Jean

Tuner1

The way I look at it, reduce 10-20% (depends if engine or chassis dyno) to your torque numbers and add another 10-15% to the ratings given by Sachs (their own margin) and that will be the rating that you need. My engine dyno readings were over 600lbs.ft if I recall correctly, I must have around 550 lbs.ft in real life though, at 1.2 Bar.

If your car goes faster than 6s from 60-130mph you might have a slippage problem indeed.

Red9

Don't want to hijack but it sort of has relevence --what has happened to Jussi? He was here every 5 minutes a while ago and now ??????

TB993tt

This is the clutch I have in the 993tt and just had fitted to the 7GT2.

890NM rating is pretty high, not many engines will overcome this clutch, feels just like stock. For even higher torque a sintered disc can be used but obviously not much fun for the street.

Jean

That's a very good price! Yes this combo is the PP 883082 999764 with the modified organic plate part number 881864999973.

LAT

Jean, welcome back and good to see your experience on this board again.

Levino

Tuner1

If I can ever get my hands on a proper timing device I would love to test the 60-130mph time. Is everyone still using the AX22 or are there other options? The car ran 136mph in the 1/4 mile so I know it isn't slow

Thanks Jean and TB993tt for the clutch info. When mine gives up I will move to this combo.

LAT

For comparison sake, the Ruf CTR-2 in R&T Feb 1997 ran a 11.4 sec 133.7 mph with 520 HP at the crank. This was a RWD car.

Tuner1

Sure, but who has ever seen an independant dyno test of this CTR-2 engine? Just because the RUF spec sheet says it makes 520hp doesn't mean that it isn't closer 600hp. Did the 211mph Yellowbird really have only 469hp? Not knocking RUF, but we can't take all #s at face value.

The 136mph run in my car was a very soft launch at full weight (2wd form) with the boost set to make ~700hp (crank).

Neither the Enzo nor the CGT will crack 136mph in the 1/4, despite having great aero, massive traction and 660hp and 605hp respectively.

Anyway, I am getting way OT with all this 1/4 mile stuff! Let's get back to hearing from Rennlisters who own powerful 993TTs!

JJayB

Interesting comment. I met Steve Bedore with his CRT2 at Willow Springs several years ago and we had some spirited sessions. His car had many special modifications and was running slicks. I would say it was at least 600 hp based on my encounters with Venom 600 and 650 hp vipers. The Andial car had a slight edge as I could pull him slightly on the straights but often that may be indicative of gearing. I see the Ruf car has now changed hands belongs to a Rennlister!

I tried to run the AX22 (thanks Jean) but managed to have my results invalidated due to too much elevation change. My car has run 11.3 at 133 mph with Hoosier tires. The launch is really too brutal on the drive train for these to be meaningful. I built the car to compete with race cars with a street legal and be bullet proof and that it has.
Jimmy

LA964RS

@ 1.2 bar, mine is certainly knocking on the door w/just 16/24s. But I also run mixed gas, no mufflers and push around less than 2800 lbs.

TB993tt

Ruf didn't really want to get involved in racing the 993tt platfform, in Europe the 993tt GT2s were heavily developed and raced reliably around the 630PS/820NM mark at 1.2bar, with the Secan intercooler being the route to this performance. At these levels the engines were race houred and broke on time.
Ruf has never used the expensive intercooler technology and still doesn't so he is in an interesting postion today where he still builds reliable engines which he rates in Porsche style hp and is now limited at around 685-700hp on his latest RT12S and CTR3 - he has stated that this is as far as he can/will go.

We are not talking Jussi/Protomotive style mega boost monsters here but engines which can take autobahn thrashing day in day out and not break or need rebuilds every 10K miles (9ff builds those if you really must have 800hp in Europe).

The CTR2 Sport was rated at 580PS by Ruf and we are fortunate on RL to have LAT who actually owns/ed one and has driven it at sustained speed on the autobahn where he has witnesses the high IATs which come from these engines without the expensive high tech intercooling. LAT measured an IAT of 70DegC in 30DeEgC ambient (please correct me if I'm wrong) at speeds approaching 300kph in his 580PS CTR2. At these IATs the engine will not be producing its DIN 580PS, more like 520 or less but still enough to propell that extraordinary vehicle to its ~211mph top speed.

So create whatever myths you like about Ruf's CTR2's power outputs but in the end it was/is limited by intercooling and was never meant to be raced, it was and is an iconic ~520-580PS (depending on IAT) legend

Oh and the Yellowbird did only have 469PS, you could twist the boost up to 1.2bar and maybe 520PS but it soon heatsoaked back despite mega fuelling to keep things cool....

vincentdds

We used ATS carbonetic triple carbon.
http://www.carbonetic.net/products/twinandtriple.html

vincentdds

How have you been Jean?

Tuner1

Hi TB993tt

Great info. 70C (almost 160F) intake temps are a bit scary. Does RUF consider this acceptable and sustainable for 'Bahn blasting or was there something wrong with the car's set-up? Maybe the small turbos are out of their efficiency range at that power/boost level and contributing to the high temps?

Maybe we could set a benchmark for IATs? Run 100-150mph and check the IATs at the end of the run? It would be a near certain jail sentence to attemp an IAT reading at a steady 300km/h on this side of the pond


I have no desire to create false myths and the car's performance speaks for itself.


I will always believe that the Yellowbird, as test by R&T at Ehra-Lessien, put out more than 469hp

"Although the CTR was rated at 469bhp at 5950rpm, company head Alois Ruf would later admit that ‘we use very big horses in Pfaffenhausen’. "

TB993tt

the air cooled Motronic turbos start pulling timing at 37degC IAT but will still produce power up to 80DegC (if you search on here I posted an IAT timing/boost data printout somewhere) .

It is not efficiency of the turbos it is the intercooling which is inadequate and allows those IATs.


CTR was VERY low drag, small frontal area and decent Cd. The power was between 469 and 520PS but as top speed approached would be closer to the 469PS, this was enough for the 213mph....... I owned a CTR and the package worked brilliantly (for 1988) but the power numbers are as stated.