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Questions for SGT owners that track (race) their cars


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Looking for some feedback from SGT owners that regularly run their cars on the track or road racing courses as to what driveshaft you are running.

 

I bought our car from a friend who had a number of mods done to the car on the advice of a shop that is big into drag racing. Hence, a few mods that I would have done differently, especially for track use. One of them was the Axle Exchange 1 piece 4" aluminum driveshaft. I found a clearance issue this weekend, when I had the car out on the track for the first time since we bought it. At the end of a long high-speed straightaway, upon braking hard and downshifting prior to heading into a turn, the Shelby Hurst shift linkage caught the rubber boot on the driveshaft and ripped a hole in it. A loud bang ensued, a puff of smoke blew out the back when the grease inside the boot hit the exhaust, and I had to shut her down 1/4 of the way into my paid-for track experience.

 

Clearance above the rubber boot is too tight, and it looks like with the type of on-track use I want to get out of the car, I may have to install a different driveshaft. The front part of the driveshaft at the boot is closer to 3.5" - 3.75" dia. One of the suggestions is to go back to a 2 piece DS to gain the clearance, and eliminate the chance of the DS and tranny pivoting directly in front of the shift linkage, allowing the DS (or it's boot) to hit the shift linkage. I did get some advice to change to a particular shift linkage, but upon contacting the mfr of that linkage, I was told I wouldn't gain any additional clearance over what I already have, and that I should consider a 2 piece DS due to some of the clearance issues with 1 piece units.

 

So, advice, other DS options, or other options in general that any of you may have dealt with would be greatly appreciated.

 

Thanks in advance.

Edited by bandit67
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Not sure about the extra clearance... this is what Steeda says about their 1 piece alum drivshaft.

 

"The GT model driveshafts are a tapered 3.5" to 4 inch design giving them extra clearance needed to avoid interference that can happen on lowered cars with full 4" shafts."

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This is a new one for me. Look forward to hearing the final solution.

 

However, I wonder if the if an adjustable 3rd link on the rear would help if it's not already in use. I'm guessing here so please correctl me if I'm wrong, but if the rear pinion angle was no corrected for being lowered such as how the SGT came from Shelby, that under hard braking is what forced the driveshaft into the shifter to begin with, so dropping the rear pinion angle should, in theory improve clearance by dropping the driveshaft, albeit very little.

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One of the most important things you need to upgrade is the brakes. The stock ones will be toast after about 4 laps.

At a minimum, stainless lines, new pads, and better fluid ate a must. You can also pick up a used set of Brembo GT500 front brakes for around $400-600. If you can afford it, go for the Shelby/Baer 6 piston set up. You will find no better. Also another must on the road course is to make sure you have the traction control disabled. If you leave it on, you will waste your rear pads in about two sessions.

 

These cars really excel on the road course with only brake upgrades. You may not be able to out drag race the straights, but with some practice they are a terror in the twisties.

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The drive shaft issue was fully vetted some time ago and it was resolved that a 3.5" shaft would avoid what you reported. It is unfortunate that you had to experience what you did. Here is one thread: http://www.teamshelby.com/forums/index.php?/topic/66216-drive-shaft/page__p__1135464__hl__shaft__fromsearch__1#entry1135464. Here is another one: http://www.teamshelby.com/forums/index.php?/topic/63289-aluminum-one-piece-driveshaft/page__p__1114038__hl__shaft__fromsearch__1#entry1114038

 

Good luck.

 

Jim

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Not sure about the extra clearance... this is what Steeda says about their 1 piece alum drivshaft.

 

"The GT model driveshafts are a tapered 3.5" to 4 inch design giving them extra clearance needed to avoid interference that can happen on lowered cars with full 4" shafts."

 

 

If you can get past the skinny runt runner playing weightlifter........here's the Steeda tapered aluminum driveshaft mentioned above. I hardly put it through the paces you do, but perhaps the 1/2" will make the difference. Best of luck.

