Gtech Pro RR

[KayGee]

New toy arrived today, good fun so far.

see www.gtechpro.co.uk for details.

Gave it a blast earlier tried 0-60 and recorded two nearly identical 5.45 Sec times.



Got the car weight wrong (forgot about the lardy bloke in the drivers seat and used 3489lbs which seems light anyway according to AW).



Recorded 225Hp expecting this should go up later when I try again with more accurate curb weight.



Seems about right for my mods.

[KayGee]

Have uploaded pics to my gallery.

http://www.rs246.com/modules.php?op=mod ... &cat=11110

Did several runs to confirm results and to my suprise results seem very consistent (well as consistent as my driving anyway)

So here is where all the flames start.

0-60: 4.83 secs.

BHP: 256 HP, 297 Ft/lb. This is "road HP", that comes to about 325 Hp with basic correction (27%).

These figures seem to be reasonable for a stage 2 car running downpipes.

[jeffw]

Do you have wheel HP from a rolling road to compare the results with ? It would be interesting to see what your WHP is.

[KayGee]

Not put it on a dyno since putting the new chip on.

Last time I had it on the dyno(Gforce) with the Upsolute chip it recorded 234hp WHP.

Will do a another Dyno run before and after it gets K04s. Also plan on get the car weighed at the local weigh bridge to verify the weight I'm using.

I'll also do a drag strip run at Santa Pod to get the Pitch Factor dialled in which will help improve accuracy on the Gtech Pro as well.

[jeffw]

What chip are you running now ? 256 WHP seems a little high for a chip & full exhaust. A standard S4 runs (apparently) 180-190 WHP, standard RS4 runs 288 WHP......My S4 with full Milltek, K04s and AmD remap runs 280 WHP (measured at 2 different dynos).

I've given up using flywheel HP as there appears to be no point....there is no accurate way to measure the losses involved so why waste your time trying....

Have a look here
http://www.ktrperformance.com/services/ ... h_main.htm

They have a large range of WHP figures for S4s with different modifications.

[S2tuner]

Jeff, about driveline losses and so on:

I too have read what all the US/australian dyno companies say, and I too was thinking they were right about the driveline losses.... until I got to tune cars in the US last summer....

We've had bone stock C4 S4's (230 crank HP) putting out as much as 225-230 wHP on their dynos, on dyno dynamics they would put out 195-210 wHP, etc etc ... so I thought, ok, but something's wrong, those cars were totally stock, stock boost, some of them running crap fuel, and yet they put those figures out on those dynos...

I agree with Dyno Dynamics that there is no way to accurately measure crank HP, other than putting the engine on an engine dyno... HOWEVER, what I figured is that each time I've used a Bosch, Maha or Rotronics (very high-tech french dyno manufacturer) dyno, if I had a stock car on it, it always gave the stock crank power rating (provided everything was ok with the car of course). On a Bosch/Maha/Rotronics, you don't have to input the car manufacturer/model/HP/weight/gear ratios/blah blah blah from a given list, as you have to do on a Dyno Dynamics, Dynapak, Mustang, etc etc etc, you just sync the RPM with the dyno so the software knows the RPM in the selected gear for the test, run the test, let the car coast down and you have a realistic within 10HP crank HP figure.


If Dyno Dynamics were right about their "no way to measure driveline losses on a chassis dyno" thing, then how come every time I've had a stock S3/S4/RS4/whatever on a Bosch/Maha/Rotronics dyno, they always came out within 5-10HP of the manufacturer's crank HP rating? How come that I've seen a few weeks ago an MTM TT dyno 252 crank HP and 360Nm when MTM rated the chip at 254 HP/360Nm?

All these questions have so far remained unanswered by all those Dyno Dynamics/Mustang/DynaPak dyno places in the US where the operators think they are real experts and smarter than anyone else, although still helpful and smart for some of them... yet, none of them could tell me why a stock C4 S4 came out at 210 wHP on a DynoDynamics using californian 91 octane (equivalent to european 95 RON but actually worse)...

So my point about dynos is that either it gives you a figure at the crank+figure at the wheels, and in most cases they are consistent and make full sense (one exception is one Maha dyno in the UK that reads ridiculously low at the wheels on quattro models), or you just don't dyno your car if you're using an Australian dyno. It might offend people from OZ to read what I'm saying here, but it is my experience and I do seriously and honestly think that dynos from OZ are crap. No offense to OZ people but their dyno manufacturers have some very serious issues to deal with.

