STR Z4 Coupe "build"

[John V]

Sounds like you have it all figured out. I think you have some steady state and transitional testing to do, though... At least if you want to be fast.

[z3papa]

It's not that simple. After driving a couple other STR cars recently that might as well be called farm implements (plowing all day long), I'm comfortable saying this one is set up neutral, leaning oversteer. Here is the first run, dead cold tires, more aggression in transition, more understeer ONLY on transition entry:

I hope you're not talking about my car or it and I will need to bring the wood the next time we meet up in Rantoul.

[TeamZ4]

And before we get into a discussion about shocks, we've already been above and below where they are with both adjusters, the car just doesn't take bumps well at anything but where it's set. That said, it may be instructive to try a few things and focus on the effects on transition entry, body control over bumps be damned.

shock valving may need adjusting
shock physical dimensions may need adjusting
differential selection may need to be revised

[John V]

Mark - his shocks are PERFECT. Nothing needs to be changed.

I expect mad crazy national championships from here on out.

[illinipo]

I don't understand the animosity.

It's a compromise right now. In order for it to take bumps well, the shocks have to be set so that transitions aren't perfect. This is in cold weather only.

Anyway I'm nowhere near consistent enough to be making changes like this to shocks and see a difference in time. How many times do I have to make it clear in here that I know where I stand nationally and know that I'm still a relatively novice driver? Need to dominate the local field by a second or more to start thinking about Lincoln.

Also I'm not rich, so I doubt this car will see a national-level course for another year or two anyway. 500 bucks for an autocross weekend? I have bigger fish to fry.

[CGS12]

Question, have you ever had a nationally competitive driver take the car out and evaluate its handling?

[illinipo]

Good question, and the thought has occurred to us. We had a top dog here (also 1st place CS, Peru 2012) drive it last year, back when there was still far too little rear toe, and he was extremely impressed and mentioned that once the toe issue is fixed the car would be a winner. Still in the process of getting faster drivers in the left seat, but it is tough to get the stars to align with other top 5ers who want the seat time in their own car. The next step, as discussed, would be starting to make more friends in Chicago and spending the cubic dollars that comes with travel and SCCA event/member fees.

[mrazny]

I don't understand the animosity.

It's a compromise right now. In order for it to take bumps well, the shocks have to be set so that transitions aren't perfect. This is in cold weather only.

Anyway I'm nowhere near consistent enough to be making changes like this to shocks and see a difference in time. How many times do I have to make it clear in here that I know where I stand nationally and know that I'm still a relatively novice driver? Need to dominate the local field by a second or more to start thinking about Lincoln.

Also I'm not rich, so I doubt this car will see a national-level course for another year or two anyway. 500 bucks for an autocross weekend? I have bigger fish to fry.

My Peru trip from Chicago will be quite a bit less than $500. Hotel will be $50 total after it's split, $95 entry, ~350 miles round trip, so travel gas is at $55, autocross gas a little bit more. Pack lunches, eat two good dinners, and by your math I have mountains of beer swap money. As it stands I'll be bringing something like $40 in beer and making long distance beer friends. All in all, so worth it why wouldn't I do it? (besides the fact that I only shook the car down at one event thus far and will get pants'd by the rest of the STX field)

[illinipo]

It's also about $30-40 in tires.

...okay $500 is exaggerating.

Let's just say, I like to drink really good beer My latest haul from a Milwaukee trip:

[mrazny]

It's also about $30-40 in tires.

...okay $500 is exaggerating.

Let's just say, I like to drink really good beer My latest haul from a Milwaukee trip:

You best be making the Craft Beer Week bar crawl down there in the 'Paign.

For future notes, if you have trades and want to do a CR trip up or a TSSCC event, let me know. I've got stouts and stouts and stouts. I have the most equity in '13 KBS if you didn't get any and i still have a few '12 Darkness if the trade is right.

[John V]

No animosity. You're just reluctant to even discuss the possibility that your car could use some setup help.

I doubt it would be very difficult to find a top driver who wants to hop into a potential STR winner for a tour. Or a Pro; Z4s should launch very well and be pretty competitive I'd think.

