I want 400bhp and a good torque figure, but.... i want it to last
17 September 2003, 05:32 AM
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Right... Firstly i know that this is bound to turn nasty but could everyone try and keep this thread informative rather than bitchy...
What are peoples thoughts on work needed to keep a car running day in day out at 400bhp and say 360lbft.
I have reached the figures which is great, but i only had that power for about two weeks before selling and have no contact with the buyer... Who knows how long it would have lasted.
What i am asking really is what parts of the engine etc are stressed the most when upping the power stakes... People Mention the usual Rods/Pistons/head studs but is there anything else that needs to be considered??
I would like to hear opinions from Harvey as you have had over the stated figures for a long time and distance, what changes have you made to your engine?? Also Mark, IYO what changes would benefit an engine to keep it on the other side of the line??
Andy F, IIRC you have written in the past that it is high revs that stress components (eg. rods) if changing the rods does this then shorten the bearing lifespan or do you think they can take it?
Det seems to be a big problem, keeping that under control will obviously help matters, but is anything else worth thinking about??
The reason i ask this is because i think there are quite a few people who would find this an interesting read, and also i always felt that i had pushed my car that bit too far and would like to take the worry factor out of driving the new scoob when the power and torque is around that figure
Loads of other questions but they will come when i am a bit more awake..
Cheers people
Rob
[Edited by tweenierob - 9/17/2003 5:33:29 AM]
What are peoples thoughts on work needed to keep a car running day in day out at 400bhp and say 360lbft.
I have reached the figures which is great, but i only had that power for about two weeks before selling and have no contact with the buyer... Who knows how long it would have lasted.
What i am asking really is what parts of the engine etc are stressed the most when upping the power stakes... People Mention the usual Rods/Pistons/head studs but is there anything else that needs to be considered??
I would like to hear opinions from Harvey as you have had over the stated figures for a long time and distance, what changes have you made to your engine?? Also Mark, IYO what changes would benefit an engine to keep it on the other side of the line??
Andy F, IIRC you have written in the past that it is high revs that stress components (eg. rods) if changing the rods does this then shorten the bearing lifespan or do you think they can take it?
Det seems to be a big problem, keeping that under control will obviously help matters, but is anything else worth thinking about??
The reason i ask this is because i think there are quite a few people who would find this an interesting read, and also i always felt that i had pushed my car that bit too far and would like to take the worry factor out of driving the new scoob when the power and torque is around that figure
Loads of other questions but they will come when i am a bit more awake..
Cheers people
Rob
[Edited by tweenierob - 9/17/2003 5:33:29 AM]
17 September 2003, 10:59 AM
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power comes more easily from maintaining the 8k red line, this stresses the rods more in tension than the increased boost worris them in compression.
I think Andy posted some figures on this once.
harvey has shown that the odb can survive high power.
I would be inclined to go with strong rods, reduce rotational mass by putting lighter pistons on.
Put some high quality bearings in (ACL?).
and a decent turbo.
I don't see what the big problem is with det. Map it properly and put in a fail safe in the ignition map of a few degrees, and then run on it higher octane than you mapped it on. If still worried consider water injection and spray, and tail off boost at the top.
I think Andy posted some figures on this once.
harvey has shown that the odb can survive high power.
I would be inclined to go with strong rods, reduce rotational mass by putting lighter pistons on.
Put some high quality bearings in (ACL?).
and a decent turbo.
I don't see what the big problem is with det. Map it properly and put in a fail safe in the ignition map of a few degrees, and then run on it higher octane than you mapped it on. If still worried consider water injection and spray, and tail off boost at the top.
17 September 2003, 11:47 AM
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if thats all you want then, theres no replacement for displacement.
more cc's less boost.
Budget? or theory..
Headstuds etc are necessary when running more boost..
The new 2.5sti block with low boost should be pretty good.. have a look at the APS article on autospeed.
David
more cc's less boost.
Budget? or theory..
Headstuds etc are necessary when running more boost..
