AJAX 50

Could someone explain why which gear is used when measuring RWHP is so important.

NineMeister

Thanks Geoff. At some point soon I will try to do another acceleration run in favourable conditions like you suggest. We think that the car is capable of just doing a sub 12 second 1/4 mile given a decent launch and grip in 1st gear, so I suppose that there is only one way to find out.

In answer to the rest of the above, I have already stated that I cannot afford to retest the engine on an engine dyno just for the sake of someone else's doubts. However what I will do in the very near future is to arrange a dyno shootout between similar normally aspirated Porsches including a GT3RS, that way all atmospheric/humidity/temperature errors will be negated. Thus, irrespective of the overall (in)accuracy of the dyno, we will have a meaningful set of comparable results which even Jean could not debate.

Hopefully then I can get on with what I do best.

MPB993

Colin,

in my opinion. Most of us who know you trust what your saying. Its probably just an academic exercise.

Mark.

Jean

Colin

It is your money, your engine and your time. Like you said earlier you have nothing to prove to anyone and much less to me and my doubts. I hope at least that my pushy and annoying debate made you think a little about what I was saying, after all I assume that you are after performance and not numbers, and you are the most interested person to find out how your engine compares to others.

Since it seems like I am the only one on this board left debating, just as Christer, I don't have anything else to say, all the best and good luck.

Thanks for sharing. Jean

akolodesh

personally, I think this has been an excellent discourse in the true spirit of Rennlist and it has definitely gotten me thinking more about engine mods.

NineMeister

Jean,
Let's have a proper end to this debate. Since you obviously do not believe the results of my Bosch dyno (or any chassis dyno for that matter), first of all do you actually believe that it is possible to build a 993/964 aircooled 3.8 normally aspirated engine that produces over 410bhp?

If the answer to this is yes, let's say that a conceptual engine built to your specification is fitted in a 1220kg (without driver) 993RS clubsport with standard gearing & tyre size. What do you think would be the exact acceleration performance achieved from 0-130mph (in 10mph increments) and time / terminal speed for 1/4 mile? (Be specific over conditions as appropriate).

NineMeister

Jean,
I could not sleep on this one, so I did some fishing through the original post on acceration times. Strangely enough it appears that you have either mis-read the figures or distorted them to suit your needs.

Toby posted the correct 964T figures in a reply to you:

Jean
Am I right in saying the 964T reffered to is the Turbo S lightweight. Paul Frere's book says it weighs 1290kg full of fuel and give sthe following acceleration numbers:
0-100kph 4.7s
0-160kph 9.2s
0-200kph 14.2s
381PS @6000rpm and 490NM @4800rpm

You could argue that the Turbo S test was done on an empty fuel tank (92 litres ~ 68kg) and therefore weighed in at approximately 1230kg, thus having 3.22kg/hp & 2.51kg/Nm.

After checking my data I recalled that my car was weighed by a Porsche Club official at 1252kg, but since then I have replaced the doors with carbon and left off the interior door trim, saving at most 30kg. Thus my car has 2.97kg/hp and 2.78kg/Nm.

Given the superior kg/Nm advantage of the Turbo S (i.e. more area under the power curve) and making a small allowance for the corner negotiated on the acceleration run of my RSCS, it would be fair to assume that the 100-200kmph times of 9.5 and 9.8 respectively are actually much closer in every respect than you have made out.

I'll leave it at that and look forward to knowing how fast that you think my car should run.

Jean

Colin


I don't care what numbers you are getting. I tried to have an intelligent debate by posting numbers etc.. and all I got was a bunch of defensive arguments and excuses and turning it into an integrity debate rather.

Of all people you should know that the turbo S was a 3.3 Ltr and not a 3.6 Ltr car. The car which acceleration figures were quoted was a 3.6 turbo, NOT turbo "S" and NOT a 3.3. The 3.6 Turbo Flachbau was a 3.6 with 381hp and weighing 1480Kgs or so, that is why I assumed that it had 380BHP as it is a "factory" 0.93Bar. I know it straight from the source. Can you sleep better now?

What about the GT3RS acceleration numbers. or 993TT, you only picked on the one you thought you could get away with?

Now you come and say that afterall your car weighs more than what you said. The RS Clubsport car weighs less than 1200 Kgs. If yours weighs more, then that's fine, I did not post the weight, it was you who did.

You are still mentioning the famous 0.6G corner when I am giving you comparisons up to 100 mph to allow for that!?. You mentioned slippage, I gave you numbers that do not include slippage, do you expect me to keep posting numbers until you find one that matched yours? Come on Colin, this is ridiculous.

