Probably another question for SiRacer...

Anyone actually experience chassis stiffening helping handling? (6th gen civic in particular) like front/rear strut bars and lower tie bars...

 

It depends on what class you are in. You gotta read some of the rules for autocrossing. If you are in stock class and you install strut bars you would be in a harder class. But if you are in the harder class because of just strut bars then you would be basically slaughtered because your car is not maxed to the rules.

 

If you're planning on STS, or any higher class (STX, SP (street prepared), SM, etc) most aftermarket chassis and suspension braces are legal. However, the amount of gain in performance that you will receive is negligible, especially compared to the benefits of improving the driver, tires, springs, shocks, swaybars, and alignment.

This is because taking your typical street car to a higher level depends mostly on increasing traction (tires) and roll stiffness (springs, swaybars, shocks). If you don't have enough traction to even keep your car on your intended line, there isn't going to be much energy going into the body to flex the suspension mounting points.

Front to rear balance (ie eliminating prominent understeer) can be achieved with springs, shocks, swaybars, and alignment. At this point, you will have enough cornering ability to be concerned about slight changes in camber or toe based on chassis flex/deflection of suspension mounting points. But I could argue that you should upgrade all of your suspension bushings to urethane before you should worry about how much your chassis is flexing.

What level driver are you? Small nuances in handling won't be readily apparent until you've had a fair amount of experience with autocrossing.

Also, the traction issue again. Are you running on true street tires, STS-legal autox tires (ie Kuhmo MX or Falken Azenis), or DOT-legal autox race rubber like Victoracer V700s, 710's, or Hoosiers?

Again, the more traction you have, the more you have a concern with chassis bracing.

Finally, on a FWD car as light as a Civic, only the front strut tower brace is really worth doing IMO. Most of the work (braking, turning) is done by the front tires. You'll see that your front tires get hot after your runs, but the rear tires usually get only 1/2 as warm, if that (indicating they're not doing much other than keeping the body off the ground).

Notice how under hard cornering my EG doesn't even keep the inside rear tire down. That means there's a lot of force on the outside rear, yes - but again, compared to the front, there's not much going on back there.

 

Great info, thanks!

I've been reading the rules but in several cases I'm not always sure how to interpret them due to my noobieness.

I'm stuck in a position where my car needed a new suspension because the stock one wore out. Since I was replacing the worn out stuff, I went with a mild upgrade with aftermarket parts: H&R OE springs with KYB AGX's (set at 1/4 and 2/8). I've had an AEM CAI too. Now that I'm looking into autocross, my CAI definitely bumps me out of the stock category. But if I put my stock intake back on, I'm wondering I'm not sure if my suspension still bumps me out of stock. The height is still near stock, rate is near stock, and dampening is near stock, all on stock mounts. My goal at the time was to improve daily driving handling but NOT turn it into a race suspension.

But looks likes I've screwed myself into STS... where I have no intention of doing the mods necessary to max out that class.

 

Oh... I just read SpecialED's article that plainly states that aftermarket springs are not allowed in stock class. I must not be reading the rules very well.

 

As you've figured out, technically with the H&R OE springs you're not legal for stock classes. Are you on stock wheels or not? If not, there's another reason you wouldn't be legal for a stock class.

I scanned through some of your other posts, but I can't figure out if you've actually every participated in an autocross or not.

If not, just pick a class (either stock or STS) and see if you enjoy it enough to pursue it more seriously. With your current set-up, I doubt you'll be anywhere close to competitive in either class (STS cars get to run unlimited stiffness springs, swaybars, and shocks; Stock class cars can run unlimited stiffness shocks with DOT R-compound tires), so don't worry about "breaking the rules."

If you decide you like it, then you need to decide what class you want to be in. If you're willing to get a dedicated set of race tires/wheels, you should go for stock class - although IMO, the AGX's are too soft/weak to be competitive against the best drivers in stock - the Koni Sports (yellow) would be a better but more expensive choice.

If you want to continue "building" your street car and improve its handling overall (stiffer/lower springs, add swaybars, add a strut tower brace), or want to add a header, catback exhaust, or keep your intake on fulltime, you will need to up the ante and go STS - and commit to running a competitive STS tire, like the Kuhmo MX or Falken Azenis - on your regular wheels, or buy a set of wheels for those as well.

 

You got me. I'm still a wannabe autox. I'm dying to go out but I'm the type to do my homework first, and this forum is one of my research sources.

I've got 99-00 Si OEM 15" rims (with Yoko ES100) on my EX (came with 14" steelies), a knock off of the OEM front strut tower bar, and put the 99-00 Si OEM 13mm rear sway bar on too. (My car is becoming a wannabe Si). Are these considered "stock" for my EX because it came from the same family of cars?

It looks like I'll just enter STS and watch my name caboose the standings forever. But that's ok, I'm actually wanting to learn to drive my car in the STREET settings, not to be competitive in the class. I want to be a better driver with my car.

If I get addicted, then I'm in trouble for other reasons... heh.

 

You can update/backdate but it has to be on the same lines in the Street Prepared rules. Which you are not doing.

The 15" wheels already bump you out of stock class as well as the strut bar, and sway bar.

So you would be legal for FSP or STS. STS is a fun class. I've been running this class sicne it was created back in 1998. You get to do most bolt ons and play on street tires. It's nice not having to change tires at the event and before you go home. I do it in my nice cool garage

 

Run STS. When you wear out the ES100, replace them with Kuhmo MXs or Falken Azenis autocross tires, or BFG g-Force KD (not the KDW2) - if you can afford them (I can't) - the BFGs are $130 each in a 205/50-15, vs. $80 or less each for the MXs or Azenis.

That will give you enough to start being competitive with some of the STS guys - and faster than those who are not good for sure!

CivicSiRacer is right - STS is a fun class. It's generally well attended, and you'll probably have hardcore National-level contenders all the way down to beginners like yourself.

 

It's a frustrating class now with the EF Civics My car and I used to be top dog for about 4 years until someone found out about the EF Civic Sis (89-91). Now I'm like 1-2 seconds behind these guys in my heavy weight 00 Civic Si

So I had to go out and buy myself one too