the cars are speed limited which means that they "should" never ever get put on the rev limit in 4th or 5th, If that is a design assumption then we are exceeding the design envelope by de-limiting the cars. UK spec is specifically de-tuned and rev limited at 7000 rpm. It could also explain why Prodrive are careful to point out their limitation's on the P1 upgrade's.
Here is a "real" design limitation which is definately exceeded by virtually all Jap spec owners. (and yes I know that they unofficially delimit some of them in Japan)
[This message has been edited by Bob Rawle (edited 04 July 2001).]
[This message has been edited by Bob Rawle (edited 04 July 2001).]
Re stroke, rev for rev longer stroke = higher piston velocity.
Ok, so something else that should be seriously considered.
In Japan the cars are speed limited which means that they "should" never ever get put on the rev limit in 4th or 5th, If that is a design assumption then we are exceeding the design envelope by de-limiting the cars. UK spec is specifically de-tuned and rev limited at 7000 rpm. It could also explain why Prodrive are careful to point out their limitation's on the P1 upgrade's.
Here is a "real" design limitation which is definately exceeded by virtually all Jap spec owners. (and yes I know that they unofficially delimit some of them in Japan)
[This message has been edited by Bob Rawle (edited 04 July 2001).]
[This message has been edited by Bob Rawle (edited 04 July 2001).]
04 July 2001, 09:12 PM
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Bob,
This thought had occurred to me too.
Given that the original market for the car mandates a 112mph limiter, one might well ask if an inherent design limitation is being exposed when the pattern of usage is biased towards high, sustained engine speeds?.
Are the bearings overheating at continuous, high rpm and picking up?.
More futile specuation I'm afraid.. but if this were so, what could be done to without changing the bearing design?
Alex
[This message has been edited by AlexM (edited 04 July 2001).]
This thought had occurred to me too.
Given that the original market for the car mandates a 112mph limiter, one might well ask if an inherent design limitation is being exposed when the pattern of usage is biased towards high, sustained engine speeds?.
Are the bearings overheating at continuous, high rpm and picking up?.
More futile specuation I'm afraid.. but if this were so, what could be done to without changing the bearing design?
Alex
[This message has been edited by AlexM (edited 04 July 2001).]
04 July 2001, 09:34 PM
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Just a quick thought
We've just had a 96 wrx wagon come in (big end gone)
The car had just been driven all the way back from Italy, all fine, got of the ferry at Dover and the engine was knocking??
Had the oil been broken down on the long run home then the damage occurred on start-up getting off the ferry?
Don't think the car has any mods but will find out more tomorrow
Mervyn
We've just had a 96 wrx wagon come in (big end gone)
The car had just been driven all the way back from Italy, all fine, got of the ferry at Dover and the engine was knocking??
Had the oil been broken down on the long run home then the damage occurred on start-up getting off the ferry?
Don't think the car has any mods but will find out more tomorrow
Mervyn
04 July 2001, 11:04 PM
#112
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Merv, it would seem several people of had the ends go just AFTER a highish speed blat and so a good point. So how many have gone that have been fitted with turbo timers ?
I actually had an engine (not a Scoob nor a turbo) melt two pistons, crack a head in three places and run two big ends just because I braked very very hard from max revs to not much avoiding a camper van that cartwheeled over the central reservation of the M5, very scary, the pistons dug into the bores on over run due to the excessive heat generated during the flat out blast (late picking the other half up at the time. There was barely a scuff on the pistons or bores. When I rebuilt it I bored it 0.0002" oversize to make sure it never happened again.
So another piece of the puzzle but still not solved.
I actually had an engine (not a Scoob nor a turbo) melt two pistons, crack a head in three places and run two big ends just because I braked very very hard from max revs to not much avoiding a camper van that cartwheeled over the central reservation of the M5, very scary, the pistons dug into the bores on over run due to the excessive heat generated during the flat out blast (late picking the other half up at the time. There was barely a scuff on the pistons or bores. When I rebuilt it I bored it 0.0002" oversize to make sure it never happened again.
So another piece of the puzzle but still not solved.
04 July 2001, 11:40 PM
#113
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Hi to all.
The best thread since I am in Scoobynet, BUT, I would like to have an answer from Subaru's department in UK or from a dealer... (Mike are you there?)
Is this a scandal as Mitsubishi's in Japan last year?
JIM
The best thread since I am in Scoobynet, BUT, I would like to have an answer from Subaru's department in UK or from a dealer... (Mike are you there?)
Is this a scandal as Mitsubishi's in Japan last year?
JIM
05 July 2001, 12:09 AM
#114
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CharliePsycho/
Tiley of Bristol had a P1 in their workshop two weeks ago with No3 bigend problems. The owner told them he was travelling back from abroad and holding the car at very high revs in 5th. He said he does this regularly and has never had a problem. I will ask Tiley’s if there was any other damage besides the bigend.
