What is your opinion of adjusting the rake?

I haven't measured yet on the stock suspension and when I get my coils put in I will most likely set back to same rake and only make one change at a time.

but just curious as to the guys with a lot of experience on this platform and whether its actually used for suspension tuning to ad some adjustment to dial in more understeer/oversteer instead of just for looks or better aero efficiency for the crazy aero cars.

Suspension specs right now

Stock Shocks/springs (no perch mods)
Hotchkiss sways F&R - set to 3rd stiff on front, middle on rear
Kinetix front arms (unmodified for now), -1.4 camber (at stock height) (need to fix this i know)
BV rear arms, -1.2 camber

Caster & toe within stock range

 

Good question, in for answers too

 

Do a search for weight jacking or corner weighting. This is the closest you'll come to answering your question.

Start here: https://grassrootsmotorsports.com/ar...orner-weights/

 

Rake can have a limited effect on suspension dynamics but its more a function of aero.

 

Thanks for the link, good info.

but... i'm already familiar with cross weights and balancing the car, from years and years of setting up my dad's tube chassis circle track car. I'm a little rusty with that though so the information is still useful.

Adjusting the rake is another tool for dialing out oversteer usually and I'm just looking for info on how adjusting it affects the Z chassis. I've found information from Miata guys and S2k pages but nothing on how the z is affected by these adjustments or what it likes. Adjusting it, i know will do very little with respect to weights of the car. its all about roll center and suspension dynamics

Most people add or take out the rake purely for looks.. others need it to increase aero effeciency and downforce.

Like I put in my op, i haven't measured my car on a level surface with the non square setup, but the z naturally has some rake induced with the staggered setup. and there is still some, visibly, with a square setup



^^Picture is stock shocks/springs no suspension modifications to ride height. only a square tire setup

So overall I'm just wondering if any of the dedicated track guys have some rhyme or reason to have a specific setting for the rake on our chassis. I know Miata's like .25" positive rake front to rear, and i know S2k's like .25" to .5" negative rake front to rear. but can't seem to locate anything on the Z outside of what people think looks best.

 

I like watching that video.. i've jacked up the view count up quite a bit myself.. haha

on the Aero note.. i don't have any added.. so i think that would be a very slight change if i went super positive and the air flow over the top of the car increased which would have some slight effect on increasing oversteer. But how much more of an effect would be caused by the change in suspension geometry by the increased ride height/ altered roll center?

If I had Aero I would agree whole heartily.

 

Aero on stock body is affected, just not as much as a car with aero. Rate also changes your caster angle. With my square setup, I run about 15mm of rake

 

I have found rake adjustment to be pretty sensitive on my autocross car. So it definitely can have an effect on the car at slower speeds. I have about 13mm of rake with a square setup, if I drop the rear 10mm the car will tighten up, very similar to one notch on the rear swaybar, maybe more. On 275/35/18 tires my front fender is around 25.5 and rear 26 inches.

 

great, Thank for the info Terrasmack and Steidz.. that's along the lines of what I was looking for. I'll be sure to measure stock suspension before I put the coils in that way there will be more information out there

 

I actually just adjusted the rear ride height on my autocross car to attempt to make it dig out of corners a little harder. I was initially at around 25.5" measured from the ground to the top of the wheel well in the front and 26-26.25" in the rear. I lowered the back 25.5"-25.75" and after one autocross session felt the car was more neutral and did not tend to oversteer quite so much.

Interested in your results to prove it wasn't just in my head.