Andy.F

Your Sti 3 maf will be fine, it's much bigger. Its the 93-96 cars that have a smaller maf, it's not a problem on a TD05 or VF turbo hence so long in surfacing !
The maf/map box is on hold just now, it is so time consuming to map it that it would not be economical to supply with the ECU.

Andy

Bob Rawle

Paul I would concurr that a VF34 is not a turbo capable of 400 bhp, it should be possible to squesk 360 from it though with a bit of effort. Clearly the "somone" that has threatened you is mistaken.

bob

john banks

911, MAFs can be rescaled, substituted, housings enlarged, and flow patterns altered.
The MAF conversion worked, but we both preferred the response and consistency of a MAF to simulating it. It was a case of not just doing it because we could IYSWIM. Transient response is better off MAF, particularly at low speed. It is well documented that MAF response time is far quicker than the time taken for MAP to alter (not really the transducer but the air sitting in the inlet being gulped in by a throttle opening). It would be very difficult to make an emissions compliant speed density system, you end up with algorithms to look at delta TPS and enrich/enlean accordingly. Consistency was noticeable, speed density systems in common use don't know the EGT and the exhaust manifold pressure. Both of these affect the VE and make the AFR less consistent than MAF based.

911

Thanks for the replys, makes a change for me not to have to buy something else.
AlanG has kindly offered me a 63mm pipe, couldn't resist...

Great thread, the best I've read for a long time so focused on one subject, and I even nearly understand it all (maybe)

911.

Andy.F

Oooh JB...... can of worms alert

Andy.F

Er 911, a bigger inlet pipe 'may' lead to surge problems at low rpm in a tall gear. although having said that, Alan didn't have problems with his.

Andy

hypoluxa

Paul,

Is this the same company that claim Proboost will give you an extra 100lbft at 1600rpm?

Pavlo

Nissan z32 maf
Sti 3/4 maf may also be workable
Phase 2 maf also an option, using newer more robust sensor

Paul

Andy.F

I've mapped a few sti3/4 on a 20G Paul, MAF is well up to it.
Same year of UK is a different story !

Andy

Pavlo

I would love a quasi TPS/Maf system to give good low down light throttle use, plus high flow consistency of MAF. I think some stock ECUs do this now, also with MAP input on top.

New black box please john!

paul

Andy.F

We did discuss this at some length Paul and I currently have both systems on my car for monitoring purposes, the tricky part came when you decide when to read maf and when to read mapxrpm.
It's easy on a 'normal' induction system but when you get a big bore/short induction and a big ported shroud turbo anything under 2500 rpm is a bit of a mess on maf yet thats where you need the maf signal, ideally off idle and for low rpm transients.
Add high overlap cams and its a bigger mess as the measured airflow can actually drop as you open the throttle at low rpm

Andy

Pavlo

Andy,

TPS based, not MAP based

Andy.F

Should be within the realms of Andrew Carrs black box me thinks At what point would you changeover ?

Andy

AlanG

True. Don't know if it's been mentioned in this thread, but the only other issue i had with the 20G was boost creep, but that was sorted by Andy porting the exhaust housing.

AndrewC

There is an extra wire on the boxes I supplied to Andy connected to a spare ADC port on the uController specifically to allow TPS to be used aswell.

Black boxes are the easy bit, getting the code right is the hard part and Dr Banks did that.

Funnily enough I was thinking of using a MAF to modify the MAP signal on the Link to give better low load control

Andrew...

john banks

Indeed, if the mixture of signals required could be described accurately then it could be done. Using a hybrid of TPS/MAP could be nice, this is described in a paper I previously linked to. Using a MAF signal that can have wild oscillations at the low load conditions just where it is needed is obviously tricky. Perhaps this underlines how far away from a "sensible" road car these beasts are becoming?

I think if there was a smooth, emissions compliant speed density system it would be used by OEMs a lot because of the problems so many manufacturers are having with MAF reliability.

I think the OEM ECUs do use some input from TPS into load, but it is difficult to characterise. Are you not effectively doing the same with adjustable acceleration/decel enrichment on the Power FC?

Andy.F

Yes the PFC does this but perhaps we need low load steady throttle fueling from TPS, perhaps then a combination of maf spike and tps enrichment during increasing TPS, then map and TPS during decreasing TPS and finally maf only at WOT on boost.

Maybe a new thread would be appropriate ?

Andy

I'll go do that

Here >> http://bbs.scoobynet.co.uk/showthread.php?t=386172

CustomScoobyIOM

300ZX or 200 Nissan sensor I think?

Jon.

Andy.F

As mentioned above Jon this is only really an issue on 93-96 cars. One cheaper option (which I use on my car) is just put the early sensor in a larger tube and remap to suit.

Andy

CustomScoobyIOM

Got you.

