Everything is original.I'm not changing carriers. I agree though that they are neccessary, but where does it stop? By the time you look up you have spent more than the difference in just buying a GT2. I'm going to take the TT platform as far as I can get it, then take another look. And for me the farthest it will go without changing the geometry is in AWD. Regular suspension mods wont do it.

 

Funny, I was expecting the exact same thing with mine, which would have put me in the 1:34's at BMP. You may get a second just on the straights. The track dynamics are so different, it could be a completely different story. I lost time in distinct areas, sweeping turns notably with elevation changes, and one with decreasing radius. Other wise I was the same. Which is still dissapointing.

Now if you add some coaching and gain a couple seconds we wont know how much of it was the changes and how much was the car difference. Go out for a few sessions first to get a feel and see how it feels. I'd bet money the car is better off with the front diff in and disconnected. The weight is as low as possible without being unsprung, so it has a very positive effect on the center of gravity as well.

You can run those heavy springs on Sebring because it's high speed, but that wont help with a JIC setup on tracks like Barber, the front end will bounce and push would be horrible. I had to soften mine dramtically to keep it from going straight off the track.

 

our set ups are not exactly apples to apples but I will overlay the traqmate stuff and set what turn in apex and exit speeds do.

 

Doesnt matter as long as the AWD and RWD setup are built on the same platform and suspension geometry, suspension mods, power, tires, gearing.

That will eliminate the guessing factor as to where the increase is coming from.

Other than the LSD, AWD removal, the car is essentially the same no?

 

I think a couple things need to be considered here... Dialing bunches of camber is great. What about caster? You also want to check for bumpsteer and ackerman.

Dez, you may need to have your shocks revalved to compensate for the lack of weight, and looking at spring rates as well. Youve still got the car set up for an AWD chassis, which it isn't. You should also seriosly consider the Motorsport LSD. That'll help a lot with your understeer issue.

There's a lot of work left on this, and I don't think a first impression will be your last. Buying a GT2 isn't the answer, and you're not gonna give it up. I'm pretty sure you're just beginning this experiment!
Mike

 

LSD doesnt help plant the front of the car. In fact more grip at the back will undoubtedly make the push worse, and this has been confirmed by members here who have done it. The front of the car needs to be addressed, be it DF, or suspension. I'm not willing to take 5 steps backwards to take 2 forward.

Thing is I was SOOOOO close to no power understeer in AWD, and got greedy. The only places I pushed was turn 1 and 5 @ VIR, Turn 2 @ CMP, and 3 and 17 @ Barber. Other than that, the car was a gem.


You can literally have 130 lbs difference in front ballast if you go from a full tank in AWD to a 1/4 tank in RWD. That cannot be ignored, either the ballast has to be added back, DF, or a complete suspension overhaul. Or a combination of all three. I'm not willing to put all that effort in unless I'm wheel to wheel racing.

 

I'd have assumed (I guess wrongfully so) that the LSD in the rear would help the car with rotation. Guess the weight over the rear tires is killing you up front.

Mike

 

You're gonna have some teething problems with any new setup. I run full front rebound and full rear bump damping to keep the nose out of the air. Worst case scenario you'd need to run smaller rear tires to reduce the push. Some folks prefer 4wd though and that's ok too.

 

Dez:

I guess you went to RWD because you wanted to get more out of the car than you felt it could deliver in AWD-correct? Haven't been in your car in a while, but I know there's more left in it as a AWD.

I took a ride at RATL last weekend in Al's monster and he has that car dialed in perfectly. We all know he's got extreme power, but that's only half of the story. I'm sure he's not completely satisified with it, but short of an all-out race car I can't imagine a better performing 996TT in the braking and handling departments. If your going to stick with AWD-ask Al what he did to his brakes and suspension, what he would do differently (and why) and then set up your car the same way. If you still need more you have a heck of a platform to work from in RWD.

Good luck.

Alex

PS-Al, thanks for the ride!

 

Well my logic was based mostly on weight loss. I remembered being pretty darn fast even with PSM on at RA last year and that was only with a half conversion. And in December I drove Jeremy around in my car on MPSC running 1:34.5 and as soon as he got out I ran 1:33.6 without trying and not even on a clean lap. I drove Al around, after putting on the NT01's and running mid 1:35's and as soon as he got out 1-1.5 seconds gone immediately. That was about 170-180 lbs which I'd also lost going into this weekend. And having added significantly more power by fixing the boost leaking from the DV's I had more power. My butt dyno would say that about 1/2 to 3/4 of the speed increase at Barber was power and the other 100 + lbs I had lost going into the weekend. I could really only feel the drag difference in 4th gear, which I was rarely in at Barber.

The RWD just like you see at the drag strip is faster than AWD on the top end, 4th gear and up. On the low end, the TT is so torque heavy, that the drag doesnt make much difference at all, when you get into higher speeds and hp takes over, and the amount of it required grows exponentially, just like aero drag, is when you start to see the difference.


So I had very good reasoning based on my prior experience that I thought would net me some lightning quick lap times. But the turning issue was the problem. And I already know where I would be pushing and struggling at RA too. Turn 1, the sweeper before turn 4, turn 5 maybe and 7. And it would cost me time.

 

Funny thing though is that other than turning, the car handles the exact same, with aggressive camber settings you really can make the car in AWD handle just like a RWD car. I also did it for that reason, I wanted to make sure the AWD wasnt saving me from disaster, and I got the car completely sideways into a tank slapper and managed to fix it pretty easily.

I'm going back to AWD asap, and back to barber asap, to nip this thing in the bud.

 

Tom,
Did you get a chance to test your new settings. I found this thread is very interesting.
Thanks.

 

He did, his writeup is coming with data etc.

 

Thanks!

 

will post some vids and traq mate when I can syn it but here it is in general..

RWD TT 3220 pounds LSD 50/80 lock up as full race JIC set up as possible
rear toe links, -3 front -2.7 rear camber FRONT and rear sways.

front wheels 9 inches with 265's rear 12 inches with 335's R compound

stock gear and R+P ratios.

hybrid K-24's dynoed at just over 600 hp. car driven with PSM off always.

I drove my car close to 4-5 full hours on the track at Sebring past weekend, dry conditions 95 degrees out track temp about 117.

also several Pro level drivers drove my car and rode along......vids to come..

We all agreed the car is wicked fast and handles as near a Cup car as can be.
flat smooth fast in the long sweepers, good trail braking and rotational characteristics in hair pin. stable rear planted the faster you go the better the car liked it. no mid sweeper push in high speed sweepers, crisp sharp turn in. car actually felt "nimble" and not like a heavy pig.

is the car safe and easy to drive, no. it required much more attention to throttle input or it would kick out. is this a conversion that I would recommend for street use, no. hard core skilled track driving only if you are going to push this as it will push back some.

money question is it "better"..... for me and my use I say yes. equaled my fastest lap times with this set up and was driving 8/10's all weekend. I expect more from this set up and it feels dialed in and ready to perform.

got it sideways (big time) once in traffic off line in the marbles pretty much pilot error (vid to come) otherwise kept this thing on the track all day.

I think the LSD had ALOT to do with the trackability of the car. it wasnt just an AWD with no front drive shaft, cause not sure how the car under power in a sweeper could put smooth power down, also the 80% lockup made it possible to go much deeper into corners and trail braking seemed more sure footed.

this is my experience only in the above car, I am sharing, not making any recommendations, your results may vary.

If I have left anything out other than the upcoming vids (no time to edit and post them now but by the end of the week) let me know.

I will post my sideways event as well as several hot laps with other race cars in off line race conditions............soon.........

tom