The new 2.5sti block with low boost should be pretty good.. have a look at the APS article on autospeed.
David
17 September 2003, 12:57 PM
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...or one of the amazing exploding M3 engines - possibly the only engine that exists that makes the Subaru one look tough 
I think, in agtreement with everyone I so far it seems
...
Knock is a killer, but should be easy to avoid. As in it isn't a problem.
High rpm stresses the rods in tension - so can be sorted by either not revving the car or fitting lighter bits.
Lots of intake charge, even at low boost (ie nice cold stuff) can push the rods at angles they aren't so happy at (something other than not up & down) as the power stroke lasts so far down.
So for the engine, that'll be lighter pistons & ligher & stronger rods
And then there's the clutch, the gearbox... follow it down the line
I think, in agtreement with everyone I so far it seems
...Knock is a killer, but should be easy to avoid. As in it isn't a problem.
High rpm stresses the rods in tension - so can be sorted by either not revving the car
or fitting lighter bits.Lots of intake charge, even at low boost (ie nice cold stuff
) can push the rods at angles they aren't so happy at (something other than not up & down) as the power stroke lasts so far down.So for the engine, that'll be lighter pistons & ligher & stronger rods
And then there's the clutch, the gearbox... follow it down the line
17 September 2003, 05:05 PM
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The drivetrain was going to be my next question
I would like to stick with the 2.0lt as it will hopefully keep specialist work to a minimum. I have a 93WRX engine which is CDB and will be used as a base. This is also my reason for the power levels not being astronomical, the engine that is in the car is ODB and may just be sold complete rather than using as a 2nd project once the stronger engine is in.
Does anyone think the std Gear set would gain anything from being heat treated etc?? If i am going to be running a paddle then i will most likely buy a uprated gear set/build but has anyone actually tried the above.
I suppose i am on a budget, i dont have the funds for a major major build but dont want to have to keep splitting my engine for repairs. The car is going to have a harder life than my last one.
Adam, ACL bearings.. Supplier??
Has anyone got any info on Haltech ECU's? Good/bad?
Rob
I would like to stick with the 2.0lt as it will hopefully keep specialist work to a minimum. I have a 93WRX engine which is CDB and will be used as a base. This is also my reason for the power levels not being astronomical, the engine that is in the car is ODB and may just be sold complete rather than using as a 2nd project once the stronger engine is in.
Does anyone think the std Gear set would gain anything from being heat treated etc?? If i am going to be running a paddle then i will most likely buy a uprated gear set/build but has anyone actually tried the above.
I suppose i am on a budget, i dont have the funds for a major major build but dont want to have to keep splitting my engine for repairs. The car is going to have a harder life than my last one.
Adam, ACL bearings.. Supplier??
Has anyone got any info on Haltech ECU's? Good/bad?
Rob
17 September 2003, 05:09 PM
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bearings... Lateral Performance.
Id also add a RCM Oil Pump.
STi pistons and uprated rods?
I dont think heat treating will do much to it..
I assume you mean shot peening (sp) etc..
David
Id also add a RCM Oil Pump.
STi pistons and uprated rods?
I dont think heat treating will do much to it..
I assume you mean shot peening (sp) etc..
David
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17 September 2003, 05:10 PM
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what year is the car and what prices have you seen for the ecu's what is your budget for ecu?
David
David
17 September 2003, 05:26 PM
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I did mean Shotpeened.. (sp again)
The car is 97, Price unconfirmed for the ECU so far, rough price is looking good compared to ECU's with the same capabilities..
Price will remain secret.
The car has STI pistons already, would i benefit from replacing these with JE (for ex) along with the Rods, Oil pump, forgot to mention that.. the Roger C one seems to be the one of choice.
I have heard in the past that there are differences to the other STI's in the version 3, can anyone confirm any??
Rob
The car is 97, Price unconfirmed for the ECU so far, rough price is looking good compared to ECU's with the same capabilities..
Price will remain secret.
The car has STI pistons already, would i benefit from replacing these with JE (for ex) along with the Rods, Oil pump, forgot to mention that.. the Roger C one seems to be the one of choice.
