Hi

I've recently took ownership of a Hawkeye STI which has an RCM induction kit, BC coils, uprated pads/discs etc.

At the moment it has a prodrive downpipe/sports cat and a haywood and scott 2.5" system to the rear.

I've having a Miltek 3" decat installed next week and trying to get JGM to come do me a map. What other mods are people running in terms of power? I assume the standard turbo is good for 360bhp, I guess the next thing is something like an SC42/SC46? What are the internals good for on this car?

Lee

 

350-400hp seems to be the consensus. Jap engines more of course the 2.5 engine seems to have "chocolate pistons" though ...

TX.

 

So are the rods / head / crank etc suitable but it's more the pistons themselves?

 

https://www.scoobynet.com/general-te...t-failure.html

TX.

 

Lee, 370-400 ish , just get Simon to check the map and you have no det, any higher and you are getting into forging territory.

 

AT 360-370 i would be more concerened at HG failure than ringland as the standard 11m head studs are not up to loading under boost / any higher then you run the risk of both, 350 at no higher than 1.3 boost with a well looked after engine & its 60/40 in your favour .Any higher its a time bomb

 

So the consensus is: replacement ARP or Cosworth head studs, OEM gasket is OK but some forged pistons. Are the rods OK?

 

Headgaskets and arp kit, pistons a must, the rods are fine and have been run well over 400bhp with no issues, as an engine builder I would say safe at 400bhp but go fully forged over that. the 2.5's are reaching the limits of the block at 450bhp, many are running closer to 500bhp but they are marginal at that.

 

So there are some Cosworth 11mm head bolts (260,000) high tensile for sale which i'm going to be buying. Should I be looking at 1mm or 1.3mm cometic head gaskets?

Going to be researching the pistons next Just starting to collect parts to make the engine rock solid.

 

The consensus if you want more power is a full rebuild, if you want more than 450 then you really need the block pinning.

 

ARP headstuds(standard size 11mm) should be enough for your needs, pistons Mahle or Cosworth,CP-Pistons(which is Carrillo),rods depends on your budget Manley H-Beam rods should be OK for your needs,K1 or Carrillo will be mine choice

Headgasket Cosworth will be better choice,not sure about the Cometic


Jura

 

Less consistency to the 2.5 block in terms of what it can take and can’t take, I have seen a fair amount with head gasket and ring land failures in the last year, head gasket being more common. If you’re planning on upgrading the stock turbo then engine upgrades are best put in place imo.



Head gaskets and ARP studs a must followed by pistons which “can” be drop in, saving costs. If you’re planning much over 400 then rods should be added.