NineMeister

That's the point, I have literally hundreds of test resultss from the same Bosch Dyno for every car we have ever tuned and each car has been tested in top gear for the reason stated above.

A Mk1 GT3 tested on the same day as the GT3 RS made 370bhp, retested with an expensive cone air filter conversion it made 360bhp. A typical perfect standard 993RS with a remap makes 315bhp with 275-280 at the tyre. A standard 964RS makes 270bhp, with Motec conversion same car hits 320+ with nearly 300 at the tyre. Christers 964 3.8 made 356bhp with around 315-320 at the tyre. Typical K27/headers/cams/1.0bar 930's make 400bhp. My car with modified Porsche heads made 392bhp with 342 at the tyre. With the billet heads & revised pistons it made 412-415bhp with 350-357 at the tyre. Whatever way I look at the above I am comparing onions with onions, since they were all tested on the same dyno under the same conditions.

I am not trying to big the results up, the number obtained is exactly as measured (I posted a photo of the dyno screen before it was moderated), I am happy with the comparative gains that the engine has made. Given the level of expenditure so far, you will understand that I have no desire to spend any more of my time and money proving the result further, after all as you said, I have already given more info up than less transparent tuners have released in a lifetime.

Red rooster

I think Jean has raised a valid point re accelation but in Colins defence his numbers were aquired in what sounds like less than ideal conditions and aerodynamic effects have been ignored or assumed.
I think that the bottom line is that an engine dyno , where temps etc can be controlled , is the definitive measurement.
Chassis dynos are OK for improvement assesment , eg. Timing up by 2 degrees -bhp up by + 5bhp,but less reliable for definate power figures.

I have calibrated motors on both and the engine dyno gets my vote every time.

Geoff

Christer

I am only interested in rwhp personally.

johnfm

I missed the original post. But my (limited) knowledge of Colin is that he lets the engineering speak for itself. He engineers real improvements and, if necessary, goes back to the drawing board, designs components and has them fabricated (the UK being the home of most GP teams, there is a pretty decent, high end fabrication infrastructure).

If he posts 350 HP at the tyre, he's probably right - after all, he's not just drilling hole sin the air box and inserting a pre-programmed chip. THere's 'real' engineeering going on...

..oh, no affiliation etc etc

Jean

Somehow it was managed to turn this thread into a question on Colin's integrity or trust, so I have to give it another shot.

I am not debating Colin's integrity or know-how. I am not in a position to do so, and would not be pretentious enough to do it.

If a tuner or member posts numbers for informational purposes and backs them up with acceleration figures, he should expect a debate. I analyzed the numbers posted by Colin on acceleration, I did not make them up, and came back with an opinion based on those, to each his own in believing or not, it will not really change anyone's life. Slippage is not a factor when you are comparing 100-200KPH runs. I know about aerodynamics and rolling resistance, I have worse in my car.

My calculations can be wrong, it really does not matter, we can talk about it as we did, can't we?

For Christer what matters is the RWHP number shown, for me it is how that RWHP is achieved, how is it measured (6th.-5th?) and how fast does it move my car, two different points of view, that are not exclusive, fair!

I hope no one describes this as the "skeptical" people (to use a good word) on Rennlist like I have read in a few other forums, just because we debate tuner numbers. It is methodolgy that is being argued, not integrity.

To Colin ( I am going to say it once more!) my respects and encouragement and thanks.

Oh... and just as Christer and John, I have no affiliation either, nor with any other tuner!.

Geoffrey

Jean,

With respect to dyno results, you should see the same numbers regardless of what gear you do the test in. As Colin mentioned, the higher gears are used to help avoid heavily strapping the car on the dyno, and/or avoiding wheelspin.

It seems not to matter which form you post dyno results, they are always questioned (aka 993tt).

Colin, what exactly was the issue with a Rennlist Member posting development results on one of the forums? I thought that was the purpose of being a Rennlist member, or is that the difference between a member and a sponsor?

Jean

Geoffrey

Do you mean the results converted to flywheel hp do not make a difference whether they are measured in one gear or another if no conversion factors were applied? Can you please enlighten me?

Numbers are questioned when they lend themselves to be questioned, it is not a hobby. High numbers are almost always questioned, yes you are right, sometimes thay can be backed up others not, when they can, they are duly accepted. Acceleration numbers don't show it, that's all. If they do in a second run, all for the best.

As far as what was the story with posting results and members vs. sponsors, there is no story. Results and dynos can be freely posted. When a thread is interpreted as self promotion by the moderators (read the top of the main page), they are deleted, out of respect to paying sponsors. If you were a paying sponsor, would you object? Maybe you can ask friends, suppliers and customers of yours who are paying sponsors here what they think.

NineMeister

Jean,
The dyno test was done at 1022hPa (Pd), intake temperature 22C (Tc), relative humidity was around 50-60% and the head temp for reference was between 120-140C. The formula for correction factor to DIN standards (without rh correction) is:

cf = 1.180[ (1013/Pd) * (Tc+273/293)^0.5 ] - 0.18

which, to save you the maths, works out at 0.9934

This means that the actual corrected rwhp measured on the day is 354.7, the corrected/calculated flywheel hp is 412.1bhp. The dyno is a Bosch FLA203, so it would surely be reasonable in assuming that the manufacturer of every ECU ever fitted to a Porsche had enough technical ability to make a piece of test equipment that was reasonably accurate.