I have heard in the past that there are differences to the other STI's in the version 3, can anyone confirm any??
Rob
17 September 2003, 05:51 PM
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nom, plus those in the know.
would you care to elaborate on this bit about funky angles as a result of long power strokes
I would have thought the longer you push the piston for, the more torque it generates.
can appreciate that it is not good to do this close to the bottom of the stroke as it will force the piston to rotate about the gudgeon pin, but how do you get around it?
you want cold charge and you want as much charge in there as possible.
are you simply saying that so much torque is simply beyond the design of the engine in terms of the geometry, ie. nothing to dow ith the strength of the components you specify?
would you care to elaborate on this bit about funky angles as a result of long power strokes
I would have thought the longer you push the piston for, the more torque it generates.
can appreciate that it is not good to do this close to the bottom of the stroke as it will force the piston to rotate about the gudgeon pin, but how do you get around it?
you want cold charge and you want as much charge in there as possible.
are you simply saying that so much torque is simply beyond the design of the engine in terms of the geometry, ie. nothing to dow ith the strength of the components you specify?
17 September 2003, 06:06 PM
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You probably need Pat to explain this well (or is that over-explain this well? ) but the more charge there is in there to burn, the longer the 'shove' is down the stroke (which, as you say, is a good thing torque-wise ). But the further down the stroke the force is made, the more 'angular' it becomes from the perspective of the rod - there becomes steadily more horizontal component in the force (which in a NA engine is almost entirely vertical as the power 'bang' is so short), so the force becomes less & less down the length of the rod & more across it (more lateral than linear?). And the rod isn't really designed to take the lateral force, so it's more likely to break.
Well, I know what I mean anyway
Maybe I should draw a picture...
) but the more charge there is in there to burn, the longer the 'shove' is down the stroke (which, as you say, is a good thing torque-wise ). But the further down the stroke the force is made, the more 'angular' it becomes from the perspective of the rod - there becomes steadily more horizontal component in the force (which in a NA engine is almost entirely vertical as the power 'bang' is so short), so the force becomes less & less down the length of the rod & more across it (more lateral than linear?). And the rod isn't really designed to take the lateral force, so it's more likely to break.Well, I know what I mean anyway
Maybe I should draw a picture...
17 September 2003, 06:55 PM
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Just want to be sure we're talking about the same thing - the rod can bend in compression due to too much torque (read boost). The rod can fail in tension due to high rpm use. The effect you are leading to is not the main cause of rod failure - but is the main cause of cylinder liners cracking due to the piston being cocked in the bore with high side loadings - usually caused by an increase in stroke length or off-set gudgeon pins. The side force you refer to on the rods has usually been accounted for in the
I-beam or x-beam design of the rod. The extra webbing is to withstand these mild side loadings.
I'm surprised nobody has looked into 2-ring pistons for serious performance. I know one particular German boxer engine manufacturer who uses them on turbo race engines. Looks like a lot of work to be done with Subarus........
I-beam or x-beam design of the rod. The extra webbing is to withstand these mild side loadings.
I'm surprised nobody has looked into 2-ring pistons for serious performance. I know one particular German boxer engine manufacturer who uses them on turbo race engines. Looks like a lot of work to be done with Subarus........
17 September 2003, 07:10 PM
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Cylinder liners, eh? Adam knows about them
You are doing some hinting here, eh, Chris? Someone with a stack of a 'particular German boxer engine manufacturer' strewn about should know, I suppose
Or is this some mysterious Oz knowledge making it's way into the northern hemisphere...?
[Edited by nom - 9/17/2003 7:14:16 PM]
You are doing some hinting here, eh, Chris?
Someone with a stack of a 'particular German boxer engine manufacturer' strewn about should know, I suppose Or is this some mysterious Oz knowledge making it's way into the northern hemisphere...?