Just my 0.02,

Mihnea

[jeffw]

I know which Maha your talking about

I have 2 dyno runs, one from a Aussie Dyno Dynamics and another from a Maha (not the one your talking about) which read within 1.5 HP at the wheels.....The calculated result (not using run down losses) on the Dyno Dynamics is within 2 HP flywheel of the figures of the Maha your talking about

Have a look at this http://www.pumaracing.co.uk/power3.htm

[s2driver]

Many dynos are ONLY useful for shootouts and modification comparisons when developing a car. The absolute BHP figures are often misleading but can be fantastic for pub talk. On my motor I have had 80bhp peak losses at peak power in standard and remapped forms at multiple outlets that measured the power profile on coast down. With the G-Force RR they 'estimated' 40 bhp losses based on some fudge of entering various vehicle specs....not reliable IMHO.

Driveline losses are not a percentage of engine power! If you double the power, you will not get double the losses unless peak power revs changes significantly and other drastic mods are made. We had several S2s on a Maha dyno and the loss profiles through the revs were very similar for S2s from 300 to 480 crank bhp running everything from 205 to 255 rubber.

Mihnea, do the US dynos have extra fudge factor built in? Most US car manufacturers quote their power figures (DIN?) based on an engine with all ancillaries removed. Could the figures be optimistic due to the correction factors used. Doesn't altitude play a part in the correction too?

Accelerometer based performance meters only produce reliable figures if they have been calibrated on a 1/8 and 1/4 mile track. They cannot compensate for vehicle pitching so their figures for acceleration are mostly optimistic. As the car squats under power the acceleration vector cahnges as the unit is no longer level so you start introducing a proportion of gravity into the calcs. Once you have calibrated the unit for your particular cars suspension settings, your acceleration times will be quite reliable but when it comes to guessing the power you are likely to be way off. These performance meters are like inertia dynos...great for checking the comparative improvement of certain mods on a car i.e how did the power profile change when a part was changed: air filter, ported head, exhaust, remap etc

Inertia dynos are great for shootouts too as they are consistent and if you compare tractive effort at the wheel surface you can compare the cars on test on the day.

Normally aspirated cars are more consistent on RRs. Turbo cars are so dependant on the cooling system employed at the facility. If the cooling is poor you may 'lose' a lot of power due to the test conditions (and the operator action..BTDT recently!).

[KayGee]

The Gtech Pro RR has pitch correction, uses a 3 axis accelerometer.

Includes shift lights and can be used as a circuit mapper and data logger on track.

So far it seems to give very reproducible results unlike some of the earlier accelerometers I have tried.

Once the pitch factor is dialed in and fed with good weight data, it should be accurate. I think it'll be a very useful tool. It costs about the same as three dyno runs and therefore also seems good value for money.

I'm not claiming its any more accurate than any other dynometer (engine dynos being the only exception), however as a comaprison tool it's a heck of a lot more convenient than a RR.

[s2driver]

Comparison tool, it certainly is good for, if the test conditions are comparable. Sorry, missed the fact that it was the Gtech Pro: I assumed it wasn't, from the performance figures indicated.

[KayGee]

"if the test conditions are comparable"

Can't see the relevance here, this is true for every measurement device.

I assumed it wasn't, from the performance figures indicated.

Not sure which figures you have a problem with, virtually every tuner claims @320 Bhp for a chipped and full exhaust S4. 0-60 on b5 S4 is 5.4 sec, add another 60+ Hp, shed load of extra torque. I'd of thought that was worth .5 second.

[s2driver]

That comes across as an aggressive response. It wasn’t intended to arouse such responses.

I was a senior design engineer in the space industry and I understand the limitations of accelerometer, rate gyros, GPS as well as other position, attitude and rate sensors. I also understand the statistics involved and the probabilities of data reliability based on the accuracy of the sensors employed especially when multiple sensors are fed into a system to produce ‘figures’.

Many people, not suggesting you at all, do not understand the reliability of the measurements. The effect of air speed, wind direction, track temperature all affect reading reliability and you will be amazed how many do not understand it and quote figures from systems like the AP22 as if it were produced by an optical Datron system when they haven’t even been calibrated for their particular vehicle.

I am a qualified engineer with a scientific background with a lot of practical experience in measurement systems and their reliabilities…even when dealing with $multimillion hardware.

