GT350R Springs for GT (high rate, minimum lowering)

CrazedAntelope · Apr 25, 2017

I would agree with you that harshness comes from the rear. I'll try turning the rear rebound down. Currently at +3 compression and +6 rebound. I'm just afraid of being oversprung and underdamped. At this point I have a bunch of springs (4 sets) at my disposal it's just a matter of swapping in and out.

The car felt awesome confident and comfortable on the street with 780 rear spring rate and the shocks at a much firmer setting. But I'm sure the current setting outperforms it in HPDE. I'm hoping the 880 rear will be a happy medium.

A lot of this is just to satisfy my own curiosity

BmacIL · Apr 25, 2017

CrazedAntelope said:
I would agree with you that harshness comes from the rear. I'll try turning the rear rebound down. Currently at +3 compression and +6 rebound. I'm just afraid of being oversprung and underdamped. At this point I have a bunch of springs (4 sets) at my disposal it's just a matter of swapping in and out.

The car felt awesome confident and comfortable on the street with 780 rear spring rate and the shocks at a much firmer setting. But I'm sure the current setting outperforms it in HPDE. I'm hoping the 880 rear will be a happy medium.

A lot of this is just to satisfy my own curiosity

I would turn the front rebound down along with the rear. Try a reduction of 2 or 3 and see how it feels. When you go over a drop-off/curb/uneven pavement, the shocks want to keep the wheels were they are rather than letting the spring rate and gravity keep it on the ground. In the front, this means the car just falls rather than the wheel falling to meet the ground.

The upside of firm rebound is excellent sprung mass control as it will have resistance to roll and quick reaction, but it can make street manners trying at times.

CrazedAntelope · Apr 25, 2017

BmacIL said:
I would turn the front rebound down along with the rear. Try a reduction of 2 or 3 and see how it feels. When you go over a drop-off/curb/uneven pavement, the shocks want to keep the wheels were they are rather than letting the spring rate and gravity keep it on the ground. In the front, this means the car just falls rather than the wheel falling to meet the ground.

The upside of firm rebound is excellent sprung mass control as it will have resistance to roll and quick reaction, but it can make street manners trying at times.

Thanks brotha. I will also do some reading up on Eibach vs GT350 vs PP rear swaybar.

BmacIL · Apr 30, 2017

Today was my first autocross (and a rain-soaked one at that!) since I did all this:

CB005
GT350R/SP085 springs
Pro Action dampers
Wheels and Tires
Billet Shock mounts

WOW. Even in the wet this car was brilliant. I think I will want to add a little more front camber to cure a smidge of mid-corner understeer (only at -1.5 now). Time for camber plates! I also have BMR RLCA bearings on the way, so that will only make it better

Norm Peterson · May 1, 2017

Nice.

You might want somebody to get some good head-on pictures of cornering to help guide your camber choices.

Norm

ansibe · May 1, 2017

BmacIL said:
Today was my first autocross (and a rain-soaked one at that!) since I did all this:

CB005
GT350R/SP085 springs
Pro Action dampers
Wheels and Tires
Billet Shock mounts

WOW. Even in the wet this car was brilliant. I think I will want to add a little more front camber to cure a smidge of mid-corner understeer (only at -1.5 now). Time for camber plates! I also have BMR RLCA bearings on the way, so that will only make it better

Great news! Any trouble putting the power down? I realize it was raining - mine spins in 2nd going straight!

Camber plates are a great idea, and I think I'll get the MM ones for mine. But, with more grip in the dry the front end may gain traction faster than the rear. You're running a pretty stiff rear spring, so once the body starts to roll, it's pretty likely the front will roll more than the rear. The added neg camber from roll might solve your mid corner understeer. One caveat: I like a bit of understeer in a car this powerful, so I'm biased.

BmacIL · May 1, 2017

Norm Peterson said:
Nice.

You might want somebody to get some good head-on pictures of cornering to help guide your camber choices.

Norm

I normally use chalk on the sidewall and temp gauge after runs to check that

BmacIL · May 1, 2017

ansibe said:
Great news! Any trouble putting the power down? I realize it was raining - mine spins in 2nd going straight!

Camber plates are a great idea, and I think I'll get the MM ones for mine. But, with more grip in the dry the front end may gain traction faster than the rear. You're running a pretty stiff rear spring, so once the body starts to roll, it's pretty likely the front will roll more than the rear. The added neg camber from roll might solve your mid corner understeer. One caveat: I like a bit of understeer in a car this powerful, so I'm biased.

I actually ran in first! The course was tight and with the rain you couldn't go faster than 1st gear allows anyway. Other than when I was overdriving a little, it put power down really, really well. Very predictable.

I also like a little bit of understeer for this kind of car. Easy to neutralize with throttle.

BMR Tech · May 1, 2017

So I have been testing out some stuff for a while now.

Thinking about offering a 7/8" ISH front drop Linear spring in the 250lb/in neighborhood....

This would make a BMR spring combo something like:

250lb/in Front Linear (7/8" Drop)
980lb/in Rear Linear (1/2" Drop)

Seems like this would be a homerun. Agree?

BmacIL · May 1, 2017

BMR Tech said:
So I have been testing out some stuff for a while now.

Thinking about offering a 7/8" ISH front drop Linear spring in the 250lb/in neighborhood....

This would make a BMR spring combo something like:

250lb/in Front Linear (7/8" Drop)
980lb/in Rear Linear (1/2" Drop)

Seems like this would be a homerun. Agree?

Agreed.

... They'd be on my car if they existed in December!

strengthrehab · May 2, 2017

BMR Tech said:
So I have been testing out some stuff for a while now.

Thinking about offering a 7/8" ISH front drop Linear spring in the 250lb/in neighborhood....

This would make a BMR spring combo something like:

250lb/in Front Linear (7/8" Drop)
980lb/in Rear Linear (1/2" Drop)

Seems like this would be a homerun. Agree?

Could this be well-paired with the FP Track dampers?

BmacIL · May 2, 2017

strengthrehab said:
Could this be well-paired with the FP Track dampers?

I would definitely say yes.

BMR Tech · May 2, 2017

^ Yes.

BMR Tech · May 2, 2017

You guys keep in mind. Don't let the massive spring rates out back scare you.

It honestly doesn't take much to control these high rates in the back, with that .49X~ motion ratio.

BmacIL · May 2, 2017

BMR Tech said:
You guys keep in mind. Don't let the massive spring rates out back scare you.

It honestly doesn't take much to control these high rates in the back, with that .49X~ motion ratio.

^^^ This!

See my Ride Frequency chart. It also shows the Wheel Rates, which are the effective spring rates taking into account the motion ratio.
http://www.mustang6g.com/forums/showpost.php?p=1637308&postcount=145

GT350R Springs for GT (high rate, minimum lowering)

CrazedAntelope

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BmacIL

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CrazedAntelope

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Norm Peterson

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ansibe

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BmacIL

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BMR Tech

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BmacIL

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strengthrehab

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BmacIL

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BMR Tech

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BMR Tech

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BmacIL

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