GT350 Track Suspension Issue

[Hooncop]

Hey guys recently went to Buttonwillow CW13 with my 2017 gt350 this sunday, I feel the car did well, I was top of the beginner group but was still unhappy since my goal was to get under 2 mins. (Best time was a 2:03.5, although it was 45 degrees and my first time driving the track)

A very weird issue I was having was in the corners I was scraping the front lip, and actually broke one of the gt500 splitter addons, you can see from the picture posted it was grinding on the ground.

My car has the Ford Performance Springs and the Steeda front brace, and gt350r front splitter but besides that is stock on 305 re71rs.

I was thinking of upgrading to stiffer sway bars front and rear hoping to resolve this issue, any advice? Thanks

Also side note car felt decently balanced, but was oversteering a bit, part of my plan is to upgrade the rear aero

 

[67GTA]

Congrats on the 2:03 - that’s a very fast lap for a first time at BW. Sub 2 on a first time at BW is an aggressive goal - probably unrealistic depending on your track experience elsewhere. How many track days and what other tracks have you driven?

I would remove the GT500 splitter extensions and not do anything to the suspension at this time. Again, depending on your experience, I wouldn’t spend a dime on your GT350 that isn’t safety, cooling, or maintenance related - it’s a very capable track car as it sits.

Great looking car - welcome to TMO and look forward to connecting with you at a SoCal track day soon.

 

[JAJ]

If you're understeering, then the front is already too stiff. I've always been skeptical about the FP springs - the fronts are stiffer than OEM but the rears are a lot softer - understeer, here we come.

The factory springs might give you more roll stiffness and more ride height - I'm sure there are people on this forum with the factory setup on their GT350's who run at BW - they can fill in more of the blanks for you.

 

[Hooncop]

Congrats on the 2:03 - that’s a very fast lap for a first time at BW. Sub 2 on a first time at BW is an aggressive goal - probably unrealistic depending on your track experience elsewhere. How many track days and what other tracks have you driven?

I would remove the GT500 splitter extensions and not do anything to the suspension at this time. Again, depending on your experience, I wouldn’t spend a dime on your GT350 that isn’t safety, cooling, or maintenance related - it’s a very capable track car as it sits.

Great looking car - welcome to TMO and look forward to connecting with you at a SoCal track day soon.

I have done 1 half track day at Auto Club Speedway, and I did race in Lemons at Sonoma Raceway.
Besides that it's just autocross.

 

[Hooncop]

If you're understeering, then the front is already too stiff. I've always been skeptical about the FP springs - the fronts are stiffer than OEM but the rears are a lot softer - understeer, here we come.

The factory springs might give you more roll stiffness and more ride height - I'm sure there are people on this forum with the factory setup on their GT350's who run at BW - they can fill in more of the blanks for you.

I'm actually not getting much understeer, atleast at bw. I was getting mainly Oversteer.

 

[JAJ]

I'm actually not getting much understeer, atleast at bw. I was getting mainly Oversteer.

Oops, sorry, misread your post. A little more stiffness at the front might help, then.

 

[trackdao]

I have done 1 half track day at Auto Club Speedway, and I did race in Lemons at Sonoma Raceway.
Besides that it's just autocross.

Nice times! Believe me, autocross really helped me quite a bit when I started tracking, knowing the limits on 'balancing' a car, looks like you have that 'feel'. See ya soon, here comes 2022. ACS in Jan w Speed Ventures?

 

[Hooncop]

Nice times! Believe me, autocross really helped me quite a bit when I started tracking, knowing the limits on 'balancing' a car, looks like you have that 'feel'. See ya soon, here comes 2022. ACS in Jan w Speed Ventures?

hopefully! I will be going on a roadtrip and make not make it back in time unfortunately.

 

[navseng]

That looks like off ramp. I don't see any issues here to be honest, my car looks the same way in this corner, only I have no splitter or anything on it.. Its just a heavy braking area and the corner is slightly banked going into it.

You could try slightly stiffening the front end of the car and see if that helps, but it may just be the splitter add ons being a little to much for that corner.

 

[trackdao]

Also entering offramp on 13CW try taking more the middle line then tight on the apex coming out. Avoids that extreme right dip.

 

[blacksheep-1]

I'm trying to think of what these things use for bump stops on the front, or do they rely on coil bind, in any case, I don't think the problem is the sway bars, you might try placing some goobers in the front spring if you don't have bump stops up front. You can usually find different viscosity of bump stops and goobers so the car lands softly.

goobers..

