Acropora

Well I have an opportunity to have some GT2 flares put on my 993tt, just not sure about taking the plunge. I guess gert has the best fitting ones, I already have a 993 clip/spoiler for the front and a GT2 tail for the rear.
I'm kind of worried about what it's going to look like after and what hacking will be necessary to make it happen.
If the car performed markedly better at the track with these changes that'd be a strong inecentive to proceed but the stock 993tt body and rear deck sure is suble and pretty.
Any recommendations either way?
Thanks!

Jean

Brad,

From an esthetics POV, each has an opinion.

From a functional point of vue, track width is directly proportional to mass transfer and cornering Gs. You increase by 1%, you get 1% better lateral G forces, all else being equal.

If you go ahead with it, make sure you go as wide as you can about wheel offsets and tires to benefit the most possible. Go too wide and then you will have wheel bearings to worry about.

If you end up doing it, Gert is certainly a great source. Think of widening the front track more than the rear (in % terms) when you order your wheels..

Red9

When you trim the guards it needs to be done with very fine cut-- then it is reversible if there is ever a reason to. The offcuts need to be stored carefully . I have done exactly that in the past and re-attached original parts and it worked out fine. Takes a lot of the pain out of the cutting part!
Can't beat the aesthetics of the GT2 look-makes the cars look all business and makes Cup cars look effeminate!!!
Re the track performance-- everything else being equal -- real improvements in corner speed is there for the taking.
You get it right to the potential of the 993 with that engine your 996 will not see which way it went!!!!!

Spartan

I've got cargraphic fenders from Gert sitting in my study as we speak so you can guess what my thoughts on the matter will be

Geoffrey

Widening the wheel does not necessarily give you a wider track. In some cases, it will narrow the track.

In the front you should remove and reinstall the front suspension in the wide body position, however, that requires a wider front sway bar that I've not found to be available any longer.

chris walrod

I thought this was a 964-only option for the front?

Geoffrey

No, 993 RSR race cars also were delivered with the suspension in the outboard mounting position. The GT2s I've worked on have been in the outboard position, but I don't know if they were delivered like that.

Jean

Geoffrey

I am not sure I follow, less offset with same tire widths will give you a wider track.

As to the suspension mounts, I have read this elsewhere on RL (in fact Chris Cervelli told me about it once) however I don't know what it refers to, maybe I have already done it on my car without knowing , do you have any pictures? I know I have as wide a track as the Le Mans GT2 EVO racers and have not changed to a special swaybar. Would be interesting to find out what's the real deal.

Geoffrey

Hi Jean,

The subframe side members can be bolted in 1 of 2 positions with the positions being about 25mm apart. You can see it easiest if you open the trunk and look where the rear subframe mounts to the tub by the power brake accumulator on the pass side and the ABS pump on the driver's side. There are 3 holes. If there are bolts in the inner and center position, then the suspension is mounted on the inside location. If the bolts are on the middle and outer position, then the suspension is mounted in the outer position. There is also a corresponding change to the upper camber plate where it is installed 180 apart between inner and outer mout position. See the picture here.

You can have the same track with the suspension in either position by changing the offsets, but the scrub radius will be different.

What I was saying about the track and wheel offsets was not really important to the conversation. Track is measured in the center of the tire, so if you have two wheelsets with the same offset, same width tire, but with a different inner wheel half size (say 12" vs 11"), then the wheel with the smallest inner wheel half will provide for the widest track.

chris walrod

To use the wide mounting option, does one use a different cross member to connect the control arm mounting castings?

Yes, this would change scrub radius, potentially change roll center as well.

Geoffrey

No, all of the suspension remains the same except for the tie rod ends and sway bar. The upper strut mount is rotated 180 degrees.

budge96

Geoff, glad I was paying attention today! Also this could be done on earlier C2
chassis as well? Right? Thanks Bert

Geoffrey

This modification dates back to the 964. I believe that the early 964s (89-90???) don't have the outboard holes, and I know the 1991 and later ones do.

LAT

What is the effective difference in front track width and is there a measurable difference in cornering performance?

Jean

Hi Geoffrey

Thanks, a picture is worth a thousand words! I will check it out this evening.
About track width, certainly it is the offset that needs to be modified, not the wheel width alone. I run 10" ET22 upfront.

LAT, track width is proportional to mass transfer and lateral grip all else being equal. It is not much difference unless you are racing in very competitive series. It has many drawbacks as well.