suspension set up and changes.

[Catwood]

OK...I'm learning as I go. I just got back from a weekend at Willowsprings. Great weather BTW.

A few weeks ago I installed a new set of springs and adjustable shocks. They are adjustable coilovers also....Thank you Dave "racecars" Cawthorne.

Anyway, I had set and adjusted ride height a few times as the springs settled before going.

Once at the track I had horrible oversteer and the rear brakes were locking in the heavy brake zones. 1 & 3 for those that know the track. I discussed what was going on with one of the Radical mechanics and he suggested making some changes, like take two turns out of the rear and going back one click on the rear shocks. I did that and the Viper got better. He came by and suggested taking another turn out. Car improved better. His explanation was that by lowering the rear rideheight more weight was transferred to the rear....seems to make sense.

So I'm curious how those that have corner weighed their cars. Do you strive for a 50/50 balance front to rear? And how much side to side variable to you allow.

Thanks,
Carl

 

[opnwide]

You can't get 50/50 front to rear. that's not possible. But you can try to get 50/50 R/L on the front tires. I think most people go for a balance diagonally or something.

 

[Catwood]

so then should I assume to get as much weight in the rear as possilble?

 

[Bad_Byte]

Yeah Carl, put some lead in that asp.

That'll slow you down.

 

[Catwood]

Yeah Carl, put some lead in that asp.

That'll slow you down.

funny guy! You missed a great time at Willow Art.

Rather than work to ride height I'm trying to figure out where to set corner weights. and if anything I'd strip weight if possible.

Put Jan and March on your list of willow dates.

 

[Tom F&L GoR]

Try for 50-50 on the front wheels; you'll end up with more weight on the LR. Don't forget to sit in the car when you do it.

What spring rates did you put on? Are you in this range of front to rear?

250/450 stock
325/500 Roe (325/550)
400/750 ACR v1
450/650 Woodhouse
500/1100 OEM ACR that everyone thought had too much oversteer
500/850 mod ACR that people liked better
550/800 me
600/800 Verges
700/900 NDW on Archer revalve

Softer springs in back would keep the rubber on the track - if springs or shocks are too stiff, the nose droop under braking or heaves in the road will momentarily lighten the rear enough to lock, then they won't easily go back to rolling.

 

[Irid]

Assuming you can do it, every SAE analysis and race research program points to a slight rear weight bias as what you want for the best lap times. This is a different (but related) topic than getting your cross weights correct.

If you could, getting 53-56% of the car's total weight over the rears puts one into the sweet spot for lap times. It increases traction and braking ability (considerably). In other words: if you can, strip weight out of the front of the car first if you're a lap time freak.

The Gen II's do pretty well stock compared to the competition in this area. Most of those are nose heavy, whereas the GTS has a slight rear bias.

In any case, you'll want to get the cross weights correct so the car behaves similarly in right and left hand turns, and so you don't fry one corner under braking or acceleration.

Raising or lowering the rear (or front) of the car changes the effective lever arm between the CG and roll center. Generally, if you lower the rear you'll reduce oversteer.

And it sounds like you should have a brake bias valve ;-)

 

[Chuck 98 RT/10]

Carl, you're in Kali. Leave your car with Erik Messely EMI Racing.

 

[Catwood]

They are 500/750.

I had too much weight on the front for sure and yes, it was hard to get the rears to roll again in the first session. It actually, for the first time felt like I had no front brakes. I'm going to somehow borrow or buy a set of scales. I just needed to get an idea of where to try and set things.

Bias valve is on the list of things to get. But since I've run before with my "minor" brake changes and it was reasonably balanced one would think I should be able to get it close again. I don't want to hide problems with the turn of a bias knob but rather use it to fine tune.

Thanks
Carl

Try for 50-50 on the front wheels; you'll end up with more weight on the LR. Don't forget to sit in the car when you do it.

What spring rates did you put on? Are you in this range of front to rear?

250/450 stock
325/500 Roe (325/550)
400/750 ACR v1
450/650 Woodhouse
500/1100 OEM ACR that everyone thought had too much oversteer
500/850 mod ACR that people liked better
550/800 me
600/800 Verges
700/900 NDW on Archer revalve

Softer springs in back would keep the rubber on the track - if springs or shocks are too stiff, the nose droop under braking or heaves in the road will momentarily lighten the rear enough to lock, then they won't easily go back to rolling.

 

[Tom F&L GoR]

Another thought - since you have "minor" brake changes along with stiffer springs, it may sensitize the car to possible oversteer if not braking in a straight line. Body lean under will load/unload the outside/inside tires and if the rears are threshold braking already, you may lose enough cornering power at one of the rear tires to initiate oversteer.