 

[TeeLew]

If you're understeering, then the front is already too stiff. I've always been skeptical about the FP springs - the fronts are stiffer than OEM but the rears are a lot softer - understeer, here we come.

The factory springs might give you more roll stiffness and more ride height - I'm sure there are people on this forum with the factory setup on their GT350's who run at BW - they can fill in more of the blanks for you.

You're reading what you want to read and then filling in the blanks. He said he was _OVERSTEERING_.
---------------

Front stiffness, whether through front spring or front anti-roll bar is needed to reduce body roll and stop you from damaging your splitter. A 35mm front anti-roll bar, either BMR or Steeda, would be an easy, effective addition.

I don't know what the rates are on your springs, but it sounds like they are along the lines of the Mach 1. I've personally found that raising the front spring rate _does not_ increase understeer, but, to the contrary, provides better response, a much more direct feel and ability to aggressively load the front of the car without excessive chassis pitch/roll. Yes, on paper in a steady-state scenario, we will have theoretically increased understeer. In practice, I don't find this to be an issue.

I find the same with the rear of the car. Softening the rear rate helps the car in powerdown situations, but it has very little effect on the actual balance. If anything, the ability to accelerate off the corner without sidestepping the rear gives a ton more confidence than a flat/stiff rear which tends to chatter over curbing or brake-zone bumps.

I feel like a lot of the popular 'canned' spring combos are undersprung on the front and oversprung on the rear, likely in an effort to cure an understeer which is induced more by bad driving than improper roll-couple distribution. Obviously, it's possible to create problems with a lack of font or rear, but I find the S550 front end to be quite strong in general. YMMV.

 

[TeeLew]

I'm trying to think of what these things use for bump stops on the front, or do they rely on coil bind, in any case, I don't think the problem is the sway bars, you might try placing some goobers in the front spring if you don't have bump stops up front. You can usually find different viscosity of bump stops and goobers so the car lands softly.

goobers..

View attachment 71184

This is a 5 x 1.5" ShoreA 70 polyurethane spring rubber on a 220 #/in Vogtland front spring. I'm guessing it took me to about 280 #/in spring rate. It was a _big_ positive behind the wheel. It significantly increased front support and, if anything, provided better front grip.

RES 5.00" SPRING RUBBER

RE Suspension’s new line of spring rubbers, now available for 5" springs! Made from the same high quality material as our bump stops, these are designed to fit the new 5" springs used in asphalt and dirt track racing today. Offered in 5 durometers, 50A-60A-70A-80A-90A. Color coded so that there...

www.resuspension.com

 

[JAJ]

You're reading what you want to read and then filling in the blanks. He said he was _OVERSTEERING_.
---------------

Front stiffness, whether through front spring or front anti-roll bar is needed to reduce body roll and stop you from damaging your splitter. A 35mm front anti-roll bar, either BMR or Steeda, would be an easy, effective addition.

I don't know what the rates are on your springs, but it sounds like they are along the lines of the Mach 1. I've personally found that raising the front spring rate _does not_ increase understeer, but, to the contrary, provides better response, a much more direct feel and ability to aggressively load the front of the car without excessive chassis pitch/roll. Yes, on paper in a steady-state scenario, we will have theoretically increased understeer. In practice, I don't find this to be an issue.

I find the same with the rear of the car. Softening the rear rate helps the car in powerdown situations, but it has very little effect on the actual balance. If anything, the ability to accelerate off the corner without sidestepping the rear gives a ton more confidence than a flat/stiff rear which tends to chatter over curbing or brake-zone bumps.

I feel like a lot of the popular 'canned' spring combos are undersprung on the front and oversprung on the rear, likely in an effort to cure an understeer which is induced more by bad driving than improper roll-couple distribution. Obviously, it's possible to create problems with a lack of font or rear, but I find the S550 front end to be quite strong in general. YMMV.

You missed this: https://trackmustangsonline.com/threads/gt350-track-suspension-issue.18251/post-272906

That's ok. You're entitled to your opinion.

 

[TeeLew]

You missed this: https://trackmustangsonline.com/threads/gt350-track-suspension-issue.18251/post-272906

That's ok. You're entitled to your opinion.

Yes, I am entitled to my opinion, which is backed up by actually testing a bunch of different combinations.

 

[Kaj]

Good to see the Mustang community hasn't changed much in the past 20yrs LOL.