61 replies to this topic

[VIX]

German Tuner Grand Prix?

When's that then?

[Thorney]

Chris, its a track day, not pistols at dawn Surely we all buy these cars cos they're fun to actually drive not spend all day staring at computer screens seening where can shave 0.1 seconds off a 30-50mph drag race? The idea of the track day is for people to have fun in their cars not actually race (for that you need a race licence and a fair bit more) so I suggested it as it would be FUN. Vix, the German TUner Grand Prix is the German version of the UK Car tuner grand prix (indeed it was their idea in the first place), details on the concept are here; www.tunergp.co.uk TMS are entering 3 cars into the German event (we cant enter the UK one as we run it) and as its a bit of the fun the idea is to maybe have a Speedster meeting at the same time to get together (we've been trying to sort this for years).

[earlystock]

Steve, Its usually at whitsun, normally the day before the Swiss Automobile Club have their weekend meet, if there is a day before it this year then I am up for it. I could make it a full week (track day, Tuner GP and then the weekend event......instead of LeMans?

[VIX]

Thanks Chris, End of May then.

[Joe-Turbo]

glad i started this thread now, its made some good reading

[earlystock]

I will talk to Speedy about what might be possible

Edited by earlystock, 14 November 2006 - 06:37 PM.

[chris]

But, always not curves or data for comparison between British and German phase 3 upgrades ... Only dyno plot (performed on 150 k£ dyno bench ) and statement of Thorney who said that engine equipped with Z20LEH turbocharger cannot deliver more than 277 PS ... Whose care for 8 PS (EDS said 302 PS for maximum 265-270 PS) Who believe without data or curves ?

[Spiderman]

Plan a small trip to Milton Keynes Chris and everybody will know who have the biggest . Thorney will lend you its dyno bench and you will do the same with your G-Tech ! "Problem" solved Spiderman that will make soon some acceleration tests more accurate than with the G-Tech, with its heavy CC car

[chris]

Plan a small trip to Milton Keynes Chris and everybody will know who have the biggest .
Thorney will lend you its dyno bench and you will do the same with your G-Tech !
"Problem" solved

Spiderman
that will make soon some acceleration tests more accurate than with the G-Tech, with its heavy CC car

Question is not to know who have THE BIGGEST one !

I like proven figures and data, not the superlative words ...

It is the reason why I insist to get these data ...

Dyno plot are easy to fake (I know someting with my misadventure with EDS),

But acceleration performances like those performed by professional in sport magazines seems more difficult to contest ...

Moreover maximum power is not all for a car.
Their are lot of others parameters which contribute to the performance of the cars ...

Such records regarding upgraded VXT, does'nt they exist in UK car press, in order to have reliable and fair comparison ?

[speedster]

Plan a small trip to Milton Keynes Chris and everybody will know who have the biggest .
Thorney will lend you its dyno bench and you will do the same with your G-Tech !
"Problem" solved

Spiderman
that will make soon some acceleration tests more accurate than with the G-Tech, with its heavy CC car

Question is not to know who have THE BIGGEST one !

I like proven figures and data, not the superlative words ...

It is the reason why I insist to get these data ...

Dyno plot are easy to fake (I know someting with my misadventure with EDS),

But acceleration performances like those performed by professional in sport magazines seems more difficult to contest ...

Moreover maximum power is not all for a car.
Their are lot of others parameters which contribute to the performance of the cars ...

Such records regarding upgraded VXT, does'nt they exist in UK car press, in order to have reliable and fair comparison ?

Show us a plot! I am interested in looking at your curves

[Thorney]

Acceleration tests as seen in magazines are about the least accurate test known anywhere, I've worked with lots of magazines and almost all of them apply very little technical consistency in testing. 0-60mph test specifically are simply a question of how hard you want to wreck the gear box, in gear tests depend on road surface, weather, driver etc etc. Surprised you mention mag tests as some kind of decent measure? I've no experience of the Gtech so can't really make an informed conclusion save to say that power measurements based purely on mathmatical assumption are only as accurate as that assumption, the only good thing about them is that they are consistent so as a measure for comparison there maybe an argument for them but as as absolute measure I'd still think they were a waste of time. As regards dyno faking, yes, its very easy but one of the reasons we bought a Dyno Dynamics dyno was that we can run cars in 'Shootout' mode where every function of the dyno is locked out, the operator cannot manipulate any data whatseover to change the result. If you look at the TMS site every dyno plot for all the cars is run in Shoortout mode (its written on the chart at the bottom).

[chris]

Basically, Gtech measure Acceleration of the car :



This measure is an intrinsic value, not results of calculation by Gecth with weight of your car as parameter.
By integration of this acceleration, speed increase is calculated by Gtech :



By integration of speed, covered distance is found :



Gross power at wheel could also be founded, by calculation with the value of your car weight.
I NEVER said that Gtech is a concurent to dyno bench.
I only use gross power given by Gtech, in Excel files to ponderate this Gross power (by adding of mechanic and aerodynamic losses) and analyse results of modifications performed on my car ...

But basic value of Gtech (acceleration, speed, distance) are reliable and quite accurate and give good indications of car's performances.

Thorney you said trial run performed by magazines are not accurate and according to skill of rider performance could be bad.

Bad yes, but not better like dyno plot could be, it is reason why I mention it
Because this kind of trial are difficult to fake if done seriously by reliable magazine.

I had the occasion to compare my Gtech result with measurement performed with professional apparatus and correlation was good.

So Mr Thormey if you can bought a 150k£ dyno bench you could bought 200 £ Gtech and perform trial run curves like that we could compare our results and our feeling bout this apparatus !

For your information this is dyno plot of VX performance stage 3 (I do not know the price of its dyno bench) :

Edited by chris, 15 November 2006 - 07:20 AM.

