lightweight ruf conversion
 

i've posted som current and planned weight reduction mods on my 2001 996tt; please comment on the numbers if i'm off. using the dyno charts from member sean's black ruf 550 conversion i've added a table of weight to power ratios after my own ruf conversion is complete. i'm amazed at the results relative to e.g. the fia cup rsr (i know, i know, this is "different" nat. aspirated power, dedicated track car, but still...). it actually matches a couple of my mc's.

also, alot has been stated about the tt's awd versus the gt-2's rwd. i'm tracking more and more, and - having driven a gt-2 a couple of times - at the limits the rwd is clearly preferable, to me mostly due the turn-in handling. my question is whether dropping the tt's front link will mess with the tt's psm or abs systems. i anxiously await cjv's results on eliminating the psm entirely, but in the interim would like to be able to ride rwd if possible. i know that the brakes are controlled independantly but that would not change by eliminating power to the front wheels. is the tt's psm different from the (now available on 2004 models) gt-2 psm in that it anticipates power to the front wheels?

i'm prepared to go to a gt-2 if needed but if can stick with my baby then why not? please no comments on gt-2's superior suspension as i have plans for that area beyond what is rational.

i apologize for the formatting; i have no idea what i'm doing (maybe someone can make the comparo legible)

mods:

2001 tt weight: 3,350.0

removed:
spare wheel/tire -25.0
compressor -4.0
tools -3.0
jack -2.0
rear seats -30.0
rear belts -3.0
rear wiper/motor -5.0
console delete kit -2.0
insulation/carpet -60.0
mats -1.0

replaced:
seats (gt-3) -45.0
battery (odyssey) -30.0
y-pipe -10.0
clutch assist delete -8.0
doors (now cf) -100.0
rear window (lexan) -10.0
fenders (cf) -15.0
exhaust -20.0
rear wing (gt-2 carbon) -30.0
wheels (now bbs) -40.0
hood (cf) -25.0
brakes (x) 0.0
front bumper (gt-2) 0.0
roll bar 20.0
suspension (ohlins) 0.0

ruf 550 package:
turbos (modded k24's) 0.0
intercoolers (gt-2) 0.0
exhaust (now ruf) -5.0
intake (ruf hoses) -10.0
clutch/flywheel -30.0
gear changes 0.0
ecu 0.0

removed -493.0

new weight 2,857.0

comparison:

car turbo gt-3 gt-2 gt-3 rsr mine
lbs 3,395 3,042 3,175 2,425 2,857
bhp 414 381 462 445 590
lbs/bhp 8.20 7.98 6.87 5.45 4.84
tq 413 284 457 298 590
lbs/tq 8.22 10.71 6.95 8.14 4.84

c-ya,

sean

Interesting - have you done any of these mods yet or is it all currently theoretical?

Did Ruf quote the weight change on pipes/exhaust/flywheel etc?

Guy

guy,

i've done everything but the doors, windows, fenders, and y-pipe. i still have an h&r susp. kit on the car pending a full sorting of the ohlins kit and the ruf conversion in november. gt-2 wing and bumber are not mounted yet as i want the "turbo r" logo on the back before i pose in wolf's clothing...

i'm currently running an upsolute chip with a ruf exhaust which dynoes at 443 to wheels according to other members' tests.

numbers are estimates; i have not received quotes. i believe ruf uses the sachs racing clutch/flywheel. i may go with s-car-go's carbon intake instead.

nice car by the way. do you have track experience with awd porsches as well? any thoughts on the psm issue?

Light is right. i would also like to do all the lightness i can.
Do you have the CC brakes?

If you disonnect the front power shaft you'll get lighter
and get all the rear-wheel drive feel. I don't think PSM is
an issue. You can turn off PSM so you can get as sideways
as you want.
Joe

One of the guys (Chase) at Perfect Power worked for RUF for two years... he said the Turbo conversion to RWD was one of the most common mods they did. Nothing complicated about it.

I love RWD. But the Turbo's AWD system is such that you can't really tell it's AWD until you get really bent out of shape. It's a pretty invisible (non-intrusive) system.... not the type that easily upsets balance of car.

Stephen
'01 Turbo Ti Upsolute
455rwhp, 505rwt1 - Dynojet

Joe,

Thanks for the input. I'm undecided on the ceramics as there seem to be issues. I thought I'd wait and see...

The only problem with the psm is that it re-engages as you apply the brakes. I'm awaiting cjv and others results on eliminating it all together.

Stephen,

Thanks for the RUF info. Clearly I can remove the awd permanently and save the weight; If I decide to make the car track only I'll go that route. The thing is, as you correctly point out, the awd system is pretty unobtrusive, which is why I want to keep it. I'm simply inquiring about dropping the front link on the most intense track weekends, maybe just a few times a year. As I said in my original post it is only at the limits that the awd IS obtrusive, most notably on turn-in. I'm glad to hear that RUF does a lot of this, I can't imagine they mess with the psm so that is good news. I have a contact at RUF in ze fazerland so I'll give him a call.

What about the rear cooling fan, can the 911tt live without it? a couple of extra pounds off I guess...

Best,

Sean