GBruce

Hi,

Have had a Gems ecu fitted and mapped on my 98 uk car with the following spec

TD05/06 20g
APS FMIC
Walbro pump
FSE Regulator (3.2 bar warm idle vac disconnected)
Denso 550 injectors
Pipercross induction kit
Bailey VTA Dumpvalve
Gruppe-s V2 Headers
SS 2" solid up pipe
SS 3-2.5" open downpipe
SS 2.5" centre
SS 2.5" Backbox

I had decided to run 1.4 bar boost and try to get 400bhp. Steve said it wouldn't last and suggested 1.2bar. I decided to go mid way and try 1.3bar.

Results........ 350 bhp and 325lbsft @1.4 peak 1.28 held
On the road it peaks higher than 1.4 and holds just over 1.3

I have some printouts which I will try to put up later, one shows power/torque and the other power/boost.

When I changed the turbo I forgot to swap the brass restrictor in the boost pipework, this was not noticed untill I was there and ready to go. A 1.1mm restrictor was fitted, the only one they had left. Is this the correct size for a 98 UK car?

Whilst mapping, Steve said the car struggled to hold boost at the top end boost duty at 100% and there was a point at around 6000 rpm like a sort of ignition cut. New plugs were recommended and installed PFR7B gapped to .5mm. The old plugs were the same but I had gapped them to .7mm. The problem was still there but improved slightly when he incresed coil charge time?

There is a slight leak in the exhaust system. Headers to up-pipe and backbox to centre, you can just hear it and when cold there is normally some watery soot around these areas. Could this be causing this much power loss?

It was suggested that I tightened the actuator and invested in a 3" exhaust system to gain more power. I would like to keep the downpipe that I have at the moment for ease of swapping centre cat at mot time. Has anyone tried HKS super dragger centre and back with SS downpipe? Is that step down in size at the end of the downpipe really that restrictive?

Could the pipercross cone filter be restricting power? Should I now change to a large universal cone with samco hose, maf is no longer used?

I would be looking to change the components and go for remap in the future

Any help/advice on what could be restricting the power would be appreciated

Thanks


George

Fangoria

iTrader: (1)

Hmm

Airfilter wont be causing any restriction for that Turbo - I went from a APS tiny one in the wing to a Large K&N - increased the fuel so yep increased the flow but no power increase!!

You reckon you have slightly leaking headers........ you'd know if they were properly leaking headers!! - if they were leaking bad on the rollers power loss is circa 20bhp (thats what I lost at PE with them on....... I went to G Force next day and got 20bhp more with them fixed and the two run similar power)

Your exhaust is restrictive but not that restrictrive - maybe 10bhp....... you do need a 3 Inch all the way through for peak power

You only ran at 1.28bar - you should have been fine at 1.4bar......... if you ran more boost you should get more power

Dont understand the 100% duty - you saying the injectors maxed at 100% on 550's on that sort of boost?!

If thats a problem you increase the pressure but should'nt be

Also what fuel were you running?

Dont forget also its very hot.......so you'll get less power

Dont know what ignition advance you were running at the top end

Do you know what sort of Lamda you were running i.e. 0.78 or 0.82-84, etc....... the lower the number the richer it is...... but it leans out a bit in the winter so it needs to be a bit richer in the summer...... I dont know what sort of Lamda your mapper put in - ask them...........

To give you some comparisons on my td05/06

1. 383bhp with Optimax and full bottle of NF
2. 415bhp with race fuel and pressurised 3d mappable WI (i.e. hardly uses any water)

These took place in January - COLD

3. 398bhp in April with race fuel
4. 323bhp with just Optimax at the end of June - running fairly rich and it was hot

I got 419bhp in January at G force with race fuel - same day that I got 415 at PS

I got 409bhp at G force in April, same day I got 398bhp at Power Station

These were all runs at 1.6-1.65Bar of Boost

The run at 323bhp was a surprise.......... just mapped on Optimax but PS seems to have no compensation for the heat/pressure diffs and they run the car up for ages on the rollers - but it gives you an indication anyway

On your boost if you were just running say Optimax I would really expect about 340bhp...............

