Topic: Autocross - stock class and available options

[iaus10]

Hi there,

I'm seeking some input regarding how to insure a 2008 solstice GXP remains SCCA Solo (stock) legal when converting to Z0K.  The car belongs to a relative who's fairly new to autox but is hooked, and wants to travel with us to Tours and possibly Nats in 2010... thus the desire to comply with the letter of the rules.  I've found the appropriate part numbers for swapping the mechanical bits.  

More specifically, I'm not sure which option packages or items were available and possibly must be switched along with the Z0K suspension/chassis parts.  This GXP has leather seats, A/C... and for reference, it came with chrome wheels.  For instance: Were the seats a stand-alone factory option which would be allowed, or would the seats need to replaced along with other trim-level pieces with which the Z0K could not have been ordered?  Or (finger crossed) was the Z0K package available to order from the factory with any/all other GXP configurations?
Any input is appreciated, Thanks!

--Ivan

[Critterman]

The GXP ZOK package was an option.   There are a couple of very serious autoXer's on here that will be able to help.  SnaponBob should be around shortly.  He X's a Sky but it is the same platform.

Hope your sister enjoys her ride.

[snaponbob]

And here he is.

Here is what you can do. If it isn't listed, you can't. That's the way the SCCA models their rule book. The rulebook can downloaded as a PDF from this link -- http://www.scca.com/contentpage.aspx?content=61

* ANY shocks that attach to the stock locations (upper and lower). If they are three way adjustable, one of the adjusters must be disabled.
* Springs must located in their stock manner top and bottom.
* Spring must be the correct GXP Z0K springs.
* Rear bar must be the GXP Z0K bar and mounts (they are different then the stock ones).
* Front bar is "free" (any bar allowed), but the stock FE3 will usually be best (separate discussion).
* Rear GXP Z0K frame cross member.
   That takes car of suspension/Z0K conversion.
* Wheels can be any that you like as long as they are 18x8 and +/- 1/4" offset. Plenty of 18 pound wheels out there vs 26-27 pounds stock.
* ANY exhaust you want AFTER the cat. (Solo Performance straight 3" "Race" pipe is the lightest solution, and while noisier than stock, it is still under 90dB WOT @ 50' and is not much louder than a Magnaflow as the turbo is a very effective muffler.)
* Any brake fluid, but do NOT use DOT5, but rather DOT4. VERY effective fade fixer upper.
* Any brake pads. He WILL fry the stock ones. (Again, a separate discussion.)
* Any P/S fluid. By all means, switch his to Redline Synthetic P/S fluid. It WILL stop the P/S moans that develop from overheated fluid and frothing.
* G/Lock seat belt lock is very effective in keeping one in place in the seat.
* Any pump gas is legal. Up to about 95-96 octane the car will do its best. Higher is a waste and may DEGRADE the output. (This assumes you have Sunoco available nearby.)
* Any alignment is legal. (Separate discussion.)
* Any DOT approved tire is legal.
* If you want to haul race wheels/tires to/from events, trailer hitches are legal.

I think I have touched on everything. Questions?
 

[boardkat]

it sounds like he's also concerned about having additional factory options installed AND converting to Z0K and remaining legal, when *no* options were available when ordering a true factory optioned Z0K car.  rest easy, there's lots of us in that same situation at the national level (my car, the kozlaks, dahl, etc).  due to c&c (comfort & convenience) allowances, the a/c, leather seat covers, power windows, monsoon sound (speakers/subwoofer/6 cd changer) are *all* legal to be installed in conjunction with the Z0K parts whilst still remaining legal for BStock.  so long as *all* of the necessary Z0K bits are installed (rear crossmember, rear sway bar & mounts, Z0K springs), you'll be good to go, and free to do any other mods (stock legal wheels, shocks, brake pads, fluids, cat-back exhaust, etc) as bob mentioned in his previous post.

[iaus10]

Thanks to you all!  Those are exactly the option specifics I was having trouble with, and hoping to find.  The setup tips are appreciated as well.

[Critterman]

The car is very streetable with the above mentioned changes.  Most of those changes +/- a few others have been done to my 06 NA, and I drive it most dry days

[boardkat]

ivan austin, right?  i think i remember you from a few years back - yellow rx-8 in BS?  my co-driver used to compete against you (adam ruff - in a borrowed 350Z of glenn austin's).  and a friend of mine just moved to your region not too long ago (josh svoboda - stu evo).  small world.  come back to the new BS, there's always room for another talented driver!!

edit: just saw your intro thread, looks like memory serves me correct!  hopefully we'll see ya out in your sister's car next year.  if things work out, i'll be in lincoln for the may long weekend to test out the new shocks.  whatever you do, *do not* try to run the stock bilsteins there - there just isn't enough compression to prevent serious diving, coupled with body roll central, as i found out last year (not my choice, shocks weren't ready, c'est la vie).  otherwise, see ya in august!

