What Handling Attributes do you Like about your GT350 and GT350R?

[TheLion]

I'm looking for something a little more detailed other than "it handles good". Things like turn in, mild or moderate push (aka under steer), corner exit etc.

I'm going to do a re-work of my PP GT suspension and OE GT350 parts are cheap to acquire. At the present time I'm thinking BMR SP083 springs which are very close to GT350R spring rates and FP Track Dampers which use the same valving as the GT350 dampers. But i'm wondering about how much bar to run front and rear.

PP GT runs a 32 mm bar up front and 22.2 mm rear bar stock. I believe the regular GT350 runs the same 22.2 mm rear bar while the R runs a 24 mm rear bar. Both Shelby variants run a 34 mm bar up front. I can pick up OE bars and bushings cheap so it's a matter of deciding where to start.

Here's where I'm a little undecided. The BMR springs run a slightly (not much) higher rate at 980 lbs/in vs. 914 lbs/in in the rear. So I'm thinking of staying with the PP / GT350 22.2 mm rear bar with the above strut / spring setup unless those running a GT350R are going to say the car over steers with throttle mid-corner (in which case a 24 mm rear bar and slightly stiffer rear rates would reduce that).

Any feedback on how your stock setups work and what you would or would not change and why would be appreciated. I may not get the balance 100% first pass, but I think I can get fairly close then tweak with bars from there. Since I have a PP GT I can play with front and rear bar combinations, but I'd like to get a good starting point.

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[Eritas]

Different front spindle, different front wheel bearings, different unsprung weight, different track widths, different downforce.

Running the same spring, bars, and whewl/tire sizes as a GT350 won't make a GTPP handle like a GT350.

 

[TDC]

With proper tire's (RE-11 / RE-71) sized square 305, camber front @ 2.5 deg rear @ 2.0, on track the handling is neutral with progressive breakaway. Very stable at speed in high speed corners (120+). I drive the car about 8/10's on track. A more aggressive driver would need more camber up front otherwise I think she'd push. The magnetic suspension soaks up bumps well keeping the car composed over rough pavement on track and on the road.

 

[Hack]

I really like how the GT350 handles as a daily as well as on the track. It never has felt too softly set up for control of body motions at the track, but yet it doesn't feel overly firm or harsh on our rough Minnesota roads. I don't know whether Magneride, spring rates, sway bars or which components are responsible. I suspect it's a combination that does the trick. Not sure whether only swapping out some of the bits and pieces will have the same impact.

The GT350 definitely understeers at the limit. That's not a great characteristic in my opinion or one that you should copy. I think a lot of people on the board have gone to wider front tires to reduce the amount of understeer. I haven't switched yet.

 

[Eritas]

I really like how the GT350 handles as a daily as well as on the track. It never has felt too softly set up for control of body motions at the track, but yet it doesn't feel overly firm or harsh on our rough Minnesota roads. I don't know whether Magneride, spring rates, sway bars or which components are responsible. I suspect it's a combination that does the trick. Not sure whether only swapping out some of the bits and pieces will have the same impact.

The GT350 definitely understeers at the limit. That's not a great characteristic in my opinion or one that you should copy. I think a lot of people on the board have gone to wider front tires to reduce the amount of understeer. I haven't switched yet.

Do you trail brake?

 

[Hack]

Do you trail brake?

Yes

 

[Trackaholic]

I've found the GT350 to be pretty neutral with mild trail braking. Too much speed will definitely cause understeer, so I tend to take it a little easy. I don't have camber/caster plates because I put on so many DD miles and don't want to start adjusting the car for the track, but I do think some added front camber would reduce the need for tralbraking and make the car that much more responsive on the front end.

I feel like the rear puts the power down quite well, and the balance is neutral enough that when it does step out, it is usually pretty slow and easy to catch. I did get pretty sideways at Buttonwillow though, when I tried exiting a corner in 3rd gear rather than 2nd, and as I passed 3500 RPM the torque jump caused the rear to come around more quickly than I've experience in other situations. Usually the car seems very controllable and easy to catch.

My 350Z with lots of camber, R-comps, koni's, and sways was a sharper handling car, but with more sudden breakaway and still wasn't as neutral as even my stock GT350. I really like the compromise Ford made between the street capability and track capability on the GT350. As I get older I really enjoy the ability to jump on the track without having to spend a long evening changing tires, brake pads, shock settings, camber settings, etc, like I did on my Z.

-T

 

[Hack]

The thing about trail braking is it only helps with initial turn in, not in the middle of a turn when you are under maintenance throttle and not as you are trying to get back into the throttle at the end of the turn.

 

[Eritas]

The thing about trail braking is it only helps with initial turn in, not in the middle of a turn when you are under maintenance throttle and not as you are trying to get back into the throttle at the end of the turn.

I thought trail braking was blending off brakes as you added steering down to the middle of the corner. Not just at "turn-in".

If the car does not turn when on maintenance throttle, then get off the throttle and let the car turn.

 

[Hack]

I thought trail braking was blending off brakes as you added steering down to the middle of the corner. Not just at "turn-in".

You can drive the entire track with your brakes on if you want. I'm not an expert, but what I've been told by instructors is that trail braking is normally done occasionally at some corners (not all) and that you should be under maintenance throttle as the car settles into the corner. Yes everything is blended, but my comments on understeer are related to corners where there is an appreciable time spent with the car in a corner under maintenance throttle waiting to be able to add more throttle.

