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View Full Version : Some ITB Audi CGT questions



TurboCGT
07-02-2006, 11:00 PM
Ok, so i finally picked up a good running 85 Audi CGT to prepare for ITB and had a couple of suspension and rule clarification questions. First off the car runs great and has coilovers with #400 front springs and #375 rear springs, a larger front sway bar and a rear sway bar along with koni adjustables. I was curious what rates I can or should run on the car without a revalve of the shocks. I drove the car last friday at thunderhill out here in california and it seemed alright but still had a a tendancy to understeer, it was possible to get the car to come around but it was challenging at times. I am also planning on picking up some camber plates, ss brake lines, and Hawk blues this week. The only other issue I had was excessive engine movement... even with new stock mounts. Having read the rule book it seems that an engine stay rod is allowed, I am not exactly sure what this means and how one might be implimented. It also doesn't seem that stiffer engine mounts are allowed. Is this correct? I am trying to get the suspension sorted on the car while I am working out here in california for the summer so I can just have the cage done over the winter and get to racing. Any help or imput on suspension setup and cost effective mods to get the car going well would be greatly appreciated. Thanks.

Jared

Tom N
07-03-2006, 06:29 PM
Jared,

Raymond or Stephen will probably give you a reply. Check out their website www.rstperformance.com they race 2 coupes very competitively on the east coast. I am planning on running one as well, just have to find one first. I had an 84 but sold it.

Tom

BobsAuto
07-04-2006, 08:06 AM
Might I also suggest that you check out their (Raymond and Stephen) website at
www.rstperformance.com

Good luck.

RSTPerformance
07-05-2006, 11:03 AM
Jared-

Hey welcome to the madness!!! You have picked out the BEST car for ITB (IMO :birra: ) Anyway, as you mentioned you must use stock motor mounts... be sure they are all good. The two side motor mounts really don't help the issues that you are talking about. THe front mount (wich is really not mounted, I am sure you know what one I am talking about). and the rear tranny mount really hold everything together. Be sure those mounts are as tight as possible, especially if the car has ever been "tweeked." Always keep a spare tranny mount with you at the track as that one probably goes through the most stress out of them all.

Coilovers good.

Spring rates, way to low try getting something in the 700 -800lb range for the front and move the 400lb's to the rear. That is a starting place anyway. We are in the process of trying new rates on our cars later this season. We are also getting ready to work with a few different companies on struts for the front. The Koni's we have just can't handle the abuse. We gat about 1 weekend out of them before they are blown with no rebound dampaning. It is mainly caused by the side load we are putting on the strut. Koni has been excellent with us and I can not say enough about them and their support. They have helped us a lot over the years and I am sure they will come up with a cost effective and efficient solution.

Camber plates are a must, as you need to get some camber into those front tires. You have about 850lb on each front corner and 425 on each rear corner. The more camber you give the car though be aware that you will run into alignment issues.

Stainless steel brake lines, not needed, but I am sure they help somehow right? LOL we have them in our cars with a brake bias to the rear wheels... didn't help much IMO

Brake pads, best option IMO is Carbotech, tell them we sent you!!!

Best advice... hummmm

Quaiffe, Quaiffe, Quaiffe... oh and camber plates!!! A quaife is about $1300 at most places for an Audi coupe (Porche 944 diff), we have found them for around $1100.

Anyway as mentioned we have a bit of experience with the cars so feel free to PM me with your number and a good time to get ahold of you. We are a bit busy this week but will try our best.

Raymond Blethen
RST Performance Racing
www.rstperformance.com (Last Updated 6/26/06)

veeman
07-05-2006, 05:07 PM
Jared... Welcome. (I recognize you from motorgeek).

Stephen has been helping me set up my ITB Coupe and I ran it for the first time this past weekend at Mid-Ohio with the new "type-Blethen" suspension. Basically, I removed the front sway bar, kept my rear bar (adapted from another Audi) and switched the spring rates. I was running 450 in the front and 350 in the rears.

Upon Stephen's suggestion, I went to 700# in the front (with no sway) and put the 450's in the rear. Along with a good alignment and some custom valved Bilstein's, it was an instant transformation. I don't have the greatest of tires (Victoracers from a few seasons ago) and I still picked up over three seconds on my fastest lap times from last year. I was impressed. I was happy to trophy for the first time and the car felt great.

The springs help the roll stiffness while the lack of swaybar helps the suspension "droop" and keep more contact with the track...at least that's my theory. The corner weights Stephen mentioned are around the same for my car and my car is still pushing a bit. I played with brake bias and tire pressures in efforts to get the back end to rotate, but that only worked a little.

I'm anxious to try a quaiffe in my transmission and get some custom camber plates fitted as well. We'll have to see how adding the plates affects the suspension that I just changed. Should be fun.

I found out this weekend that we can run 15" rims on our cars now (didn't know that), so I might be shopping to see if I can find a nice light set that are within budget. We'll have to see.

Stephen... as far as a "stay rod"... how would that benefit us? I've heard of people adding a chain / rod with joints to the front of the engine to keep it from rocking front to back. Mine has a poly mount on there now.

