The Mustang Forum for Track & Racing Enthusiasts

Taking your Mustang to an open track/HPDE event for the first time? Do you race competitively? This forum is for you! Log in to remove most ads.

  • Welcome to the Ford Mustang forum built for owners of the Mustang GT350, BOSS 302, GT500, and all other S550, S197, SN95, Fox Body and older Mustangs set up for open track days, road racing, and/or autocross. Join our forum, interact with others, share your build, and help us strengthen this community!

New member - need some advice

This site may earn a commission from merchant affiliate links, including eBay, Amazon, and others.

343
300
Exp. Type
Time Attack
Exp. Level
Under 3 Years
Bulgaria
Welcome and sorry to hear the car is unstable at speed. That’s def not normal.

I would also be surprised if it were from the aero as what you have is not capable of that much DF. You can test that though. Pull the wing and splitter off and try it out. If the problem persists my money is on alignment.

also go through all the suspension bolts and make sure torque is good.

BC coils are not great but unless they’re completely blown they would not create a floaty feeling at speed in a steady state (damping wise).

Also it getting worse with the new tires makes me think alignment. These cars can “tram line” badly with certain tires and alignment settings.
The other thing that can make that floating feeling in speed is wheel hub bearings but I doubt it. Worth checking though.
 
20
28
Exp. Type
HPDE
Exp. Level
Under 3 Years
Howell, NJ
Welcome and sorry to hear the car is unstable at speed. That’s def not normal.

I would also be surprised if it were from the aero as what you have is not capable of that much DF. You can test that though. Pull the wing and splitter off and try it out. If the problem persists my money is on alignment.

also go through all the suspension bolts and make sure torque is good.

BC coils are not great but unless they’re completely blown they would not create a floaty feeling at speed in a steady state (damping wise).

Also it getting worse with the new tires makes me think alignment. These cars can “tram line” badly with certain tires and alignment settings.
This is basically what Steeda said. Also said that since I didn't use a shop that can high speed balance the tires they could be a bit wobbly at speed.

I finally found a really good article on the topic and it did say that a bad combo of aggressive front camber with not enough caster to match will create that floaty feeling.

But this car was supposedly corner balanced by a really good shop in northern NJ - but that was with different tires and a slightly different stance.

So Steeda gave me a suggested "starting point" of 1.5-1.7 with caster around 6.0-7.0 to accommodate the speeds and to keep toe 0.05-0.15max. See how that feels on the roads and the first track day. After that, as I gain experience, we can put the square setup on the car and get a bit more dialed in.

I still plan to make some calls this week to Steeda and BC Racing and find out my spring rates that come with that setup. Then I will get back to you guys with that info and likely try a stiffer set in the rear (not that expensive of a swap) and see what that does. I also may consider new fresh springs all around. I will follow up with what info I get.

I want this to be an enjoyable work in progress and, ultimately, a track weapon that I can enjoy in retirement a few years down the road.

Thanks again everyone!!
 
343
300
Exp. Type
Time Attack
Exp. Level
Under 3 Years
Bulgaria
This is basically what Steeda said. Also said that since I didn't use a shop that can high speed balance the tires they could be a bit wobbly at speed.

I finally found a really good article on the topic and it did say that a bad combo of aggressive front camber with not enough caster to match will create that floaty feeling.

But this car was supposedly corner balanced by a really good shop in northern NJ - but that was with different tires and a slightly different stance.

So Steeda gave me a suggested "starting point" of 1.5-1.7 with caster around 6.0-7.0 to accommodate the speeds and to keep toe 0.05-0.15max. See how that feels on the roads and the first track day. After that, as I gain experience, we can put the square setup on the car and get a bit more dialed in.

I still plan to make some calls this week to Steeda and BC Racing and find out my spring rates that come with that setup. Then I will get back to you guys with that info and likely try a stiffer set in the rear (not that expensive of a swap) and see what that does. I also may consider new fresh springs all around. I will follow up with what info I get.

I want this to be an enjoyable work in progress and, ultimately, a track weapon that I can enjoy in retirement a few years down the road.

Thanks again everyone!!
`check out rear wheel hub bearings though. Should be very easy just jack up the car and test here is a video:

 

Dave_W

Cones - not just for ice cream
984
1,275
Exp. Type
Autocross
Exp. Level
20+ Years
Connecticut
I'd say to get the recommended alignment first, so you know you've got a good baseline to work from. It's inexpensive compared to replacing parts, and it may fix the problem. Work with the dials you have now (alignment, shock adjustments, etc.) before deciding to replace the dials.

Have you tried setting the shocks to their middle setting? If the shocks were reasonably valved for the springs they were supplied with, I'd think the middle setting should be a good guess at a starting point, given no other information.

Corner balancing is different from alignment - corner balancing deals with adjusting the spring perch heights to change the percentage of total weight each tire is supporting (think of changing the lengths of the legs on a 4-leg chair). When you say the corner balance was done "with a different stance" it seems like changing the stance /rake / ride heights would change the corner balance. Good alignment is more important than corner balance.
 
20
28
Exp. Type
HPDE
Exp. Level
Under 3 Years
Howell, NJ
Well the tramlining was an "easy" fix as it was a loose control arm bolt that had backed out and seized so had to be heat soaked off and then replaced. Kinda hairy. Makes sense that the torque of turning snugged it into place and then higher speeds on the straights it wobbled.

Ended up going 18x11 square 295s and the current setup is front -2.4 camber, 7.0 degree caster, 0.04 toe and rear -1.9 camber, 0.12 toe.

Bearings all look good.

Car feels good - HPDE day 4/21.

Still plan to swap out to the Ford Performance Suspension this summer and pull off the rear spoiler for an adjustable wing. I'm also going to bring the car up to SCCA Time Attack and Hillclimb Safety Level 2 over the course of the year so I can do some of those events in the future. At that point I'll get a dedicated set of race wheels with 305s.

Thanks again for all the help - I'm sure I'll have more questions before too long.
 

TMO Supporting Vendors

Top