Has anyone every autocrossed/tested the stock 17" wheels vs. the stock 18" wheels, with the stock tire? I drove my co-workers Performance model (both are 2004 model) and with the 18" wheels it has a much better on-center steering feel and inputs feel much more precise. I'm assuming most of this is sidewall stiffness, but I'm wondering at grip limit if it's really better or not. I found a good deal on some Performance model wheels w/new stock Bridgestones and I'd consider buying them, but I was wondering if they're really that much better than the 17's for autocrossing or track days.

 

For autocrossing I would say it depends on what class you plan on running. If you want to run in the B-Stock you have to run the wheels that came with your model, or completely upgrade your model to one with the wheels in question.

I haven't done a track day (too afraid to put my daily driver into a wall) so I can't say how they would affect the track.

 

My first autocross with the Z will be this weekend so I could just list it as a Performance model from the beginning and hopefully no one will notice, or check for the tire pressure monitor or VDC. The people in my region are so picky so I doubt it would last long (see other thread about AutoX), but worst case scenario is to go into SM (Street Tire) and then I can use the lip spoiler, intake and brakes I bought. Sometimes I'd rather just go all our for fast time than worry about PAX anyways.

 

I never heard anybody asking me what trim level is my car...

 

you don't live in my region either (see othe Autocross thread about wheels)

 

Carter Thompson and Jim Thompson seem to do pretty well on the 17s with 275 tires crammed on there

I'm wanting to go down to 17s for tire price and tire selection reasons. I only run local, and I don't think I'll get called on it. Most the the people that run regularly in BS here probably have something that disqualifies them (Audi TT that is chipped and has drilled rotors for instance).

 

Darn Andy,

I see you caught on to the S2000 antenna I added for speed.

 

When you register your car in the SF Region there is no question on model type only make and model.

This is a real interpretation issue that some person gets to answer. Is the model type asked for at division competion? I am also a local only autocross player.

 

phoenixZ33,


Whether you run a "clean" car according to the rules or not is up to what you're comfortable with... the rules are there to keep things fair. I've stuck to the rules, running 18s even though 17s seemed to have a cost and performance advantage. I did so because I suspected I might trophy in the events I planned to compete in. If you don't see yourself hauling off the club's trophies, I wouldn't think too many of your fellow drivers would mind having more cars in their class.

In local events, having as fast a competitor as possible is an advantage in preparing for larger events... I personally don't mind having a competitor that pushes me to try harder every local event... even if I suspect the car is not quite "clean"... which is my current situation.

Five events of out eight SCCA Regionals, I've won one and I'm third or fourth in the standings... if I was running a car not prepared in accordance with the rules... I personally, wouldn't feel right about taking the points away from the other competitors. That's just me, it doesn't matter to me if anyone else thinks the same way.

I'm probably like most local competitors, I don't care about local standings in terms of what others are/are not doing... and at the larger events, car legality becomes a bigger issue and things are going to sort themselves out anyhow when the top competitors hammer it out amongst themselves... me, I'm not going to protest anyone... another "just me".

Now, take the situation you are proposing... each trim level of Z has the same springs, swaybars, etc... the Track has 8.5 inch rear wheels... and for A/X, that's probably the only significant suspension difference... but it's still not as big a difference as other makes... where the "performance" model is significantly different from all other trim levels. It's not like you are trying to add Corvette Z06 options to a non-Z06. I think whether you choose to run 18s or 17s is of minimal difference... like mentioned before, the highest placing Z at Nationals was on 17s. When shod with the recommended tire sizes... there isn't that much dimensional difference... and if I had a choice, I'd go with 17s to get more sidewall... just a personal preference for more sidewall to absorb my cloddy accelerator inputs. The stock size wheel choice on any trim level of Z isn't going to hurl you into an unfair advantage. Go out and have a blast.

