Autocross Push bad help
 

Hey guys,
So raced my z today in autocross and I had severe pushing or hoping in the front. Only mods are Whiteline Front sway bar and CBE. Tires were at 38 all around. It was extremely hot day.

Any ideas on how to get rid of the major push. btw, front sway bar is on stiffest setting.

Granted I am in B Street class so major mods will push me out of that class but I am thinking coilovers would be key?

Tires. I had severe understeer and bought a set of square wheels and 285/35r18 hankook ventus RS3's. That got rid of all of my understeer. Get the best tires you can for your class

What size and type of tire are you running?

I have the sport wheels with Continental Extreme Contact DW tires.


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What wheel size do you use?


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If you are running 245/40-19 up front you can go to 275/35-19 on the stock Rays.

18x10.5 all around

First thing I would do is get a bigger front tire, it will help tremendously. if you want to stay BS just run 275 square. I am fairly new to this car but been autocrossing a little while. I have koni yellows, eibach front sway(on soft) and 275 RS3's square. I was pushing yesterday with my tires being new and greasy, the afternoon I decided to run the konis stiff up front, about 20% rear, 36f and 33r psi and it was handling great.
with all this said I would recommend tires first then possibly the konis if you want to do this every month

Like everyone else said. The easiest way to dial that understeer out without getting booted from B stock is a front tire upgrade and more width. Check the books though as there might be a limit to how much wider over stock you can go in that class.

Make sure if you end up getting new tires you get the Bridgestone RE-71R's. Currently, these are the street tires to have for autox.

That front bar setup is too stiff for your current setup and track conditions. Once you have more tire (wider and stickier) it will work better. Until then go softer on the front bar.

Set the front bar to full soft and rear to full stiff. Try again.

Thanks guys going to soft for now. The sad thing is I just bought brand new front tires! I will be moving out of b stock since I am getting air intakes plus oil cooler and 4.08 rear gear soon.

Really appreciate all the information!


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Wow...right up to...ASP? Or is that SM2? Not sure on the rear gear...may be a EM?

Last I knew I believe rear gear sends the 370Z to F-Prepared. If the OP wants to be competitive, doing the rear gear is a bad idea. As a couple of the top FP cars in the country are local to me, I can say there's no way the 370Z can compete. At least not without spending an absurd amount of money.

You never answered what size front tire you are running.

Sorry running the stock tire sizes for 19" Rays. So 245/35/19 I believe


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Thanks man. I figured that might be useful info if anyone references this thread in the future.

I've really like going 38 psi front and 40 psi at the rear, but I'm still on stock suspension.
Is the push as you enter the corner or is it on the exit?
If it's at the exit you may need to brake a bit more before the corner and get on the gas just a bit later, I've noticed that usually in a chicago box more than sweepers or slaloms.
If I come in a bit too hot the front feels like it's pushing out hard and it almost sounds/feels like the tires are rolling a bit. If I come in a bit slower and get on the gas a bit later my times have usually improved in those areas.

The best solution to help with understeer is getting wider front tires. Everyone has already said this, but I thought I'd tell you from experience. I was on FR 245/35R18, RR 275/35R18, then went 275/35R18 square -- night and day difference.

Also, I just got RE71s and highly recommend. I hear the RS3s are decent as well. On the stock 19" wheel, it looks like you can go 275 or 285 square on RE71s. RE71s

Shocks (konis) will help the cars handling and your times might decrease, but if you're in the middle of a large sweeper with the narrow tires, you're still going to have the understeer. This was true in my experience when I had Konis and narrow front tires.

The 370 can be competitive in B Street (where I plan to stay). Not sure how well it does in ASP or other classes.

Don't you mean you want to come in slower and then get on the gas earlier??

Thanks guys, my next set of tires will be 275 for sure all around on the 19". Most likely the re71s.


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ADDCO used to publish a handbook on sway bars. If you can get a copy READ IT!.

If the front end pushes you increase the stiffness of the REAR sway bar not the front.

This is a generalization. There are other factors that contribute to proper sway bar selection and settings. Suspension geometry and maintaining negative camber under cornering loads are an example.

Sorry guys I admit I am a noob but hooked on track racing now. Primary goal track times. Secondary goal auto cross times.

Hadmajor issues with clutch and fuel pickup. Clutch would stick after lap or two. Then once I got to half tank then fuel pickup issues on certain corners. I think I will stick with stagger setup for now as I was quick on track.


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are you filling up before the track? you should be at a full tank or close to it. Personally I fill up at the closest station to the track and I'll be good for the day (4-5 sessions). As for the clutch, flush out the clutch system with some good fluid and hope your CSC isn't toast!

Autocross Push bad help
 

I had clutch issues at a track day too. I was on third 20 min session. It came back if I pumped the clutch VERY slowly. Eventually I changed the fluid (which looked horrible) to Motul and now it's fine. Only 21k miles on the car. Get a pressure bleeder when you change the fluid -- it was very easy.

I burned 8 gallons at the track night with only:
<60 min on track
15 min paced laps
5 min street driving


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I answered your questions in your other thread. ;)

Yep thanks Rusty and everyone else!!!



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