I get that you are implying that no way does the GT350 understeer and I'm doing it wrong. I think the designers did a great job on the car and they made it easy to drive. As such it understeers rather than oversteering. This is generally really good for any car, and I especially appreciate it in high speed corners. However, my opinion is that the car isn't neutral at steady state in a corner. It understeers a little more than I would prefer in that state.

 

[Eritas]

You can drive the entire track with your brakes on if you want. I'm not an expert, but what I've been told by instructors is that trail braking is normally done occasionally at some corners (not all) and that you should be under maintenance throttle as the car settles into the corner. Yes everything is blended, but my comments on understeer are related to corners where there is an appreciable time spent with the car in a corner under maintenance throttle waiting to be able to add more throttle.

I get that you are implying that no way does the GT350 understeer and I'm doing it wrong. I think the designers did a great job on the car and they made it easy to drive. As such it understeers rather than oversteering. This is generally really good for any car, and I especially appreciate it in high speed corners. However, my opinion is that the car isn't neutral at steady state in a corner. It understeers a little more than I would prefer in that state.

Racing school teach trail-braking as a tool to reduce understeer and that maintenence throttle unloads the front tires, reducing front grip, and settling the rear of the car.

I don't think you want a car to be neutral under maintenance throttle. If it were, and you lift off the throttle, you now have oversteer.

If you have understeer from maintenance throttle, then get off the throttle to put weight on the front tires for grip. If you're now too soon in the middle of the corner, then carry more entry speed with more....trail braking so you trail off the brakes as you add steering -with the front tires loaded for grip. Once the car rotates, then you can get back to the gas.

At least that's what I was taught in a racing school and not from Joe blow "instructor" at an hpde day.

I like how you put words in my mouth in attempt to win an argument.

 

[nastang87xx]

Instead of thinking about what makes the GT350 handle so well (which it does with a few caveats), think about what YOUR GT car does and correct issues as you find them. The GT350 has several fundamental differences that aren't even translatable to the "base" cars in the suspension. Simply bolting on GT350 parts is not going to make it handle like a GT350. You're never going to get the sensation of the GT350's with MagneRide (btw, magnetic shocks and struts DON'T have valves) because of how well controlled the electronic tuning is.

First things first, do you road course or autocross? Or do you street drive only?

 

[Austinj427]

I'll agree that the car has a mild amount of under steer but it's safer that way. I usually run a few psi less in the front tires to try to help it rotate, but I'll eventually square up the tires.

Turn in - not bad at all on a more natural turn. With a heavy trail brake it gets downright aggressive.

Mid corner - if you over cook it the front tires will go first. You need to carry a decent amount of speed to find this and it can be dealt with.

Corner exit - it puts the power down well and is very controllable if it gets away from you.

Any deficiencies that the car has is easy to make adjustments to your driving style. This isn't a hard car to drive.

 

[Hack]

Racing school teach trail-braking as a tool to reduce understeer and that maintenence throttle unloads the front tires, reducing front grip, and settling the rear of the car.

I don't think you want a car to be neutral under maintenance throttle. If it were, and you lift off the throttle, you now have oversteer.

If you have understeer from maintenance throttle, then get off the throttle to put weight on the front tires for grip. If you're now too soon in the middle of the corner, then carry more entry speed with more....trail braking so you trail off the brakes as you add steering -with the front tires loaded for grip. Once the car rotates, then you can get back to the gas.

At least that's what I was taught in a racing school and not from Joe blow "instructor" at an hpde day.

I like how you put words in my mouth in attempt to win an argument.

I'm really not trying to win an argument. I'm saying what I think about how the GT350 handles. Your opinions don't invalidate mine. I am pushing back on your implications that I must be incompetent based on my opinion, though.

I like how you believe that any instructor that says something counter to your previous statements must not know what he's talking about.

Did I put words in your mouth? I am glad that you are implying things in a stronger manner now rather than asking leading questions. FYI, you could just say what you think rather than beating around the bush.

I understand how to balance under/over steer with throttle, brakes, etc. Good subtle insults though, implying that I don't know that.

I understand that a completely neutrally balanced car will lose rear grip in a corner if you let off the throttle. Did you read where I said that I want the GT350 to be completely neutral? Putting words in my mouth? I just think that the GT350 is pushed pretty far towards understeer. A little more than I would prefer. Is that more clear to you now?

A number of members on this board have gone to wider front tires, and none of them have complained about having issues with oversteer. Does that support my opinion?

 

[Eritas]

I'm really not trying to win an argument. I'm saying what I think about how the GT350 handles. Your opinions don't invalidate mine. I am pushing back on your implications that I must be incompetent based on my opinion, though.

I like how you believe that any instructor that says something counter to your previous statements must not know what he's talking about.

Did I put words in your mouth? I am glad that you are implying things in a stronger manner now rather than asking leading questions. FYI, you could just say what you think rather than beating around the bush.

I understand how to balance under/over steer with throttle, brakes, etc. Good subtle insults though, implying that I don't know that.

I understand that a completely neutrally balanced car will lose rear grip in a corner if you let off the throttle. Did you read where I said that I want the GT350 to be completely neutral? Putting words in my mouth? I just think that the GT350 is pushed pretty far towards understeer. A little more than I would prefer. Is that more clear to you now?

A number of members on this board have gone to wider front tires, and none of them have complained about having issues with oversteer. Does that support my opinion?

When or how did I imply you were incompetent? On the contrary, your statement of having understeer mid corner with maintenance throttle makes perfect sense. You're just causing and making your own understeer worse.

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