The Official 370Z Autocross Thread

[pgrmstr]

Originally Posted by AutoX Z

Getting this thread back up top.

The shocks are still not completely on the car. It has been a nightmare trying to make these shocks legal, getting the overall and compression lengths correct. However, we are getting closer and should have them on the car for nats. Whether or not they'll be dialed in correctly is a different story...

I'm in the same boat....shocks finally arrived a couple weeks back, and have been struggling with getting them corrected, had to send the rears back and they needed to replace the cylinder with a longer one to make the length legal. Had to do some tinkering on the fronts as well, but they are all sized correctly now and got them on the car this past weekend finally. I have 2 local events before Nats to try and get them dialed in....assuming they are valved correctly, otherwise its back to stock shocks. Sure woulda been nice to have these back in July though

[TheNose]

Originally Posted by pgrmstr

I'm in the same boat....shocks finally arrived a couple weeks back, and have been struggling with getting them corrected, had to send the rears back and they needed to replace the cylinder with a longer one to make the length legal. Had to do some tinkering on the fronts as well, but they are all sized correctly now and got them on the car this past weekend finally. I have 2 local events before Nats to try and get them dialed in....assuming they are valved correctly, otherwise its back to stock shocks. Sure woulda been nice to have these back in July though

At least you guys will have the fit and valving figured out by the time I go to order them over the winter! Thanks for being the guinea pigs

Now I just need someone to figure out if 315s will work in the front

[pgrmstr]

Originally Posted by TheNose

At least you guys will have the fit and valving figured out by the time I go to order them over the winter! Thanks for being the guinea pigs

Now I just need someone to figure out if 315s will work in the front

well then, since we were the guinea pigs for the shocks, i think its only fair for you to be the guinea pig for trying to get 315's working on the front

[ChrisSlicks]

I'm sure I could make 315's work but they wouldn't be on the stock 9" rim unfortunately. 315 on a 10" works.

[pgrmstr]

i thought I read a thread on sccaforums awhile back where the corvette guys had stuffed them on an even smaller rim......and i think there was something about the tire wear difference between the two sizes...but i cant recall what the results were....but i thought it was an odd conclusion

i imagine a spacer would be needed up front as the 295 even rubs so not sure what the spacer would do to the outside clearance....

don't know why Nissan rolled the rear fenders but not the front

[TheNose]

Originally Posted by ChrisSlicks

I'm sure I could make 315's work but they wouldn't be on the stock 9" rim unfortunately. 315 on a 10" works.

The only reason I'm tempted to try on the 9" wheel is that I've seen C6 Vette guys running 315/30/18 on an 18x8.5" wheel. They said it gripped as well as the 295 but had much better wear characteristics. The Hoosier spec sheet even says they're the same diameter as the 295/30. With a stock legal 5mm spacer, I think there's a good chance they'll clear on the inside.

Originally Posted by pgrmstr

well then, since we were the guinea pigs for the shocks, i think its only fair for you to be the guinea pig for trying to get 315's working on the front

Fair?!?! Who said anything about fair? When I try it in the spring, you'll be the first to see how it works. It'll probably be with 315s in front and 295s in rear for the first event

[pgrmstr]

Originally Posted by TheNose

The only reason I'm tempted to try on the 9" wheel is that I've seen C6 Vette guys running 315/30/18 on an 18x8.5" wheel. They said it gripped as well as the 295 but had much better wear characteristics.

yup, that's what I read!

[cossie1600]

I ran in the nationals with a C6 2 years ago, we used 295 on the stock 8.5"

[AutoX Z]

Originally Posted by cossie1600

I ran in the nationals with a C6 2 years ago, we used 295 on the stock 8.5"

I was goona ssay I know the C6's use a 315/19 on a 9 in rim up front. I'm more worried about strut clearance even with a spacer. It depends on how the tire deflects once it's squeezed onto that rim.

[cotizi]

anyone using aftermarket sways for autocross? thinking of getting some but i dont know if it will improve anything. Running BSP, so i have really wide front tires as it is. Car feels pretty neutral as is.

[ChrisSlicks]

Originally Posted by cotizi

anyone using aftermarket sways for autocross? thinking of getting some but i dont know if it will improve anything. Running BSP, so i have really wide front tires as it is. Car feels pretty neutral as is.

For SP it can help a fair bit which quick direction changes as you can run a matched set, although I found it was pointless unless you also had camber arms. I have coilovers, front camber arms and sway bars. The combination of the 3 makes the handling pretty damn good.

Here's a video from yesterday. Unfortunately I didn't have race tires on as they were still sitting in a friends trailer from the previous weekend.

[cotizi]

my AX venues are loaded with quick changes and slaloms . I think i get to the top of 2nd maybe once in the entire course, usually stay in mid power band 2nd the entire time. I use 10.5" wheels on all 4 corners and it helps a lot with understeer. My understanding is that a stiffer front sway is just going to make understeer even worse, especially at low speeds. Correct?

curious as to what control arms are you using. I've been in contact with SPL parts for product development and test fitting since im local to them in Austin. They said they will get with me when they need a test fitter, they are working on other projects it seems.

[ChrisSlicks]

Yes it did make understeer worse at low speed but that was all but eliminated with the increased camber.

I'm using the SPC upper control arms. Not the easiest to make small adjustments with but they get the job done. You do have to torque the lock nut quite tight to prevent it from slipping. Currently running about -3.5 degrees. Wheels are 10" front, 11" rear.

It would be great if SPL comes out with a part as well. It will be more expensive but will be lighter than the steel SPC part, the OEM arm is aluminum.

[AutoX Z]

Originally Posted by cotizi

my AX venues are loaded with quick changes and slaloms . I think i get to the top of 2nd maybe once in the entire course, usually stay in mid power band 2nd the entire time. I use 10.5" wheels on all 4 corners and it helps a lot with understeer. My understanding is that a stiffer front sway is just going to make understeer even worse, especially at low speeds. Correct?

curious as to what control arms are you using. I've been in contact with SPL parts for product development and test fitting since im local to them in Austin. They said they will get with me when they need a test fitter, they are working on other projects it seems.

The stiffer front sway can increase grip if your are running very sticky tires, aka Hoosier's. The front sway will keep the car from rolling further, which can improve the front tire's camber. It can also help with putting down power at the rear by reducing roll and changing the stiffness ration of the car.

SCCA Nationals update pending, getting my videos uploaded, stay tuned.

[cotizi]

Had a really good ax this past weekend, but co-driver noticed the wear on the rear tires isn't in the center, but more towards the outside edge. thoughts? more negative rear camber?