I'll be quiet now

Jon.

EMS

A bit late perhaps, but I would also like to say that it is impossible to reach 400 HP with a VF34 on pump fuel without NOS!

Mark.

carlos_hiraoka

Mark, where have u been ?????

Carlos H.

EMS

I was very busy lately and it takes about a full days job to check all Subaru Forums....

Cheers,

Mark.

Pavlo

The threat of legal action has dispersed, and the matter closed.

Paul

911

That is good news Paul. These threads have to be taken in the right context; open debate with healthy argument is excellent.
The buyer will make his own mind up! (and I'll learn a lot in the process)
911

Aztec Performance Ltd

iTrader: (234)

Paul: Spill the beans then mate...

Pavlo

it's not in the interests of anyone for me to spill the beans, the matter IS closed.

Paul

P20SPD

iTrader: (1)

Having just driven Alan Bells 2.0l with his recently mapped td06 20g i can report the following.

Bit of background as a basis for comparison:
My old 2litre, with similar mods to alans previous setup, except for TD05 on his and MD304 on mine, was consistently around 340-360bhp for more than 18 months and nearly 40000 miles was quick in my UK Wagon, and was excellent to drive day in day out.

My 2.5 with GT30R turbo etc, was also quick, but never perfect.

Both variants of my car, would have detsroyed Alans previous setup of the TD05, and i had told Alan this. Having said that, it is was my gut feeling, or rather Butt feeling, using a stretch of road i have used for more than 10 years, and know it inside out, and where i can be doing what speed etc.

Right, enough of the background, on with what you want to know.

Alan initially drove, and i was the passenger. As a passenger it felt very smooth and progressive on WOT, except for Alans gear changes , in gear it again felt very smooth and progressive, and very suited to the 2.0l with the UK 6 speed gearbox. Observing the info on boost, in 4th 5th and 6th boost appeared to reaching max boost, 1.4-1.5 bar by roughly 3600 rpm. Impressed so far.

Now it was my turn for a drive , so off we go, bit of wheel spin in 2nd, and a small hint 3rd, the roads were damp, round a long corner in 5th on gentle throttle, and then WOT, instant pull from 3000rpm and pulling hard by 3500, into 6th and away it pulls, judging by Alans foot movement, it seemed i should brake, so did .

Onto the section of road i know well, so test begins, initially with in gear acceleration, it pulled well and smoothly in whichever of the top 3 gears i chose to accelerate in, from differing speeds. Very smooth, no sudden boost hit, just power throughout the rev range, right to 7000rpm (sorry Alan you should have said stop at 6900 earlier ).

Now for a couple of full WOT acceleration from 2nd gear to as far as we could go. 1st run i misjudged slightly and didnt leave enough clear road to get fully going in 6th, so that suggests its got some umph Steven, impressive.

Round the roundabout at the top and back down the road, which was now completley clear, roll off roundabout in 3rd at about 25mph and apply WOT. WIthin 1/4 mile i am well into 5th and its away, up into 6th, small hesitation, but nothing detrimental, and its pulling again. Manged to get to just a tad over 6500rpm in 6th before Alans twitching was suggesting i brake. Braked down for the roundabout ahead, and then cruised back to mine.

The test road is crudely 1.33 miles from roundabout to roundabout, 6500 with alans tyres and gearing would suggest 155ish, with the needle being just off the clock.

In summary, very impressed, very smooth for general driving, ie in gear acceleration without dropping down gears, and an absolute hoot on full WOT. Absolutley suited to the 2.0l and UK 6 speed with the supporting mods that Alan has.

In comparison to my 2 litre, its the first scoob i have driven, that is a better all rounder than my 2 litre, and definately had more power and torque.

In comparison to the 2.5, its a better package as it stands, but my 2.5 has never been settled or right. The 2.5 definately has more torque, comfortably, and probably a tad bit more bhp. At the same point we hit 6600 rpm in 6th, i have hit 6900 in 6th.

As for power, i would guess, based on my 2litre at 360ish, and 2.5 being around 400-420ish, Alans is a surefire 380 to 400bhp car now, and is excellent to drive. Low boost threshold with excellent power.

Only thing that worried me slightly, was as a passenger i could hear a slight whining/chuffing from the turbo area, but couldnt hear anything whilst driving.

I think this turbo would be superb on the 2.5, with very low boost threshold, and would be a genuine 400bhp.

If i still had my 2.0l, i would be tempted to change from the MD304 that i had.

Congrats to all involved in the setup of Alans car.

Steven

CustomScoobyIOM

Perfect cheers Steven

Jon.

911

Oh boy, hope mine will be as good!
Any thoughts of that car running a 5 speeder with the same engine?
Excellent report too, get a job at Top Gear and you can add the facts that are missing in that show!
911