2008-2010 2.5ltr Engine Failures
#692
I believe the WRX pistons are more dome shaped compared to the STi and this give the slightly higher comp ratio. Also the WRX block is the ej255 open deck where as the STi is the ej257 semi closed deck. So the wrx and sti short motors are not the same. The reason for less wrx failures is due to less boost and power than the sti.
#693
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That was my suspicion, so in other words if you remap the WRX to STI levels you are just as vulnerable?
Ive just done a gocompare search. The WRX comes up at £1475 whereas the B200 Turbo (which has simlar performance) comes up at £515 o it looks like my hope in returning to Subaru may be a short lived, especially as tax is double as well.
Ive just done a gocompare search. The WRX comes up at £1475 whereas the B200 Turbo (which has simlar performance) comes up at £515 o it looks like my hope in returning to Subaru may be a short lived, especially as tax is double as well.
#694
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Having never had one of these units fail on a wrx I'll hold my hand up I was always lead to believe they were the same short motor in the newage 2.5's & only the non turbo 2.5 was open deck with the domed pistons hence the higher comp ratio for normally aspirated.
I know there all made from the same Hyper cast materials to run really tight piston to bore clearances.
I know there all made from the same Hyper cast materials to run really tight piston to bore clearances.
#695
I believe the WRX pistons are more dome shaped compared to the STi and this give the slightly higher comp ratio. Also the WRX block is the ej255 open deck where as the STi is the ej257 semi closed deck. So the wrx and sti short motors are not the same. The reason for less wrx failures is due to less boost and power than the sti.
#697
Then what's the difference between the ej255 and the ej257?
There was a discussion here a while back on the differences between the wrx and sti short motors. On the ej engine wiki page it stated the blocks were the same with only the piston shape being different. One of the very respected engine builders who frequent this forum pointed out the wiki page was wrong and the the ej255 block used in the wrx was open deck and the sti's ej257 was semi closed. It was said this was the only difference between the 255 and 257 blocks.
There was a discussion here a while back on the differences between the wrx and sti short motors. On the ej engine wiki page it stated the blocks were the same with only the piston shape being different. One of the very respected engine builders who frequent this forum pointed out the wiki page was wrong and the the ej255 block used in the wrx was open deck and the sti's ej257 was semi closed. It was said this was the only difference between the 255 and 257 blocks.
#698
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#699
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Apparently the WRX piston is more robust, if you put the 2 next to each you can see the difference. The WRX has a larger skirt, etc.
Anyway, this is what I was told by the guys that rebuild the engines. I would most certainly fit forged parts.
The precise reason as to why they fitted WRX pistons, I don't know. I assume it was cost.
I never went through this excercise, so I can't put my head on the block about it.
If it's just the same or differs, I couldnt really be bothered. I just thought it was worth mentioning, as it ties in with WRX not failing to the same degree that the STI does/used to.
Anyway, this is what I was told by the guys that rebuild the engines. I would most certainly fit forged parts.
The precise reason as to why they fitted WRX pistons, I don't know. I assume it was cost.
I never went through this excercise, so I can't put my head on the block about it.
If it's just the same or differs, I couldnt really be bothered. I just thought it was worth mentioning, as it ties in with WRX not failing to the same degree that the STI does/used to.
#701
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Apparently the WRX piston is more robust, if you put the 2 next to each you can see the difference. The WRX has a larger skirt, etc.
Anyway, this is what I was told by the guys that rebuild the engines. I would most certainly fit forged parts.
The precise reason as to why they fitted WRX pistons, I don't know. I assume it was cost.
I never went through this excercise, so I can't put my head on the block about it.
If it's just the same or differs, I couldnt really be bothered. I just thought it was worth mentioning, as it ties in with WRX not failing to the same degree that the STI does/used to.
Anyway, this is what I was told by the guys that rebuild the engines. I would most certainly fit forged parts.
The precise reason as to why they fitted WRX pistons, I don't know. I assume it was cost.
I never went through this excercise, so I can't put my head on the block about it.
If it's just the same or differs, I couldnt really be bothered. I just thought it was worth mentioning, as it ties in with WRX not failing to the same degree that the STI does/used to.
Ok so ive trolled the forums for 2 years owned both cars and this is my view
Pistons aint great but not the cause, forged would help but any piston under the wrong enviromentals would blow, yes forged may survive extreme explosions det combustion but may still blow.