 

WeightSaverLifter.jpg

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To digress, what is the benefit of the Al shaft besides weight or is there one?

 

Also does the Al ever become "work hardened"?

 

 

 

Thanks~!

 

 

 

Wow, lots of good info to pour through.

 

The aluminum DS saves weight, and the lighter rotating mass helps to slightly increase the amount of power & torque that makes it to the wheels, also helps the wheels get rotating a little quicker. Hard to tell just how much of a benefit it is, but every little bit helps.

 

As for the Axle Exchange DS that is on my car - it too has the tapered front end similar to the Steeda DS.

 

I don't quite understand why the stock 3rd link is not replaced when Shelby does the SGT package. I was under the impression that it was required to maintain proper angles and avoid DS vibration. However, there is no vibration on my car. I do plan on installing an adjustable 3rd link, since I don't know all the variables that went into the SGT both at Shelby and with the aftermarket work that my friend had done. Unfortunately, I am not convinced that spacing the rear of the DS further will have a big enough impact on the front where it connects to the transmission. Maybe that slight adjustment out back will keep the DS boot from getting too close, but there is a bit of play with the rubber spacers on the transmission mount, so a good twist of the tranny could put the boot right back into the shift linkage again.

 

Right now, I can just get a finger between the boot and the shift linkage. I was told that is way too tight for what I'm doing with the car, which is obvious based on what happened yesterday. I'm leaning toward installing a 2-piece DS, so am going to see what kind of price I can find for an aluminum one, then just sell the Axle Exchange DS to a Mustang owner that isn't running it on the track. That axle should be fine on a high powered street car or drag car. The reason I'm afraid to keep the AE DS on my car is that AE told me there are clearance issues with the Steeda short throw shift linkage on lowered cars, and my car is very low, partly because of the 18" track wheels. With all the differences in even similar components on various cars, there could just be a more substantial clearance issue on my car than other SGT's. Not sure my car's suspension is any lower than most other SGT's, since the springs are the blue FRPP ones that Shelby put on (that is what they put on, correct?).

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I have the Leonards Racing- Spydershaft Aluminum 1-piece in both cars.

 

Several track days without issue even on 130+ mph straight aways.

 

 

 

------------------------------

Edited by FordFan1
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Does anyone know how much play in the rear tranny mount is acceptable? As in if you put a small pry bar between the rear tranny cross brace and the transmission and lifted up on the tranny?

 

I am able to lift the back of the tranny at least 1/4" without too much effort. Doesn't appear to be much to the rubber bushing that the tranny mount bolt goes through. I could see how the rear of the tranny could pull up a good 1/2" - 5/8" during a downshift event at high speeds/high engine rpm, so starting to get an idea of how the DS boot moved that close to the shift linkage.

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Finally! :happy feet:

 

I found out about another Shelby GT owner that had a similar setup to my car and ripped a hole in the rubber boot on his 1-piece DS with the Shelby Hurst short throw shifter. The guy ended up shimming the tranny mount down to gain a little more clearance and adding an adjustable 3rd link (upper control arm) to get the pinion angle back to where it should be. The word I've gotten from a couple of different sources is the Hurst linkage seems to sit just a little bit lower than some of the others out there, and causes issues on SOME cars.

 

So, with a few upgrades at the back of the suspension (adjustable 3rd link, billet lower control arms, adjustable panhard bar & panhard brace), that should take care of any issues. We're thinking the upgraded parts alone should fix the problem. Not yet sure we want to shim the tranny cross member, so we'll see where all the new parts put us.

 

I spoke with a number of different suppliers that were of little to no help whatsoever, so I really appreciate Steeda giving me all that info rather than trying to sell me a new shift linkage right off the bat. They also recommended another slight modification to my upcoming order in an effort to save me a little more money - a rare thing these days. :shades:

Edited by bandit67
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