Regarding acceleration figures, as the car got to 90mph I began to negotiate a 0.6g bend which would affect tyre drag significantly. I thus recommend that you use the sub 100mph speeds as reasonably true guide to the cars performance, provided that you allow for a particularly poor 64ft time (0.4seconds off my best) due to the damp track.

Geoffrey,
I have no problem with the moderators/sponsors, however if one of them would care to reply to my request I would happily re-post the dyno result photographed from the dyno display.

As for 6th gear testing, the other factor affecting performance is of course drive train inertia. Such is the low inertia of the Bosch dyno that testing in lower gears is extremely difficult and wheelspin is a big issue, so I always test in top gear to make the job easier and make the engine work harder on a pull.

Red rooster

Colin,
Sorry but is your Bosch FLA an Inertia chassis dyno or Absorbtion with electric retarders?
Geoff

NineMeister

The Bosch FLA203 uses both modes for testing.

For fixed rpm use you can drive the car aganst the electric retarder and measure the rwhp. I use this mode for low to mid rpm mapping, adjusting the fuel & ignition at various throttle positions at fixed rpm.

The inertia mode is used to measure flywheel hp, whereby you accelerate the car through the rev range against the inertia of the rollers and then measure coastdown losses. The problem with this mode as indicated above is that the rollers are fairly low inertia, therefore I have to use top gear to iincrease the time of the run.

At some time in the future I will be updating the control hardware of the dyno so that I can run both modes simultaneously, e.g. inertia +10%, but until I can afford this the standard package will have to suffice.

Christer

Jean

I have also heard about how dyno pulls should be done in a particular gear, but I can tell you that last year when I had the initial dyno session for fuel mapping (after the engine was built) I actually asked if we could do a pull in 4th rather than 5th as Colin was doing. From memory, the rwhp difference was a couple of HP.....maybe 3 at most, and I don't remember whethher it was up or down. I have heard other people question which gear the dyno runs were carried out in, but from what I personally saw it made no real difference at all......so I woul dlike this explained if anyone knows what they are talking about

Jean

Christer

I wish you were my customer, you're very loyal I am not a dyno expert, there have been hundreds of debates about dyno accuracy on this forum. Uncorrected dyno readings with different gear ratios will give you wrong numbers when translated to FWHP if they are not corrected. A 10% ratio difference will give you a 10% difference in conversion to flywheel.

In any case, my initial debate is that performance does not match dyno HP, what initially looks like great acceleration numbers, once you apply KG/HP and gear ratios, does not look so good anymore. I gave some examples, but since Colin had to negotiate a 0.6 G bend at 100 mph, I will post some others up to 100 mph and compare. No wheelspin, slightly different aerodynamics will impact somehwat the numbers , the 993GT2 has the same aerodynamics than a CS, so I used it here for reference.

50-100MPH test... and compared to Colin's numbers. Other than the ones mentioned yesterday, the 450 hpTT measurements were done by "Rassel" numbers are posted on the TT forum.

RUF CTR: 469BHP- 1150Kgs: 4.2 Sec. KG/HP : 2.5 (LBS/hp: 5.4)
993 GT2: 430 BHP- 1316 Kgs: 5.1 Sec. KG/HP: 3.1 (LBS/hp: 6.7)
996GT3RS: 381 BHP- 1373 Kgs: 5.8 Sec. KG/HP: 3.6 (LBS/hp: 7.9) 1 Gear change
993TT: 450 BHP- 1570 Kgs: 5.9 Sec. KG/HP: 3.5 (LBS/hp: 7.7) 2 Gear changes

993CS: 415 BHP- 1190 Kgs: 5.9 Sec. KG/HP: 2.9 (LBS/hp: 6.3) 1 Gear change

To each his conclusions. I view torque and hp a way to achieve better acceleration numbers.

Christer

You are pretty good at sneaking those little digs in, and then pretending they are not in fact 'digs'...I like that, I usually do it myself.

Just for the record, I am a customer of Colin's but I would be the first to post about anything that I was not happy with. And Colin knows this. I know you will deny it, but the insinuation you make is distasteful.

I hope you find answers to your questions, I am 'done'

Jean

Christer

No need to leave on a bad note. If it offended you I am sorry about that, that is what I felt.

I do it sometimes too with whoever does some work for me, it is no big deal.
My questions were answered long back, I was trying to provide back up to my reasoning.

I could not care less if I am wrong, seriously, but I honestly do not want you to be upset. As I said, I apologize if it was of bad taste, I meant it more like a joke.

Red rooster

Colin,
This debate seems to be revolving around the accel figures you got in non ideal conditions. Maybe it would be a good idea to repeat the excersise on a good flat surface ,moderate temp day , low wind speed, though with UK weather the last two may be difficult !
With the summs being done by others ,small measurement errors due to conditions are not doing your figures any favours.
I can understand you using other cars results as a proof of the integrity of your numbers but the problem I have is that these numbers are so good that the measurement system is crucial.
Again , The absolute method is an engine dyno where road conditions,temps etc are all dialled out.The down side is that they are expensive and setup time is massive compared to a chassis dyno.

Anyway, Good luck with the project and I will be keeping an eye open for a road 3.6 version.

Geoff