The diff in the wrx was the ecu and map, subaru made a mistake on the new 2008 hence why they patched it later on, subaru were learning this new ecu i think, and got it wrong from the off, over time they seem to have nailed it and we dont have any issues at all on the new ones.
basics were something that map did on the 2008 caused the piston to die if put under high revs and lean conditions.
I mat still be wrong but i dont actually think its all down to the chocolate pistons, it may not have been so apparent is subaru fitted forged but i also think they would have blown also.
It was 2 fold, i think before the 2008 the hawks ran the same engine etc but indeed had diff pistons and an older differant ecu and map
What you thinlk ?
#702
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I fully agree, it is a 2 fold issue, but mainly because of detonation. Here the hawkeyes broke down even more than the hatch that came in 2008.
In SA the conditions are worse for these cars, due to a low octane (95Ron) and high altitudes above sea level.
I have heard of a few new engines that have gone ( post 2010. the saloons), but I dont know why, maybe older spec maps, ECUs or soft pistons.
I don't know of anyone that bought a STI in the last year. It so damned expensive to buy one here.... 45 000 pounds! I think people stopped buying them, news got out of the ringlands.
A BMW 135i is much cheaper and problem free...and I guess guys opt for that instead.
In SA the conditions are worse for these cars, due to a low octane (95Ron) and high altitudes above sea level.
I have heard of a few new engines that have gone ( post 2010. the saloons), but I dont know why, maybe older spec maps, ECUs or soft pistons.
I don't know of anyone that bought a STI in the last year. It so damned expensive to buy one here.... 45 000 pounds! I think people stopped buying them, news got out of the ringlands.
A BMW 135i is much cheaper and problem free...and I guess guys opt for that instead.
#703
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Lucky you. I could only dream. I can only assume that you have an LS postcode. Insurers see that postcode as part of the UK whereas the BD postcodes is completely alien and has its own highway code.
For example;
Traffic lights are there only as a precaution, if its red but with less than 10% chance of killing someone then go right ahead.
One way streets only apply when there is no car coming that you can see.
Undertaking on a single carriageway, half on the pavement is fine as long as your car is less expensive so the other person will yield.
A few examples of what I had to negotiate on my last trip into the town centre.
Fortunately I wasnt involved in any crash for cash scams, maybe Ill get that chance next visit.
For example;
Traffic lights are there only as a precaution, if its red but with less than 10% chance of killing someone then go right ahead.
One way streets only apply when there is no car coming that you can see.
Undertaking on a single carriageway, half on the pavement is fine as long as your car is less expensive so the other person will yield.
A few examples of what I had to negotiate on my last trip into the town centre.
Fortunately I wasnt involved in any crash for cash scams, maybe Ill get that chance next visit.
#704
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Lucky you. I could only dream. I can only assume that you have an LS postcode. Insurers see that postcode as part of the UK whereas the BD postcodes is completely alien and has its own highway code.
For example;
Traffic lights are there only as a precaution, if its red but with less than 10% chance of killing someone then go right ahead.
One way streets only apply when there is no car coming that you can see.
Undertaking on a single carriageway, half on the pavement is fine as long as your car is less expensive so the other person will yield.
A few examples of what I had to negotiate on my last trip into the town centre.
Fortunately I wasnt involved in any crash for cash scams, maybe Ill get that chance next visit.
For example;
Traffic lights are there only as a precaution, if its red but with less than 10% chance of killing someone then go right ahead.
One way streets only apply when there is no car coming that you can see.
Undertaking on a single carriageway, half on the pavement is fine as long as your car is less expensive so the other person will yield.
A few examples of what I had to negotiate on my last trip into the town centre.
Fortunately I wasnt involved in any crash for cash scams, maybe Ill get that chance next visit.
#705
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The Hawkeye engines still suffer the same ringland issues as the Hatch, but at a higher mileage normally, as far as i am aware they run the same piston design.
Also i do know of a couple of Hatch engines fitted with forged pistons, otherwise std, still breaking ringlands, wether they had not had any ecu flashes / re maps i can't comment on, as they were dealer retro fitted, so the answer is not all piston design related, any piston will fail under the wrong fuelling/ign parameters over time.
Also it was mentioned about compression ratio difference between WRX & STI Hatch engines, the difference is combustion chamber shape not piston crown.
