hrubago

Heard something about front entry conversion ..... ??

Andy.F

Yes you will need a front entry converted compressor housing to fit a TD05 to a 97 onwards Impreza.

Andy

hrubago

Have good offer for this turbo:
T04E TURBOCHARGER
3" INLET DIAMETER
2" OUTLET
WET FLOATING BALL BEARINGS
T3 / T4 FOOTPRINT
.57T GARRET COMPRESSOR WHEEL
.50 A/R COMPRESSOR
.63 A/R TURBINE

Found some infos on the net:
http://64.225.76.178/catalog/t3t4.html

compressor maps: http://64.225.76.178/catalog/compmaps/fig15.html

But Im asking all turbogurus if this turbo is optimum (or better) for my 2.5 l aplication than VF23 or TD05 16G

john banks

You never know until you try it...



... but I don't think I'd bother.

hrubago

Thanks a lot.
Graphs are now looking like petrol Impreza version again.

hrubago

But. Todyz I made shrt test run on old 2.0 maps (safe driving - max 15% throttle). The car is very unstable and looks like bad timing problem. I asked some peoples. They said that US STi engine can have different timing or my cam profile cannot suit 2,5l aplication. Whats your opinion?
Im little bit sad. :-(

RB5SCOTT

John

What will you be doing with your heads? I take it you will be porting, adding cams, bigger valves

As iv'e got all the other base parts (apart from injectors) bolting this block to my heads will be the easiest option, especially if it can take around 450bhp!

Not sure that the Ecutek will be up to the job though, especially having to rely on the MAF!

Scott

john banks

Not sure what the problem could be hrubago. My car is driving fine with the last map I had on it for the 2.0 - it fired up the 2.5 fine and is apparently fine for light throttle/cruise in terms of AFR and timing - HOWEVER it is MAF based.

Scott, I am using STi 5 heads/cams, they have been ported. I think and hope they will be about right for peak power at about 6000 RPM on the 2.5 with a 7000 RPM limit. If you look on NASIOC there are dyno graphs with this block with WRX heads/cams. It seems to drop off a bit at the top, but doing OK.

The valve sizes and head castings should be fine for my power targets. The heads are capable of revving to 8000 in the STi, and are producing over 450 BHP for Bob and Harvey, so I am optimistic.

Originally I was going to try it with MY00 UK heads. I'm glad I didn't, but it may be fine. I can't see 400 BHP being a problem, may well be fine for 450 BHP. Until you do it who knows? Bear in mind the bottom end is unproven for this sort of punishment and some very wise people advise against over 350 BHP!

Re Ecutek, I am planning to ditch the MAF sensor once I can test my little microcontroller board can successfully decode the ECU's RPM signal. A little multiplication with the MAP voltage and out pops a linearised but usable MAF voltage.

It has already been done successfully with a Unichip

[Edited by john banks - 11/18/2003 8:53:27 PM]

john banks

This shows a nice 20% or so gain WITH WRX HEADS. Same boost was used, VF30 on the EJ25, TD04 on the EJ20. Neither are ridiculously tuned, so I don't think the turbo should be the limiting factor. Maybe as you stuff more air through though the WRX heads might struggle and peak power point would come in lower down the RPM range? Dunno.

RB5SCOTT

Thankyou very much John I will be doing head work but if it means that it will be better to modify STI5 heads, i will do that

If you manage to make a MAF thingy. i will buy one

Scott

EMS

Mark.

john banks

Mark, didn't want to steal your thunder, would make an interesting post for many if you could describe your results from this.

Dxx

HELP!!

Need thoretical bit of advice. What would be the preferable choice of heads to run wth a US 2.5 STI short block???
Was thinking poss STI6 standard, or do they need porting to get decent gains?? WOuld STI 5/4 be better - (?don't they have a more radical cam profile??)
Would a different choice be preferable?? Cam profile is an important consideration, as aftermarket cams can be a bit pricey!!

