john banks

I believe that standard EJ257 gaskets were used on my build. This gives a compression of about 8.7:1 on the same heads that are on your car.

Replacement of other items depends on if you have had a failure of your present engine and what the failure is.

The spare crankcase breather is unbaffled and flicks out oil from the crank. I have been collecting mine into a catch tank, but am planning to block it off.

If you are staying at sensible power with a VF28 your present gearing will be fine. If you increase the torque a lot, then IMHO your gearing will be too short. My UK gearing actually feels a little on the short side for this engine! Bear in mind you will need to drop the rev limit to 7000 RPM for this bottom end so your maximum speed in each gear will be lower...

The following from a recent Delta Dyno log in third gear which only a few mph shorter than your fourth gear:

In Gear Acceleration:
30 - 50mph = 2.3 seconds
40 - 60mph = 1.7 seconds
50 - 70mph = 1.6 seconds
60 - 80mph = 1.8 seconds

This is using 1.25 bar dropping to 1.1 bar on a 20G with FMIC.

This means that if you tuned yours like this (sounds like you're not planning to though) then if you go up through the gears you will be in 4th at about 70mph and be grabbing 5th only about 3 seconds later. That is indeed incredibly manic, and would be quite hard work IMHO.

For about 300 BHP you could probably get that by running about 0.5 bar boost, maybe a bit more

[Edited by john banks - 12/1/2003 10:07:24 PM]

Sonic Blue Type R

iTrader: (3)

Basically I need to replace the short motor in my STI V5, I was looking to use a P1 short motor as that is the same spec, just found out the price. So I am now seriously considering the USDM 2.5 STI short motor.
But I need as much info as possible, first of all, what else will I have to buy on top the short motor, I know that I need the EJ25 head gaskets, but not to sure if I will have to replace anything else e.g. the oil pump etc....
Also will my VF28 turbo be okay, or would this need changing and is there a issue with the gearing, I have a V-Ltd Type R.
I've not got much of a clue when it comes to technical issues such as these.
I now there are a few of you that have the 2.5 STI short motor, but I'm not really looking for big BHP, or Torque for that matter, just as long as it puts out around 300bhp.

Any info on this would be great, BIG help please!!!

Oh, I also know that you have to block off a breather on the block somewhere, not sure where about though

CataIunya

What kind of power can you extract from these with standard internals? the bore is different on the 2.5l ? or is it just the stroke or both ?

john banks

No one knows.

It is a larger bore and a longer stroke.

Sonic Blue Type R

iTrader: (3)

Cheers John, I was hoping you would reply, since you are running the 2.5 STI. It's good to know that it will be okay on my car, still deciding what option to go for, but that has helped me very much.

Ewan.

CataIunya

Apologies everyone misread the title I though it was a none sti 2.5l ie the normally aspirated 2.5l.

ticky

Is it only the version 5 heads suitable for the USDM sti short motor, what about the early heads v2,v3,v4 etc.

john banks

I just used V5 because they were available and relatively proven on high power cars.

I do believe that the Phase II heads are better flowing than earlier ones, although STi 3 is reputed to be quite wild.

However, with only a 7000 RPM limit for this bottom end, you might not want something too wild.

sg72

S.B.T.R.

YHM.

David_Wallis

wanna buy a 2.5sti block?

I might have one spare

David

hrubago

I run USDM STi 2.5 on STi 3 heads with no problem. Still running in.
Next week (or month ?) I will upgrade to TD05 big 16G turbo, then mapping on the engine bed will follow

deez

Hehe I have a EJ257 block... in my USDM STI And with only a few mods, I got over 270whp. Shouldn't be difficult to break 300whp.

WUZ

iTrader: (14)

David - I have someone looking for one, is it complete short engine ie pistons, rods, crank and block?

mail me with what you are looking at for it!

Russell

hrubago

2.5 USDM STi shortblock (incl. pistons, rings, conrods, crankshaft, bearings) - 2500 Euros :-)

Mike555

I have ask rallyspec this question:

1 Can i swap just the shortblock with the oem one, without any modification? Like the intake, throttle etc etc
This shortblock can be installed without modification. You must use 100mm headgaskets in the correct thickness. We can supply 1.4mm headgaskets which will provide a 8.1:1 compression ratio when used with the 2.0L WRX cylinder heads. These headgaskets are $95/set.

With this mods, the distance of the bolts on the cylinder heads will be increase. So how can you put the intake manifold and the manifold on it??

Someone knows?

Mike

john banks

Does c.1.6mm (original gasket is 0.6 IIRC) really matter across the length of a manifold? Wouldn't think so since most have a slip joint in the middle anyway.

However, I would and did go for the extra compression every time! I am even achieving slightly better fuel economy out of my 2.5 at 8.7:1 than I was out of the 2.0 at 8:1.

[Edited by john banks - 12/5/2003 9:13:38 PM]

[Edited by john banks - 12/5/2003 9:14:15 PM]