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-   -   Dedicated Track TI...Spring Rates (http://www.318ti.org/forum/showthread.php?t=44516)

jdehaan 01-05-2019 04:26 PM

Dedicated Track TI...Spring Rates
 
I'm building out my TI to be a dedicated track car and was wondering what kind of spring rates everyone is running. My car has an S52 swap, is fully stripped and caged, etc. I need to work on weight distribution some, as I'm at 54% in front (weight's down to 2640 lbs with a little over half a tank and no driver).

I'm running 600 lbs up front and 750 in the rear. I'm thinking I might be over sprung in the rear some. I've found that I can spin the rear tires in 4th gear if my tire pressures are just a little too high, which is making me think perhaps the rear springs aren't letting the car squat enough.

Anyone willing to share their experience?

spidertri 01-07-2019 01:42 AM

550F 700R, 28mm front bar full stiff, no rear bar. M52 swap. I can overpower the rear if I try but it sticks pretty good right now. I'm on TCK SA shocks all the way around. I've heard our rear responds pretty well to DA shocks where the compression can be adjusted.

I also moved to a torsen diff as I read E30 guys had more success with those putting the power down smoothly than a clutch type. I like it so far.

jdehaan 01-09-2019 02:51 AM

Quote:

Originally Posted by spidertri (Post 389897)
550F 700R, 28mm front bar full stiff, no rear bar. M52 swap. I can overpower the rear if I try but it sticks pretty good right now. I'm on TCK SA shocks all the way around. I've heard our rear responds pretty well to DA shocks where the compression can be adjusted.

I also moved to a torsen diff as I read E30 guys had more success with those putting the power down smoothly than a clutch type. I like it so far.

Very Interesting. I tried no rear bar and found I was happier with it on. I have a 27mm front bar on the middle setting. My car seems to be very sensitive to weight transfer at turn in, so I'm fighting understeer at turn in and also at the apex as I roll on power.

I have Ground Control SA shocks and haven't tried playing with the adjustments at all yet.

spidertri 01-10-2019 06:31 PM

My car is at 2900lbs with me in it, also 54% on the front. I'd like to get that back closer to 50% but would probably have to remove the rest of the front interior, find a carbon hood, etc.

I really never turn my rear shocks up, they are usually 0.5 to 1 turn from full soft, otherwise it doesn't behave as well. On the front I set them 0.5 turn from full stiff. No rear bar is a must for autox, on track, it matters more coming out of slow tight corners but is manageable.

Also, I'm running 205/50-15 maxxis RC1 on track but I'm going to move to 225/50-15 this spring when I order a new set.

How aggressive is your differential?

dennis.santomauro 01-12-2019 12:39 AM

Quote:

Originally Posted by jdehaan (Post 389890)
I'm building out my TI to be a dedicated track car and was wondering what kind of spring rates everyone is running. My car has an S52 swap, is fully stripped and caged, etc. I need to work on weight distribution some, as I'm at 54% in front (weight's down to 2640 lbs with a little over half a tank and no driver).

I'm running 600 lbs up front and 750 in the rear. I'm thinking I might be over sprung in the rear some. I've found that I can spin the rear tires in 4th gear if my tire pressures are just a little too high, which is making me think perhaps the rear springs aren't letting the car squat enough.

Anyone willing to share their experience?

do you have a anti roll on the rear end

Sent from my SM-S327VL using Tapatalk

jdehaan 01-15-2019 02:29 AM

Quote:

Originally Posted by spidertri (Post 389917)
My car is at 2900lbs with me in it, also 54% on the front. I'd like to get that back closer to 50% but would probably have to remove the rest of the front interior, find a carbon hood, etc.

I really never turn my rear shocks up, they are usually 0.5 to 1 turn from full soft, otherwise it doesn't behave as well. On the front I set them 0.5 turn from full stiff. No rear bar is a must for autox, on track, it matters more coming out of slow tight corners but is manageable.

Also, I'm running 205/50-15 maxxis RC1 on track but I'm going to move to 225/50-15 this spring when I order a new set.

How aggressive is your differential?

No sure to be honest. It's a medium case 3.64 that I got from Diffsonline years ago, and I can't find any information on it.

jdehaan 01-15-2019 02:31 AM

Quote:

Originally Posted by dennis.santomauro (Post 389929)
do you have a anti roll on the rear end

Sent from my SM-S327VL using Tapatalk

Yes, I added back the stock active TI bar in the rear and found it settled the car more to my liking. Given I'm fighting understeer I'm contemplating going to a larger rear bar to see what kind of impact that makes.

spidertri 01-15-2019 02:57 PM

What about camber/caster in the front? Are you maxed out?

joe1602 01-15-2019 03:57 PM

I am currently running 500 front, 650 rear. Ground Control Coilover kit with Koni Yellow adjustable. Have the X-Brace up front, with an Eibach roll bar, 28mm adjustable on the stiffest setting. Also have Turner Camber Shims up front, all 3 of them in to give around 3.5 to 4 degrees negative camber at each wheel. Have the toe set out on each front wheel at about -1 degree for each. This seemed to help with my understeer more than anything else. I also am full poly or solid bushings up front. I am looking at the Ground Control Camber/Caster Plates for the upcoming season. At the rear I have the stock bar and a cheap strut brace. All bushings in rear are race/poly as well as the subframe mounts. I run the front shocks at about the mid point and the rears about a half turn from being as stiff as they will go. Springs are adjusted as low as they will go all the way round. I am running Kosei K1 wheels, 17x8.5 with Re-71r's (245/40x17). Front tire pressures around 26-28psi with the rears about 2-4 pounds higher. This seems to have helped the car rotate a bit better. So far have only used the car for Auto-X but will be doing Track days at WGI this year so we will see how the setup works on the track. I am looking at a front strut brace this winter as well as an improved (stiffer) brace for the rear. We have worked very hard at dialing the understeer out and it is pretty good right now.

jdehaan 01-16-2019 02:07 AM

Quote:

Originally Posted by spidertri (Post 389944)
What about camber/caster in the front? Are you maxed out?

I'm running -3.5 degrees camber front, -2.5 rear.Caster is just over 8 degrees. Toe -0.1, 0.2 rear.


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