Just a bit more info on charge temps as we have now had some hot weather, charge temps are always approx 3 degrees above ambient whatever the temp once the car is on the move, the intake temp is always higher than the charge temp which is understandable. However it is supporting my orignal presumption that the std STi top mount with larger scoop is effective at the current power levels. I'm still seeing approx 13-15 degrees of rise on a full on 4th gear run, haven't had the opportunity to check repeated full boost runs yet to see the additive effect.

bob

 

did you ever check for pressure drop in the inlet? (sorry have read most of thread but can remember)

 

No not yet David, just monitoring temps at the moment, and I still have my undertray on for the time being although that WILL be coming off in the near future but I want a bit more data first with it on. I'll stick a differential manometer across the intercooler and see what I get.

bob

 

Have you fitted the VF34 yet Bob?

 

Nope, hadn't even considered it.

bob

 

How about the VF36?

 

Got one in the garage but thats no better than the vf37 thats on it apart from spool due to titanium shaft/turbine wheel and there is no problem with that.

bob

 

Which one was next then? I knew you said you had something lined up for stage II?

 

race fuel.

 

And Nitrous

 

LOL ... haven't decided yet, I want to stick with the oem headers complete which means sorting out something based on the twin scroll, quite what I am not sure yet.

I've been "playing" with the Sti5, now thats having some more TLC I will refocus on the '9.

bob

 

Not much left to do with the sti5 now??

 

Just a bit of "fine tuning" nothing earth shattering.

bob

 

Bigger compressor wheel in the std. turbo seems to work well from what I have heard from the US! I want to test that in my 2.5 liter project in a few month. I hope to achieve full boost (1.2 - 1.3 bar will do for me) around 2500 RPM.....

Mark.

 

Bob don't forget you have a willing guinea pig here for turbo time

 

Mark, is that like a PE 1825?

 

Mark I can get 1.4 bar at that with the turbo just like it is but surge is a problem, do the I'm a bit behind with the US specs, what car(s) has the twin scroll setup? Whatever i go for has got to be MORE than capable of giving me 400 bhp, that means I need a 450 bhp jobby as I do mean more.

Thinking about a big shoehorn ...

bob

 

Now I like the sound of that

 

None of the US STi models yet have twin scroll.

Interestingly my 2.5 swap completely got rid of all hints of surge, but it only makes 1 bar at 2500 and won't do 450 BHP.

Combination of twin scroll with rotated Garrett (with ported shroud compressor housing), with a proper Garrett exhaust housing could be nice? I thought David Taylor's setup is along these lines and seems to spool up nicely and make adequate power.

 

Thats what I thought John, I want to keep this plug and play (remap of course) so no garrett exhaust hsg stuff allowed. This is about keeping as many std bits on the car as possible. Its "easy" to do the full garrett bit and get the power as we have seen.

The turbo has to compliment the std engine and allow 400-450 bhp to be achieved, thats the objective.

bob

 

Are the standard injectors and FPR going to be able to cope with that level of power?

Nathan..

 

As for the modification of the std. VF36/37 turbo, you can fit a bigger compressor wheel which converts this turbo in something like a PE1825. I doubt if you can achieve your power goals though. You will need something bigger.......

For my project I want to have quite some torque from as low as possible, 360 - 380 HP is more than enough to have a lot of fun in a 1200 kg car! For me that is.... I am not after quick 1/4 mile times or high topspeed, I want to have fun drifting and driving fast on the racetrack. (that is why it gets probably the 6 gear gearbox with electronic center diff or at least a "normal" JDM 6 gear with a decent plated rear diff )

Mark.

 

Mark, yes indeed thats why its got to be thought about, Nathan, injectors ceratinly not, fpr ... probably not either and a pump and reg upgrade will be needed.

Talking about pumps, anyone else had a Walbro pump play up on them ? The one in my STi5 seems to be having trouble delivering the goods when low fuel levels exist, probably dur to heat, its been in the car about two years and has done some work.

bob

 

I'm having a problem around 4-5k rpm mark when carrying less than 1/2 a tank and sprinting. I have a feeling it may be the Walbro pump pickup. The pump is about 2 years old. I wonder how hard it would be to set up a swirl pot and a 2nd pump on the bulkhead.

Mark

 

Bob,

It could be the pick up. I´ve seen Walbro kits where the pickup is a bit higher in the tank compared to standard. I don´t think the standard pickup from the pre 2000 cars will fit the Walbro. From MY00 there is a smaller pump fitted as standard and you can easily swap the pickup. (what I always do with these newer cars)

P.S. I have a swirl pot with 2nd pump (from Powerstation) fitted in my own car (with standard pump in the tank), works like a dream and it´s not difficult to set up! (it´s a bit expensive though.....) I can drive on the track until the fuel tank is completely empty without any lack of fuel pressure.

Mark.

 

Mark

Could you take a picture of the swirl pot with the various the inlet & outlets marked. This way I could have one made up.
For pre 2000 how do you extend the pickup ?

Mark A

 

I run with a Walbro on the original filter sack - no problems (on a classic). Same cannot be said when I originally fitted it with the supplied sock.....

I now refit the OE sock to all Walbro pump changes, and no probs so far.

During my intermittent (poorly mapped!) intermittent det. investigations, I actually swapped out a pretty noisy Walbro (original one that had suffered starvation from fitting it with the supplied sock) in an attemot to fix/rule out. New pump was quieter, but no change in symptoms.

Richard

 

I don't think this will work on the pre MY00 models with the "big" standard pump. On the newer models this is what I do aswell!

Mark.

 

The problem is clearly a knackered pump, its nothing to do with pickup etc, I will want to avoid extra pumps and so on, if the walbro is installed using the factory filter then there is no pickup problem, the supplied item is too small and doen't get to the bottom of the tank. When it is plauying up I get lower fuel pressure (I have gauge fitted) for a while then it gradually creeps back to normal.

I was curious as to any other known incidences, I have been running it at 3.4 bar hot idle vac connected so making it work hard, that means just over 5 bar on full boost, probably asking too much, since my injector duty was stupidly low (75%) I've dropped the pressure back to standard for the next pump.

Mark it does fit, you need to be "ingenious" but its not a big issue to sort.

bob

 

Mark
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