If you really want to get this car (and your driving) working you need to get someone really good into it and then learn from them.

[TeamZ4]

+1

All I see are a lack of understanding resulting in poor choices supported by excuses. There's no animosity. It's just the reality of being stubborn and inexperienced.

Example: If you can't immediately afford the proper OSG diff you wait and save up for it. Spending what you had only dug yourself that much further in the hole from having what you need.

My best Pro Solo launch in a Stock class 225 hp Z4 was 1.85 sec, that was on Hoosier A3 or A4 tires but no lsd, 1.95 -2.0 sec was pretty much the norm. Back then the best launching car in the class was the mid-engine MR2 cutting 1.8 - 1.9 sec. For a front engine rwd car to be any where near that without an lsd says a lot about the launch potential of this chassis.







.

[z3papa]

I know the OP and while we don't always agree on every direction to take in preparing cars, Pete definitely thinks the process through, is willing to explore outside the box, and will concede when unorthodox approach is not working the way he'd like. I respect that given the circumstances. NO ONE has really taken a Z platform that close to pointy end of STR. I've choked in every critical event which I chalk up to the driver and have had a number of very high Nat'l trophy winners drive my car with the assessment it can get the job done but it takes an awful lot of trial and error to overcome the sea of information exchanged on the S2Ki forums. I'd agree that having the right or most optimal differential helps the car immensely but part of the skepticism I'm reading is based on not having run at Nat'l events or not having good data points. Since we have three STR drivers who have been to in excess of 10 Nat'l events including the last two Nat's, I'd say he's at least had the opportunity of knowing where he stands.

[John V]

This may be the first STR Z4 that has been taken to this level, but it's not the first modified E46 platform competing. There is a wealth of knowledge on E46 chassis setup and the problems he is describing with his setup (even though it's perfect) can be fixed.

I appreciate that he is running against some people who compete nationally, but that's not the same as having a top driver drive the car, nor is it the same thing as taking the car to a big even to see where it really stacks up. You really do learn a lot doing that.

[z3papa]

John -- I agree with what you are saying. A friend, Noel Leslie, out east has probably gone taken the furthest steps with a Z4 before throwing in the towel and getting an S2000 AP2. I know where you are coming from in references to E46 resources. I use information on those boards along with Matt Murphy in considering what if anything can be done relative to the M54 header issue. I had Ricky Crow, (2nd in 2012 in BS) co-drive with me for two events and found it re-assuring that I wasn't far off from where my car had to be and know that helped. Certainly, going to bigger events where you have to assess setup adjustments for the surface and get it done in three runs for a day also helps you know how the car/driver stacks up. I've encouraged Pete to venture out of his comfort zone for this very reason. All else fails, you get to meet some very fascinating guys who are hilarious to shoot the shit with.

[BTM]

I have to chime in here. The E46 and E86 chassis do share a fair amount from a "do these parts fit?" standpoint, but are otherwise so different in setup (and the parts are not identical)...it's like saying I should've set up my Z4MC like an E36 because the suspension parts are compatible. does not computer. I don't think there is much to be gleaned from how E46 guys set their cars up.

[John V]

The geometry is slightly different but the basic setup will be extremely close. Driving style and personal preference will play a bigger part than the small differences between the cars.

Our E46 is almost identical to some of the fastest E36s in spring rate, alignment, ride height, etc.

[z3papa]

The geometry is slightly different but the basic setup will be extremely close. Driving style and personal preference will play a bigger part than the small differences between the cars.

Our E46 is almost identical to some of the fastest E36s in spring rate, alignment, ride height, etc.

I'm open for insight -- what spring rates, alignment and ride height are you running? I tried searching your posts but did not find this.

[John V]

I PM'd you, but it depends greatly on the site.

It took me a while to learn this but with a lot of help from Sam Strano and Jon Lugod I discovered that we weren't running nearly enough ride height front or rear and we were all out of whack on the dampers.

[Dubbedown]

Curious, how have the subframe bushings worked out for you?

[PrinceE30]

Got an itch for a Z4.... any further updates/status with this car? I thougth I saw results for it this or last season...