GT28RS with H&S results. (now with PTS results)

Good luck Tim, I'm still really impressed with that power figure. Exchange the 28RS for a 28R, and put the standard cat and rear box back on, and our cars will be very similar. Looking forward to getting it back even more now

Suba - The H&S downpipe throttles down from 3" to 2.5" at the cat, so I guess that Tim has a 2.5" cat-back system .

Phil

That would be right, thanks. Sorry, brain just died and would not remember the size It happens sometimes, a sign of too much work I rekon

315 bhp and 253 lbs/ft @ 1bar (282 bhp at wheels)

350 bhp and 292 lbs/ft @ 1bar (321 bhp at wheels)

Might want to edit the bottom one to say 1.35 bar

lol
edited now

I've just noticed that on those figures your car has 'gained' 39bhp @ wheels yet only 35 @ the fly...

Are nice curves though m8, so much be fun to drive

Is anyone else doubting the figures? The mods dont add up.
No offense to you v666.
Ross

Nope, not doubting them at all.

Some roads are more generous than others yes, but its a monster.

Tranmsission losses stated are not possible. 29bhp off 350 is about 8.3%, which is less than half the average Coupe transmission losses (average is about 18% - 20%)

Each rolling road is different, so never easy to compare.

There's not been many GT28rs rolling roaded, but at the top of my head

(0.64) housing

330 bhp
333 bhp
335 bhp
350 bhp

(0.86) housing

338 bhp
350-360 bhp

Most of the recent info has come from PTS and has proved a bit of a becnhmark for a lot of coupe owners, but all sorts of factors will change the results, such as atmospheric conditions ,oil temperature, tyre temperature and pressures etc, so even on one day doing 10 runs, you may well get 10 different figures!

I admit that the results are a bit 'high', but its not to dispute them, the only way to more easily compare would be another rolling road day....

Joe

Just personally find it weird, that people before PTS with simliar mods have figures well below the more recent ones. The thing that kinda rings alarm bells for me is the torque. For that kinda bhp i would expect higher. That kinda torque figure is usually associated with kinda 300-310 bhp.

Ross

I agree, the results could well be high. The guy who ran the car did say that they are a little higher than another RR that he knows. Both of them claim to be accurate so who knows.
I think its more important to keep to the same RR when looking to see what difference is made after changing something to get a true representation of the effect it has.

I have no objection to going to PTS as I think it would be good to get a comparison against other coops on the same RR. Its just time, as PTS are a fair drive from somerset.

One thing I can confirm, it is much quicker than standard

maybe i'll talk to PTS about a unichip, might be worth the drive then

To be honest i dont think the unichip would provide extra power from your current setup. IF the figures are true then that car must be crazy to drive!

Ross

A unichip WILL improve your car. If it's running rich then you will get at least 10bhp and improve your car's performance further. As for whether or not you will 360bhp or not well I guess only one way to find out.

Not after more power, looking to sort the overfueling at the top end.

and some RS car figures from hall of fame for comparison.

Bursa 330 bhp 284 torque
Jari 357 bhp 307 torque
Doctorfrag 335 bhp 300 torque
Dan20VT 328 bhp 308 torque

v666,

I think a unichip or somekind of decent mapping would be a sound investment. Maybe not gain more power, but certainly keep the car 'safe' and may also pay for itself in saved fuel!

You also have the right idea in always using the same RR. Its only worth using another if you wish to compare with exactly the same spec.

I think Busa has 330bhp.

oops, your right. i'll go edit the post and give him back his 30 horses

lucky , if not Busa would fall off his Busa.

hehe.
.

The figures do look odd to me. Why don't the power and torque curves cross at 5252rpm?

The peak torque figure at 1 bar is also lower than my currently standard 20vt.

Some good results there I can understand the scepticism but for the most part I think the results can be explained and ratified somewhat. There are couple of things I have noticed which doesn't make a lot of sense but I'll come on to that later First off let's take a look at your results in comparison to everyone elses

Torque Graph

BHP Graph

Well the most obvious thing is that you are running a little laggy especially given that you have the 0.64 turbine and the 3" downpipe off the turbo. This could well be due to the way you have setup your ebc. The advantage of this very progressive and slower buildup is that there are no boost spikes with the turbo just entering efficiency towards the redline therefore maximising torque from 5500rpm. This is where you'll get your nice headline figures from as it keeps a good torque band right up to 7000rpm+

I think there is scope to really fill out your torque down the bottom end. If you want to make your coupé not only go faster but also feel faster then beefing up your low down torque will do wonders If we strip away everyone else lines and leave mine and yours you'll see what I mean.