[snaponbob]

iaus10; Ditto the comments on street worthiness. ALL of the changes will IMPROVE the car. Really. 

P.S. You have an e-mail coming.

[iaus10]

ivan austin, right?  i think i remember you from a few years back - yellow rx-8 in BS?  my co-driver used to compete against you (adam ruff - in a borrowed 350Z of glenn austin's).  and a friend of mine just moved to your region not too long ago (josh svoboda - stu evo).  small world.  come back to the new BS, there's always room for another talented driver!!

edit: just saw your intro thread, looks like memory serves me correct!  hopefully we'll see ya out in your sister's car next year.  if things work out, i'll be in lincoln for the may long weekend to test out the new shocks.  whatever you do, *do not* try to run the stock bilsteins there - there just isn't enough compression to prevent serious diving, coupled with body roll central, as i found out last year (not my choice, shocks weren't ready, c'est la vie).  otherwise, see ya in august!

Hey there.  Yeah, a couple of us commented in the '09 Nats impound about Adam's raw times.  Saw Josh S. at a few local events, can't miss that Evo.  Came on real strong in STU towards the end of the season.
Even if I stick with STX in 2011, I'll definitely hunt you down in grid to check out your Coupe... those look sweet!

[iaus10]

... if things work out, i'll be in lincoln for the may long weekend to test out the new shocks.  whatever you do, *do not* try to run the stock bilsteins there - there just isn't enough compression to prevent serious diving, coupled with body roll central, as i found out last year...

Good point.  If this is to be a "build" in stages, perhaps concentrating on tires/wheels/shocks/alignment should come before Z0K parts.  Hopefully some off-the-shelf Koni singles will provide enough artificial spring rate for the increased grip.

[snaponbob]

Let me share some impressions. The Bilsteins do not have enough ANYTHING for Solo work. They are very nice on the street, but with ANY better tires they are just too soft. That said, it's the lack of rebound that is what is happening. Small changes in rebound net substantially more and better results than compression. This is why single adjustable shocks have rebound adjusters. And increased rebound WILL help level a car in transitions. Compression is best used for fine tuning after the rebound settings are optimized.

For purely budget reasons, I am still running Koni SA's, even with spring rates nearly triple that of stock, and they ARE working fine. If the right situation comes up, I will change to Motons or AST's, but not this coming year. With that as background, if somebody is going to be real active in a GXP in Solo, the Hoosiers WILL provide a much greater positive impact on times than ANY other mod, but an alignment is a must, as without that the tires will die (cord out) very quickly. Shocks would certainly be a close second.

HTH.

[iaus10]

Good points.  I figured there would be some similarity of the 18x8/285 - 295 A6's/double a-arms we've previously tuned on the Rx8.  On that car I immediately went with a DA conversion and custom valving on the Koni sports.  Same with our previous Miata.  Koni sports are just a good product with a range of adjustment allowing for a wide range of variables (which can't be dealt with otherwise in Stock classing).  Seemed like a lot of diminishing returns to consider port-valved monotubes in stock trim.  Anyways, I'm excited about all the front neg camber available on the Kappa and comparing grip and tire life once the GXP is more set up.  Sounds like the 275 or 295 A6's are the way to go for gearing on the GXP?

I'm also hoping to stumble across some Moton Club sports or Koni 2812's on the used market for our STX car.  I'm still on the fence about AST, having seen one local BMW owner send them in multiple times in 2010 to be serviced.  Admittedly, AST did bend over backwards to get his repairs done quickly... even expedited them directly to Lincoln for the August TnT when several of us were there from Mpls (Pretty sure I remember you were in attendance there too).

[snaponbob]

The AST's sometimes have issues, but mostly they are great. The 295's seem to be the right tire for the B/S Kappas while they are too big for the C/S Z0K's. With a 6200 rpm limit in Stock trim, ALL of the A6s are smaller in circumference and thus bring the car to the rev limiter at lower speeds. With 245s it's about 51-52mph. Stock tires are ~58mph. As I recall, in 2008 at the Solo Nats, none of the (then) A/S Kappas were on less than 295s if they ran Hoosiers. It doesn't seem like much difference (on paper), but it is. The only apparent reason the RX8s didn't run 295s was clearance.

