Yep, .5" bigger and 3lbs lighter, the weight came off the hat. I did the swap because it was allowed in STX. I saw no reason to go with the stock size, not enough blingage. Also the 13" rotor was offset a 1/4" further in then the OE size, which helps for wheel clearance - although it turned out not to be an issue with my wheels, I think I can just about change pads without removing the wheels I have so much space.

I think the whole STR class is a cluster. I hate that from one class to another ST has no continuity. STR gets ST/STS cat and brake rules, wheels and LSD rules from STX, and tire sizes that do not coincide with any of them.

At a minimum I think STR should have gotten a 265, just to help the bigger cars and put it more in line with STX. But honestly I don't think a Z has a chance even on a 265, to much power and weight, it needs to move to STU.

 

Don't you think telling him to "shut up" is a little harsh?

Or is something else going on?

I value his posts and his experience, wouldn't want someone elses disrespect to have him not post as often here.

 

John can take it.

 

Another noob with a question. . .

So if we bump out of STR because of mods (tires or whatever) where do we end up? Can we still run in BSP ?

 

An STR Z would go to BSP. In the past you could not because SP did not allow brake kits and control arms, but now the rules are lined up. But keep in mind mods beyond SP will move you to SSM.

 

No way!

That's what I was asking for two years ago...

https://my350z.com/forum/autocross-r...ire-class.html

 

In these past two years have you done anything to better your case? Sent in any letters, data, anything? Now you have a foot in the door, don't just sit on it. Do nothing and you will just waste away in STR on skinny tires.

 

I competed in STU-2 at our floida state championship last year. (we tied for the best turn-out of any class)

I just drove from the bottom of Florida to Milwaukie for the National Street tire Challenge.

I am even considering trying to get a co-drive for the STR class, at national events this year.

I have supported street tire classes for the Z, and put my money, and time, where my mouth is.

 

That is great. However, unless you sent information in to the SEB/STAC they won't even know you were around. They can't possibly track all of the local events held around the country. Running your car in BSP at a National Tour would have been a better data point, they see those results.

 

I was simply demonstrating demand for a street tire class.

Since that original thread, I have helped my brother prep his car better for STU. I was surprised at the extra power we were able to get out of his car, and with AWD, that power gets to the ground pretty well. I can't imagine NA cars getting those kind of power gains within the same rules, much less get it to the pavement well.

While I still want into STU, I have my doubts about parity with the AWD, FI cars.

The STU-2 class worked well at state, but I think John Ward was the only "national" competitor in the class and he co-drove someone else's S2K.

-Neither of our cars were fully prepped though.

I think the AS and BS cars have a prima facie case for admission into STU. What "data points" did the SCCA use to pick and choose which cars would be allowed into STU to begin with?

The biggest problem is that the SCCA's rules regarding tires is 180 degrees out of phase with the rest of their rules.

The SCCA makes all kinds of rule changes to level the playing field when the field is covered with race tires. At least that's the case at Nationals. At the grass roots level, many (if not most) autocrossers drive their cars to the track and "run what they brung".

Thousands of rules regarding mods that will bump cars all over the class map, and race tires, the one mod that trumps all others, is largely ignored.

Did you roll your fenders? That could change your class.
Those springs that lowered your car 1/2"? Bump.
That power steering cooler you installed? Bump.
On and on and on.

Race tires? No problem! Everyone is on race tires. Right?

Street tires, race tires. "Whatever". What the SCCA really wants to know is the offset of those pretty wheels you put on your car.

The SCCA agonizes over the most trivial mods, but the mod that eclipses all other mods is an afterthought in the classing system.



It's like having a drag-racing organization that nitpicks over the weight of floor mats but allows forced induction in almost every class.

Senseless.

/Rant

Sorry for the thread-Jack.

 

Actually, I drive on DOT-legal street tires -- they have measurable tread in two places at least 180 degrees apart. They also have a treadwear rating of 40-50. And yes, I've driven on them on the street, and *VERY CAREFULLY* when it's wet. They are not "race tires" by definition, since race tires would not be legal to use on the street. They are simply very sticky street tires.

 

I have to - I build stuff for magazine writing primma donnas. :-)

 

BTW... I'm not as negative on the 350Zs prospects in STR as others. Weight reduction and rear traction improvement plus a Solo2 God behind the wheel might rule the day. Unfortunately I'm not in a position to build my car to the rule limits and nothing about my driving is God-like (except when my passengers/instructors start praying to their God).

Here's my thoughts:

1. Reduce weight every legal way possible. An ounce here and an ounce there can add up. Wheels are the most critical and be prepared to spend a lot on custom wheels and run Hoosiers. Whatever weight you can't remove, move to the back of the car if the rules allow.

2. Play with track width. Experiment with wider front narrower rear and vice-versa.

3. Alignment is important and you'll want as much positive caster as possible to plant the inside rear wheel. Do whatever you can to the point of making the power steering pump scream and then back off a tad. Run as little rear camber as possible.