[Thorney]

What are we arguing about again? All I said was that the average magazine (doesn't matter how reputable) will always generate vague results, with regards performance. I'm not doubting the Gtech (like I said I've never used one) but by definition it is making a correlation of power based upon vehicle weight, gps position (acceleration) and distance. So it is a mathmatical calculation based on those parameters. Nothing wrong with that of course. However (to take your point on faking something) if you simply enter a different weight then you'll get a different figure. If the gps signal is poor you'll get a different figure, if the road surface is less grippy than another - you'll get a different figure, thats my point. I'm quite happy to have a go on a Gtech but you have to accept its no less (and IMO more) falable than any other testing method.

[chris]

I agree with you, there is no perfect method to quantify qualities of each upgrade, but the dyno plot does not take into account dynamic quality of the car nor motors function. To be convinced of that, you can compare performances of Exige S and stock VXT. With 6 gearbox, 20 aditionnal bhp and lighter weight Exiges S, runs performances are not noticeably better than a stock VXT ... If you consider only engine power curves of exige S, analysis could be different ... You could put more 400 bhp in a VXT engine, but I am not sur that the result was not a running coffin, if not other modifications are obtained on brakes, suspensions, tires, etc And to quantify this part of upgrading process, runs tests seems to me necessary ... PS : As said before, Car's weight is not taken into account in basic measurement of Gtech (acceleration, speed, distance). Car's weight parameter is only take into acount by Gtech for calculation of gross power (at wheel) What are you proposing : Only superlatives to qualify results ?

[speedyK]

the Bemani job is much more efficient regarding final power output and also efficiency for long runs.

The Swiss Lotus dealers are all happy to sell an Exige S, but say that the Bemani is bettere enineered. I've never seen high temps on mine, whether stuck in traffic or pounding it on a Dijon trackday (with double use, as I let a mate who's car packed in share mine). Never missed a beat to date

It seems that Bemani also has some reliability problems but less important than Lotus ones.

Would like to hear more on this – the only (non-) issue that I and other Bemani Exige owners have experienced that I have heard of (and I've met a few) is the occasional lighting up of the engine management light (it has been suggested that the Bemani sports exhaust is the culprit). Has no effect whatsoever on performance though.
--------------------------------------
Thorney/ Earlystock

Wrt Hockenheim, I'll deffo do the SAR Whit course on the Sunday/Monday (helmets obligatory now, btw). If enough people are up for joining me, I'll get SAR to organise English-language instruction again. Would be nice to see some VXs in action again



When would this "Speedster day" be? The Friday is reserved for Tuner GP training, AFAIK. If you could get the track for the Thursday, I might be tempted to join in (if you will let me play ). Would this be the GP circuit or the small circuit (quite fancy doing that again )?

[Thorney]

Keith, dont know. The Friday pm is reserved for Tuner GP competitors but not all day (wasn't last time anyway) but Thursday looks best bet. Just need a German speaker to see what Hock can offer?

[Bic]

Thorney - May I ask why your rolling road power charts show cars to be run up in 3rd gear and have excessive tyre pressures (40-50psi i think the charts illustrate) ? I was always led to beleive power runs to be more acurate when run in 4th as this is (generally) the closest ratio of 1:1 so far more accurate in giving wheel and calculating an estimated flywheel figure. 3rd gear is most definately going to infalte the figures shown is it not ? rolling roads, as you say, and i agree are of most benefit for comparative purposes of tuning & development and although day in day out there always disputes over power claims shouldnt really be used for out and out BHP promises, only a true engine dyno declares such accurate information. I must say the gtech product looks like a great peice of kit for the individual to be able to also compare their own development and improvements without having to rely on inflated or badly operated rolling road sessions, albeit we need our own private test tracks to get the most out of a gtech run, lol. also you say 270bhp is the max to be seen from a stage 3 conversion on the vxt, but i thought you claimed 285bhp from your conversions at this level ? Although i notice your 285bhp stage 3 dyno chart seems different from the others in terms of information offered and layout. Thanks Bic

[speedster]

I must say the gtech product looks like a great peice of kit for the individual to be able to also compare their own development and improvements without having to rely on inflated or badly operated rolling road sessions, albeit we need our own private test tracks to get the most out of a gtech run, lol.

I'm not sure I agree, it looks like a nice piece but its data aquisition looks limited.

IMO I think you still need some RR time to get the best of everything. I have a data aquisition set-up using Innovation kit. Over time I have managed to get a good road tune but I still feel I need to bring the car to an RR to fine tune and validate my set-up.

Edited by speedster, 15 November 2006 - 11:57 PM.

[Thorney]

We inflate the tyres to 40psi (50psi on other cars) purely to keep consistency on all the runs on all the cars and to avoid tyre deformation which occures at lower pressures, it means all the cars are tested in exactly the same way. 3rd/4th gear run are actually identical in terms of power but 3rd is more consistent. We've not done a 285bhp stage 3, which chart are you referring to?

[garyk220]

Its usually at whitsun, normally the day before the Swiss Automobile Club have their weekend meet, if there is a day before it this year then I am up for it. I could make it a full week (track day, Tuner GP and then the weekend event......instead of LeMans?

Wrt Hockenheim, I'll deffo do the SAR Whit course on the Sunday/Monday (helmets obligatory now, btw). If enough people are up for joining me, I'll get SAR to organise English-language instruction again. Would be nice to see some VXs in action again

Chris/Keith
I'd be interested in this too. Been too long since I was at Hockenheim! Might be worth starting a thread in the Events section?

Gary


And back on topic. Like Bic I've always been told RR runs should be done in 4th gear to stand a fighting chance of estimating sensible power at the wheels. Might explain why so many cars appeared to be down on estimated power at wheels at the rollong road day?