Pushy-Loose a tale of a poorly setup car (and how to fix it?)

[captdistraction]

I’m starting to get real comfortable in my car, but one of the things I’m chasing is that the car can get fairly pushy on entry in medium speed corners (and some lower speed ones as well, not many high speed corners out here for me to qualify one way or another). However, all of my adjustments so far have just changed when, how, and to what degree the oversteer is on mid and corner exit. (there’s logical reasons why, more on that later)



What I’m seeing in data is I’m often adding more wheel than the car is turning, and spending time modulating throttle/gas mid corner to try to get the car’s nose going where I want and getting the rotation to happen earlier in the turn. I’m also not seeing a ton of attempt by me to carry too much speed into a corner, at least not compare to the peers I’m running against.



Here’s some video where you can see it happen:

– race on a medium length track with lots of switchbacks, sweepers and “carousel” type corners

– testing at a short track on 295s



The car’s setup:

JRZ Motorsports 1132 dampers (set to OOB race baseline)

600F / 300R spring rates (rear spring over damper, true Coilover)

Eibach front bar, full soft

18mm V6 convertible rear swaybar

(some minor stuff like rod-end LCA/UCA and medium relocations on each for “in the middle” approach to rear antisquat).

Very high rear roll center setting on watts link (BMR, chassis mount)

315-30-18 Hoosier R7 tires in square

Alignment 3.3/3.4* camber (by my gauge, may not be accurate), 0 toe slightly towards 0.1* out



Known issues:

I’ve been running too much rear wing, I pulled some out and found improvement

I have not corner balanced the car (WHAAAAT?! Problem one right there)

Some weight on the front that can stand to go (both sprung and unsprung, probably 30-40lbs between rotors, braces, and unneeded hardware)

I was running slightly too much front camber (hard to adjust my existing camber plates trackside as they require removal) as told by my pyrometer (insides would be a bit on the hot side.



What else should I be looking at? Should I consider trying some lighter front springs (like 550 or even 500? I have plenty of compression damping range to play with if I need to stiffen it back up)



In for thoughts, don’t underestimate my lack of knowledge in chassis setup

 

[ArizonaBOSS]

Try carrying 5th gear through all corners

 

[venom52]

I'm not a pro or anything but when my car pushed the front through corners. I spoke to old timer and some local track friends and they recommended stiffening the rear shocks to stop the rear compressing so much.

I understand you have taken some rear wing out so that's good. You could stiffen up the shock a tad and give it a shot.

Again not a pro just a suggestion flame suit on now

 

[Fabman]

I’m starting to get real comfortable in my car, but one of the things I’m chasing is that the car can get fairly pushy on entry in medium speed corners (and some lower speed ones as well, not many high speed corners out here for me to qualify one way or another). However, all of my adjustments so far have just changed when, how, and to what degree the oversteer is on mid and corner exit. (there’s logical reasons why, more on that later)



What I’m seeing in data is I’m often adding more wheel than the car is turning, and spending time modulating throttle/gas mid corner to try to get the car’s nose going where I want and getting the rotation to happen earlier in the turn. I’m also not seeing a ton of attempt by me to carry too much speed into a corner, at least not compare to the peers I’m running against.



Here’s some video where you can see it happen:

– race on a medium length track with lots of switchbacks, sweepers and “carousel” type corners

– testing at a short track on 295s



The car’s setup:

JRZ Motorsports 1132 dampers (set to OOB race baseline)

600F / 300R spring rates (rear spring over damper, true Coilover)

Eibach front bar, full soft

18mm V6 convertible rear swaybar

(some minor stuff like rod-end LCA/UCA and medium relocations on each for “in the middle” approach to rear antisquat).

