Woodster

I was looking thru some old articles I had and found a copy of
an article that was in European Car I believe.
It was of Autothority's Black 96/97 993TT. It did have a huge
intercooler, different cams, etc. The damn thing ran a 10.7
or so 1/4 mile at 136mph!!! WOW that is fast!!
Claimed H.P. was 603 or so (sounds accurate to me)

I thought you guys would find this interesting,
I wonder if Craigs GT950 could kill this thing??

Marty K

Peter S 993tt

I don't know about that. What I do know is that after that run - the transmission was probably toasted. 993tts don't like 0-60 runs.

K24madness

Yes thats true 993's don't like drag racing. Ask me how I know.

Q

i just ran those numbers through my trusty 1/4 mile calculator
interesting results....

a 993TT would need 660 HP to run a 10.7 [at 127mph]
a 993TT would need 810 HP to run 136 mph [et 9.98]
[calc says a std 993TT runs 12.6 @ 108 mph]

K24madness
How do you know ?

Miles965uk

Yea please tell me more about our fragile tranny ( I have a 993TT tranny and 4WD) are you saying you can bust it after a few hard runs from standstill?

Jean

Online calculators can be all over the place. The best way is to compare the performance of several Porsche cars since you will be comparing apples to apples as far as weight bias, losses, etc..

Having done many comparisons, I found the formulas below to be quite accurate at least as far as giving an approximation. A few miles up or down, but close enough for our type of cars. Net weight of the car has to be increased by +200lbs.

MPH = 234 (hp/weight)^ 1/3

The ET is not very relevant, as it will vary greatly with the driver skills, tire spin, etc. The measure of power is rather indicated by the MPH achieved.

ET = 6.269 X(weight/hp)^ 1/3


Based on the above the 993TT stock weight is somewhere around 12.8 seconds and 112MPH in the quarter.

Miles, the 4WD shaft is not very strong, but for your optimum launch you need to drop the clutch at around 2200-2300 RPM, so there is no need to abuse it anyway.

Based on the above formulas also, you will see that a stock 996GT2 is quite close to the calculated numbers, the 996TT as well.

Trivia...Guess what the trap speed for a 900HP 3100 lb 996TT should be? 152MPH....A 140mph quartermile trap speed on a 3100lbs 996TT is equivalent to 720HP or so.

Q

this wasn't an online calculator.
I am not sure where you got that idea....???

This was a program written for me, and specifically the 1/4 mile racing i did in my 993TT [x2] and boxster S.....


I have other calculated and actual times for the car when standard, and also for the other cars.

0.111 sec and 1.2mph aren't really "all over the place" - are they ?
Paul

Jean

Paul

The "all over the place" statement that you wrote in bold was referring to online calculators as a general statement and I assumed (wrongly) that you were using one. Didn't mean to offend you.

Based on comparisons with other 993TTs, with 482FWHP your trap speed should be quite higher (around 118mph or more with that 60ft.). So the calculated HP in the model, or the dyno (in case it is a manual input) seem incorrect.
Are you on GT2 K24s?
Thanks

Miles965uk

Thanks Jean

Peter S 993tt

Yes - the danger is if you rev it and side step the clutch you will most likely corkscrew the integrated first gear/input shaft. The AWD grabs and the strain is felt by the shaft. The solution I have been told is to put in a GT2 input shaft with a seperate first gear - much stronger. If you want to tell whether yours is toast drive it in 2nd gear at about 10 to 15 mph (16-24 km/h) and put it into first. If you hear it whine - then you may have a problem (this presumes that you have a good clutch and the related clutch hydraulics).

Q

It is a big an assumption to match a 60ft to a mph expectation - too many driver variables.......
As a reference point point, what sort of mph do you see from standard 993TT's ?

Turbos were K24's, with new impellors, enlarged wastegate, etc



Cheers
Paul

chris walrod

One very important factor that doesnt seem to be considered is aero drag, or c of drag. Drag increases vs. speed as a squared law function. Very important as speed increases beyond about 60 MPH.

LT1

I ran a 12.8 111mph last summer on a hot (95+) humid day. It was my first attempt. Good launch and reaction time but I did not power shift nor side step the clutch.

Q

Decent time !
What was your 60ft time ?
Any mods to the car ?



.

Jean

Paul

I have seen 113mph on stock 993TT on this forum. I have seen 112MPH on a friend's stock 993TT with 91octane and very hot weather.

A low 60ft. will help your trap speed as you will be carrying more momentum, but not greatly.

If I recall correctly Rassel with his factory 450hp and 2 people did a 116mph. Acropora with Kevin's stage 2 (500ish) did a 120mph trap speed.
I think LT1 has a stock 993TT with Fabspeeds only (which I am not sure improve performance).

I think there is a possibility the model is not very accurate, Based on the above it seems the car is not seeing real 482FWHP on the road. If you have stock GT2 K24 compressor sizes, you will be seeing 450hp maximum.

Cheers
Jean