Tuning a GP

[Snowie]

Updated with latest figures 15th April 2008

Yes at last I am posting my Dyno results and the tuning history of my GP.

All modifications have been done in stages with dyno results before and after each modification.

All 5 Dyno runs have been done on an independent rolling road at Surrey Rolling Road which is close to me and has a good reputation.

My aim has been to have a fast road car that looks as close to stock as possible. I was never after bragging rights on the subject of BHP achieved - I want and have driveability.

The mods and dyno runs
Run 1 is fully at stock to set the base line
Run 2 is with GTT + 3% crank, GTT Hybrid filter and GTT tensioner mod and pulleys, boost gauge.
Run 3 down to Minimotorsport center for Tony Franks to fit JCM 4-2-1 sports manifold and sports cat. This is from the JCW 225 pack.
Run 4 is back down to GTT for Stage 4 cylinder head, Shrick valves, Shrick high lift cam, AFPR, 450cc injectors, modified bypass valve.
Run 5 GTT - 15% SC pulley, shorter sticky belt and AFPR adjustments to resolve stumble on pull away - remember this is one of the first cars to have AFPR some some tweaking was envisaged.
Run 6 As above but more boost has been found in the last 3500 miles - must of been a leak
Run 7 As above but with GRS IC to see if it improved the situation (thanks Graham for the test) Car back to stock GP IC after the test
Run 8 As above with JCM German challenge rear exhaust set up - Full pipe and very free flowing and lots of sound

So what did all of these give in terms of results - full figures in the attached PDF
Run 1 202.7 BHP & 176 Torque
Run 2 208.7 BHP & 174 Torque
Run 3 211.6 BHP & 177 Torque
Run 4 227.9 BHP & 191 Torque
Run 5 236.1 BHP & 198 Torque
Run 6 251.8 BHP & 207 Torque
Run 7 251.8 BHP & 203 Torque
Run 8 260.1 BHP & 215 Torque - 218.9 at the wheels



Note

• No increase in top end RPM
• Car is running standard map

How does it go?
Absolutley fantastic.
Mid range and top end are excellent, overtaking is a blast, smiles per mile increased, Sound is brilliant - roar and pop pop pop !!!
New exhaust is TOO loud

Am I pleased YES

A big thanks to Roland & John at GTT, Tony at Minimotorsport centre and Charlie at SRR for all of their support and work

Is there more to be had & how

• Exhaust Back pressure is high at 3.4 - is this due to the flat bit on the JCW system and can the flat bit be removed needs follow up - anyone know what is an ideal BP and how to remove the flat bit at a sensible price? No I am not going Miltek or other routes.
• Remap - discussions ongoing as to if this is worthwhile, conclusion is yes, question is with what product to do a custom map and at what price? MTH seems to be the one that I favour.

When I bought the GP I was never going to do any engine mods - well I got bitten by the bug and the mystic of modding and I am really glad that I changed my mind and went ahead.

Did I get what I expected
YES and NO
I was warned by Tony Franks that the car would not dyno at BMW quoted figures of 215, when Tony worked at JCW they had prodrive develop a complete air flow system to ensure that the SC was getting suffient cooling as if the car was doing 100MPH - to my knowledeg no dyno house can do this and we will always see AIT on the dyno above real road driving figures and the consequences of this in terms of power. So the base line was lower than expected.
With the mods I have had done I was hoping for circa 250 BHP and driveability - need to decide if this is realistic and what it is that is holding the car back, exhaust is the nagging factor here.

How much have I spent - No comment to any of you or my wife !!!

Do I think I have value for money - YES but I always new I could have gone about things in a cheaper way, but then I would not have learnt as much.

Smiles & Smiles all the way

Today 15th April I am smilling even more - there were a group of Scoobies at SRR today and they were very surpised with my results.

[Paul@1320]

Excellent report Snowie I can see a long lengthy discussion coming up.

Have you done any different mods for Saturday?

[lucachiarelli]

I would try getting rid of crank pulley and just running 15% pulley and swapping jcw exhaust and getting a milltek catback with bigger intercooler.

[Fin]

How much did you spend on phonecalls to your insurance company?

[GRSmotorsport]

Alan,

How did the ambient temps compare between each run? obviously all these runs have been done on different days.........

[MINI-Morgan]

I'd agree with loosing the crank and either 15% for HP or 17% for torque.