RSTPerformance
07-05-2006, 06:02 PM
Jared... Welcome. (I recognize you from motorgeek).

Stephen has been helping me set up my ITB Coupe and I ran it for the first time this past weekend at Mid-Ohio with the new "type-Blethen" suspension. Basically, I removed the front sway bar, kept my rear bar (adapted from another Audi) and switched the spring rates. I was running 450 in the front and 350 in the rears.

Upon Stephen's suggestion, I went to 700# in the front (with no sway) and put the 450's in the rear. Along with a good alignment and some custom valved Bilstein's, it was an instant transformation. I don't have the greatest of tires (Victoracers from a few seasons ago) and I still picked up over three seconds on my fastest lap times from last year. I was impressed. I was happy to trophy for the first time and the car felt great.

The springs help the roll stiffness while the lack of swaybar helps the suspension "droop" and keep more contact with the track...at least that's my theory. The corner weights Stephen mentioned are around the same for my car and my car is still pushing a bit. I played with brake bias and tire pressures in efforts to get the back end to rotate, but that only worked a little.

I'm anxious to try a quaiffe in my transmission and get some custom camber plates fitted as well. We'll have to see how adding the plates affects the suspension that I just changed. Should be fun.

I found out this weekend that we can run 15" rims on our cars now (didn't know that), so I might be shopping to see if I can find a nice light set that are within budget. We'll have to see.

Stephen... as far as a "stay rod"... how would that benefit us? I've heard of people adding a chain / rod with joints to the front of the engine to keep it from rocking front to back. Mine has a poly mount on there now.
[/b]


Elliot (this is elliot correct?)-

My Hours of e-mail are over... Its RAYMOND you have been talking to all this time :018: .... and I even put my name at the end of every e-mail :rolleyes: !!! LOL You even met me at Mid Ohio... My brother never went :wacko: !!! You are sooooo in the dog house :bash_1_: .

Ok now that I am done yelling at you for that I will continue to work with you in our efforts to make Audi completely dominate ITB :035:

As for the engine moving, we have not put a stayrod in our cars yet. A few years ago I did have a solid front motor mount for a while (stephen did not) however I took it out as soon as someone pointed out to me in conversation it was illigal. I checked the rules and sure enough you can add a bar but you can not replace another mount, even though one could argue the front mount is not a mount as it is not attached... hummmmm maybe we need to rethink this? :wacko: Maybe not though as I didn't notice much difference between the cars. Maybe someone else of a different mark can chime in to the advantages they feel are gained.

At any rate though I would not concentrate on that in the begining, if you are in the shop "building" something cool in your spare time I don't think it would hurt, and you could make a few nock-offs and I am sure a couple of us will buy them B) .

Anyway Stephen thanks you for the credit and I am out;

Raymond

veeman
07-05-2006, 11:01 PM
>>My Hours of e-mail are over... Its RAYMOND you have been talking to all this time .... and I even put my name at the end of every e-mail !!! [/b]

Raymond... I'm so sorry about that. I answered that post just before leaving for work and somehow your brother's name popped into my head. Not sure why... I've never talked to him or even seen him. I do indeed know who you are though, you jamoke. My bad. Simple mistake. Feel free to call me Bob or Tim or something.


I checked the rules and sure enough you can add a bar but you can not replace another mount, even though one could argue the front mount is not a mount as it is not attached...[/b]

That sounds familiar...like the rule in Solo (street prepared). I saw some rabbits that ran on a national level and basically what they had done is to make a boxed bracket around the front snubber "cup", then added a bar with heim joints from it to a specially made bracket that came off of where the original mount attached to the engine area. The original mount stayed in place, but in reality, it was along for the ride since the bar / bracket were providing the extra support.



>>hummmmm maybe we need to rethink this? Maybe not though as I didn't notice much difference between the cars. [/b]

That's a good point...in addition to that, who knows what kind of stress that would put on the front core support. I think the rabbits had some difficulties with stress / cracking in that area. As you say, that rear trans mount is pretty key in keeping everything in place. Incidentally, have you seen 034 motorsports trans mount that they have? Pretty neat. That'd be legal, right?

http://www.034motorsport.com/product_info....products_id=286 (http://www.034motorsport.com/product_info.php?cPath=25_66_67&products_id=286)

Jared... how are your bushings in that car? The previous owner equipped my car with delrin control arm / subframe bushings. They seem to be sturdier than the stock rubber units and I'd imagine that they take a bit of play out of the stock steering / road feel.

Next...about the limited slip diff. Does Peloquin make one for the 944 / Coupe GT? A few friends have them in their VW's and seem to like them a lot. I've heard other options thrown around (stock 944 LSD, phantom grip, stock diff from a V8Q Audi, etc), but I'm not sure any of those options would be quite the same as just buying a Quaiffe...


Anyway Stephen thanks you for the credit and I am out[/b]

I'll probably never live that down.

