RLE

iTrader: (2)

tbh Dave I've never driven a ppp-the conversion was done before I bought the car so cant really give a true comparison.

Certainly more refined pulls hard in 3rd and 4th. Really notice it on the back roads as I never really need to change gear (4th/ 5th).

Was originally looking to up the power with TD05 20G turbo etc but ended up selling it and am going with mods to the suspension. Going to ask Powerstation about the lack in torque while I'm there tomorrow but I guess they'll recommend an exhaust swap; possible decat and remap.

cw42

iTrader: (1)

excuse me guys, am I the only one who's noticed that jacey boy here has "got used to the power of a P1 in days"
wtf! are you sterling moss or something So you can drive your P1 to the limit of it's abilities can you? and are now after yet another scooby with even more power. I sense your after more bragging rights than anything else, down the pub with your mates
Yeah, used to have a P1, but they're too slow, got me an sti with wrctech 400 conversion now

It's not what you've got, it's what you do with it that counts.

Elmer Fudpucker

I live in Southampton and only last week took mine to Falmouth,thats almost 250 miles further

RB5_245

There is two basic things to look for in turbo selection. Exh turbine side and Compressor side.

The smaller your exh side the quicker your turbo spools and you get boost at lower rpm, but higher exh backpressure. Pressure is directly related to temperature, if the exh temperature gets to high you can melt valves, create hotspots which cause detonation on destroy the turbo. On our relatively 'soft' uk engines I would suggest the engine would die before the turbo though. The VF35 has a P15 exh housing which is small compared to proven 350bhp turbo's. The VF34 with the larger P18 exh housing and the TD05 16G with similar sized exh side are both on there useful limits there on pump fuel.


The next thing to look at is compressor size, the VF35 has a compressor matched to it's exh side, ie small. Compressors work within an optimum efficiency range. For a set boost if your airflow is too low the turbo will surge (the wastegate chatter noise wrc cars make when they come off throttle), as you increase the airflow the efficiency will rise until it reaches it's sweet spot, if you keep increasing the airflow (as you need more air for more power) you pass through this sweet spot and the efficiency starts to decrease. As we're taking boost to be a constant here, a reduction in efficiency equates to an increase in temperature. As the air flow increases so does the temperature until it get's to a point when the intecooler can no longer cool it enough. Here the Air inlet temperature starts to rise, as a rule of thumb every degree rise AIT is a degree rise exh temp.

This then brings us back to the problem compounded by the small turbine, which on a VF35 running a sensible map and boost with the correct supporting mods and pump fuel is about 330bhp.

Dave

reano

iTrader: (2)

Not sure a lot of women would agree with this

aaronhowe

I'm running 390bhp on an STI8 which is used daily. Fantastically fun car to drive now.

Its the Greenwood Racing stage 3 pack

3" straight through exhaust
Unequal length tubular manifold and upipe
Apexi AVCR
APS SR40 turbo
Hyperflow topmount I/C
Sytec fuel pump
Hyperflow cold air intake
Turbosmart supersonic D/V
Ecutek remap
Exedy Hyper single plate clutch and racing flywheel

Not all the above is in the stage 3 pack but you get the idea.

Jacey Boy

Wow thats some poke!

I drive a VX220 Turbo, 250BHP 260ft/lb, its mental and would tear the P1 a new *******!

But am gona keep that for the weekends and use the scooby everyday

davedipster

Interesting, that's probably why prodrive limited the wr1 to 320hp then, cos that's within the limits of the VF35 turbo.

Thanks for the in depth knowledge.

dipster.

RB5_245

Got it in one

You're very welcome, any time.

Dave

hypoluxa

356hp on SUL seems to be within the limits of my VF35

RB5_245

I don't want to sound rude here, but that has to be down to some rather optimistic rollers unless you have some particularly advanced engine most people don't know about.