Cheers
Dxx

hrubago

And flow chart for VF34 and VF39?
(thanks for previous graphs - very important for me. TD05/20G is expensive for me. I choose t3/t4 but it has different layout (no wastegate ventil + connection to wg) and Im not sure how it works on garett. Then Im thinking of turbo in IHI range. Used VF 34 cost around 350L and VF39 around 480L.

hrubago

Engine now runs well. Cleaning of all conectors helped :-)

john banks

No easily available maps for VF30-39.

Re cams/heads, I am trying STi 5 ported heads with STi 5 cams on mine.

The USDM 2.5 STi heads would be a good choice, but what model/year car do you have?

STi 7 or 8 UK could be a bad choice as they use small ports which seem to be restrictive compared to the JDM models.

hrubago

VF34 and VF39. Never mind. But which is bigger one?
Comparsion to VF22?

john banks

Difficult to say.

dowser

Isn't the vf34 a bit small for a 2.5? I'd guess it would become a bit too restrictive above 5k to make it worthwhile for the low down gains? No evidence to back this up, of course, just a wild guess

If cost is an issue why not just do a front entry td05 now and add the 06 wheel/cover at a later stage? I reckon the 05 will be a very good road solution for this engine, but will still ultimately limit top end power. I'll be trying this before whacking on the 05/06 with my ej25

Richard

john banks

The 20G on the 2.5 feels very strong on spool up, and er, a little too strong at higher RPM (Needs a bit more work on the wastegate porting, but it is not dreadful). Pressing the throttle at 3000 RPM is 2nd gear produces a quick response, not a load of lag. However, this is only running low boost, so the difference between off and on boost will be more pronounced. However, at only 8 PSI there is still a lot of torque. A few stopwatch tests using the speedo produced 4.2 second for 30-70 using 6000 RPM change from 2nd to 3rd gear, and about 6 from 60-100 in 3rd changing to 4th at 6000 RPM. Midrange boost was 8 PSI, it creeps to 16 PSI at 6000 RPM, don't know what it does over 6000 RPM. Fuelling is 10.5-11:1 and the timing is very retarded. Mileage is 750. I am not holding it under load for a long time, just quick blats to 6000 RPM now and then. Need to check on oil usage over the coming miles after my holiday because there were a few puddles on the nearside chassis leg near the breathers. Could be those from run in - it is the "extra" STi breather on the block that is making the most.

dowser

Sounds nice John - why not cancel the holiday and sort it out sooner?

Richard

Andy.F

Don't tempt him

Dxx

Back to the heads discussion, is there massive differences between the STI 4/5/6 heads and cams?? Currently have a set of uk MY00 standard heads but i'm thinking these might not be suitable
Will porting the heads, whichever set, make a large difference to performance?? And will it be a case of gaining top end power, but loosing bottom end instead?? I know that increased torque from the 2.5 should make up for this, to a certain degree.
Assuming heads of the STI variety are preferable, how easy are they to source??
Dxx

deez

Here in the states, I am making 276whp on a stock motor with just exhaust modifications. No problems yet. A few tuners are making 300whp on internally stock motors with just bolt-ons and some fuel mgmt. You should be fine!

LeoneTurbo

A friend of mine is currently running a stock EJ25 block in his MY92 Legacy Turbo. I built it. We're running the standard turbo heads, standard ECU and electronics, modified exhaust though. Mind you: because these heads have a larger combustion volume (different valve angle than Phase 1 and 2 heads) we're running stock atmo EJ25 internals!!! Block is pre 1998, so still with #3 thrust bearing.

So far, estimate is that the engine is developing around 260-270 hp and around 260 lb-ft on standard boost.

Turbo is standard IHI VF12. Engine starts pulling hard from as low as 2200 rpm, and as we haven't taken it over 5000 rpm yet (still breaking in) there's no sign of lack of power up to there. Legacy Turbo heads have same valves and port size as Phase 1 heads, however, cam profiles seems to like higher rpms.

I bet this is the cheapest EJ25 conversion yet! We're keeping an eye on timing and fuel injector duty cycle, as we're max on stock fuel injection.