Also i do know of a couple of Hatch engines fitted with forged pistons, otherwise std, still breaking ringlands, wether they had not had any ecu flashes / re maps i can't comment on, as they were dealer retro fitted, so the answer is not all piston design related, any piston will fail under the wrong fuelling/ign parameters over time.
Also it was mentioned about compression ratio difference between WRX & STI Hatch engines, the difference is combustion chamber shape not piston crown.
Last edited by MOTORS S GT; 30 August 2012 at 08:06 AM.
#707
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The piston material is the same hypereutectic the piston size is the same the only indicated difference is the compression height. Hardly an upgrade wouldn't ever fit wrx parts in an sti engine, if you cant afford a set of forged pistons this day in age then it's a bad job really as a std piston is £47 each plus vat
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I fully agree, it is a 2 fold issue, but mainly because of detonation. Here the hawkeyes broke down even more than the hatch that came in 2008.
In SA the conditions are worse for these cars, due to a low octane (95Ron) and high altitudes above sea level.
I have heard of a few new engines that have gone ( post 2010. the saloons), but I dont know why, maybe older spec maps, ECUs or soft pistons.
I don't know of anyone that bought a STI in the last year. It so damned expensive to buy one here.... 45 000 pounds! I think people stopped buying them, news got out of the ringlands.
A BMW 135i is much cheaper and problem free...and I guess guys opt for that instead.
In SA the conditions are worse for these cars, due to a low octane (95Ron) and high altitudes above sea level.
I have heard of a few new engines that have gone ( post 2010. the saloons), but I dont know why, maybe older spec maps, ECUs or soft pistons.
I don't know of anyone that bought a STI in the last year. It so damned expensive to buy one here.... 45 000 pounds! I think people stopped buying them, news got out of the ringlands.
A BMW 135i is much cheaper and problem free...and I guess guys opt for that instead.
#709
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When the cars are remapped over there do the mappers knock back the new maps so they can run on the low octane fuel? I never have understood why Subaru would sell the car in SA with a map that needs 97 ron when the fuel is not available. Total madness in my opinion especially given the rate of failures on highr grade fuel.
As far as i understand the standard map goes off and a new custom map goes on. the car in repeatedly dynoed and so the new map takes shape.
The throttle response is immediate and the car is set to run much richer to combat the detonation.
Subaru SA is not part of Subaru Japan, I was told, it's just a company that buys the cars from Subaru Japan. SO they do no R&D on the cars in local conditions, they simply pull a parallel between Australia and SA and slap a 95 RON sticker in the filler cap.
Australia has 98 RON I believe, available freely.
When I initially found out about all this detonation issues, I asked the exact same question as you just did. It's really amazing how they simply ignore the facts.
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HTH.
#711
Then what's the difference between the ej255 and the ej257?
There was a discussion here a while back on the differences between the wrx and sti short motors. On the ej engine wiki page it stated the blocks were the same with only the piston shape being different. One of the very respected engine builders who frequent this forum pointed out the wiki page was wrong and the the ej255 block used in the wrx was open deck and the sti's ej257 was semi closed. It was said this was the only difference between the 255 and 257 blocks.
There was a discussion here a while back on the differences between the wrx and sti short motors. On the ej engine wiki page it stated the blocks were the same with only the piston shape being different. One of the very respected engine builders who frequent this forum pointed out the wiki page was wrong and the the ej255 block used in the wrx was open deck and the sti's ej257 was semi closed. It was said this was the only difference between the 255 and 257 blocks.
the ej255 has different heads and valvtrain to the ej257. I have had my engine out twice to two different engine builders and both confirm the ej255 is semi closed
#713
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#714
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guys a bit off topic, but I read this on a thread.
Am I right in thinking the older Blobs only got 200 to a tank ? and this 2.5 in the hawks lifted the bar slightly.
I get about 250 to 300 outa mine which is good, and acceptable. I can see why scoobys got a bad name for guzzling if the older cars only did 200.
anybody know ?
Am I right in thinking the older Blobs only got 200 to a tank ? and this 2.5 in the hawks lifted the bar slightly.
I get about 250 to 300 outa mine which is good, and acceptable. I can see why scoobys got a bad name for guzzling if the older cars only did 200.
anybody know ?
#715
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hi Ted
Mileage i dont't know about, but those 2litre engines were tough. they didn't break, even here in africa with this diluted garbage excuse for petrol.
Mileage i dont't know about, but those 2litre engines were tough. they didn't break, even here in africa with this diluted garbage excuse for petrol.
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