The Official 370Z Autocross Thread

[Brendan]

Did some measuring this morning. I'm currently running a 275 on my oem 9 inch wide wheels. I have a little over an inch to go before it would cause rubbing with the fender. This is with stock camber which is a little over -1.0 on the "good" side. There will be even more clearance once camber has been optimized. I'm not too worried about the rear.

Seems like anything from a +35 to a +20~ should be able to clear without issue.

[howardrjarret]

hi was hoping I could find someone on here that could guild me to a proper autocross shock and swaybar , I have a 2016 370z nismo I ve been running re-71s for about 6 months now I run in A street and don't want to change classes I am only allowed to change shocks and 1 sway bar front or rear but not both. Ive been racing againt 2012 z06 vettes and 1le cameros porche 911and getting spanked, my driving skills need work but so does the car could someone guide me in the right direction please

[gomer_110]

Hotchkis front bar and a set of Koni yellows is what you're looking for.

fwiw Investing in the nut behind the wheel is always going to be a better investment than upgrading the car. It's easy to blame the car when you're just starting out but over time you'll learn more often than not, it's the driver that's the limiting factor.

[zpower86]

Originally Posted by howardrjarret

hi was hoping I could find someone on here that could guild me to a proper autocross shock and swaybar , I have a 2016 370z nismo I ve been running re-71s for about 6 months now I run in A street and don't want to change classes I am only allowed to change shocks and 1 sway bar front or rear but not both. Ive been racing againt 2012 z06 vettes and 1le cameros porche 911and getting spanked, my driving skills need work but so does the car could someone guide me in the right direction please

If your budget is less than $2000, then Koni Yellow shocks and Hotchkis front sway bar will do well. You might want to try a bar slightly less stiff than Hotchkis.

If your budget is higher, you might look at JRZ RS or RS Pro (which I have). Other good brands to think about are Motion Control and Ohlin.

Another tip on alignment. The front is non-adjustable on camber, but of course the car wants more. To address this, I would suggest loosening the upper control arm (a-arm) bolts with the car in the air, then lowering the car on the ground, then tightening the bolts while on the ground. This will take up any slop in the joint and possibly give you a little more camber. I never got to try this on my 370Z before selling, but on my nd miata, I gained about .2 degrees (more negative).

[Brendan]

Has anyone put any effort into STU build 370Z for the coming season? We finally got what a lot of us wanted. Hopefully we will see a nice turnout nationally.

[zpower86]

Originally Posted by Brendan

Has anyone put any effort into STU build 370Z for the coming season? We finally got what a lot of us wanted. Hopefully we will see a nice turnout nationally.

I know of one person who is near me. I believe it will debut at Dixie Champ Tour or Charlotte Match Tour.

[Brendan]

No 370z at Dixie, but I would like to start discussing ideas on what route to go with an stu build.

Mine will take place over a couple seasons but I want to do coils and alignment correction first over the winter break in 2018.

I want to try out the fortune auto 500s or have a set of 510 made. Going with them because of price and the fact that they are serviceable in the US. They are pretty well regarded in the time attack community so they should be able to stand up to solo. I want to stay in the 1.8hz range front and rear for spring rate. If anyone has feedback on what frequency would be better, I would be interested.

For camber correction I like the z1 kit. It seems to fall into the rules of the class and adds some caster. I'm not married to this option and would like to see what else is out there and legal for scca stu rules, but it seems to be slim pickings.

Last will be wheels and tires. I want to wait until suspension is sorted before I purchase pricey aftermarket wheels because I want to be able to accurately measure clearances. The z seems to be blessed in this area. I am running square 285 on the stock wheels and its clearing easy. 18's would be the obvious choice. With the tall second gear we could drop a few inches in overall diameter and still top out at ~65mph in 2nd gear which is the magic number. I admit the only reason why I would be hesitant to drop down would be aesthetics.

The rest of the allowance will wait depending on how I develop as a driver but I would be interested in what we feel are particularly weak areas on the chassis that should be addressed with stu allowances and what the impact might be.

[zpower86]

I misspoke about Dixie -- Charlotte will be his first National event.

Brenden- will you be doing an LSD early on?

[Rusty]

Originally Posted by zpower86

I misspoke about Dixie -- Charlotte will be his first National event.

Brenden- will you be doing an LSD early on?

[gomer_110]

Just my two cents but I can't see a STU 370z being worth a damn without a proper clutch type LSD.

