Here's my A/X set-up, looking for ideas. I've been doing this stuff for many years, not that I've learned it all... but this is not my first few seasons either. I'm pretty satisfied with my set-up, but I'm always open to ideas and other's opinions.

Part of my set-up is limited by the fact that I drive this car ('03 Touring) 100 miles a day as a commuter car... and love every mile of it. Went with a Touring due to my transition from a 95 Mercedes S320 as a commuter being quite a drastic change as it was. Weight disadvantage?... I don't have any room to talk about my car being 100 pounds over weight.

Shocks: Koni Sports (SA), run fronts with one turn off of full soft; run rears two turns off of full soft.

Swaybar: 350EVO on the stiffest position.

Alignment: (Set to maximize tire life, long commute, pricey Michelin Sport A/S tires for Northwest weather) Front: chamber -1.07 (R); -.83 (L); toe total +.12; caster +7.64 (R), +10.88 (L) Rear: chamber -1.22 (R&L); toe total +.20. Is there ever going to be a way to get some front chamber? How do body shops repair Zs that are out of spec?

Wheels: Enkei RPM2 18 X 8 (F/R), 35mm offset, use 5mm spacers to prevent mild front end rub. The Z's stock wheels have 30mm offset, my RPM2s have a 35mm offset; therefore, I'm allowed 5mm beyond stock... total of 10mm. Would it be worth while to run a 10mm spacer to maximize the allowable under SCCA rule book?

Tires: I understand the Hoosier A3S04 (275/35-18 F/R) is obsolete, but I have too many onhand to not use them up first. I run 64 (F), 58 (R). The rears are dropped 6 PSI, just balance out the fronts. I realize this inflation is way high compared to what people confess to using. I have two pieces of physical evidence that support my pressures: pyrometer and long tire life (100+ runs). The tires feel fine, within their limitations... no real understeer problems (unless I fail to stay on my game), mild oversteer on exit (right foot, old tire condition and rear toe all contribute) but not anything dramatic. But like I said, I'm always open to input. And watching the Corvettes & the Bauer's 968 run on Kumho 710s, generates huge amounts of envy. What tire do you recommend after my S04s are finally worn out? The 710 is offered in a 245/35-18 (same size as my Hoosier Wets... which I have yet to use... we've had some unusually great weather this year... figures) those are short tires... and little narrow as well... and in a 285/30-18... won't fit an 18 X 8 wheel. I haven't heard anything about the Hoosier A3S05... other than they're not available in 275/35-18 yet. I'm open to them as well. I realize my tire pressure research will be reset with any tire change.

Avalon Harness Bar: works as advertised... it was scary to pull in the Z's B-pillars like that! My harness is a Willen set, kind of narrow, would like wider ones.

Stillen Exhaust system: which is a True/True dual exhaust system. Unlike other "Ture Dual" systems, it doesn't share a muffler with the L & R pipes... which leads to a very heavy set of SS mufflers hanging off the Z's hind end. I had a pair of pipes fabbed to replace the mufflers, using the stock hanger points, etc. Dyno pulls with and without mufflers said it makes a difference... jettison the muffler's weight. It is loud, too loud to run everyday... but they are easy to swap out.

K&N air filter: because it's allowable.

I think that's it. I'm relatively happy with how the car functions. I would like more ability to accelerate out of corners. But I realize that this is mostly attributable to my electing to: (A) compromise my alignment settings for daily driver tire life, (B) use up my inventory of 275/35-18 Hoosier A3S04s.

I want to share what I 'm using... and hear some other's inputs about the A/X set-ups they are actually using on their Zs.

Adios,

BC

 

I have a question about the harness bar you are using. Is it a telescoping harness bar? A solid bar is not legal in stock class.

Here is my setup.

05 enthusiast

Shocks: Koni SA full hard front and back. I don't change this ever. I think full hard is not hard enough, plan on revalving to DA soon.

Swaybar: Hotchkis set to full stiff. New one is going to be made soon that is hopefully much stiffer.

Alignment: 1/8 toe out on front, 1/4 toe in rear. 1.5 -camber rear.

Wheels Enkei RPF1 17x7.5 48mm offset w/ 20mm spacer in the front. 17x8 35mm offset rear.

Tires: Kumho 710s 275/40/17 These are the best tires I've ever owned. They have over 50 runs on them including 24 prosolo launchs and still feel new.

Exhaust: currently running Jic y-pipe to full Ti Jic single outlet. The entire thing weighs under 20lbs. I'm having a new one custom made out of mandrel bent titanium but it isn't going so smoothly at the moment.

Air Filter: HKS foam filter. I can see through this thing so its not filtering much. When I remember I swap it for the stock one when not auto-xing.

Car currently weighs 3030-3040 lbs. Don;t think I can get it any lighter than this. The car is driving awesomely IMO. Cater Thompson took 1st at the ATL nation tour in it, I took 3rd in the ATL prosolo in it. Some improvment is needed in the shock and swaybar area and the car will be even faster.

 

Shocks
SA Konis, full stiff front, full soft rear. looking at compression options now

alignment
1/8 toe out up front, 0 in rear, as much negative camber up front as I can get

swaybar
350evo full stiff

Wheels
stock 17s with a 1/4" spacer up front, looking for some new wheels soon.

tires
710s 275 45 17

exhaust
stock with the muffler removed

air filter
fram, screw the k&n, it jacked my MAF

fuel
always 93, as little as I can go

car at nationals weighed 3075, on scaled that were rumored to weigh 50lbs heavy. Need to get some lighter wheels see if I can break the 3k mark.

