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wha's the truth about hawkeye pistons?
Hello folks.
I have a 2006 Spec D with 43000 on the clock, doesn't use very much oil. Was planning on getting remap/exhaust etc. Reading the scare stories about the pistons being weak has put me off. I've searched but still dont know the definitive answer. Am I asking for trouble? Are they a liability that may well break anyway? Is there anything I need to have checked or change? Cheers, Rick |
You won't know until it happens.
Oil/pistons wasn't the issue with mine, it was the heads relaxing resulting in head gasket leakage under boost in all cylinders. Perhaps a leakdown check or coolant system pressure check - but that's about it unless you want to take the engine out and strip it. |
Rick,
I have a 56 plate Hawkeye with 17k on it. When i was buying mine i had a tough time with it all myself. What i found was the general consensus was that the piston were made of chocolate and over 320bhp was a case of when not if. I wanted to eventually make 400- 450 so decided to replace the pistons with forged items but any more would require a complete build. The best help i got was from a member on here call Fiestaboy who also did most of the work on my car to bring it up to its curent 342/362. I would advise either trying to contact Fiestaboy(he works out of Hiwycome/maidenhead) or talking to your intended mapper if you have one so you can get the whole picture. What you want to do with the car in the future will have a large impact on what you do now. But in the end i think it was all worth it the car is such a different animal it has so much torque and just keeps on pulling. Has made love the car even more. |
Originally Posted by a5h
(Post 9617625)
Rick,
I have a 56 plate Hawkeye with 17k on it. When i was buying mine i had a tough time with it all myself. What i found was the general consensus was that the piston were made of chocolate and over 320bhp was a case of when not if. I wanted to eventually make 400- 450 so decided to replace the pistons with forged items but any more would require a complete build. The best help i got was from a member on here call Fiestaboy who also did most of the work on my car to bring it up to its curent 342/362. I would advise either trying to contact Fiestaboy(he works out of Hiwycome/maidenhead) or talking to your intended mapper if you have one so you can get the whole picture. What you want to do with the car in the future will have a large impact on what you do now. But in the end i think it was all worth it the car is such a different animal it has so much torque and just keeps on pulling. Has made love the car even more. even the old 2.0 classics uk turbo engine will run fine over 320, not sure where you got that figure from, seems a bit overly cautious to me. P.S. i;ve got a uk turbo running 340/315 for the past 3 years (although don;t do huge milage in it) |
See STD ones go just as much as modified ones.
Pistons will see 400/400 if det free. 350-360 is pretty straightforward and safe. |
I was told it was the 08 hatch wich had a batch of bad pistons.
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Originally Posted by I Catman
(Post 9617966)
I was told it was the 08 hatch wich had a batch of bad pistons.
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When I did my 2.5 build, I was advised by three different respected tuners on here to budget for forged pistons as a priority. In the end, the car got rods, pistons and ACL Race bearings.
Approx 400/400 |
I read on hear that there were some 08's with a batch of dodgy pistons or something to do with the map causing a det issue can recall exactly which one to be honest. I have always been told that as the 2.5 has cast pistons rather than forged pistons it would not handle much beyond 1.6 -1.7 bar of boost. All the forged pistons do in my understanding is allow you to run higher boost pressure before they melt.
I bought mine from Cross Roads and they said it was very popular for them to change to forged pistons with the 2.5 type UK lump. I standby speaking to your tuner who you intend to do the job and tell them exactly what you want. Then have a look at some old posts as there have been a number of discussions on this subject within this forum. Good luck mate. |
Originally Posted by Tidgy
(Post 9617663)
assuming its a 2.5 i've seen better results from standard engines decatted and remapped than 340/360 :s
even the old 2.0 classics uk turbo engine will run fine over 320, not sure where you got that figure from, seems a bit overly cautious to me. P.S. i;ve got a uk turbo running 340/315 for the past 3 years (although don;t do huge milage in it) 320bhp is a little cautious but as i had thrown £14k + £3k of mods of my money into a new car i think my wallet was only listening to the cautious advise. Just like Alcazar i was recommended by 2 tuners and most people in my local club that a piston change was advisable. |
Originally Posted by a5h
(Post 9618362)
From what i understand mate its the boost pressure that is the issue with the cast pistons.
320bhp is a little cautious but as i had thrown £14k + £3k of mods of my money into a new car i think my wallet was only listening to the cautious advise. Just like Alcazar i was recommended by 2 tuners and most people in my local club that a piston change was advisable. |
The issue was the programming at the rev-limiter. The fuel cut was causing "mild" detonation.
The new map shuts off the ignition before the fuel, side-stepping the piston ring-land cracking detonation/knock, by avoiding a sudden lean mixture. |
many thanks for the replies. The feeling I get is it would be better safe than sorry. My plans are now changing. It seems rather than the performance bits and remap, maybe i should just spend my budget on the bloody pistons instead. Not sure I can afford both. Not what I had hoped, but I really couldnt afford my engine to go pop. I was warned scoobies were expensive. Was gonna use scoobyclinic. I will give them a buzz when I get back to england and see what they reckon. Cheers again.
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My 06 STI engine went with about 27k on the clock. Piston ring lands went and Subaru did the big FU job and refused to pay for it under warranty. I sent mine to API for a rebuild and remap and was totally happy with the price and results.
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Originally Posted by Tidgy
(Post 9618492)
it realy depends what your aiming for, they arn't as strong as proper forged jobies, but 350 is easily achievable and stay on the safe side. I hear what your saying about wanting to stay safe though. just get the impression that saying it is trying to push you down the rebuild route when not needed.
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Originally Posted by a5h
(Post 9619547)
I should point out that before I bought my car Cross Roads had to change the head gasket. As in the long run I want to see 400+ it was an ideal time to change the pistons as it only cost me the price of pistons, ARP head studs and 2 hours labour. So it was cost effective and would of needed to been done eventually so made perfect sense. From what I was told just putting the usual exhaust, filter and map would not require a rebuild.
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Originally Posted by mark@wrx
(Post 9618653)
My 06 STI engine went with about 27k on the clock. Piston ring lands went and Subaru did the big FU job and refused to pay for it under warranty. I sent mine to API for a rebuild and remap and was totally happy with the price and results.
Sounds a bit sh1t to only get 27K out of it. |
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