Dave

WRXewl

iTrader: (1)

S.S.S. you did warn me about coming to a meet and wanting to mod, 02 STi Type UK still in warranty (2k saved for PPP)

This thread has made me think TSL/WRC/PPP which one

aaronhowe

I have to agree. There is no way the VF35 can flow enough air for 356bhp on a decent set of impartial rollers.
330bhp to 340bhp is about the max you'll get without fiddling figures and even then i wouldn't of thought it would be a very nice power curve. One car i saw running about 340bhp on a vf35 had a massive flat spot in the mid range to cure det so they could get the peak power figure at the top of the rev range I don't see this as a real figure because the mapping has been fudged to get it.

zip929

Fuel...ive been running tesco 99 since my remap. Admittedly decatted since then.
Just put a tank of optimax in and the car is so..so.much better.
when it was rempped it was on BP.
Used that and tesco 99 and thought all was well, until the latest fuel fill up at Shell.
Sems like a new smooth boost that was never there before.

Al the hype about fuel, dont know what is good or bad.
But the last doze of Optimax was def very good!

marklemac

I like to know how much boost is being run to achieve these high power figures on the VF35.... too much I would think !

p1doc

pmsl-that is quality
martin

Nixon

My STi8 UK ran 1.7 bar on the VF35 to acheive 344.9bhp / 360ft/lb, and yes the boost was too high, car started to run like a bag of nails and ECU knock correction pushed the advanced multiplier back to 8.

Now running an Andy.F TD05/06 18g hybrid turbo with Andy.F Tek 3, running approx 370/370 and all the better for it

Has cost me £3,300.00 to date but required second map (£500.00) to put things right.... guess 370/370 could be had for £2,800.00

MikeWood

All

I've been reading this (and another) thread about what power is achievable from the UK STi engine with a standard turbo with some interest.

The results from the various modifications that people have had done seem to vary greatly in the numbers achieved. This will be for two reasons.

1. The way the car has been modified and subsequently remapped

2. The way the power and torque figures have been measured.


To explore #1 first.

The turbo has an efficiency envelope (compressor map), outside of which it will be operating in a way that's either not good for the engine or the turbo (or both) As an example, too much boost at lower rpm will lead to too large a pressure differential across the inlet turbine leading to compressor surge. This is basically where the turbo is producing so much boost and flowing more air than the engine can consume so the pressure builds up to the point that air flows back through the turbine the wrong way until the pressure differential drops and 'normal' flow can be resumed. Running a turbo in this way will eventually lead to it's failure. As an example, Group N turbos quite often run like this, that's why they fail so often but they are treated somewhat as a consumable and are 'lifed' as a result. Surge can be heard as a fluttering or squeak as boost is building and is the noise that is heard on a WRC car as they don't use a dump valve so the only way to lose the pressure is for it to go back through the turbine the wrong way. Reducing the inlet vacuum can help with this however by reducing the pressure ratio across the turbine.

Another limitation of the std turbo is that at high rpm (and hence high exhaust flow rates) the exhaust side of the turbo can't cope with the flow, the wastegate can't flow enough to bleed the pressure away and the turbo overspeeds. This leads to what is known as boost creep, although the wastegate is open the boost keeps rising, sometimes to dangerous levels (does give good power though but with no safety margin if the ECU isn't happy with what's going on). In our testing we have found that this happens when the pressure differential is too great across the turbine and this as a function of fitting an exhaust that gives very low back pressure. A well designed 3" system gives low enough back pressure and is therefore something we wouldn't fit with a std turbo. (As a small note; this is even more apparent with the 2.5 STi!)

High boost levels at high rpm will lead to overspeeding of the turbo and a huge increase in turbine outlet temps which means the onset of det is lower. The ECU then retards the ignition to stop the det but this pushes up the exhaust gas temps which increases the pressure in the exhaust pre-turbo which makes it turn faster so it heats the inlet even more. Hello boost creep!!
One sign of this will be a depressed Advance Multiplier but most owners wouldn't know this without the right software to see it.



2.
The ONLY way to accurately measure power and torque in absolute terms is with an engine dyno. With the greatest respect, any other way is a guess, albeit well informed and sometimes quite accurate. Comparing figures measured on different dyno's is fraught with potential errors.