Flea Vs v666

Now for the confusing bits First off, I have to agree with Nigel. Your transmission losses are very low @ 10% and your wheel power very high!! This is technically a very good thing but it is does raise a few questions. Normally you would expect FWD to have in the region of 15-18% losses which would put your fly figure at nearer 370bhp

Secondly, you are running relatively low boost 315bhp @ 1bar is going some and 350bhp @ 1.35bar is relatively low too When I ran my car unmapped i.e. just the G-Tec II I achieved 360bhp - 315lbs/ft but this was with a 1.6bar midrange. With my current state of tune at 1.4bar I get 360bhp - 325lbs/ft so you can see how your results don't quite follow the usual 20vt trends i.e. your mods lb for lb, but they are not so extreme that they totally unrealistic

The final thing is your rev limiter. You are hitting peak power at 7300rpm You certainly win the rpm / highest peak power output for a 20vt Now I don't know which G-Tec II you have but from what I remember the rev limiter wasn't raised from the standard 6800rpm. That is not to say Graham doesn't know how to do this but when he was developing the chip he decided not to do this as most 20vt coops are hitting peak power at around 5500-6500rpm. The only chip that currently does raise the limiter is the Squadra but this actually kicks in at 7100rpm some 200rpm sooner than your peak power So it's a strange result in that you appear to be running a chip that is doing something that it shouldn't

Anyway, some of my thoughts to mull over. There may be something a little unusual about this rolling road so may be worth a chat on the phone or simply go to another to compare. Either way you have a very fast coupé there but I reckon you could get a bit more out of the old girl yet

Cosmo, they are using different scales either side of the graph for bhp and torque. If you plot them on the same scales then they do cross at 5252rpm.

The Gtec II mark one has a raised rev limit, not unlike the squadra

Fergie, very few people have the G-Tec II mk1 as that was a prototype but even so it doesn't go above 7100rpm whereas v666 is hitting 7300rpm.

Again, could be the rollers...

@ Flea
Thank you for the very informative post, it does make me think.
The ebc is the GB one saint did (hybrid) so maybe cosmograph could shed some light on that, it is very smooth though.
The boost reading was taken from the gauge, so maybe that’s out. And as to the rev limit, yes that does worry me a little ( I do not drive it that high tho). The Gtech II was ordered from graham quite early in the proceedings but I would have to ask graham about it. Looking at my first graph that ends at 7000 revs so I'll go for a drive on sat and see how far the rev counter goes in 3rd - is it accurate ?. Also, what would you suggest to bring the torque up to a better level and just how far should I push the max boost at higher revs with some regard for engine safety?

Alright, where are pts (web link would be handy)

Unit D, Kingsway Ind. Est., Kingsway,
Luton
Beds.
UK
LU1 1LP

www.pts-tuning.co.uk
info@pts-tuning.co.uk
01582 731 733


there is a map on there website with some good directions also.

v666 I think that would be a wise investment for you, for safety's sake and for comparison too

Might interest some of you to know that my rev counter reads 200rpm higher than the Apexi.

Would explain 7300 on the rev counter

My boost gauge matches the Apexi as well.

To reduce lag could think about an evo style FMIC, not sure how the Pro Alloy compares. Full 3" exhaust all the way would help to. Then think about electronic boost controller and maybe a unichip.

Thank you yellafella.

Thats about a 3 hour drive, but i'll phone them in the morning and book an appointment.

Yep, that could explain it.

Most rolling roads use a similar method of calibration, normally then run the car at 2000rpm, then they relat that to the roller speed. Then by extrapolation they can work out the revs of the engine.

This might expalin why the two power runs bhp/torque curves cross at different points, suggesting that at least one of the runs was innacurate.

I agree with Flea, I suspect from the modifications that v666 is running a car that is slightly less laggy, but also slightly less peak power. That's why my first suggestino was that the torque curve appeared like the larger housing. Another 3-500rpm less it would be more like the 0.64.

Joe

OK booked into pts.

They have booked it in for a RR tune which I think is a bit OTT.

They said that as I want the fueling checked I would need there tune session. But what do they do for that ?
If its stick a wide band up the exhaust and 2 power runs (about 1/2 hour all in) then I will reconsider, as I will not pay £300 an hour

£300 an hour?

You're getting your trousers pulled down m8!

Phone them and ask exactly what they are going to do for that money.

Tell them you simply want an hour on the rollers to check the fueling and to get some power figures.

I agree with you Fergie , I'm booked in on Tuesday for a Unichip remap and that's at their standard rate of £65 plus VAT per hour (for about 2 hours on the rollers).

Definitely phone them

I'll ring them on monday then as they said that the standard charge for a RR tune (which I would need to get the fueling) was £150, and i'll ask what they do and how long it takes.

Fueling is measured with a wide band lamda probe

Maybe they are offering to fit a fuel pressure reg and alter it that way?

Only other way to alter the fueling would be with unichip etc or Apexi AFC

v666, I've often got several runs with wide band fuelling for less than £100 there.

If its a Unichip remap then it takes a bit more times,.. right, must get my car in for her finam remap now!, at last!

Joe

Post deleted by GreyFurby

I have now spoke with AP Motors (original RR) and asked about the high revs on the graph. They said they do not go by the rev counter (as this is often incorrect) but take the reading from the engine. That would mean they either got it wrong or there is something amiss with the my rev limit .

I also rang PTS again who said that a tuning session was not required, just a couple of power runs with fueling check at the standard hourly rate . I’m booked in for next week and will put the results up.

