Autocross Questions

[Templisk]

I've read through several threads, and the FAQs and I still have a few questions.

I want to follow the tuning guide, and go through both stage one and two of the suspension section.

The car is going to *primarily* be a daily driver, but I would like it to handle it's best *secondarily* in auto cross. It is a 2g GSX

Handling is more important to me than the ride quality, but I want it to be reasonable so I can drive it to the mall or whatever.

The entire section reads for stages one and two as:

-Stage One-
High Performance Tires and Wheels
Swaybars
Struts
Springs
Shocks
Brake Pads

-Stage Two-
Coil-Over Suspension
Polyurethane Bushings
Big-Brake Upgrade
Steel-Braided Lines

I'm curious what are the differences between some of the suspension parts, if I plan on going to stage 2 are some of the things in stage 1 not needed or get replaced?

And what components typically work best.

For example in the struts section on the site there are "Strut bars" and "Strut Tower Bars" what's the difference?

It doesn't sound like there's a definitive "best" setup, but what have some of you tried, and works well?

 

[HokieDSM]

In terms of autocross, you really need to define what class you want to be running. That, more than anything else, defines the boundaries of the modifications you can do to your car, without bumping up to the next class.

For a 2G GSX, you can be in D-Stock, E-Street Prepared, Street Modified, or C-Prepared, in order of the amount of modification allowed to the car. What you're doing under the hood has a big impact on this, if you so much as add a boost controller, it'll bump you to SM. Most of the "Stage I" modifications you list above, aside from lowering springs, are allowed in Stock classes, and everything else comes in a little later.

It's really a question of how you'd like to compete.

Checkout http://autox.dsm.org/ if you haven't done so already.

 

[Templisk]

I think given the class choices I eventually want to go for Street Modified. I've also started researching the power modifications listed in the tuning guide, I'll have to go back to the autoX site and compare what's legal for that classification though.

 

[HokieDSM]

Well then that leaves you pretty wide open as far as what you can do, so to address your original questions:

I'm curious what are the differences between some of the suspension parts, if I plan on going to stage 2 are some of the things in stage 1 not needed or get replaced?

Stages are made up, really. But Stage II items of course will substitute other items from stage I (coilovers for springs/shocks for example).

Strut Tower Bars and Strut bars are the same thing, and I've never really seen the benefit of one design over another, though they do vary greatly in price.

As far as what works best... that's up to you, the nut behind the wheel, which is the very first thing you should work on addressing (yes, even before tires). If you want to jump into SM right away, that's all good - but when choosing how to modify your car for handling, you should get a good handle on what you're looking to improve.

Some people get away with just Shocks, Springs, brakes, and tires, and do great. Others find they want the adjustability of coilovers, or to stiffen up the rear with a set of swaybars. Every car is unique, as is the driver - so that will tailor how you perform the modifications. (How much money you're willing to shell out will be the other biggest decisive factor - a $2000 JIC Magic Coilover setup will probably be incredible, but will you really drive it that much harder than a $700 Spring/Shock combo?)

In any case, good luck - and browse around. There are plenty of good topics discussing ideal setups for 2G on this forum.

 

[jim97gst]

I would skip the Big-Brake Upgrade mentioned in stage 2, or at least put it last. I have yet to fade the stock brakes in autocross. Just some good pads will give you a little better initial "bite". Probably the only thing upgraded brakes would buy you in autocross is a potential un-sprung weight savings.

 

[jtmcinder]

For a 2G GSX, you can be in D-Stock, E-Street Prepared, Street Modified, or C-Prepared, in order of the amount of modification allowed to the car.

Actually, we're now in F-Prepared, not that we have two sh*ts of a chance against gutted M3s and 914s. You also left out STX, just in case the turbo and IC piping are all still stock.

- Jtoby

 

[Templisk]

I'm still doing some research, here's what I've got so far. Added in a couple things and changed around a little bit of the order.

Can I get some feedback on this setup please?

1. High Performance Tires and Wheels
a. Bridgestone Potenza S-03 Pole Position 245/40/17 - $208.00 each : $832.00 total
*Note: When compared to stock tire I will be driving 0.6% too fast (When the speedometer displays 60mph I will really be driving 59.6 mph)
b. *wheel 17x8 +38-40mm offset*

2. Swaybars
a. RM Racing Front and Rear Swaybars - $300.00 total

3. Struts
a.

4. Springs
a. Eibach ProKit Springs 1.0" drop - $275.00 total

5. Shocks
a. Koni Shocks - $139.00 each : $556.00 total

6. Brake Pads
a. PBR/Axxis Metal Masters Front Pair - $33.49 total
b. PBR/Axxis Metal Masters Rear Pair - $29.99 total

7. Brake Rotors
a. Power Slot Slotted Front Pair - $158.00 total
b. Power Slot Slotted Rear Pair - $168.00 total

Stage two:

4. Steel-Braided Lines
a. Goodridge Stainless Steel Braided Brake Lines - $119.00 total

Still trying to find struts, and wheels, and the polyurethane bushings. The big brake upgrade and coil overs don't seem all that great considering my wants.