Very high rear roll center setting on watts link (BMR, chassis mount)

315-30-18 Hoosier R7 tires in square

Alignment 3.3/3.4* camber (by my gauge, may not be accurate), 0 toe slightly towards 0.1* out



Known issues:

I’ve been running too much rear wing, I pulled some out and found improvement

I have not corner balanced the car (WHAAAAT?! Problem one right there)

Some weight on the front that can stand to go (both sprung and unsprung, probably 30-40lbs between rotors, braces, and unneeded hardware)

I was running slightly too much front camber (hard to adjust my existing camber plates trackside as they require removal) as told by my pyrometer (insides would be a bit on the hot side.



What else should I be looking at? Should I consider trying some lighter front springs (like 550 or even 500? I have plenty of compression damping range to play with if I need to stiffen it back up)



In for thoughts, don’t underestimate my lack of knowledge in chassis setup

Been in this same situation exactly.
Removing the 600's and going back to 500's helped me considerably.

 

[ArizonaBOSS]

I think this is a phenomenon worth investigating, but before you delve too deep into this--how much could be related to the tires? Not sure if you ever had a whole, good set of tires for Mondo, IIRC?

 

[JAJ]

Is it possible that it's two separate problems? You're reporting understeer on entry and mid-corner, which is hard to see in the video. What's visible in the video is oversteer as you return to power and start to unwind out of the corner. It also doesn't sound like you've done much work on tuning the damper settings at this point.

I think that the first thing you should do is adjust the dampers and optimize them for the setup you have. Fabman's probably right and you probably need less front spring, but until the shocks are adjusted, it's hard to know what you've got. The best adjustment advice I've ever found is on the Koni Racing website (http://www.koniracing.com/rrtuningguide.cfm). This is their instructions for setting up double-adjustable race shocks. Then spend a day at a practice venue tuning your 1132's. Once you're getting the best handling they can give you, you can start playing with springs and geometry, but if your shocks are less than perfect, they can cause problems that look like other issues. Don't be surprised if you end up with shock settings that are a lot softer than you expect.

 

[Fabman]

"Spring in and Bar out"

Less front spring and more front bar is what I'm thinking...once the front is hooked up start dropping the rear roll center.

 

[Fabman]

Dumping the 600's and going from full soft to the middle hole on my front sway bar was worth over a full second at Laguna Seca.

 

[Big Black]

Maybe try one end of the car at a time, starting with the rear.

Standard (inexpensive) oversteer corrections:

-- More rear tire pressure (use your pyrometer to make sure you are currently in the right spot for them (fronts also of course), this could give you some clues for suspension changes).
-- Is your rear sway bar not playing nice with your watts link? Disconnect (free!) and try a lap or two (someone chime in if this is a terrible idea...thinking a little out of the box on this one).

EDIT: Missed it in your post...another quick and cheap oversteer correction is to reduce front camber...you're running quite a bit...take your front tire temperature on the outside, middle and inside, or just take out a degree and test.

 

[The_Dead_Cow]

I would fix that list of known issues first then reassess the handling. Obvious I know but part/all of the solution may lie within that list.

I think a corner balance & alignment would go a long way towards solving your problem.

 

[Grant 302]

I was running slightly too much front camber (hard to adjust my existing camber plates trackside as they require removal) as told by my pyrometer (insides would be a bit on the hot side.

Start here. I tried to suggest this to somebody, and he did this:

"Spring in and Bar out"

Or the opposite? Less spring more bar.

When your front tires are telling you, "too much neg camber" and you don't change anything, what do you expect?

------

Globally, I think you're looking in the wrong direction(s). Both of those tracks have a lot of low speed sections and you need to be able to get the power down.

(some minor stuff like rod-end LCA/UCA and medium relocations on each for “in the middle” approach to rear antisquat).

Eibach front bar, full soft

Gotta ask: why?

JRZ Motorsports 1132 dampers (set to OOB race baseline)

Aside from the camber adjustment, I'd look at turning some of them knobs you paid for.

 

[2012-Boss]

Have you tried lowering your watts pivot? That might help exit oversteer.

Less front bump might help entry understeer and exit oversteer.

More rear rebound might help entry understeer and exit oversteer.

Make one change at a time.

