Heyo,

Looking to leave the stock classes and give STR a try. I run a non-track model 350 though, so no Brembos. I know the conversion is fairly simple, but to stay within the letter of the rules, everything else track package-wise must also be done (minus creature comforts).

Aside from brakes, shocks, aprings and I think differnt guards under the car, what might also need to be done? Taking into consideration that shocks springs, sway bars and wheels will all be swapped out for aftermarket anyhow (or already have been).

 

You have it pretty well covered. STR is tough class for the 350z....we are simply to heavy to be competitive with the 255mm tire limit. Good luck though. Doesn't the track have some slight aero changes.....not sure....I really can't remember.

 

I think it has a pseudo-rear diffuser, and the chin spoiler up front.

 

No deal. It will cost $$$ to convert a no-track to a track. And what do you gain? If you want a track buy one.

 

The Brembos won't really buy you much performance-wise in AutoX. Big-brakes are about heat management, not stopping distance.

You didn't mention the year and model you have, so it's hard to say exactly what will be needed to become a "track" model. If your car doesn't have VDC, then it's virtually impossible. If you have a Performance, then all you need are the brakes, the aero mods and the rear spoiler.

If you're going to STR, then you don't really need to stick to "stock" configurations anyway. Just follow the guidelines for STR.

 

^Dave....he has a touring.

 

I think this is the biggest point to be made. (For reference, http://www.zeckhausen.com/testing_brakes.htm) If you notice the stopping distance is within 2-4 feet at speeds up-to 100 m.p.h.

 

I beg to differ on Zenhaussens findings. When i upgraded from the teeny weenie single piston sliding calpiers to 6 piston 13'' BBK with race pads, even cold and short stops were shorter and more consistant.

 

Race pads ?? That could help, especially since even the stock pads will show some fade in 1 stop from 100mph.

 

How many autoX courses allow speeds of 100 mph???????

autoxr - I'd suggest reading these two threads...

https://my350z.com/forum/autocross-r...str-build.html
https://my350z.com/forum/autocross-r...solo2-str.html

Both deal with the STR class. From there, you might get some ideas of what would be useful modifications as a starting point. You'd be better off investing money in mods that will help the Z in STR, not just doing mods that while are beneficial, they may not provide much bang for the buck.

 

Yeah I dont even auto-x and I think your plan of attack is a little misquided. now this might be where my lack of auto-x comes in, but couldn't you just modify your car to str levels seperately from what the Track model limitations are? I would think for auto-x you want a pad with high initial torque that requires little to no warm-up time.

I would think RBF, lines and pads would go a long way in improving your current braking needs.

The track vs touring difference are marginal in an auto-x environment. It's just brakes and "aero" panels under the car. I doubt those parts alone are going to make substantial improvements to how the car performs within 1-minute and at speeds less than 75mph.

I would invest your money and efforts elsewhere. Can you do bushings within the STR guidlines? A full or partial Whiteline bushing kit would be about the same as a brembo upgrade (granted it would be more effort).

 

Not to defend his findings directly, but I know my single sliding binders worked alot better when they were new vs. now. Do you think it possible your brakes' degradation played a part?

 

Thanks for the comments guys. I guess I should have added that I track the car now and again for time trials. I've pretty much opted to go for a better rotor and pads for the moment. As has been mentioned, the rest of my time will go into sorting out the allowable modifications for STR.

Yes, I know the 350 is a huge underdog, it can't seem to escape this. I love the car though, and it just means I have to work even harder to better my own driving. Fun Fun Fun

 

Two points to make:

1) pads and fluid will get you as much performance advantage as the Brembo/Track upgrade will in terms of autocross. Both have plenty of power to lock the wheels/engage ABS, so all you gain is fade resistance, which is a non-issue in autocross.

2) In STR you don't have to do package conversions. Brakes are free upgrades (within the rules in the book). Download it and read it carefully.

That stuff said, I too have a 350Z in STR. I paxed second with it at the last local (and trophied with it at the Tri-State NT last October), but it's off the pace of the S2ks and MX5s. I think with another $5,000-$6,000 in lighter parts and more power/grip (especially a good LSD), it might (MIGHT) be competitive. I already have a pretty damn good suspension setup. Even at ~2,900lbs (the absolute lightest possible) and with ~265whp, it won't likely be a class winner at nats though.

My car as it sits is retardedly fun to drive, however, and the STR modifications make for a car that's still streetable and definitely quick in the corners.

One thing you should definitely be aware of is the ice mode situation with these cars. It only gets worse once you upgrade pads/fluid and start kicking in lots of negative camber and putting on stiff springs. Check out my close call from this past weekend for evidence. Losing almost all brake power at 50+mph is no fun:

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That was scary and that's why I hate parking lot autocrosses. That didn't look like a situation where ICE mode would have kicked in though.

 

Agreed. Ice mode typically happens when there's a wheel in the air or some sketchy traction issue.

I left foot brake, though, so it's probably just that I never was off-throttle and off the brake long enough to rebuild vacuum for the brake boost. Still, you'd think 3-4 braking elements in a ~50 second course wouldn't completely deplete the boost on a sports car. It doesn't in any other car I've autocrossed (and that numbers in the dozens).

 

I autocrossed mine for years and never had a brake issue like that. You may be right about the left foot braking having depleted the vacuum reserve.

 

I think the Factory Service Manual has a test for your brake booster to make sure its operating correctly. The track layout didn't seem hard enough on brakes to cause that without a problem.

 

The car doesn't dive very far on braking because it's running 650lb front/500lb rear springs with shocks to match.

Before the three hard turns (each seen twice except for the last one, which was obviously not quite made ) I'm on the brakes HARD, going from the top of second to less than 30mph in well under a second. It might not seem that fast, but if you watch the tach, I'm near redline in second several times, and ~50-55 mph going into each braking zone. Redline in 2nd on these tires is about 58 mph.

The car has pulled >2g on braking on street tires (even with -3.2 degrees of front camber) when I've had data acq on it, and I'd say it was close to that in each of those zones.

I'll check out my FSM for the test, though it works just fine if I right-foot brake and make a point to leave a gap between gas and brake. Of course regular ice mode is still an issue occasionally, but that's just the Z's nature, I guess. LFB is just so much faster when I've got to balance all that weight on little tiny street tires.

 

Just remember that ice mode simply cuts off the brake booster. What used to take 5 lbs of pressure on the pedal may now take nearly 100 lbs.

Personally, I don't mind ice mode, but then again I'm used to driving formula cars with zero brake boost -- so rather than 8 oz. of pressure difference to "unlock" the front tires in a skid, it's more like 10 lbs of pressure difference.