Rank: Driver's Permit
#1 Posted : Monday, May 18, 2015 10:20:46 PM(UTC)
Hi guys!

In need of some desperate help tuning my 1970 Ford Mustang Boss 429. I'm new to tuning muscle cars and haven't much clue how to solve the rear kick problem. I have been playing with it for a few hours now and just can't get the rear end to stop kicking out. Only thing I haven't tried is increasing the rear down force, but I don't see that fixing my problem, as it's a constant problem whether you're on the throttle through a corner or not. It just wants to go sideways. I'm currently running it in C class, 422, and would like to keep it there for now. I was thinking it may have something to do with the tire compound as it is currently stock.

I'm currently sitting on 310KW and the weight is really heavy at 1,621KG. Which could also be a problem. I haven't made a whole lot of changes, apart from the air filter, exhaust, intake and throttle body, carby, oil and cooling and the flywheel when it comes to the engine. Have racing brakes, race springs, front and rear ARBs, sport chassis reinforcement and roll cage, street weight reduction. All drivetrain upgrades.. And that's about it really.

This thing is nearly uncontrollable through corners and a little uneasy at high speeds on straights. I am looking for a little advice on how I can keep this bad boy in check so I can finally have a decent muscle car to race in.

Thanks guys!
- Trouty
Rank: A-Class Racing License
#2 Posted : Tuesday, May 19, 2015 6:09:14 AM(UTC)
You can usually get by with stock tires in C class, so that should be fine. Any number of factors could be affecting the handling. Some of your settings for your tune would be a big help to see where your problems might be. From the sounds of it, you may have multiple issues. Alignment and suspension settings will both affect the areas you mentioned. Your differential settings are also important for controlling the car through the corners, both on and off the throttle. One last tip, muscle cars take some finesse with the throttle! It's not a Ferrari, it's a Mustang!!! LOL
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Rank: A-Class Racing License
#3 Posted : Tuesday, May 19, 2015 10:52:58 AM(UTC)
would need more information either about the tune so we can help you dial a bit of that out, and also if u can give a better description about what its doing when. Corner entry, mid corner, corner exit.

Sounds to me like the decel dif is too low for your driving style. try going up about 10 on the decel dif.

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Rank: Driver's Permit
#4 Posted : Tuesday, May 19, 2015 12:45:13 PM(UTC)
Thanks guys.

It enters the corner beautifully, with a bit of soft-mid braking. I will usually give a little throttle through the corner, which is when it can get a little slippery. Corner exit is when everything goes horribly, once I gas it out the corner, the bag and kicks out wide and I'm fighting to keep it from spinning out. I will try adjusting the decel' of the diff' settings and see what happens.

Haha, Mako, I probably do drive a little to aggressively for a Mustang, although, I think with a half decent tune up I could run it a lot better. :D

- Trouty
Rank: A-Class Racing License
#5 Posted : Thursday, May 21, 2015 4:31:07 AM(UTC)
misunderstood what your first wrote if you like how it is on corner entry and mid corner do not touch the dif. you could however bring the accell around. 30-40% is usually a pretty good range but can be higher or lower and work well.

Have you made any adjustments to spring, arb, dampers?

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