Tim

Right, I’ve been to PTS today, 7 ½ hours driving in total, quite boring apart from an hour with a 355

Got there at 9:30 and found all the staff/owner to be very friendly and helpful. Half an hour later it was being put on the rollers where it stayed for just over an hour and had 6-8 runs (was not counting). Afterwards I spoke to Paul who was great at explaining my questions (including the dumb ones) with no hesitation.

The results

The injectors are ok at 1 bar but max out at 5200 rpm at 1.45 bar.

Its fueling is just a little lean at 1 bar, but at 1.45 bar its gets to 12.5 – so its been turned back to 1.3 bar for now.

I asked about the revs on these graphs and the AP motors ones. The answer was that the revs shown on the graph will not be accurate as they check at 0 and 3000 revs then the rest is extrapolated. The laptop could not help either as it runs off the injectors which were maxed out so did not have the information above 5200 revs. The AP motors graph must be wrong tho as 7500 is just too high. However the revs on the graph do not change the power or torque results apart from moving them along the graph.

At 1 bar

311.0 bhp
37.8 loss
268.7 lbs/ft

At 1.45 bar

346.4 bhp
32.9 loss
307.4 lbs/ft

Graphs and notes here

So next.
Adjustable Fuel pressure regulator as this may sort the fueling
Then Unichip (only if needed)
And watch the C&B cams buy for the results (hoping for good results as I want them)
And , and , and…….

All in I,m very pleased

Comments / suggestions on the above welcome.

Well there is no doubting those results, you have a very nice powerful coupe there

Thank you, and I'm enjoying every moment of driving it, even if the KYB suspension is a little hard for 7 1/2 hours in a day

Cool, nice graph as well, torque comes in nice and early

What clutch are you running with that level of torque?

Joe

Standard clutch

I dont think it will last long from the comments about clutches on this forum. It's also the original one now at 80K odd miles!

heheee, keep your fingers crossed!, depends if you drive your car like me,.. or like Flea

Joe

Had my unichip fitted yesterday at last got there a little late but my car went straight in and they started fitting immediately

Tony ( the old guy ) was very friendly and even cheerful possibly as he had Pauls wife in there with him who seemed very friendly and happy to take on board comments/views re customer service and to feed them back to the others.

Some strange figures im afraid, original run without unichip gave me 245bhp?? 30Bhp down on the figure last year ( at PTS )so I wasnt too happy Paul said that this could be down to various factors: Heat soak, incorrect tyre pressures, a wheel slip ( although he did a couple of standrad runs to make sure ). Also crankcase sensor came up on the widget appeared on the preunichip run

My car was running rich when on boost and needed timing adjusting too - so Paul got to work

After 4 hours on the rollers with several power runs totalling up almost 35miles on the rollers the final figure was 275BHP with 31bhp transmission loss torque was 250lb/ft.

Apparently all my runs were with a charge temp of 48deg alll of you will know the difference with the car when running 29deg and 48deg The fans just arent the same as when on the open road, but there is nothing you can do about that. Heatsoak/air pressure/humidity didnt help me to get the figures I was hoping for im also wondering if my boost controller settings weren't that helpfull I was running 1.3BAR with a gain of 70 and duty of 15.....was that too high/too low possibly/just right?

When I drove the car though for the first time I could feel the change on the road - seems more aggressive (different fomr others) and I was wheelspinning in 3rd despite having good tyres/tread left

I have a feeling if I got back for a cold run I will see a dramatic difference to the BHP figure - I did that last year and saw a rise of almost 25BHP over night

All in all the service was excellent at PTS, they really do know their stuff, the reception was baking hot ( so I missed out on that experience ) and they had a tv in there as well as a coffee machine and fish tank. if that doesnt keep you amused bring along a dvd to watch

Aquamist group buy anyone? ................

Kevin, it might be easier for us following the PTS results if you post in the next thread down (and remind us of your mods) ta!

Mods are: GTir hybrid, 3inch downpipe to 2.25 decat, k&N induction kit, Novitec, Evo FMIC, Blitz Sbc id 3 - thats about it on the eingine side I think. Other than usual bits; new rad, new clutch, new plugs, etc.

Forgot to mention also got uprated fuel pump.

I wouldn't get too concerned , you've probably got ky jelly in the gearbox oil and super slippery wheel bearings !

I once decided to check my figures from Pts, and went to G-force and power engineering , they all gave me the same bhp +/- 2 bhp.

The only true way is to do an engine dyno , any of the 'roller' methods are approximations.

With the old forum, there were several rolling road days, and you can never please everyone ! , doesn't matter where you go.

joe

ps Flea,

~wondering... >5000 @ 1.2bar (or more boost) with NO-INJECTOR-LIGHT????? How could i have injector light keep on prompting me when i push it >5000rpm @ 1.2bar!!!

*i only manage to boost >5000rpm @ 1.10bar with NO injector-light

*sent to diagnostics, the Injector Light message with "Over boost Strategy", it's a warning...

Could be the air mass meter reaching the measure limit.

I believe it maxes out even on standard cars running standard boost before you get to the redline.