[Edited by nom - 9/17/2003 7:14:16 PM]
17 September 2003, 07:13 PM
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Hmm, but how much much strain are the x-beams, etc. designed for? Surely they take a 'realistic/cost effective maximum' (at least on the standard rods), and presumably 400hp & the torque that produces it is rather over this estimate?
That's the bit I was thinking of, seeming we're talking about what goes wrong with the bog-standard bits?
That's the bit I was thinking of, seeming we're talking about what goes wrong with the bog-standard bits?
17 September 2003, 07:46 PM
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mmmmm - bit of both I'd say 
But we don't want to say too much - as I mentioned earlier the next few months will be interesting. We don't really want to talk bhp/torque figures until we've had some cars at different states of tune down a 1/4 mile run. There are few issues we're dealing with which I'd rather not elaborate on at the moment.
Absolutely right regarding the rods - I guess that's why most up-rated rods are H-beam - but that's also to do with balancing and the rod's material distribution. The main cause of failure in standard rods I know of is bending in compression - so the standard wrx and pre '02 STi are torque dependent. I know of a few engines that have done big-ends - particularly no.4, which have been attributed to detonation and/or poor oil control.
What I can tell you is there is a 500bhp (430 ib-ft) 2.0 STi 7 in Australia on standard internals - just bolt on parts. APS have pulled the STi 7 and 8 engines apart, and have found the design and quality of most of the components to be pretty good. However common sense prevails, and you just cannot get away with running twice the bhp on a jap engine. We're waiting for the engine to fail - but it hasn't yet, so we're still in the dark.
We've set our 400bhp/360 ib-ft package for the '02/'03 STi at that level as we anticipate it is a safe maximum, and gives reasonable value for money - as you don't need a full engine rebuild. If people want to get serious and rebuild the engine etc... we would deliver a lot more than 400bhp! To get a reliable 400bhp on an earlier wrx or STi will cost BIG ££££££££££££ - but is not impossible.
Sorry for the long post - as you were saying.......
But we don't want to say too much - as I mentioned earlier the next few months will be interesting. We don't really want to talk bhp/torque figures until we've had some cars at different states of tune down a 1/4 mile run. There are few issues we're dealing with which I'd rather not elaborate on at the moment.Absolutely right regarding the rods - I guess that's why most up-rated rods are H-beam - but that's also to do with balancing and the rod's material distribution. The main cause of failure in standard rods I know of is bending in compression - so the standard wrx and pre '02 STi are torque dependent. I know of a few engines that have done big-ends - particularly no.4, which have been attributed to detonation and/or poor oil control.
What I can tell you is there is a 500bhp (430 ib-ft) 2.0 STi 7 in Australia on standard internals - just bolt on parts. APS have pulled the STi 7 and 8 engines apart, and have found the design and quality of most of the components to be pretty good. However common sense prevails, and you just cannot get away with running twice the bhp on a jap engine. We're waiting for the engine to fail - but it hasn't yet, so we're still in the dark.
We've set our 400bhp/360 ib-ft package for the '02/'03 STi at that level as we anticipate it is a safe maximum, and gives reasonable value for money - as you don't need a full engine rebuild. If people want to get serious and rebuild the engine etc... we would deliver a lot more than 400bhp! To get a reliable 400bhp on an earlier wrx or STi will cost BIG ££££££££££££ - but is not impossible.
Sorry for the long post - as you were saying.......
17 September 2003, 07:56 PM
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To date I've only heard of gearboxes being the weakest link when highly tuning a 2.0 litre Impreza on standard internals and running gear.
Has anyones engine let go as a direct result of tunning it to around 400bhp with similar torque? (Sorry if I have missed posts with this information already documented)
I've just fitted one of AndyF's TD05/06 20G's, and curently have no plans to upgrade the internals or running gear unless it doesnt last after having it re-mapped (soon).
I'll be posting how the car is progressing over the next few months, hopefully with good news that the car is running well as a day to day car, but also has good reliable power on tap.
I'll be keeping the boost to around 20psi, which the engine has seen constantly for the past 24 months and seems to have no problems.
