2,5 max boost with wich internals?
 

Hello!

What is the max Boost you can run on a USDM STI 2,5 Block without killing it?
Wich are the best internal parts you get for this Block?
Are the Crawford Pistons any good?
Wich Rods?
Wich bearings?
Wich Crank?

Wich Turbo is the best (ie the less lagiest one) for running high boost on the 2,5?

Many Questions but im going crazy now cause the biggest oponent in the local racing scene is also going to build a really strong Motor!

greets

Markus

25 PSI with advanced timing on a small turbo killed my standard EJ257.

20-22 PSI with careful timing seems OK.

Least laggy turbo and the ability to run high boost are mutually exclusive.

If you want a tough motor get a Crawford CDB 2.33 with forged internals and piston squirters.

Hello!

What means small Turbo? wich was it?
Is the Andy.F Td05/06 up to this 22 PSI of safe boost? (sure with a front mount)
Wich Turbo would be nice for this 22 of boost and less lag?

How important are the Piston squirters?

andy f is the best person to ask about his turbos try his webpage

I ran the TD05/06 at 22 PSI on pump fuel on the 2.5, and it and the engine were fine, but I did not hold this to the top, only about 18 PSI. Then I switched to an Ion P450 (which I have for sale) and that made more at the top, but still couldn't hold 22 PSI to the redline whilst remaining unstressed, well it did, and the engine didn't like it LOL. Now running a rotated GT30R-12 and that seems happy to run to the red line whatever I dare, it goes well at 20 PSI all the way, with the odd peak to 22 PSI in the midrange traction is a bit of an issue.

Are there any (safe/reliable) gains to be had using a rotated GT30 turbo on a Sti 2 litre over the 20g @ 1.4 bar (my 20g tails off from 1.4 to 1.2 = 5000 to 7500rpm.) ?
My Stiv3 peaked (once) at Well Lane at 407 bhp, but i think popular thoughts are that this is about the safe limit for a stock Sti v3.

On the Crawford 2.33:
Would the stock Stiv3 make the ideal donor engine for heads etc?

Graham.

If you have to taper the boost because of flow reasons, then a larger turbo will give you a double gain - you can flatten it, and run that extra efficiently. How the stock engine will like it is a matter of opinion. However, it will be considerably laggier, too much IMHO for a 2.0, especially on a twisty hill.

For the Crawford 2.33 you'd need to know head volume, deck height, head gasket thickness to work out a sensible CR. Quirt when questioned on his forum would not recommend a suitable CR for running 1.7 bar on pump fuel though. I've taken this on board and hope my engine will last all the better for it.

I'm also very careful as I mentioned on fuelling and timing to keep temperatures and pressure spikes in check. Higher boost (supported with octane) used in this manner should give wider flatter cylinder pressure profiles for each combustion event giving the power and torque but less stress - using a turbo large enough I think helps as well, the turbo I have now is capable of well over 1.4 bar at 7500 RPM on a 2.5, so running at this should keep the exhaust flow good and the pressures down. We'll have to see if it works in practice.

i want to use the TD05/06 Turbo first and get first new and strong internals bevor changing the Turbo. Wich internals are fine? Wich do you recommend for a safe 450hp Motor? I think the Crawford pistons are fine but which Rods, bearings and Crank?

Have anyone fitted piston squirtes himself?

What about o-ringing the Block and use a copper Gasket? Where to get these O rings? (machining of the Block for the O-Rings is not a Problem)

Do you remove the Edge wich looks into the cylinder when using a WRX Head on a 2,5 engine? I think this is a point where detonation can take place.

When you switch on the waterinjection? Wich boost? wich rev?
Are you running the boost higher if using waterinjetion or just use it for safety?

If i had my time again, i would go the 2.33 route.

The 30R will certainly hold 1.6bar to 7500, thats for sure.

cant the 2,5 made to take the same as the 2,33 block?
Thats what i want to know!
I have a std 2,5 allready fitted and whant to make this stronger instead of buying a complete new short block as i can do much work myself!
The only question ist wich parts to take?

I know that the 2,5 isnt closed deck but i think if the block is o-ringed it also gets stronger and there is less disorientation on the cylinders on high boost but 1.6 or 1.7 bar shouldnt be a problem at all.