[Brendan]

Originally Posted by zpower86

I misspoke about Dixie -- Charlotte will be his first National event.

Brenden- will you be doing an LSD early on?

Originally Posted by gomer_110

Just my two cents but I can't see a STU 370z being worth a damn without a proper clutch type LSD.

I personally don't know. The stock one hasn't let me down, but I don't know how that will be as I do more events and the car gets modified. I don't have much experience driving cars with a true type lsd so getting that seat time will def be a priority in terms of developing my own car.

In regards to the vlsd, what driving characteristics should one look for when determining that the limits of the dif have been exceeded?

Oh, and I hope he does well. I'd like to reach out to him after to get his impressions and learn more about his build.

[zpower86]

Originally Posted by Brendan

I personally don't know. The stock one hasn't let me down, but I don't know how that will be as I do more events and the car gets modified. I don't have much experience driving cars with a true type lsd so getting that seat time will def be a priority in terms of developing my own car.

In regards to the vlsd, what driving characteristics should one look for when determining that the limits of the dif have been exceeded?

Oh, and I hope he does well. I'd like to reach out to him after to get his impressions and learn more about his build.

Agree with Gomer — you’ll want the LSD. It’s prob top 5 on my list of ST mods (wheels/tires, coilovers, a-arm, lsd, power mod). Basically you’ll spin the inside wheel on every corner exit. The car won’t rotate on throttle application (which adds to understeer, but saves you from spinning out). The VLSD doesn’t allow the power to be put down. If you’re driving the car hard in BS, you’re already being held back. A friend of mine drove my Z once and thought my clutch was slipping, but it was just the inside tire smoking LOL.

[Brendan]

Why would a clutch type be more beneficial than others? I understand a lot of people prefer the OS Geiken model.

Edit: From what I understand the main difference is that a clutch type works better when one wheel is off the ground. That would seem like a pretty rare circumstance on a rwd car on street tires with more or less open suspension modifications available. Is that the main concern for those recommending a clutch type? I don't like that clutch types may affect street driving and require service.

Edit 2: If the clutch type is the way to go, what are the thoughts on the Nismo 1.5 way?

Edit 3: apparently the lock in a clutch type has more tunability. The torsion types can be tuned as well but to a lesser degree. It also seems that the poor street ability comes on the higher ends of lock and that you can build diffs like the osg to have a more progressive street friendly lock transition. The biggest knock is service but if we are talking once a year, that doesn't seem so bad. What is the typical interval?

[Justint5387]

I have a Cusco diff for sale soon if anyone wants one. Replaced all the clutches less than 3000 miles ago.

For cheap 18" wheels check out the 18x10.5 Konig Hypergram, they are $880 for the set and weighs 19 lbs

[gomer_110]

Originally Posted by Brendan

Why would a clutch type be more beneficial than others? I understand a lot of people prefer the OS Geiken model.

Edit: From what I understand the main difference is that a clutch type works better when one wheel is off the ground unloaded. That would seem like a pretty rare circumstance on a rwd car on street tires with more or less open suspension modifications available. Is that the main concern for those recommending a clutch type? I don't like that clutch types may affect street driving and require service.

Edit 2: If the clutch type is the way to go, what are the thoughts on the Nismo 1.5 way?

Edit 3: apparently the lock in a clutch type has more tunability. The torsion types can be tuned as well but to a lesser degree. It also seems that the poor street ability comes on the higher ends of lock and that you can build diffs like the osg to have a more progressive street friendly lock transition. The biggest knock is service but if we are talking once a year, that doesn't seem so bad. What is the typical interval?

ftfy

The wheel doesn't have to be off the ground to cause issue, just unloaded. When I used to have the Quaife (torsen style) in my car it was a real problem on corner exit getting the power down consistently. I imagine the vLSD would probably be slightly better than a torsen in that sense but only as long as the special goo in it hasn't broken down. Clutch types simply don't care if a wheel is unloaded or in air and will give you consistent and confident power down on corner exit.

From everything I've heard and read, the reason the OSG's are preferred is they are silky smooth unlike many other clutch type LSD's. My Cusco 1.5 way is admittedly harsh and clunky when not driving the car hard. It is still tolerable for when the car occasionally sees street driving.

While I'm no expert on the maintenance of LSD's, I can say I've had mine in the car for 2 full seasons now with no indication of needing a rebuild yet. Also consider that is with the car running on Hoosiers which can be more punishing to equipment than street tires.