BC

 

Well I wasn't proposing anything (ie. cheating). Look at some of the other threads where I rant on about how even if you wanted to, you probably couldn't get away with it for long in my area. Anyways.. I drove 17s vs 18s back to back on the street a few weeks ago and the initial turn in and bite felt really quick and precise. I was just curious if when you're at a cornering limit or doing constant turning if it still makes a big difference... I don't feel like crashing my car on the street trying to figure it out. From what you say it sounds like it doesn't matter much, or it's a toss. Thanks for you input!

 

phoenixZ33,

I apologize, didn't mean to come off aiming that stuff at you. My opinion is the 18s do not offer any advantage over the 17s. Given the opportunity to run 17s, I would.
BC

 

My last autox (yesterday) I saw Evo running on RIMS (outer front, in turn)!!!! I'm not sure was it 18 or 19... I guess 18... but there sure were stylish rims... That's it WERE.

 

I ran 275 Hoosiers yesterday on 17's, holy cow they were amazing. I've been running 245 Kumhos, and was helped out by a fellow My350z.com member with a set of 17s shod in 275s. They fit, with no noticable problems.

I've got a better writeup on things here

http://www.solo2.org/blogs/christoc/...06/14/386.aspx

 

Same situation with the 275/35-18s... I had to battle with everyone involved to convince them they would fit... when they were mounted... they looked like they were intended for a skinny 8" wheel! If someone's trying to make up their mind on their 18 inch wheels... the 275/35-18 fits fine. I'm not a left foot braker... so I have never encountered any "Ice Mode" problems... finally, a benefit to not learning how to left foot brake.

BC

 

I'm just going to go with some 245/45R17 Falken Azenis Sports and try to compete in the huge Street Tire class we have. I figure I'll go a season before buying a 2nd set of wheels with race tires, that'll give me plenty of time to figure out how to fit 4 wheels in my car.. lol. Overall I was 4th out of 15, behind two STIs and a Street Prepared E46 M3. Boy those STi guys sure can cheat with their ESP Pax! Next event is in two weeks so it should be fun with better tires and a good alignment.

Off topic - Is it possible to get any camber out of the front end? What specs are people running for AutoX? I do a lot of freeway driving so I was just going to run zero toe front and rear to begin with, then max out the front camber (but from what i hear it's not adjustable) and set the rear accordingly. Thanks for the help.

 

Azenis make a nice compromise... up here, they make wonderful rain rubber... I don't imagine that's an issue for you in AZ. I stuff my race wheels in my car, I don't like doing that to my car... but that's the way it is this year. Sounds like you are doing well in ST... you ran fourth without the Azenis?

You are correct, there isn't any chamber adjustment for the stock front components. I haven't changed my alignment because this car is my daily driver. Other Z folks say the adjusting the toe out in the front makes a huge difference on course. But I'd have a adjust between events. I understand the front likes .25" toe out, .25" toe in.

The Koni sure have been a difference... everyday of ownership.

BC

 

I posted my alignment settings earlier today
http://solo2.org/blogs/christoc/arch...06/14/383.aspx

 

I'm really confused with the result. I was told that a good guy to compare to was this black WRX STi. During the course of our four runs we traded places back and forth and he ended up beating me by a tenth. I figured since he was in ESP and I was in BS, I'd take him in PAX. Well I didn't realize that ESP is the "loophole" class that supposedly has a softer PAX than AS, or whatever the STi and EVO run in. He beat me by just a few PAX points.

I gues 4th out of 15 the first time is not bad, as I had no idea what to expect with the stock Bridgestones. I ran a 911 pax Sunday, but my goal is in the 945-955 range as that's what the top guy does in Street Tire 1 (2nd-3rd were 930-911). It's a high goal, but attainable I think after a few more events with the right setup. I improved 0.7 in fun runs at the end.. I think I can shave off a lot (relatively) more with the Azenis.

Anyways, sorry for rambling.. it's just fun to talk about racing and the Z.

 

I'm not sure how they come with PAX for STi and WRX... on every autox they are constantly faster than and BS class cars and even with some kid drivers without experience... It's just plain stupid that the gap is further increasing after applying PAX.