JDMac's Autocross

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Analyzing run videos is one of the best ways to get faster. I think part of the issue is the open differential. That will make it harder to put the power down in the sweepers. Also, what rear gears do you have in the car?

The issue the V6 faces is that it's hard to keep the car in the power and hard to dig out of slow elements. That's where rear gears, an aluminum driveshaft and an aluminum flywheel provide big benefits. Without them, it can be hard to keep the revs up. The solution is to feed throttle in early, but that can lead to losing grip with an open differential. It's a delicate balance. But finding that balance will improve your autocross skills. The other solution is to put in a Traction-Lok differential.

Do you think you could've replaced the braking at 0:32-0:34 with a partial lift? It's always hard to judge a course from a video, so I could be wrong. When I drive my V6 I have to remind myself to eliminate braking more than in my GT. Braking, then having to accelerate back up to speed really hurts in a V6. I tend to lift a little and let my 3.55 rear gears slow me down, shifting weight forward ahead of my turn. That allows me to get right back in the gas after the turn.

The shimmy could've been the rear end getting some traction back. It's hard to tell.
 
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JDMac34

JDMac34

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Analyzing run videos is one of the best ways to get faster. I think part of the issue is the open differential. That will make it harder to put the power down in the sweepers. Also, what rear gears do you have in the car?

The issue the V6 faces is that it's hard to keep the car in the power and hard to dig out of slow elements. That's where rear gears, an aluminum driveshaft and an aluminum flywheel provide big benefits. Without them, it can be hard to keep the revs up. The solution is to feed throttle in early, but that can lead to losing grip with an open differential. It's a delicate balance. But finding that balance will improve your autocross skills. The other solution is to put in a Traction-Lok differential.

Do you think you could've replaced the braking at 0:32-0:34 with a partial lift? It's always hard to judge a course from a video, so I could be wrong. When I drive my V6 I have to remind myself to eliminate braking more than in my GT. Braking, then having to accelerate back up to speed really hurts in a V6. I tend to lift a little and let my 3.55 rear gears slow me down, shifting weight forward ahead of my turn. That allows me to get right back in the gas after the turn.

The shimmy could've been the rear end getting some traction back. It's hard to tell.

I have the factory 7.5" axle with 3.27 gears that the car came with. I've been debating on either adding a limited-slip carrier to my existing 7.5" axle or getting an 8.8" axle out of a wrecked GT with limited-slip from the factory. After doing a little math, I think that somewhere between 3.55 and 3.73 would be the ideal gear ratio for my clubs if I were to regear.

The section before that had some serious exit speed leading up to a sharp turn. I would have had to let off the throttle very early in order to lose enough speed and don't think it would have been faster.

As always, thanks for your input!
 
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I hope that the input is helping. And I appreciate you sharing your videos. The car looks great out on course!

Because the V6 doesn't have a lot of low-end torque, rear gears are an important upgrade. The decision between 3.55 and 3.73 rear gears should be made on a case-by-case basis depending on the length/speeds of your local courses. 3.55 is generally a safe choice, given the factory redline for the V6.

I recently looked into having a 7.5" rear end rebuilt with a new limited-slip diff and rear gears, and it ended up being about the same cost as finding an 8.8" rear end and having the diff rebuilt and 3.55 rear gears installed. If you check out MPS Auto Salvage in GA, they usually have 99-04 rear ends listed on Ebay. You can get them at LKQ for less, but I rarely see V8 Mustangs at my local LKQs. The 8.8" rear end can take more power (not really an issue with our V6 cars) and it allows you to use quad-shocks (which I prefer to use on SRA cars).
 

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