I have seen recently on here examples of cars taken to two different rolling roads with very different figures recorded, varying by around 40bhp and 40lbft if I remember correctly. Either could be giving the correct figures but you would be much more pleased with the higher ones. This could be for a whole host of reasons, the car may have been run if a different gear, the car was tied down tighter on one dyno than the other, the dyno's themselves calculate the flywheel figures differently, the temperatures in the dyno cells were different, different fuel, different air pressure etc. We've just done something similar ourselves and found varying results across different dyno's with the same cars in the same spec. We have the ultimate confidence and respect for the dyno's we visited but the numbers generated inevitably do vary, even though the ECU is doing the same thing each time.

This may explain why one car records 360 bhp on one dyno but may well show 320 bhp on another without being changed at all.

Regards

Mike

MikeWood

Have I killed this thread?

davedipster

If I was running 350hp using the std turbo, I would go quite as well after reading these posts.

dipster.

RB5_245

Nope, you'd be on the edge

Either unsafely mapped at silly boost or on some nicely optimistic rollers

hypoluxa

Or just well tuned

Dave - Not rude at all, my engine is quite different to stock (still 2ltr tho). My point is all a turbo does is move air. The actual BHP made from that air will vary a great deal depending on many factors.

Aaron - Most of the VF35 plots I have seen are achieved with basic mods like exhaust/pump etc, then the owners tend to jump to a larger turbo for more power. Hence you don’t see many extensively modified motors running stock turbos. So to say the turbo is maxed out I think is a little short-sighted. Stick a 35R on a decatted STI and you will not get 600hp iyswim. Incidentally the car that followed me on the rollers had a turbo capable of flowing 80hp more than the vf35. Yet at the same boost it made 15hp less. Both cars STi5s.

Marklemac - Boost was 1.3bar at max power, anything more (or less) lost power.

Mike Wood - Very much agree on both points. There was a interesting thread over on the US bbs about an STi that made 700+ wheel horsepower on a Dynapack (iirc). A week or so later it ran on a Mustang dyno (same map/fuel) and only made 500 whp. I wonder which figure the owner quotes

MikeWood

I wonder if he was running the std VF39.....

Mike

edmy716

obviously dont know what ur talking about
and as for detting come on get a grip

edmy716

hit the nail on the head
also like he says depends on what other mods u have

wrct

I'm just curious how many of you guys with STi 7/8/9 cars have been down the strip at Santa Pod? If dyno figures between dynos vary so much, surely trap speed (MPH) on a known strip like Santa Pod would be comparable?

edmy716

definately im willing to post my drag strip times this summer wen i go to york/pod. but again then depends on driver so there is some dispute wether sum drivers are better than others

jay knowles

Just a small point am i correct in saying that the 06 2.5 STI runs a vf35,so what potential safe power is the ppp kit going to give.I reckon 330 max.Regards JASON

RB5_245

pmsl, that well informed reply pointed out all the flawes in my thinking and changed my view of tuning cars completely. I didn't realise the best way to get power was just to bolt on the most expensive thing there is.

That must be why all the fastest, tuned imprezas/evos in the country have chromed 19"spinners and brand names printed on everything under the bonnet.

Hypoluxia, Although I agree that it is possible I was going by the title of the thread. With full supporting mods headers/exh/frontmount and the obvious req'd a vf 34 or TD05 would make up to 350. Having said that Andy F's old Ra made up to 370-380 when running with a charge cooler.


my opinoin from the thread title. The mods claimed by 'wrc thingy people' will not provide a safe 350bhp, they will only provide an easy oportunity to waste money. 330ish would be about the safe limit for a uk sti.

edmy716

i havent got the wrc package and havent wasted money buying intercoolers and filters and big exhausts thats exactly my point and the point im trying to get across

my spec is as follows:
sti ppp
green panel filter
gt spec headers and upipe
centre decat
remap by the GOD richard bulmer
figures 357bhp/361ftlb

as for the rollers being very generous on the day there were a couple of people running big turbos(bigger than mine) big front mounts, big air filters and still did not achieve as much torque as mine and one only gave out 7bhp more!!

choose your mapper carefully and i will say it again research ur mods carefully