 

also forgot, codriver picked up some 225 hoosier wets on stock wheels

 

BA Cutler....I'm glad to see that I'm not the only one to run really high tire
press. I've found that tire temps are more even and the tires last
longer. I've tried running lower, but I can't seem to make it work.
The car won't react quick enough.

TIRES...275/35 Hoosier F 63psi R 52psi

WHEELS....Track with 1/8 spacers

SWAY BAR...Hotchkis med. on a slow, tight course
full stiff on a fast course

ALIGNMENT....1/8 out front 1/8 in rear -1.5 camber rear

SHOCKS.....Ohlins I just got these finished and installed. The rears are a
lot like Konis set med. I'm still sorting out the fronts.

EXHAUST.....custom 2" primary Y into single 3" 22 lbs. I'm working on a Ti
version that should be around 10 lbs. with muffler.

hippie

 

Minor clarification -- this is a soon-to-be-clarified gray area. There was apparently once wording in the rule book specifying that harness bars had to be telescoping, but that wording has since been removed. Someone wrote a letter to the SEB in the past month or two inquiring about the legality of their solid harness bar, and the SAC is currently weighing a recommendation.

Steve

 

Its not a grey area at all, the wording that makes a non telescoping bar illegal is:

13.2 H A horizontal "harness bar" may be used as part of the installation hardware for allowed drivers restraints. It may serve no other purpose (e.g., structural enhancement). A ridgid bar would most def. be classified as a structural enhancement.

I've seen several people running non telescoping bars in stock class. I'm not going to protest anyone for a harness bar, but I know plenty of people that would. I also don't see why you need a harness bar. You can use harnesses without it. I just doesn't seem like an item that is worth the potential hassle.

 

del105,

I never considered the Avalon bar as being capable of being a structural enhancement. Possibly if it were in a car lacking structural rigidity... or if it were placed between the shock towers or compensated for some other weakness. But I'm not sure the structures the bar attaches to are capable or are intended to do anything other than to affix seatbelts or a harness bar to. I'm thinking somewhere within my Touring model's 3100+ pounds of heft, there's a pretty stout structure, not needing anymore strength (for Stock class A/X).

I just went for the most widely used piece of equipment available, figuring it was a solid piece of engineering and offered clean installation. I'm open to alternatives and certainly will not encroach upon the limits of the rule book. Heck, I won't even change my alignment to get that little extra amount of performance. What other methods would you suggest for mounting a harness in a Z?

Thanks,

BC

 

I know your intention isn't to break the rules, frankly you may not be depending on the construction of the bar. I just wanted to bring it to your attention so you are aware of it if you ever get challenged.

I don't use a harness but I know Carter and Jim Thompson do. Maybe they can chime in. It looks as if it hooks to something on the floor in the back of the car.

 

I have picked up a set of 275/40/17 V710 and will have them mounted before my next event. Alignment will be done at the same time allowing for daily driving. No mods straight stock .
Last event I ran 255 pirelli's Pzero Corsa. Obviously not the right ticket. Could not get any power down and had to short shift to second.
What pressures should I be looking at to start with? I appreciate any input.

 

I run around 36psi front 33 psi rear on the 710s. That seems to be right around where they want to be, give or take a pound depending on surface.

 

del105,

Thanks for bringing up the topic

BC

 

I'm in the same boat as BA Cutler where I'm running considerably higher pressures than recommended in my S04's; F: 56 / R: 42. Any lower and I run the risk of rubbing the side walls. I also run in the same places that BA Cutler does. Could our need for higher pressures be a case of the terrain of the lots that we run in?

 

I am a member of the SCCA Stock Advisory Committee. In the April SAC conference call, a member letter regarding legality of a solid, non-telescoping harness bar connecting the B-pillar seat belt mounts was discussed. The harness bar clarification published on Page 226 of the 2005 rule book would appear to make such bars legal, but no recommendation was issued to the SEB; instead, the SAC referred the item back to the SEB for further clarification.

So, while your opinion may differ, both the SAC and the SEB currently consider this a gray area. As I mentioned earlier, I expect that we'll publish a clarification shortly.

Steve

 

Re harness shoulder strap mount.There is a threaded hole in the trunk area right behind the seat.We bolt our strap there.

 

You're right, I did not see the clarification on p.226 It is extremely gray after reading that.

 

People with SA Konis; Do you guys think the fronts could use more compression damping? I do. I've noticed the front rolling and diving alot on corner entry. I think an increase in compression might make the car turn in a bit faster. I was planning on getting all my shocks converted to DA but I'm thinking maybe just getting the fronts revalved. What do you guys think? I would be 200.00 to revalve fronts or 1300.00 to convert to DA.

 

Shocks - stock.

Alignment -
-Camber - -1.5 (R)
-Toe - 1/8" out (F), 1/8" in (R)
-Caster - ~

Swaybar - 350evo

Wheels - performance 18's and a 25mm H&R rear spacer once i find longer wheel studs.

Tires - going with kuhmo v700, 265's around. as of now, stock re040s running 41/38psi

Exhaust - Completeing a little summer project, similar to Mike's set-up, if i get too lazy then i will go with a borla.

Intake - K&N drop-in

Fuel - <1/8 tank of the highest octane i can find.

 

If you use that spacer with the stock 18's you car will not be legal. besides not being legal, I think widening the track in the back might give the car a tendency to understeer more.

 

Just to clarify -- you can use spacers, as long as the total difference from the stock wheels is no more than 0.25 inches (about 6.35mm). So, you could increase your track by 0.5 inch, but my issue would be, why? The car is already low and wide, why make more work for yourself by making it wider?