I haven’t got a ‘problem’ with any of the figures you posted. You said you were preparing to get flames, and because you haven’t, is that what you want to believe from the thread responses? In fact, 4.83 seconds is a very respectable figure…hats off to your clutch sidestepping and gear change techniques. I missed the fact that you had a ‘stage 2’ conversion, hence my surprise at the 0-60 time. My surprise was also borne from the 5.4 seconds on one day all of a sudden bcoming a consistent 4.83 seconds a day later. I s this a before and after modification measurement?

The shorter the time, the less reliable the reading is due to the sensors accuracies employed in all of these in-car dyno systems. One thing they are is relatively repeatable.

“test conditions should be comparable” is relevant here as many people do not understand the implications (you obviously do). This is not a personal response to you, it is a response to the Forum that wishes to learn and understand.

Sidenote: Don’t forget that all car manufacturers are famous for the vehicles they give to magazines for test purposes…I do not know of a single reliable source that managed to yield a 0-60 time of 4.8 seconds from an RS2, in fact I do not know of a single factory RS2 that produced a peak bhp figure of 315 as most actually left the factory with less than 300. Having seen the amount of BS that surrounds many 'reputable' tuning firms I am sceptical and synical about many (not all) of their performance claims.

[Dippy]

That comes across as an aggressive response. It wasn’t intended to arouse such responses.

Not to me it didn't - I think you may have been a bit too sensitive!

Never mind it happens to all of us sooner or later and now we know your expertise, please continue to contribute to the forum.

All this shows that no individual measurement can be relied upon, and only by multiple and diverse measurements can you get a good enough picture.

KayGee has provided valuable information about the potential performance of a stage 2 B5 S4, and reminded me why I do not have one of those gizmos: It always leads to 0-60 runs and I will never forget Joshie's experience with his stage 3 S4 on the drag track!

At least now when people ask me what 0-60 my car is capable of, after saying "8 seconds with me driving it", I can add "I know someone with a similar car who's made sub 5 second sprints".

[s2driver]

Nah. Not sensitive...life is too short.

It is impossible to convey emotions in posts unless those flippin emoticons are used (over used sometimes! )

Quote: All this shows that no individual measurement can be relied upon, and only by multiple and diverse measurements can you get a good enough picture.

Agreed.

Certain measurements cannot be taken as absolute (as is borne by ~80% of RR measurements...finger in the air figure, LOL), others can be informative as this one is.

[KayGee]

FYI, I too spent my youth and early years as an electronics engineer working with measurement systems, firstly with resistance and displacement systems, mostly for either military usage or the most prestige laboritories (e.g NPL) around the globe. Later I spent a couple years working with both engine test and injector test systems. Before I got fed up with being paid so poorly and went and worked with computers.

I also remember some outstanding claims....Skoda Octavia vRS, 0-60 6.7 secs?, later when Seat dropped the 225 engine into the same chassis they managed 6.9 secs (didn't take a genius to work out which engine was in the test car). Mclaren F1 - 0-100 in 6.3 secs? Both never reproduced by anyone else apart from that particular magazine, if I remember correctly McLaren even adopted the figures as they couldn't better them...

However if all the major tuning houses claim approx the same figures either they all jumped on the same bandwagon or they all got similar results. Hopefully the later.

As for the 0-60 times, well the other runs (5.4s) one bogged down and the other I got spectacular wheelspin (should of video'd that one!!), some much for my awesome driving skills. These can be seen on the G force (not the dyno bods) measurements quite clearly.

As for the Gforce dyno looking back at my two runs, I see a whp figure corrected to bhp by using 40 Hp on both runs. Seems their universal answer to all S4s is +40 Hp drive train losses.

Using the Puma figures to correct G-Force dyno results (212 Whp) my S4 comes to 264 Bhp in standard trim (Audi claim 265 Bhp). Using Puma figures on my Gtech Pro result (256 road Hp - Gtech suggest Aero drag + Rolling Resitance need to be added back to give Whp as per a dyno run) I get 316Bhp before RR and Aero. My Upsolute chipped run on the Gforce gives 295 Bhp (they claim 305 Bhp). I'll swap the chips around this weekend and see what Gtech Pro RR thinks of the Upsolute.

Wonder when the next Santa Pod "run what ya brung" session is? I feel a "calibration" session coming on.