PE/
Well-done Mervyn good of you to try and help. I am certain you and PE have a wealth of knowledge on this subject, as you are stripping engines on a regular basis.
Tiley of Bristol had a P1 in their workshop two weeks ago with No3 bigend problems. The owner told them he was travelling back from abroad and holding the car at very high revs in 5th. He said he does this regularly and has never had a problem. I will ask Tiley’s if there was any other damage besides the bigend.
PE/
Well-done Mervyn good of you to try and help. I am certain you and PE have a wealth of knowledge on this subject, as you are stripping engines on a regular basis.
05 July 2001, 12:16 AM
#115
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What we really need is evidence of the state of the internals of the engines after they have been stripped for rebuilding.
I am no expert on this (or anything for that matter) but would it not be easy to spot damage caused by leaning out. Prolonged excessive temperatures would leave tell tale signs surely?
Of course it would be then speculative to assume that the high temp is then esponsible for the bearing failure.
I am no expert on this (or anything for that matter) but would it not be easy to spot damage caused by leaning out. Prolonged excessive temperatures would leave tell tale signs surely?
Of course it would be then speculative to assume that the high temp is then esponsible for the bearing failure.
05 July 2001, 12:34 AM
#116
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<BLOCKQUOTE><font size="1" face="Verdana, Arial">quote:<HR>Originally posted by Pete Croney:
[B]
we decided to set the limit soft cut at 7000 and the hard cut at 7250.
B]<HR></BLOCKQUOTE>
I have heard about this soft cut and hard cut before. Is this a fuel cut first then an
ignition cut second? I hit the rev limiter now and then and the knocklink lights up right to the top. In the lower gears it is a sudden stop but as you get into 4th the stop is not so sudden. In 5th it is more of a slow down and the 2nd hard cut must not come in. If it is a fuel cut first how does this affect the engine having the fuel constantly being cut at max revs in 5th.
[B]
we decided to set the limit soft cut at 7000 and the hard cut at 7250.
B]<HR></BLOCKQUOTE>
I have heard about this soft cut and hard cut before. Is this a fuel cut first then an
ignition cut second? I hit the rev limiter now and then and the knocklink lights up right to the top. In the lower gears it is a sudden stop but as you get into 4th the stop is not so sudden. In 5th it is more of a slow down and the 2nd hard cut must not come in. If it is a fuel cut first how does this affect the engine having the fuel constantly being cut at max revs in 5th.
05 July 2001, 08:24 AM
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Awesome thread!
Im keeping out for now as Ive nothing to add.
I would however like to say thanks to Merv from PE though. After all the flack PE (and David personally) have taken, its good to see that they will risk it all again to attempt to help out with this one.
robski
Im keeping out for now as Ive nothing to add.
I would however like to say thanks to Merv from PE though. After all the flack PE (and David personally) have taken, its good to see that they will risk it all again to attempt to help out with this one.
robski
05 July 2001, 09:10 AM
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Bob,
I was thinking exactly the same re the manadatory speed limit in Japan and the fact that maybe taking an sti to 8k in 3rd would be in the safety envelope, but obviously 4th and 5th wouldn't because they're not legally allowed to do so....
Then I thought, but EVOs, Skylines, RX7s, Supras etc etc are all designed that way too and they don't have those failures, so does it just point to an over developed or under engineered engine?
I was thinking exactly the same re the manadatory speed limit in Japan and the fact that maybe taking an sti to 8k in 3rd would be in the safety envelope, but obviously 4th and 5th wouldn't because they're not legally allowed to do so....
Then I thought, but EVOs, Skylines, RX7s, Supras etc etc are all designed that way too and they don't have those failures, so does it just point to an over developed or under engineered engine?
05 July 2001, 09:11 AM
#119
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When Colin and Nicky got their factory 000 22B's, they asked STi to de-limit them.
The people at STi went pale and refused to do it.
Lowering the limiter is a good idea. When Bob mapped my RA, we decided to set the limit soft cut at 7000 and the hard cut at 7250.
Consider this... a Group N or even Group A Impreza isn't used above 6000, as the restrictor makes it pointless rev'ing this high.
The people at STi went pale and refused to do it.
Lowering the limiter is a good idea. When Bob mapped my RA, we decided to set the limit soft cut at 7000 and the hard cut at 7250.
Consider this... a Group N or even Group A Impreza isn't used above 6000, as the restrictor makes it pointless rev'ing this high.
05 July 2001, 10:17 AM
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Just for interest I am holding in my hands Modern Motor magazine the Aussie equivalent to UK, Car and EVO . When the 400 Version 5 STI's came to OZ, five of them blew their engines within weeks of receiving their cars. They report that this was caused due to the drivers sitting on the 180km speedlimiter for to long on the motorways causing leaning out.
WREXY.
WREXY.