4. Run a good LSD. OS Giken is the best for our cars IMHO.

5. Be prepared to spend a lot of time and money testing.

6. Only spend money on making power if the change also reduces weight. The 350Z doesn't need any more power to win, it just needs to go on a diet.

7. Big front and little rear springs. Experiment with adjustable ARBs (I like the Nissan Motorsports bars).

8. Bring three sets of new, heat cycled Hoosiers to the Nationals. One set for practice and one set for each of the competition days.

9. Sign up your Solo2 God co-driver and resign yourself to being the tire warmer - to the point of not trying for your fastest run, just making sure the car is setup well and the tires are warmed up and not hurt.

10. Pray - a lot.

 

^ all this talk about Hoosiers?! You are describing a bsp build not an str build. The z doesn't stand a chance in str. And the level of competetion in BS now, I threw down and screwed myself out of a trophy. I drove the Z on the ragged edge

 

Sorry, forgot about the street tire thing. Forget the Hoosiers.

 

It's the internet, so I can't tell if you typed this with a straight face or not.

I drove my "street tires" 3000 miles round trip to compete in Milwaukee. I haven't just " driven... *VERY CAREFULLY* " on them for special occasions. I drive on them, every time I drive my car.

 

OK, back on topic a bit: a brief review of my STR build thus far based on its first outing.

Some background: it was a on/off rainy/misty day on a moderate-grip asphalt surface. There was at least one run with essentially dry levels of grip early on in the day, but most of the others were at least slightly compromised. My fastest run was my second.

I ended up about 1 second behind the fastest STU Evo X (fairly well prepped, built along the same lines as Terry Fair's, running Yokohamas) in a six-run best-of format. Not too bad in a grip-compromised environment, and I'm certain in a higher grip environment I would have been pretty much dead on their times.

The car felt good, but I clearly have some more learning to do on street tires. I've managed to smooth out my brake/throttle inputs pretty well, but I'm still a bit too choppy on the wheel. The Z on race rubber required pretty violent inputs to get anything to happen, but it's the reverse of that now.

The car also reacts much more quickly than it did in stock form. I turned right into a couple cones because I wasn't expecting the car to get there before I was past them.

A few people noted something interesting though: on the last run, with standing water all over the course, I just had some fun, and they said that as I spun/drifted through the 'showcase' turn, only one wheel was spinning. So my viscous LSD may be shot. That's gotta be worth a little time, and I still have some weight to lose.

I'm planning two more tests before the Blytheville NT at the end of October, so I'll update with what I think of the build and its performance (and any changes/upgrades I make) in the mean time. Hopefully we can all get something out of it and put together a few (semi)competitive STR Zs.

As for the STU inclusion: on 285s and sufficiently wide wheels, the Z would be a pretty damn quick ST* car. I think another 30mm of rubber might have been enough yesterday to put me back on par with STU even in the semi-wet.

 

A lot of good stuff here (aside from the Hoosier stuff lol :P). If you compare it to my build list up above you'll see a lot of similarities. I did forget to mention the adjustable COBB bar from my BS build; it's set on the middle setting and seems to be about right.

I may need to decrease my rear spring rate a bit, but I'm betting it's mostly because it was in the wet. I could have backed off the last bit of rebound in the rear shocks (they were just 1/4 up from full soft already), but at that point, I just tuned with tire pressures.

Would you mind explaining the reason behind OS Giken choice? I'm basically starting from zero on picking a diff for this car. Haven't even decided if clutch or gear-type is best. I can see good things on both sides.

 

The question wasn't for me, but I run the Quaife, so...

I have been autocrossing the Quaife for about 3-4 years and it's great. I have very little seat time with the clutch type diffs, but I can tell you that Quaife's operation is seamless, smooth and effective.

And I still think having power sent to the outside wheel, when turning, helps the car turn (roatate) better than a diff that "locks" both wheels. (even if only by a small margin)

 

Its probably fine, that's just a typical behavior of the low dollar VLSDs manufacturers put in cars. They really aren't suited to competition.

Regarding the OS Giken...

I've run the Nismo 1.5 way CLSD and the OS Giken in my base 2006 350Z and much prefer the OS Giken. Its smoother in action and goes much more open under decell then the Nismo unit. The car rotates better under trailing throttle or trail braking with the OS Giken. The transition to power is also smoother with less (or no) jerking.

The reason I think the OS Giken might be better then the Quaife is that, with testing, you might be able to run higher rear spring rates and get the car to rotate more. That's just a hunch.

Regarding the Quaife...

I haven't run that diff in the 350Z but I have run it racing 240Zs and am very impressed with it. It might be a better choice then the OS Giken in the 350Z but I don't have any experience with it in the Z33. Since we will have to run the rear fairly soft in a STR car the Quaife might be the ticket.