It should be considered a bit experimental then toughening up an EJ257. Might you be better running the EJ257 until it pops if it does? I personally think the EJ257 is up to anything the 20G can throw at it on 98 RON.

so fine but how much can the 20G give on a 2,5 with Headers and a front mount and waterinjection? are these the 22psi max and down to 18 on high revs?

I would say so.

John when i should switch on waterinjection? 1 bar? wich rev?

I doubt you'll get much more power out of an 05/06 on a 2.5 compared to a 2.0, but you should get much more torque. No good for track of course.......

I don't run water MaeckyMY98, I used to off a boost switch (although I think mapped is the best method with safety contingencies), but I found I preferred the effect of in tank additives.

Graham, same question here ;) ..... thinking for a while on how would a rotated GT30R turbo (with the smallest exhaust housing) work with a 2L 8000rpm WRX engine.

Carlos

this setup uses the MAF sensor ;):

http://www.gruppe-s.com/stuff/GT30A.jpg

http://www.gruppe-s.com/stuff/GT30B.jpg

http://www.gruppe-s.com/stuff/GT30RKit3.jpg

When will the rotated GT35R bring 1 bar on a 2,5? Is it up to the task of 1,5-1,6 bar up to 5500 U/min on a 2,5?

?

I agree on the power bit, but torque? That's ALWAYS a good thing to have, early spool, and gobs of it, along with a fair bit of hp - that makes a quick car...however it's used.

One is not always above 5000 rpm..

/J

IMHO Secret Agent's spot-on.

Carlos, nice to 'hear' from you again! :D

Never knew Gruppe s did a kit, looks bloody good to me.
Interesting that it uses the TMIC too which makes the move in that direction even more tempting.
Have you caught up with my '407 x 340' status yet. If not, you must be the only one on here who hasn't.

Sorry if it sounds like I'm boasting. :D

First full competition run next weekend. There are no EVOs there either, but a mean BMW.
Why is hill climbing never simple and easy! :norty:

Graham.

How could I miss the "407 x 340" ..... ;)

Personally when close to 400hp I think that there are other parts of the car that need to be sorted. One thing that doesn't makes u loose reliability is taking some weight out of the car. Another area is LSDs. your STi should come with a rear plate type LSD, so a front torsen type should be of some help.

Also I don't know what is more important if low end torque or higher rev power, from what I have seen in european hillclimbing championship videos (M3's equipped with F1 V8 engine, ex Merc DTM cars), there are a lot of high revving engines and they sure look fast.

Carlos

Hello Carlos,

i know these two cars you talking about but these two are normaly aspirated and cant get the low down power thats why they are reving so high.
On a Turbo i think you should use as much as possible of the rev band (same as on other cars but with a turbo you can get mur rev band to use)

So my question is still wich are the best internals for the 2,5 block

Maecky, from my limited experience with scoob engines the max usuable power band u will get is 3000rpm. Therefore it can be a higher revving 2L STi engine with 4500-7500 rpm power band (the best from my experience) or a EJ257 with 2L engine heads with a 3500 - 6000 rpm power band (when using small turbos).

The very best setup I have seen for hillclimbing is a STi ver 6 RA with a EJ257 shortblock, a IHI VF34 with a P20 exhaust housing, using race gas and a group N dog box with close ratio gears (5th gear is 0,9) this mated to 3,9 final drive and ALS makes the car ballistic :), although driver complains that he has to change gears too often (he is changing @ 5600-5800 rpms).

Best internals for the 2,5L block ????? ...... uhmmmm depends on what r your power goals, I personally would only go for forged pistons (CP), and try to run a lower CR, something closer to 8:1.

Carlos

J - can't remember the last time I dropped below 5k on track :) I actually hope the 2.5's torque will allow me to more often, but it depends whether more acceleration is available above 5k still.

Richard

You can have peak power or very near from 5000-7000 RPM though :D

gruppe s kit is for LHD cars.

:norty:

Graham.

We will see once the season starts, still can decide to use the FE TD05-16g or FE TD05-18g turbos. Maybe less torque and power but at least 100 kgs. lighter ;).

my car is LHD :D

You drive on tracks that aren't twisty enough. :D
If we wanted a peaky, rev happy car, wtf are we doing in a scoob in the first place? ;)
Scoobs are about midrange oompfh, and alot of it makes for a quick car (naturally it has to produce power as well, but the 2.5's seems able at that as well).

/J