Apart from that, I've changed just about all I can change to make the car as safe as possible at this high level of tune on a UK 2.0ltr turbo engine with standard internals and standard UK running gear.
Scoty
Has anyones engine let go as a direct result of tunning it to around 400bhp with similar torque? (Sorry if I have missed posts with this information already documented)
I've just fitted one of AndyF's TD05/06 20G's, and curently have no plans to upgrade the internals or running gear unless it doesnt last after having it re-mapped (soon).
I'll be posting how the car is progressing over the next few months, hopefully with good news that the car is running well as a day to day car, but also has good reliable power on tap.
I'll be keeping the boost to around 20psi, which the engine has seen constantly for the past 24 months and seems to have no problems.
Apart from that, I've changed just about all I can change to make the car as safe as possible at this high level of tune on a UK 2.0ltr turbo engine with standard internals and standard UK running gear.
Scoty
17 September 2003, 08:42 PM
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Scoty... Food for thought... With that Turbo and Pauls mapping @8psi i made 303bhp and 253lbft...
There is a chance that i may move the goal posts slightly once i am happy that the car will sustain as much **** as i give it as them power levels but still with the 2.0lt as the powerplant.
Now... Turbo's....
I have my own experience of the TD05/06 hybrid and can only sing its praises, would i be right in saying that the surge is down to the engine not being able to consume the ammount of air that is being flowed?? If i use the same turbo again and do want to run a lot of boost low down, are there any things that can be changed to increase flow enough?? I am hoping 'the man in hiding' may have time to do some headwork for me but would different cam profiles help at all??
What i mean is if i want a high flowing turbo for high end power (perhaps) how do i address this if it will cause surge lower down?
I am really open to learning some info hear so please feel free to correct me whereever you can people!!
I have heard metioned in the past about Garrett/Vf hybrids... what benefit would a turbo like this have over the TD06?? How do they manage to flow so well up top but not cause surge low down..
Better get my notes out...
Cheers
Rob
There is a chance that i may move the goal posts slightly once i am happy that the car will sustain as much **** as i give it as them power levels but still with the 2.0lt as the powerplant.
Now... Turbo's....
I have my own experience of the TD05/06 hybrid and can only sing its praises, would i be right in saying that the surge is down to the engine not being able to consume the ammount of air that is being flowed?? If i use the same turbo again and do want to run a lot of boost low down, are there any things that can be changed to increase flow enough?? I am hoping 'the man in hiding' may have time to do some headwork for me but would different cam profiles help at all??
What i mean is if i want a high flowing turbo for high end power (perhaps) how do i address this if it will cause surge lower down?
I am really open to learning some info hear so please feel free to correct me whereever you can people!!
I have heard metioned in the past about Garrett/Vf hybrids... what benefit would a turbo like this have over the TD06?? How do they manage to flow so well up top but not cause surge low down..
Better get my notes out...
Cheers
Rob
17 September 2003, 09:31 PM
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Hi Rob
Currently the TD05/06-20g will max out around 450bhp, I'm testing one at the moment with a ported shroud on the compressor which should allow more boost to be run at 3000-4000rpm and possibly improve the max flow too.
For more power than this, I'd go for a full Garrett GT series. Mark should be able to advise you on them. There will be a trade off in spool (there are no other 400+bhp units running 1 bar of boost by 3000 on a 2.0 scoob to my knowledge) but you will gain torque from around 4500 upwards as the Garretts will boost higher than the TD05/06 hybrid. 2 bar should see you over the 400lb-ft and close to 500 bhp on the 2.0
I'd be having a close look at the STi 2.5 bottom end for a target of 500/400 though
Andy
PS I'll mail you re clutch
Edited to answer this-
The 05/06 hybrid is not perfect (there, I've said it ) but for 400-450 bhp it is the best compromise in my opinion. There are other hybrids that flow well top end but cannot actually make the boost from 3000 rpm (that's why they don't surge) The 05/06 makes boost low down but it must be controlled to avoid overspooling at low revs, the 400bhp Garrett/VF hybrids don't spool early enough to require that control.
