Hello guys ;

I'm building a new engine for my O4 Blob .
It's a ej257 pindeck-block . MY012 induction headed sti cranck , K1 rods with
Cosworth pistons and a gt35 on it .

Now befor i had a closed deck ej25 Rigoli performance blok but i had a rod failure and it's completly destroyed .

My old engine had the original MY04 2.0l STI heads on it completly std.and max rpm was set to 6900 rpm.

Now with my new engine i whant to make more rpm . Can i just place some std spec-c (avcs) heads on it and let it turn 8000 rpm ?

Can you guy's help me out ? ( paul B ? , you mapped my old gtt at racetech in Belgium )

 

Yes you can fit 2.0 heads but you really need to machine them out to match the bore size of the 2.5, otherwise you get a lip which isn't ideal for the correct 'squish'. You also need to get the compression correct, 2.0 heads are 49cc per cylinder 2.5 heads are 51cc.

 

And rpm ? Can they turn 8000 rpm then ?

 

 

I have some v2 STI heads coming off a fully forged EJ257 available soon

 

likely will not work with his ECU etc.


ducske916, is it an STI, and are you running on an aftermarket ECU?

 

Dn't they are going to fit an 04 STI!

 

No reason why not, but, once you have the car mapped (assuming you are) then you should be able to see the graph and work out the best way to drive it, a 2.5 is going to produce more torque and I would expect the quickes way to drive it would be changing gear lower down the rev range and use the torque. Over revving for no real gain will just cause extra heat and stress. Hence maybe why you lost a rod in your old engine?

 

Car is running on a autronic .

Old engine broke 2weeks after i bought the car . ( bolts broken of 1 rod )
Broke on 1.1bar , but must be a fault already in the engine before i bought it .
Old ouner did some run's on 2.7bar ( and engine was made to 2.4bar MAX )

 

B25(STi) or D25(WRX ) heads should be best to have

Better cams and better springs/retainers with Supertech valves and you have nice setup


Jura