 

[Fabman]

Start here. I tried to suggest this to somebody, and he did this:

Or the opposite? Less spring more bar.

Spring in and bar out is an old stock car saying.
Front Spring primarily effects corner entrance and front sway bar primarily effects corner exit. (although there is some overlap) If its pushing going in, use less front spring. if its loose coming out, more front sway bar. Its a tuning rule of thumb. Start with the front end and when that's hooked, start working on the back to hook that up.

I did reduce my front camber as part of the last spring package and I'm going to reduce it further. Like I said, it was worth about a second and a half, so that's not a bad improvement. My challenge is that with this level of power, it will roast the tires at will, so anything that loosens the car just adds to the problem. So, a good balance is much harder to achieve. Dump a couple hundred horse power and it is a lot easier to set up. Just keep loosening it up until the push goes away and your done. There is a difference between oversteer and power oversteer. For me, everything that helps corner entry has a big price to pay on corner exit. But it's getting there. I have managed to shave a full 7 seconds off of my lap times in 6 outings, and I expect to shave off even more. I'd like to be in the 1:36-1:37 neighborhood at Laguna this year. I'm @ 1:38.5 now and I know there is more in this car. A lot more.

 

[Grant 302]

I get all that!

But it'd be tough to convince me that this was enough front spring for your setup:


And I seriously doubt it would be enough for Chris' setup with all those low speed turns in the two videos in this thread.

Dumping the 600's and going from full soft to the middle hole on my front sway bar was worth over a full second at Laguna Seca.

The thing about that is that you also made other changes that day. Lowering the front, camber as you just mentioned, and tire pressures, maybe damper settings. And that's just the misc. changes that I remember. Hard to say what *exactly* was worth over a full second. And can't forget the added seat time either...

My point is more against making wholesale changes before really working with and adjusting what's already there.

 

[Fabman]

I get all that!

But it'd be tough to convince me that this was enough front spring for your setup:


And I seriously doubt it would be enough for Chris' setup with all those low speed turns in the two videos in this thread.



The thing about that is that you also made other changes that day. Lowering the front, camber as you just mentioned, and tire pressures, maybe damper settings. And that's just the misc. changes that I remember. Hard to say what *exactly* was worth over a full second. And can't forget the added seat time either...

My point is more against making wholesale changes before really working with and adjusting what's already there.

There were several changes made over several track days.....most of that was done with the 600s. My best was 1:39.4 and only a few of them. The rest were all over the place. The last outing was 1:38.5 with 500's and every run was within a second or so. Very few changes were made for that day besides the spring change.

 

[Fabman]

That pic was hard on the brakes and the rake makes it look worse than it is.

 

[Grant 302]

Very few changes were made for that day besides the spring change.

Like tightening strut to spindle bolts? I'd think *that* would be worth at least 2 seconds!

But give yourself some credit. The drop in time might have been all you!

That pic was hard on the brakes and the rake makes it look worse than it is.

As I'd expect on T11 at LS. Those WHP turns/esses/chicanes all look even slower. 23 turns in 2.5 miles...tight!

 

[Fabman]

Believe me, I was die hard for the 600's, but I couldn't get the push out of it no matter what I did, and I did a lot. I finally had to come to terms with it....meanwhile, the SCCA Championship spec mustang ran 500's. I watched a Pirelli world champ mustang win at Sonoma on 500's. The championship Pheonix mustang runs 500's and softer....my car worked awesome on 500's before I went to the 600's. I finally had to give in and go back to the 500's and its faster and more consistent than ever. Just what worked for me.

 

[Fabman]

Plus....Kevin told me not to go to 600's and I was damn well going to make them work if for no other reason than not having to tell him he was right.
Next outing I'll drop some rake out of it and go from 325 to 300 rear springs.

 

[Grant 302]

That's kind of self-selecting data. Spec mustang only has two front spring choices, 500 or 600. (400 and 450 on the rear, btw) And all of those examples are on 285? and smaller width tires? FR500S were run on 500/300...on 245s, right?