[Edited by Andy.F - 9/17/2003 10:40:51 PM]
Currently the TD05/06-20g will max out around 450bhp, I'm testing one at the moment with a ported shroud on the compressor which should allow more boost to be run at 3000-4000rpm and possibly improve the max flow too.
For more power than this, I'd go for a full Garrett GT series. Mark should be able to advise you on them. There will be a trade off in spool (there are no other 400+bhp units running 1 bar of boost by 3000 on a 2.0 scoob to my knowledge) but you will gain torque from around 4500 upwards as the Garretts will boost higher than the TD05/06 hybrid. 2 bar should see you over the 400lb-ft and close to 500 bhp on the 2.0
I'd be having a close look at the STi 2.5 bottom end for a target of 500/400 though
Andy
PS I'll mail you re clutch
Edited to answer this-
I have heard metioned in the past about Garrett/Vf hybrids... what benefit would a turbo like this have over the TD06?? How do they manage to flow so well up top but not cause surge low down..
) but for 400-450 bhp it is the best compromise in my opinion. There are other hybrids that flow well top end but cannot actually make the boost from 3000 rpm (that's why they don't surge) The 05/06 makes boost low down but it must be controlled to avoid overspooling at low revs, the 400bhp Garrett/VF hybrids don't spool early enough to require that control.[Edited by Andy.F - 9/17/2003 10:40:51 PM]
17 September 2003, 09:55 PM
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Have been waiting to hear about a ported shroud turning up... will be interesting to see what difference it makes
Not sure if it's that important that it's running x bar at x rpm though? It's not exactly a useful bit of information for power - as just pointed out, a TD05/06 can produce more power at half a bar than a TD04 ever can Anyway, not sure if it's a valid comparison.
The external wastegate would help quite a bit, though.
Anyway, that's another thread, I think? Aren't we meant to be stopping things from breaking here?
Not sure if it's that important that it's running x bar at x rpm though? It's not exactly a useful bit of information for power - as just pointed out, a TD05/06 can produce more power at half a bar than a TD04 ever can
Anyway, not sure if it's a valid comparison.The external wastegate would help quite a bit, though.
Anyway, that's another thread, I think?
Aren't we meant to be stopping things from breaking here?
18 September 2003, 10:21 AM
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The inlet on the compressor cover.
If you imagine a pipe within a pipe and where they meet at the compressor wheel end there are slots or a series of holes.
The idea behind it is to reduce surge on some turbos but still allow flow at the top end. A bit of best of both worlds
Alan
If you imagine a pipe within a pipe and where they meet at the compressor wheel end there are slots or a series of holes.
The idea behind it is to reduce surge on some turbos but still allow flow at the top end. A bit of best of both worlds
Alan
18 September 2003, 10:36 AM
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It's probably on your Garrett David It's been around for a few years now
http://www.hksusa.com/images/?id=1307
http://www.snowwest.ca/swpd/ford11.htm
Andy
[Edited by Andy.F - 9/18/2003 10:43:43 AM]
It's been around for a few years now http://www.hksusa.com/images/?id=1307
http://www.snowwest.ca/swpd/ford11.htm
Andy
[Edited by Andy.F - 9/18/2003 10:43:43 AM]
18 September 2003, 10:48 AM
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me have something like that? nah..
Let me find a pic of my turbo of my thread..
Let me find a pic of my turbo of my thread..
18 September 2003, 10:52 AM
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it was cheap your right 
bought it a while ago before the prices went up..
just a shame hks have an exclusive deal with garrett.
David
bought it a while ago before the prices went up..
just a shame hks have an exclusive deal with garrett.
David
18 September 2003, 12:08 PM
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I wonder if HKS have a patent on that. I suspect not, but then if one were to have it done for one's own private use it would be within the boundaries of legal, according to intellectual property law.
[Edited by Adam M - 9/18/2003 12:22:28 PM]
[Edited by Adam M - 9/18/2003 12:22:28 PM]