I read that you are a good racer, I have respect for good racers and Porschefiles, you made a wrong step here by trying to discredit my person, I hope you realize it. If you do not want to be debated, don't post your numbers.

Christer

One last thing from me on this one (no really). It was always going to end in tears. Whichever definition of debate you guys use, you are still questioning *each others* know-how/integrity...albeit under the farcical use of the word 'debate'. Why is anyone surprised? I think it is a bit late for either to start with the 'you owe me an apology' etc.....this was always going to happen......surely *anyone* could see that?

Colin, perhaps you want to post new numbers when you have them - or perhaps you don't? I think 'debating' the old numbers with the amount of confusion over weights, model numbers and all the rest of it is useless. UNLESS YOU HAVE ACTUALLY DYNOED ALL THE OTHER INDIVIDUAL CARS WHOSE FIGURES ARE BEING TOUTED THEN SURELY ITS F***ING POINTLESS?

Anyway, I for one would like to see more data when you have it but then that can happen offline in any case.

All the best to everyone!

NineMeister

Jean,
So, it seems at least we agree on one thing: it really hurts when people question your integrity.

I can honestly say that at no time whatsoever have I ever doubted your integrity or well meaning, your knowledge on everything 911 turbo related is astonishing and obviously well founded, so perhaps unexpectedly I am sorry that I had to resort to the above in order for you to feel similar pain as myself. That I resorted to spinning data in order to make a point is not something that I am proud of, however I could not accept being told that I have the performance of a 320bhp engine since I have driven enough 300/400/500bhp atmo/turbo 911s to know the difference from the seat of my pants.

From what you say I am truly delighted to know that others have achieved the same or more power than I have. My only question is where the **** are they? Let's get them to post their results on here so that we can compare notes and continue a discussion (not debate) on how to get even more power from these un-assisted engines.

Unfortunately I have to correct you on the weight of a 993RS CS, from my measurements of my car when I bought it and from factory sources the actual weight of a 993RS Clubsport is 1270kg, which is the same as a standard RS lightweight due to the rollcage offseting the weight of the removed trim. I did wrongly post my car at the 1250kg with driver rather than 1350kg (I weigh around 100kg) so apologies again if this radically threw out your calculations.

As a final thought, if the proposal is to accept that vehicle acceleration and not engine power is the true measure of performance, should we not also apply the same correction factors to road acceleration measurements as we deem necessary to apply to dyno acceleration pulls? In the real world I realise that this is never going to happen, which is also why I personally would rather accept the comparative data from my dyno since accelerating the drive train and a pair of fixed inertia rollers in controlled conditions is repeatable and unaffected by fuel load, wind speed or tyre slip, unlike driving a car down a straight road.

I will post further results as I take them as promised. In the meantime lets see if anyone can substanciate the other 400bhp+ engines out there.

Rassel

I dont really feel like getting too involved in this discussion, but I posted a link previous in this thread about a +400hp engine. I really don't get what all the fuzz is about.

Many engines from Porsche can be tuned to high performance engine. +400hp isn't really something to get too excited about (it's complicated but not rocket science). What concerns me here is that the discussion is missing some serious points.

1.) How long will the engine last?
2.) Is it a race engine or a street engine?
3.) How does the dyno look like?
4.) On what fuel are we talking about?
5.) Is it with mufflers and cats?
6.) What engine block are we building this engine from?
7.) Can everything be modified as long as it's N/A?
8.) Under what economy is this supposed to be done?
9.) When talking about knowledge, is everything supposed to be done by one person or can, for example, the mapping be done by someone else?

There are plenty of things to point out here, but in general:
Is 400hp from a N/A M64 engine something special?
Yes, for most people. For good engine builders, no it's not.

Rassel

The 993 RS had an official weight, but in reality they had some weight differences from the factory.

Jean

Colin

I will be happy for you if you get those numbers out of your engine. I questioned the methodology and the numbers, not intentions. It is part of the past now.

Rassel posted earlier a link with a car having quite an amazing output hp/Ltr. Micke Svens (the owner) is one knowledgeable builder and no BS person. There are some others I can assure you, but you will never see a known racing house or Porsche Motorsport have such numbers as they need to provide engines for enduro races too, but please do me a favour and don't ask me for the data

As a quick reference, and as I mentioned earlier, Geoffrey seems to get such an output from N/A engines, I think you both discuss technical stuff and share dyno results.
Finally, I would like to say that this is a hobby for me, in no way do I pretend to know more than any tuner, or even a mildly knowledgeable tech person, I have been proven wrong several times, and I actually thank them for it as it is part of my learning process.

No hard feelings I hope, I am cool.

akolodesh

Hmmm... good questions!!

NineMeister