If I know those number right you are only hitting 16PSI and I would have thought you'd be seeing 18PSI with those mods. Maybe i'm wrong though.....but id be expecting 250-260bhp with those mods.

So for me its:

1) Investigate that you are getting full boost.
2) Intercooler/monitor temps
3) Pulleys
4) Check and reduce cat back pressure
5) Check and reduce restrictions in the inlet.

Happy modding I'm sure it drives great as it is!

[Loui]

Hummmm I would have expected 250bhp at least as Roland made 273bhp with a stage 2 head didnt he from memory????

Very nice write up Snowie i wish i could be there saturday as well, but that darn pesky work. I also like the fact we can see what each group of mods have done, wish i had been a bit more methodical tbh

Grahams question about the ambient temps is very valid too i think.

Also not convinced the JCW exhaust is holding you back to much as Paul made 240- 250bhp from memory with a stock mini cooper exhaust

[Snowie]

Quote: Originally Posted by 1320autos (original)

Excellent report Snowie I can see a long lengthy discussion coming up.

Have you done any different mods for Saturday?

No additional mods done before Saturday - you will see it as it is
I had planned to have the remap done but as I am never in the UK / at home long enough at the moment then I have had to wait with further mods

Alan

[Snowie]

Quote: Originally Posted by GRSmotorsport (original)

Alan,

How did the ambient temps compare between each run? as obviously all these runs have been done on different days.........

Ambient temps varied a fair ammount

Looking back I should have bought my scan gauge earlier so I could have tracked AIT over the whole programme - hindsight is always perfect

[Snowie]

Quote: Originally Posted by Fin (original)

How much did you spend on phonecalls to your insurance company?

One phone call using the company phone

I waited to inform insurance until all was complete - I was prepared to take the risk as my insurance was due for renewal at end Sept and I new that my insurers would not really want to play ball with mods

I have changed insurers to Adrian Flux and everything is fully declared & covered on a like for like basis with a guranteed total value and not market value

[Snowie]

Quote: Originally Posted by MINI-Morgan (original)

I'd agree with loosing the crank and either 15% for HP or 17% for torque.

If I know those number right you are only hitting 16PSI and I would have thought you'd be seeing 18PSI with those mods. Maybe i'm wrong though.....but id be expecting 250-260bhp with those mods.

So for me its:

1) Investigate that you are getting full boost.
2) Intercooler/monitor temps
3) Pulleys
4) Check and reduce cat back pressure
5) Check and reduce restrictions in the inlet.

Happy modding I'm sure it drives great as it is!

Boost pressure is interesting
When Roland had the car max boost was 16 PSI
However under ceratin conditions WOT 4 to 5th (speed above the UK legal limit so verified in DE) over 18 PSI is seen and traction control is switched off - scan gauge shows code 108 overboost.

Also remember when you fit a stage 4 head with bigger valves then you can also expect to see boost pressure reduced as airflow restriction is reduced as the head breaths better - however there does not seem to be any data available on what you can expect

[gpmick]

Sounds good all this work What you up to saturday??? 236 bhp wow

[Loui]

Quote: Originally Posted by Snowie (original)

One phone call using the company phone

I waited to inform insurance until all was complete - I was prepared to take the risk as my insurance was due for renewal at end Sept and I new that my insurers would not really want to play ball with mods

I have changed insurers to Adrian Flux and everything is fully declared & covered on a like for like basis with a guranteed total value and not market value

Try A plan next year alan, adrian flux couldnt touch them for me, also gave me a darn good price mods an age considering

[Snowie]

Quote: Originally Posted by lucachiarelli (original)

I would try getting rid of crank pulley and just running 15% pulley and swapping jcw exhaust and getting a milltek catback with bigger intercooler.

Thanks for the thoughts but can you explain the logic behind the suggestions.

Why get rid of 3% crank and only run 15% SC

Miltek cat back will not work with JCM manifold and JCM sports cat

Debates on intercoolers go on and on - no one has yet convinced me that there is anything better than the GP one - again here no data is available.

Am I supposed to fund research on behalf of others - let data do some talking and then I may change my views

[Snowie]

Quote: Originally Posted by gpmick (original)

Sounds good all this work What you up to saturday??? 236 bhp wow

Hi Mick

Saturday I have a RR day set up in Surrey - check out UK confirmed events


Alan