Thanks for the feedback guys

Edit: The tire/wheel combination is for daily driving, debating a second set of wheels and tires of autoX or if those would be ok

 

[HokieDSM]

If you want a good street tire that's also good for AutoX, I'd recommend the Falken Azenis, either the RT-215 or RT-615, the latter is suposedly better in the rain, but I ran the RT215s last year and they were fantastic (selling a set, actually...)

Your Spring/Shock setup looks good - Eibachs are decent springs, and Konis (Yellows, I hope), are far better than AGXs. You already have struts in your setup (struts, shocks=same part for your car) so you dont need to go hunting for another set.

As for your brake pads, I'd recommend Porterfield R4S pads - they're not cheap, but they're simply amazing both for hard street drivng as well as autox - and on two vehicles with these pads I've never had them fade on me.

Jtoby - thanks for correcting me on the Prepared designation and for STX - I'm not completely up to date on all of the changes.

 

[Templisk]

I don't understand it, if struts and shocks are the same part of the car why is it listed in the tuning guide as two seperate items, and why are there struts listed.

What size tire, and on what size wheel would you recommend the Azeni's for autoX?

And you refer to Eibachs as "decent" is there something better? Same question for the Konis

Thanks a ton for the help

 

[Templisk]

Oh the Konis I mentioned were the Koni Sport Shocks (they're painted yellow)

http://www.tirerack.com/suspension/suspension.jsp?make=Koni&model=Sport+Shock

 

[jim97gst]

A lot of people also de well with Kumho Ecsta MXs. Not quite as sticky as the Falkens, but better heat resistance, little better in the rain, and last a tad longer for about the same price. Falkens and Kumhos are around $70-$80 less each than the Bridgestones.

For $125 more than the Eibachs, you can get Ground Control Coilover springs/sleeves. You get to pick your spring rate, have height adjustability, and can easily swap to different rates. You can also use different brands of springs as they are a standard size.

I wouldn't bother swapping out the rotors unless yours are worn and you need new ones anyway. The powerslots do look nice though if you like a little bling.

A good, pretty cheap (~$100-$200) upgrade that I thought helped me a lot is a harness.

You can also get yourself a garden spayer to cool down your intercooler between runs.

The tire/wheel combination is for daily driving, debating a second set of wheels and tires of autoX or if those would be ok

If you really want to be competitive, you'll need race tires which you can't run on the street. Or, you could run STX or just a street tire class where you'll likely compete against everyone else on street tires using a PAX time.

 

[Templisk]

Does anyone have a link to what is allowed in each category.

Like would a FMIC be legal in D-Stock etc.

Looking over the parts again it looked like the Coil over kit by Ground Control (with Eibach springs) is a better idea than the regular Eibach Pro-Kits. Any feedback?

 

[CrazyUglyCoyote]

This is what you want............

http://www.azsolo2.com/classes/ModificationsSpreadSheet.htm

 

[ACM]

How serious are you ?

Is your goal to win a regional championship, or have a fun car that plays well at the local autocross ?

What is your budget - now, and per season ?

It's important to define your goals, otherwise you will end up buying the same parts over and over again. It's quite frustrating looking at a pile of half a dozen different brands of shocks piled in the corner, a pile that would have paid for the shocks you ended up buying after discarding the hyped-up junk.


Regardless :
a) Eibach ProKits are not worth the steel they're bent from.

b) There are much stickier tyres for much less money than S03s. Personally I would start with 18x10/10.5 rims and 285/30.18 tyres unless your class choice precludes this setup, because that's where you will end up. Anything else you'll be selling off after a while.

c) If running SM get something like a TCE front kit - 2-pc rotors, Al calipers. This will save you money and headaches in the long run, as the only pads that work in a stock-braked race-tyred 2G cost $190 an axle and last about 2,000 miles - anything else will overheat and fade unless you're slow. If running stock sized rotors DO NOT remove any mass from them AT ALL. No grooves, no holes, no dimples, nothing. No plating either, unless the supplier can provide certified test results showing that their plating improves heat dissipation. SS hoses are the first upgrade to the brakes, not the last.