[boardkat]

That said, it's the lack of rebound that is what is happening. Small changes in rebound net substantially more and better results than compression. This is why single adjustable shocks have rebound adjusters. And increased rebound WILL help level a car in transitions. Compression is best used for fine tuning after the rebound settings are optimized.

we'll agree to disagree - i've had the opportunity to test in a gxp z0k locally with SA koni's, they were valved VERY digressively for rebound, and on concrete, it didn't matter how stiff i was running them, they just weren't aggressive enough for the corresponding compression (which was still more aggressive than stock, but not nearly enough), and the extreme inital dive and the associated weight transfer negated any advantage given from the rebound "squating" that followed.  that's why i went the DA route, compression is essential on concrete, but i'll agree, it plays a much less important part the less grip you have.

oh and, happy new year to all those that can celebrate!  i'm holed up in an airport hotel, have one for me tonight!!

[boardkat]

With 245s it's about 51-52mph. Stock tires are ~58mph. As I recall, in 2008 at the Solo Nats, none of the (then) A/S Kappas were on less than 295s if they ran Hoosiers.

when i bang the limiter with 295's, my data shows me pegged @ 56mph.  there's no power pretty much immediately after the crossover though, so i've gotten pretty used to shifting at any point on-course when i'm at 48-50mph - lots more pull in 3rd vs. 2nd.

[snaponbob]

when i bang the limiter with 295's, my data shows me pegged @ 56mph.  there's no power pretty much immediately after the crossover though, so i've gotten pretty used to shifting at any point on-course when i'm at 48-50mph - lots more pull in 3rd vs. 2nd.

Certainly a trade off between up-down shifts vs. riding out the power curve. It's a matter of what is comfortable for the driver. Now that I am running SP, the power delivery is different. On 100 octane it pulls hard to 6500rpm and still pulls well enough to 7000rpm that there is again a tradeoff, just at higher speeds.

[snaponbob]

we'll agree to disagree - i've had the opportunity to test in a gxp z0k locally with SA koni's, they were valved VERY digressively for rebound, and on concrete, it didn't matter how stiff i was running them, they just weren't aggressive enough for the corresponding compression (which was still more aggressive than stock, but not nearly enough), and the extreme inital dive and the associated weight transfer negated any advantage given from the rebound "squating" that followed.  that's why i went the DA route, compression is essential on concrete, but i'll agree, it plays a much less important part the less grip you have.

oh and, happy new year to all those that can celebrate!  i'm holed up in an airport hotel, have one for me tonight!!

I absolutely agree that compression has its place. The fact that the Koni's exhibited that spread in valving is exactly the advantage of true separate adjustability and why the BG or BC shocks (whichever they are) make decent street shocks and not so good race shocks. As for concrete, it does change the game some for sure. I was adjusting (while in Stock class) my Konis with FE3 suspension and I am sure that the GXP/Z0K dynamics are different. For now, the money will go towards a Spec 3+ clutch and Fidanza plate. I just found out today that I will be sharing my car with an Evo instructor at some NTs and Solo Nats, so DAs may happen if he will split the cost. Otherwise, 2012 for DAs.

[boardkat]

Certainly a trade off between up-down shifts vs. riding out the power curve. It's a matter of what is comfortable for the driver. Now that I am running SP, the power delivery is different. On 100 octane it pulls hard to 6500rpm and still pulls well enough to 7000rpm that there is again a tradeoff, just at higher speeds.

ah yes, to be able to raise the redline to 7000 and have so much power down low that it carried me there!  such is stock class.  my coupe came with the GMPP tune, but i recently flashed it back to stock.  can only imagine what it'd be like to run cat-less on a custom tune with 100 octane.  sigh....

I absolutely agree that compression has its place. The fact that the Koni's exhibited that spread in valving is exactly the advantage of true separate adjustability and why the BG or BC shocks (whichever they are) make decent street shocks and not so good race shocks. As for concrete, it does change the game some for sure. I was adjusting (while in Stock class) my Konis with FE3 suspension and I am sure that the GXP/Z0K dynamics are different. For now, the money will go towards a Spec 3+ clutch and Fidanza plate. I just found out today that I will be sharing my car with an Evo instructor at some NTs and Solo Nats, so DAs may happen if he will split the cost. Otherwise, 2012 for DAs.

totally agree that in your class, a SA valved with decent compression will work almost all of the time, especially since you're free to adjust other factors (springs, height/rake, bars, bushings, etc).  but i know from experience in both this car and my previous stock class car (DS ITR) that separate compression adjustment goes a long way to curing stock class ills when undersprung.  i know that if i'd gone the SA route and valved the compression aggressively that i'd have been washing out on asphalt - since when i ran my wendover setup (concrete) at my next packwood event (asphalt), i had to reduce my compression significantly.
all this said, i *do* think it is possible to get a compromise SA valving for stock class shocks, without giving up too much, and at significantly less cost - having the know-how or a good autox shock guy is the key.  are you running OTS, or did you have lee/somebody else re-valve?

and thanks for engaging me in conversation on an otherwise depressing night (for me) - first time i think i've ever had my hands tied on new year's preventing me from having fun!  hope you have plans, otherwise i may have to stop agreeing with you and keep things interesting!