TurboCGT
07-06-2006, 01:16 AM
Thanks for all the help and info... its funny though... those rated are like completly opposite what I would have thought would work on these cars.... go figure. I was planning on stiffening the rear to get the car to rotate more. I guess ill start with moving the fronts to the rear (#400s) and running #700s in the front.... and ditch the front swaybar. Got a set of kuhmo V710s in the mail today so those should help things. Going to run 225/50/14 front and rear. Oh... and the car has delrin control arm bushings on it now but I am planning on swapping with my 4ktq when I get back east as it has spherical bearing control arm bushings and I loved how those felt on the track. I guess ill pass on the ss brake lines for now as well.... just upgrade the pads. Thanks again for all the help.

veeman
07-06-2006, 10:26 AM
its funny though... those rated are like completly opposite what I would have thought would work on these cars.... go figure. I was planning on stiffening the rear to get the car to rotate more.[/b]

I know what you mean. I talked with another racer running a coupe (quite successfully) and he had his setup somewhat opposite. He had very stiff springs in the rear (800# or so), a rear sway and then 450-500# fronts with a stock front bar. He also dialed in quite a bit of toe_OUT in the rear by shimming. I believe he was aiming for rotation as well. He was pretty quick and did well, so I guess you can say there's more than one way to skin a cat. I'd say he's counting on the sway bar to make up for his spring rate in the front.

Raymond and I talked about the rear spring rates and based on their experience, it seems as though having super heavy rear springs might cause problems on less than smooth tracks. He'll have to fill you in more. As for me, I like a bit of rotation in the sharper turns, but I'm not 100% comfortable with a lot of oversteer / on-the -edge handling when track conditions are less than ideal. Maybe I'll get used to it and dial it up later. I do know that RST's setup works...after last weekend, I'm convinced of the improvement.

This reminds me of the classic VW debate about this same subject... big rear bar, no front bar, monster spring rates etc. Tons of debate on this on the vortex. It's somewhat personal preference and trial /error. Unfortunately, unless you can do a lot of open track days, HDPE's or practice sessions, the trial and error can add up to be pretty expensive.


swapping with my 4ktq when I get back east as it has spherical bearing control arm bushings and I loved how those felt on the track.[/b]

Wow...I'd love to see pics of those... I'm assuming that's legal as well.


>>I guess ill pass on the ss brake lines for now as well.... just upgrade the pads[/b]

I'd say the stainless lines are a pretty good upgrade. I think the pedal feel increases quite a bit. I've heard though that it's a good idea to keep an eye on the stainless lines since they don't have quite the kink resistance that DOT rubber lines do. Perhaps it'd be a good item to replace every so often. I'm running some Mintex pads on mine now and I really like them... I'm bummed I have to run rear drums (per the rules change of a few years ago), but all said, the car has good brakes.

Best of luck... post some pics!

RSTPerformance
07-06-2006, 02:33 PM
As you say, that rear trans mount is pretty key in keeping everything in place. Incidentally, have you seen 034 motorsports trans mount that they have? Pretty neat. That'd be legal, right?

http://www.034motorsport.com/product_info....products_id=286 (http://www.034motorsport.com/product_info.php?cPath=25_66_67&products_id=286)
[/b]


No time to post, will do more later, but in quick, NO that isn't legal in my book...

Raymond

lateapex911
07-06-2006, 03:44 PM
Regarding setups, and this is a totally different car of course, with a cage that goes to the towers, but an Acura that wins Speedworld Challenge races runs springs in the 7500 range in the back, but only 2500-3500 up front. Of course the wheel effective rate is less, but those are some serious springs!

Point being that yes, as pointed out above, many ways to skin a cat.

gran racing
07-06-2006, 04:56 PM
I too was surprised to hear the spring rates being used. I was (maybe still will?) running 400 lbs front, 600 rear. But obviously the set-up Steven is talking about in these posts work great!

StephenB
07-11-2006, 02:27 PM
Thanks for all the credit guys :) I don't have internet so I only show up here once every 3 months or so. Anyway I am going to Increase my spring rates this fall and try some shortened springs (6INCH). I do think that the front Bar creates understeer since the entire engine is in front of the wheels. The bar is just going to dramatize the wheel spin and increase your weight on the right front tire at Turn in. In High speed turns it may be fine but not for anything tight.

I have taken the camber plates to another dimension and installed Camber/Caster plates. This is honestly a bit over my head and I haven't been as fast since I put them in :( Go Figure I spent $1,500 and went a second slower per lap... ':bash_1_:', 'smid_13'

The Rear Tranny mount doesn't brake where the rubber mount is but the alluminum part of the mount snaps off the tranny. I wouldn't make this part stronger because then the new "weak" point would be the tranny! That is much more expensive to replace than a mount! I have only broken them at NHIS (Probably from the turn 3 transition under full throttle in second on a 100+Degree turn. Never had one brake anywhere else. Like Raymond I do blow struts frequently and have become frustrated with this.

The big wins for our cars are the same as the big wins for the A2 golfs. Look at what they do and you'll be in good shape. Again there is a big win that I have never mentioned to anyone that runs an Audi but every fast golf has this... except the Canadians (Hmmm they must have some new secrets!!)

PS: you will have issues with toe as you add camber and caster so please PM raymond before you waist thousands of $$ like we have :) He can explain the hurdles that we have gone through that you definetly should know about!