If you were running at Well Lane I'd expect a lot more!!

Dont forget a lot of the numbers banded about are on exotic mixes of Methanol running loads of advance (it made 30bhp difference within days on my car raising the advance so much)

Fangoria

iTrader: (1)

350's pretty good at this time of year........

Which RR

GBruce

Hi Mate,

It was boost duty at 100% that's why I was thinking that the restrictor used was the wrong size. Injector duty was 75%

Just plain optimax, No additives.

Even the mapper said there was something holding it back at the top end and he thought it was restricted.

George

GBruce

Forgot to say it was at G-force

Fangoria

iTrader: (1)

Cant think what would be holding it back at the top end? - exhaust issues, maybe.......... really should'nt be the fiter at that level....... erm you could be silly and take the filter off and see!!! - not advisable for long driving stints!! - i.e. just a few miles down the road to see (there we are what a bad piece of advice - you could lose the Turbo!!)

Hmmm - what Inlet pipe are you using - that could be collapsing - again unlikely at that sort of boost/power?

The more techies on here will know......... I apparantly no nothing...........

Again 350bhp aint that far off what I'd expect at this time of year at G force

You wont get 400bhp at G Force on Optimax alone thats for sure - I only got 419bhp on race fuel in winter.......equates to about 390bhp with Optimax and full bottle of NF so about 370 with just Optimax I'd expect

So you were'nt that far out.................. with your exhaust and slightly leaking headers.......

Fangoria

iTrader: (1)

Wonder why your headers are leaking - doesnt sound right as you have V2 and that up-pipe should be fine - its a 54mm one as I remember made by H&S!!

Fangoria

iTrader: (1)

A good mapper should really be able to diagnose the probs anyway........ i.e. if it was spark plugs, you'd be able to tell when mapping, same with the restrictor sizes.............!!

GBruce

Have read somewhere on here that there are 2 different sizes of restrictor for 98 cars depending on model.

Anyone using a Fujitsubo centre and backbox, meant to be 75mm pipe and quite quiet too, would this give gains over my 2.5" centre and backbox?

john banks

Sort the leaks, 3 port solenoid and try again to get the top end boost up.

I didn't find any gain from going to 3" exhaust at this level.

Check the boy-racer VTA is not leaking your boost away.

Consider adjusting the wastegate actuator if a 3 port can't hold the boost.

Try to run bigger plug gap if you can, if you can't look for an ignition system issue.

Fangoria

iTrader: (1)

Remid me of the plugs you use - you need PFR8's - I have the part number somewhere - about £65 for 4 plugs......... I found the 7's to br useless........used to blow out at high boost, advance levels...... and misfired badly even after a few hundred miles....

The PFR8's can misfire at high loads - i.e. high advance/higher boost but this happens far less............. and was primarily a problem with race fuel with the significant extra advance that I got.............

John's comments are spot on................... but then they should be - he's an old timer in the Scoob world

Edited to say I'd have nearly as many posts these days if I could remember my password for my old log on name......................

john banks

Can you get PFR8s Steve? Would like to try some but didn't think they did them.

Just got some PFR7Q to try which have a modified insulator. They are OEM on the RS4 and RS6. For the cost of a set of 8s I think I might be as well just changing the 7s when they go off, but these 7Qs are supposed to be a solution according to NGK. Will see in several thousand miles. Some worn out 7Bs will probably be sent to NGK to test what prematurely wore out, if I get any results will post the findings.

Pavlo

you need small gaps even on new plugs, 0.6mm max for the power your search for. Then you need more boost, peak performance from that turbo is at 1.65ish bar with std headers and 1.45ish with tubular ones. Nice level for your engine is probably 1.4 with std headers though.

Hesitation is going to be misfire from plugs, better ignition overall is required, small gaps is a band aid. Make sure you have good earthing from battery to engine, engine to chassis, cylinder heads to block and engine to ECU.

You will need a 3 port solenoid to hold the boost, although SS open neck downpipe is usually problematic in this area with this turbo.