d) Power is virtually irrelevant until you are winning your region regularly - it's about as useful as chrome wheels.

e) RM Racing make the only anti-roll bars for 2Gs.

f) Konis are the cheapest, most basic damper available that's worth fitting. You'll need them revalving as soon as you can afford it, and then converting to double adjustable. A coilover kit is needed and very soon thereafter you will want pillowball top mounts and coaxial upper spring seats. You can start with a GC kit and then but DG's setup, or you can start with DG's kit and save the GC cost (assuming DG's is ready in time). You will still want real dampers in a season or two though.

g) RRE makes the cheapest functioning 2G strut braces. They also weigh almost nothing - they're lighter than at least 3 Al bars I've had my hands on. Anything else is a waste of time/money (unless it's free of course).

h) Poly bushings. Energy Suspension bushing are made of Super Ball rubber - you can actually feel the bounce they impart to the car. Prothane bushings are harder and "deader". Nobody I know of makes offset bushings or subframe bushings for 2Gs. I have a machinist who does offset bushings for me, you will need the same. I do not have drawings for subframe bushings unfortunately.


Good luck

Charles

 

[DG-FNR]

f) Konis are the cheapest, most basic damper available that's worth fitting. You'll need them revalving as soon as you can afford it, and then converting to double adjustable. A coilover kit is needed and very soon thereafter you will want pillowball top mounts and coaxial upper spring seats. You can start with a GC kit and then but DG's setup, or you can start with DG's kit and save the GC cost (assuming DG's is ready in time). You will still want real dampers in a season or two though.

I don't consider the spherical bearing (they aren't "pillowballs", sheesh I hate that term) upper mounts an upgrade; they are part of the cost of admission.

It is always cheaper and less frustrating to do it right the first time than to go in stages. Sometimes this means holding onto your pennies a little longer until you can afford what you need, but in the long run it makes for a far happier camper and less money pissed out the window.

I also don't think that the Konis necessarily need revalving, at least not right away. The DSM flavour of the Konis that I've been working with have a pretty decent force curve, and have had better quality control than most other Konis. They really aren't bad right off the shelf, and they are heads and shoulders above any other readily availble shock.

DG's setup will be ready. I have a commitment to ship a full set by mid-April, and we're going to meet that target. The material for 20 upper mounts came in yesterday, and I think we're cutting them tomorow.

Nobody I know of makes offset bushings or subframe bushings for 2Gs. I have a machinist who does offset bushings for me, you will need the same. I do not have drawings for subframe bushings unfortunately.

Yet.

I'm not a big fan of poly or nylon bushings in 2Gs, especially in the lower front arms where the bushings need to pivot on multiple axis. Replacing the lower front control arm bushings with (say) aluminum or bronze would lock the suspension and steering solid.

The proper path is to use spherical bearings in these spots, and that is on my plate to turn into a product.

DG

 

[ACM]

That was my point DG - do it now or do it later. Pay the piper once if at all possible.

You're right about the bushings - I'm thinking in SP terms here. Mind you I'm not sure I would want to drive a metal-bearing'd car on the street again, it gets pretty hairy, even when it was designed that way. Are DSM inboard pickups even strong enough for metal bearings on the street ? A requirement is that the car be street-friendly. I'd hate to bend the crossmember by clipping a kerb or falling into a standard New England pot hole.

Hard(er) bushings are not the perfect solution, but if the class does not allow spherical bearings, or if the car has to see extended street use, I believe replacement bushings are a better compromise. IMHO.

Everybody calls them pillowballs, accept it, move on

Would you trade your Bilsteins for Konis ? I didn't think so, and neither would I


Oh, as an aside for anyone interested, I got an entirely more reasonable quote yesterday for my offset compression strut bushings. Between $450 and $500 a set. The cost is due to the time it apparently takes to machine 4340. I didn't know, but this material is generally referred to as tool steel in the "normal" world - so that makes more sense. No wonder it takes so long. So if anybody wants a set let me know.


Charles

 

[Templisk]

I've seen a few references made to Bilstein's, who makes them and is there a link I can check them out at?

Autocross question: are turbo-backs exhausts allowed, or only cats?

 

[ACM]

www.bilstein.com

They're not specifically listed for 2Gs, but there are units for the underlying Galant varient, so all the basic parts already exist. Just valving overall length need altering. "Just"...

There was a company a few years ago that built Bilstein-based specials, called Shocktek.

Some of us are still nurturing our relics along

Charles