Im after some info on peoples forged rebuilds/conversions as im in a dilemma and arnt sure what do to when my uk engine lets go. i could do 2.1 - budget big power nice and revvy but id like to keep a lot of torque, so could go 2.5 (althought fully CDB's arnt available?) with a md321 and have a really torquey but not revvy car. OR could meet in the middle, splash on a 2.2 and stroke it to 2.35 and have the best of both worlds?

I want a fast road car thats going to be very capable on handling/drag but i think ultimatly im going to have to have a go in something in the real world!

What capacity did you go for?
Why did you choose the above?
Pros & Cons of your build?
What power does it make?
What do you use the car for?
If you were going to do it again what would you change and why?

Any inputs appreciated.

 

Classic or newage?
If its a new age STI then no real problems but then you wouldnt really need to forge the engine if its a classic or new age wrx then its going to get expensive, more torque = new clutch and considerably more strain on the gearbox, on the classic its pretty terminal and you will be forking out for a new one pretty early on (best go for a 6 speed or a PPG conversion, the 6 speed being the stronger and cheaper of the 2 at around 2k) and then the supporting mods (brakes etc) so you will need to take all that into consideration.

Tony

 

Classic mate. brakes are k sports all round. clutch + gearbox kinda go hand in hand with the engine so its all been taken into consideration just not sure what do do engine wise!

 

2.5 every time who says they wont rev its an easier as there are more parts available,
we have a 2.5 with the semi closed deck block it hapily makes 570 hp and 509 whp on pump gas with no issues
Theres no substitute for cubic capacity!

 

2.5 here too, mine revs just fine also. I worried that it wouldn't be as much fun as a 2 litre, but all that torque is what gives you a smile on your face each time you press the loud pedal.

 

Ditto to the above. I was worried about how revvy a 2.5l would be, but a test drive in a 2.5l 485/485 classic soon put paid to any concerns...awesome!

I was going to go the 2.35 route, but the cost of the block put me off. I looked at 2.1, but struggled to understand how a 5% capacity increase could make much difference...readily admit I might be missing the point

So, in the end, a 2.5l made most sense. So far no regrets, but I'm not realising its full potential yet, as I'm still running the stock VF37 twinscroll.

Would I have done anything different? Well, ideally, my 2.0l wouldn't have needed rebuilding in the first place Other than that - no, tbh. Very pleased

 

Buy my forged 2.5, ready to go in your car.

 

Hi Tim, AFAIK the 5% is all in the throw of the crank, so it's all about bottom end torque, making the car pick up sooner and stronger. Plus an easy 8000 rpm safe motor too !

dunx

P.S. I had a 2nd "project" in mind, but the 2.1 was always plan A for next year, or Dec. 2009 before the VAT goes up.

 

the more i think about it the more the 2.5 makes sense but can you get a closed deck 2.5 block ? id want it bombproof

 

What sort of power levels you aiming for John? My new engine is going to be based on an EJ257 Block. The cylinders themselves wont be sleeved just strengthened with inserts around them. Aiming for arounf 600bhp with this.

More than enough for most applications.

 

so how much would a 2.5l engine be then as i'm having trouble with my 2l engine. but how strong is the 2.5 over the 2l engine. sorry for the hijack.

 

500/500? i want torque to match bhp but its more about the way it will drive as oppsed to pub ammo figures...

is yours semi closed daz?

 

Torque! torque! torque! for a roadcar! Gotta be a 2.5!

 

PM dave_garret, as I'm sure his new one is a CDB 2.0L block, but is going to be a 2.5......I think.

 

ive been enjoying my engine tuner built 2.5 the great thing about it is you put your foot down in any gear and you just go like a missile. 2.3 is amazing but only worth doing if your getting head work done and you got deep pockets for some after makert heads and to be honest 2.3 with lunpy idel might be great for the track etc but on the road a 2.5 wins it for all the time its just so effortless to drive. you really got to drive one to for a few hours to know what im talking about. and btw a 2.5 would rev providing you got the right turbo and set just ask shaun with the mad spec c he will tell you 2bar of boost at 3k.

 

i think daves is a 2.0 re-linered - heard liners can slip though? thats the only thing that puts me off?

i think with the right heads/cams, pulleys, flywheel and turbo i could be onto a winner with a 2.5

yea im gonna have to have a go in one i think - anyone wana take me for a spin? lol

 

Yeah, his is linered. But aren't suppose to slip he's been told.

 

no you dont want that to happen...

 

lol, sorry I mean't the guy building the engine has told him his won't slip....maybe a design reason they don't slip?

I remember reading on the american forum, they now use liners which have some sort of 'lip' so cannot slip.

 

liners with top-hats IIRC

 

yeah he told me mine wouldnt slip aswell,i'm having mine replaced elsewere now with the top hat liners.

 

tell me about it. got rid of the sti5 heads for some sexy new ones. bloody expensive with the new cams. twill need shimmed up as well

 

I have had 3 engines from "him" and none of my liners have slipped with the latest engine making 620bhp

Banny

 

I'm hoping to show that an EJ257 with cheap and simple strengthening will cope with circa 600bhp no problem.

Wrighty I'd honestly say to go for an EJ257 with rods and pistons. an MD321V on it would make a lovely car.

My previous 2.5 with a rotated GT30R was a dream to drive. sensible and civilised round the town and then out in the **** end of nowhere it was awesome!!
Standard STI5 heads will also cope very nicely with 500bhp.

 

What are the weaknesses of a EJ257? I presume they're ODB?


Edit: as in if all the other components are mint, like pistons etc, would the block actually fail?

 

Semi-closed, IIRC.

 

anyone know who can re-sleeve a 2.0 with liners that wont slip or what il need to build a 2.0 closed deck to a 2.5

 

daz, already got a 2.0 CDB i could re-sleeve etc as a base.

howd your 2.5 go through corners etc, did it pick up ok through tight twisties?

or can anyone else answer that?

 

Considering the dodgy nature of some "sleeved block" offerings I'd recommend you either go 2.1 or use a standard 2.5 block. If you are using an md321 it won't cause damage either way. We've built a number of high power 2.5's with twisted GT35's with no bother at all.
Personally I wouldn't waste a decent CDB by attempting to liner it.

 

2.5 but I wouldnt bother going the 2.5 CDB route. Std EJ257 is fine but if you can get some good liners in a new block it could give the extra headroom for pushing the torque up.

As for working in the twisties ... torque = punch out of corners.