[snaponbob]

Okay, kat, since YOU are board, we bore the rest of the folks on this board. NYUK NYUK NYUK !!!!!!!!!!

Front shocks are one step and rears are two steps up on compression. That was done just before the 2008 Nats by Lee Grimes out of the Koni trailer at Heartland Park.

The ITRs look like they will "go turtle" at any time. Amazing car. Like the RX8s, they just work far better than they look on course. But, I am sure you will admit that the ITR moves around (dive, sway, etc) than a Kappa does. ALL the fast FWD guys really use compression tweaks do do crazy stuff. Look no further than the old G and H/Stock Minis.

As for how the car feels with a down pipe, low restriction exhaust, and a tune is a real thrill. You should jump over to B/SP have have some fun there. The Evos will always own B/SP, but "best of the rest" is only 1-2 seconds back on a  day event (in the dry). The big money is in the 11-12" wheels and 315s. Other than that, there is not that much to do except brake early and gas early.

[boardkat]

Okay, kat, since YOU are board, we bore the rest of the folks on this board. NYUK NYUK NYUK !!!!!!!!!!

funny guy!!!

Front shocks are one step and rears are two steps up on compression. That was done just before the 2008 Nats by Lee Grimes out of the Koni trailer at Heartland Park.

gotcha.  was hoping you weren't running OTS, nothing like not knowing what your adjustments are doing when you make them, and unevenly matched on all four corners!  and lee, wow, he's a trooper every year at nats.  gotta love that guy.

The ITRs look like they will "go turtle" at any time. Amazing car. Like the RX8s, they just work far better than they look on course. But, I am sure you will admit that the ITR moves around (dive, sway, etc) than a Kappa does. ALL the fast FWD guys really use compression tweaks do do crazy stuff. Look no further than the old G and H/Stock Minis.

i'd never driven a well setup RWD stock car before.  enter future co-driver in (then) BS 350Z at a practice event.  one run and i was ruined.  the ITR went up for sale the next day!  as good as it is (and very likely as good as it gets, out of the box, in wrong-wheel-drive space), you can't fight physics - i'll never buy an FWD car for competition again!

As for how the car feels with a down pipe, low restriction exhaust, and a tune is a real thrill. You should jump over to B/SP have have some fun there. The Evos will always own B/SP, but "best of the rest" is only 1-2 seconds back on a  day event (in the dry). The big money is in the 11-12" wheels and 315s. Other than that, there is not that much to do except brake early and gas early.

if i hadn't have picked up a CM co-drive next season, i probably would have, AWD boost buggies be damned.  that said, this reynard i'll be driving is surely sending me down the path to ruin!  still planning on doing pros in the gxp though (which is why i'm staying in BS), and possibly nats - since the CM is gonna be a basketcase to both setup and drive with any sort of chance at doing well, at least for awhile.

[Graywolf]

Agree with most of above,Please read my post For your eyes only for camber and tire pressure. I would also change the belt to delete air conditioner-robs you of hp and its cheap. Also would buy the Solstice Performance book for about $20 Can be ordered from any GM dealership which gives you all the camber setting etc./Zok parts numbers etc before you do anything.

[snaponbob]

Agree with most of above,Please read my post For your eyes only for camber and tire pressure. I would also change the belt to delete air conditioner-robs you of hp and its cheap. Also would buy the Solstice Performance book for about $20 Can be ordered from any GM dealership which gives you all the camber setting etc./Zok parts numbers etc before you do anything.

Have you seen what the power difference is with a non-AC belt on an AC equipped LNF? If there is any meaningful difference, I can see that change this spring. That said, CAN a non-AC belt be used with the compressor still in place?

[Graywolf]

It is a recommendation in the Pontiac Solstice performance book .They recomend removing the compressor to save weight. Yes,the non-ac belt can be used with the compressor in place and I did it . Now I have the compressor removed. I didn't notice any change but it makes sense.

[snaponbob]

How much does the compressor weigh?

[Graywolf]

I am guessing it weights  10 to 15lbs. Its packed away in a crate of parts that is kind of hard to get to in my storage area. If you drive your car on the street I would leave it in place. If you do remove it then you might as well remove the ac tubing and ac radiator( cooler coils} and refrigerant.