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Track shock/spring advice

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Mad Hatter

Gotta go Faster
5,237
4,227
Santiago, Chile
I would love to have access to people like Terry and AJ in person.. but being thousands of miles away is a problem and so is a lack of money (tires eats away at your availble cash!!)... That and our packrat nature that makes us skimp on sound fundementals in search for the cheap way ahead!!
 

Grant 302

basic and well known psychic
I do have one question.....what the heck is the air valve doing on top of the shock? Didn't see any explanation.
That's for the nitrogen gas charge. Don't play with that!


You are correct.....I'm really at a loss when it comes to adjusting. I do plan on sitting down this winter and really figuring out how to work with the DA shock.

Take your time with it. Especially this CorteX style DA. Not like the rest. Lots of control, but you gotta learn it.
 
147
60
Congratulations, according to your OP in this thread you are driving the car harder and faster.
In regards to the way you are driving the car now and your feedback from the car:
If you don't like the brake dive, as Terry and others have stated, I agree, YOU NEED MORE SPRING. Period. Math doesn't lie.
Furthermore, spring rate is the (best or only) place to start. All other components follow suit.
You might want to consider 500, 550, 600, as this will save you time and money. Just my humble opinion from limited experience.
Talk to the vendors mentioned in this thread and they will definitely steer you in the right direction.
 

Grant 302

basic and well known psychic
If you don't like the brake dive, as Terry and others have stated, I agree, YOU NEED MORE SPRING. Period. Math doesn't lie.

The reason I say 'maybe' on the springs is that dive can also be reduced with geometry changes. Springs aren't the only component at work here. Lots of other settings determine the transfer and dive properties. Remember that a 450# spring is already 3x stiffer than the stock setup.
 
I ran the 450/250 springs on my Cortex/JRi SA setup and don't recall excessive brake dive. In fact the car was really well hooked up. But I was on NT01's and not slicks. Although I haven't run slicks on my Mustangs it seems most run stiffer springs with slicks.
 

domesticpower

Track Addict
190
135
NS
If the car pushes on corner exit, I'm assuming it's under power. You may have a situation where the car just puts power down too well. A T2R diff will make it worse. A more neutral balance may take care of the push but keep in mind, though, that less understeer may not be faster unless it's a very short/technical track and you need to carry as much speed as you possible can without much room between turns. Although it is frustrating, you may be better off just slowing down a bit more on entry and getting a better exit.

Seems to have already been said, but changing shock stiffness won't change the amount of brake dive, just slow it down. Springs and/or geometry take care of dive. I haven't tackled that on my own car yet so I don't know what works on our cars. Anti-dive geometry is much better than using spring rates to deal with dive because spring rates affect a lot of other things so it's better to isolate dive and tune spring rates to what works for your setup. More rear braking will help too, just be careful not to go too far with that. It's not best to always lean on ABS to save you and if you are getting too much brake dive, the rear end is light so locking up is easier.

Good luck! Please post what ends up working for you.
 

ArizonaBOSS

Because racecar.
Moderator
8,730
2,734
Arizona, USA
Lots of good input in here.
Ultimately, it is all dependent on what your driving preferences are combined with what the track surface/condition will allow.
A 600 or 800 # spring will of course have less brake dive than something lighter. I am in the "something lighter" space.
Rear spring rate will also play a factor, in conjunction with rear rebound rate.
Geometry and ride height/rake will play factors as well.
 

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