Good fuel is parramount, even if it's the best, most consistent pump fuel you can get.

Paul

TonyBurns

iTrader: (3)

So John, you dont like them either

Tony

TonyBurns

iTrader: (3)

George,

Have you done anything with the gearbox and clutch yet?
(if not start saving )

Tony

Fangoria

iTrader: (1)

John

I'll get the part no for you and send you a pm tomorrow

Initially they were very expensive - about £150 for 4......... but you can now get the racing 8's for about £65.......... on a slightly diff number............

I would not drive with 7's -especially not on engine with power over 400bhp........ on 7's I used to get misfires all the time - bit like hitting a rev limit...........as the plugs would just blow out......... do get it at times with the 8's but nowhere near as often.............. - the msd (sp?) ignition jobbie as seen on Wallis's car should sort this........

I should have circa 470-500 with the Turbo I'm currently running - but seriously considering bigger capacity and selling the 2 litre uprated bottom end

Fangoria

iTrader: (1)

Tony

Yep........... the UK G/boxes are very weak - just ask Rich Wild

I'll drop u a pm before I next come up North - I want a go in ur new spec C............... as said you can see what you think of my new Turbo........its very laggy but make sure you've been to the toilte before hand!!!

TonyBurns

iTrader: (3)

Not a problem

Tony

Fangoria

iTrader: (1)

John

Part number from spark-plugs.co.uk

Part code 5738
Description R7235-8 (racing 8's)
£65.68 for 4 delivered

john banks

Thanks Steve, it was PFR8B I was interested in, do they exist? The Racing 8s are not platinum tipped, the 7B or 7Q I am trying now are, 8B if such a thing exists would be ideal but I thought it didn't exist. Since the 7B even last several thousand and I have no issue (I don't run silly boost on the bigger engine), do the more expensive Racing 8s last longer without platinum tip?

Fangoria

iTrader: (1)

The ones I have in have been fine for the last few k miles...... including track

I dont drive the sti very many miles.......although once I have the right Turbo on I intend to!!

Only other spark plugs I used were the R7119-8's - at £145 for 4!!

Wouldnt look back as the the 7's just fouled/misfired too much (you know the symptoms........ sometimes like hitting a boost/rev cut!! after every couple of k or so........these 8's dont seem to......... (well occassionally but not ofen enough to be concerned) then again maybe it was the NF!!....... at least the 8's have a retracted tip on them.......i.e. pretty much no tip at all to fall off onto the engine!

Pavlo

NGK iridiums I have here are good (BKR8EIX or something), but blow out quite easily compared to 7119-8 racing 8s, which are platinium. The cheaper racing 8s are now iridium I beleive.

Paul

GBruce

Hi,

So recommendations are .........

Check dump valve, maybe change it for something more suitable, recirculating one, any suggestions?
3 port boost solenoid. Where can I buy this?

The car does splutter a bit at higher revs and it was suggested that it was like an ignition cut of some sort when it was on the dyno. This could be the plugs then. Would a small plug gap cause a poor idle?

Would you bother changing to 3" centre and backbox, since fitting the Gruppe-s headers the car sounds very raspy which I don't really like. Would like to change to something like HKS super dragger which is meant to be quieter and flow better. Do these work well?

Does anyone know the correct boost restrictor size for 98 uk, the one fitted in the car at the moment is supposed to be 1.1mm. The old one I have sitting here looks smaller than that. Could this be why it wouldn't hold the boost?

What are people using to fix the gasket leaks on the headers, it has 2 old gaskets in there at the moment and it's better but still leaks. Does anyone manufacture a thick gasket of some sort that has a good seal? seems like if it was softer then it would take the shape of the flanges better.

Shall I do away with the Maf sensor and just fit some hose with a cone filter on it? this must help a bit? Any suggestions on a good filter

Then a further remap for more top end boost?

Tony,
Clutch and gearbox are still standard

Steve,
Drop me a mail if you decide to sell the uprated short motor from your car

Thanks for all your help


George