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Discussion Starter · #1 ·
Hey guys, I'm really struggling on what direction to go here and was hoping to get some advice. 2004 STi, street car, currently making 320/348 and has been for a good 4 years or so. I have a g25-660, custom rotated kit, ETS 3.5" IC, and everything else ready to go. My question is should I chance the current engine setup, or sell it and shell out the money for an IAG staged longblock (probably a 700 or 900), also giving me room to grow in the future.

Current setup is an ej257 which went through a catastrophic failure in which the crank seized. Case halves were deemed to be in good, workable condition. Was rebuilt by a reputable shop around 4 years ago, has ~12k miles on it now, runs fine and the compression test was good last year. The rest includes:

  • Weisco 100mm forged pistons
  • Cosworth rod and main bearings
  • Brian crower BCROD SET
  • water pump/oil pump replaced
  • heads rebuilt by drew
  • killer b oil pickup/baffle
  • shop did not do headstuds, but if I ran this block I'd put them in

My main concern here is the cylinder walls being bored out to 100mm and warping under boost. I don't mind spending the $$ on an IAG block, but at the same time if the current setup will be adequate, I'd rather run it and get an IAG block down the line when I likely want to step up. Help and feedback is appreciated.
 

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you'd probably be fine with that block if it's still in working condition and was built properly, assuming you have a good tuner who wont go past the limits of the block itself.

headstuds is definitely somthing i'd do, and if you are doing those, i'd go ahead and upgrade the valves/springs as well, as they will be your limiting factor on how much boost you can safely run (regardless of power, but assuming they are currently stock). i'd do that and send it, assuming you dont have a crazy amount of mileage on it.
 

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Discussion Starter · #4 ·
you'd probably be fine with that block if it's still in working condition and was built properly, assuming you have a good tuner who wont go past the limits of the block itself.

headstuds is definitely somthing i'd do, and if you are doing those, i'd go ahead and upgrade the valves/springs as well, as they will be your limiting factor on how much boost you can safely run (regardless of power, but assuming they are currently stock). i'd do that and send it, assuming you dont have a crazy amount of mileage on it.
The block is OEM and technically had 160k on it before being rebuilt and honed out. It was built by a reputable builder however, and its pretty much just been broken in and driven minimally since then (I think it has right around 10k miles on it MAYBE).

I forgot about the valves & springs. That's a good suggestion. I know the heads are in excellent condition

Bro, I told you to send that shitbox.
10/4 shackleford
 

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The block is OEM and technically had 160k on it before being rebuilt and honed out. It was built by a reputable builder however, and its pretty much just been broken in and driven minimally since then (I think it has right around 10k miles on it MAYBE).

I forgot about the valves & springs. That's a good suggestion. I know the heads are in excellent condition



10/4 shackleford
if the current build is under/around 10k miles you'll be good. if you dont do the valves/springs youll be limited to 24psi safely (this is what iag told me with mine, they said others have pushed stock heads with much more boost reliably, but this is what they'd warranty when i got my motor, not sure if that has changed or not). regardless, that would be the "weak" point in the motor, upgrading the valves/springs will increase this. ive personally seen others push 27psi on stock heads without issue for long term (multiple autocross days/40k+ miles), i didnt on mine just cause motors are expensive lol. so pending fuel, you could push more than 24psi, but to be on the safe side, dont (unless upgrading valves/springs) would be my advice.
 

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They'd only warranty at 24 PSI when if the problem of not upgrading valve springs is just pushing open the valves and making less power? I can't say I've really seen an issue at 30+ PSI on stock valves.
 

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They'd only warranty at 24 PSI when if the problem of not upgrading valve springs is just pushing open the valves and making less power? I can't say I've really seen an issue at 30+ PSI on stock valves.
they said it was because of valves+springs that they suggest no more than 24, and that's what they'd want to honor any warranty issues. honestly i ran 23psi, never had any issue and the block is at 45k ish miles, so i never had to deal with warranty. they did say others had pushed further with success, but that's the "limit" for their warranty. my guess, is to keep any thing like that super conservative. i'm well past the warranty now and i'll turn it up when i do get e85. ive had plenty of friends making well over 24psi on stock heads, one guy was even running 32psi on a stock 07 longblock without issue (did this for like 2.5 years, then built it. it was still holding together when he built it). so it's probably not a big deal running more than 24. i'm simply saying what they told me which is where i got the 24psi from.
 

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I get it... Just seems silly as if they valve cannot handle more than 24 PSI, they'll just float.

I've run 30+ PSI on many stock head/valve/valve spring cars.
 

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I get it... Just seems silly as if they valve cannot handle more than 24 PSI, they'll just float.

I've run 30+ PSI on many stock head/valve/valve spring cars.
NICE. as soon as i finish piecing the fuel system together for e85 i'll be going past their suggested 24psi, idk how high, probably only to like 25-27 (whatever the blouch 20g seems happy at on e85)
 

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The above - Boost and valve springs are related?

Don't the springs close the valves and cams open them? Boost/pressure increases that force - kind of like a mat style sink drain "plug". You can fill the sink as deep as you want and it seals better, with no spring.

Normally stiffer springs are used to create faster closing allowing higher RPM.
 

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The above - Boost and valve springs are related?

Don't the springs close the valves and cams open them? Boost/pressure increases that force - kind of like a mat style sink drain "plug". You can fill the sink as deep as you want and it seals better, with no spring.

Normally stiffer springs are used to create faster closing allowing higher RPM.
I think its just IAG's way of getting out of replacing engines that fail. They say "dont run more than 24 psi on stock heads or we'll void your warranty" is their way to weed out the people who are serious racers. Most "normal" people don't want to mess with the heads, and just leave them alone.

The serious racers who use built heads wont be coming back for a warranty if they grenade the engine. They just rebuild and move on.
 

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I think its just IAG's way of getting out of replacing engines that fail. They say "dont run more than 24 psi on stock heads or we'll void your warranty" is their way to weed out the people who are serious racers. Most "normal" people don't want to mess with the heads, and just leave them alone.

The serious racers who use built heads wont be coming back for a warranty if they grenade the engine. They just rebuild and move on.
very well could be. this is just what they told me, i honestly didnt get into racing until after the engine was built. if i did, i honestly would have gone a different route to be in a separate class where i could be more competitive
 

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very well could be. this is just what they told me, i honestly didnt get into racing until after the engine was built. if i did, i honestly would have gone a different route to be in a separate class where i could be more competitive
I'm not saying you're lying. Its just an oddly specific way to weasel out of a warranty claim.
 

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The above - Boost and valve springs are related?

Don't the springs close the valves and cams open them? Boost/pressure increases that force - kind of like a mat style sink drain "plug". You can fill the sink as deep as you want and it seals better, with no spring.

Normally stiffer springs are used to create faster closing allowing higher RPM.

With enough boost, you can float a valve. The diesel world probably deals with this more.



Just run 23.5 PSI on a 7285... Assuming they aren't referencing RPM. :p
 

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I'm not saying you're lying. Its just an oddly specific way to weasel out of a warranty claim.
lol i didnt say you were, but idk why they said that. i just said ok, dont push it....motor has multiple autocross+trackcross events and 45k ish miles on it without any issue. so i'm well past the warranty
 
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