I am planning on running my Z28 in local autocross, and I need some advice. 1) What are the best subframe connectors to get? I am planning on running in SM, so I can't use any that tie the subframe together. 2) What is a good strut tower brace to use? Is three point better than a two point? I am really concerned about losing chassis rigidity by autocrossing the car, so these are the first mods I am going to do. Thanks for your help.

P.S. My car has T-tops

 

i love my BMR stuff..very strong, well made, relatively inexpensive and your choice of color (not important but nice).

i have plenty of pics of my stuff on my web page...including my recent SFC install

 

If you're going to build a car for autocross, the first step is to get a copy of your local rules. Most places sfcs will put you in a class with very modified and expensive cars.

 

Thanks for your comments. I have already checked the rules, and SM is what I plan to run in (SFCs legal so long as they don't tie the frame rails together). I am just curious as to which brand is the best, BMR, Global West, etc. Thanks!

 

OK, my opinions.

There's not a ton of difference between the quality brands. Really cheap stuff may not fit well. BMR makes good stuff at a good price. The Kenny Brown Double Diamond sfcs may be a bit stronger, I don't know if they'd be legal. They don't quite meet, but come close.

Don't spend extra for chrome-moly. Unless properly heat treated after welding it's really not much stronger than mild steel.

How the sfcs are installed is the big thing to be careful about. You want the car supported on its' wheels, so as not to weld a twist into the chassis. You want a pro who can weld on your car without setting it on fire or trashing the electronics.

 

Thanks for the info,

Kenny Brown is out b/c they tie the frames together. I am pretty much between Global West, BMR, and SLP (although I don't know if these are legal). Any from the above list you would avoid? Also, I have a couple of really good restoration shops near me that can do the work. Thanks!

 

"Any from the above list you would avoid? "

No, more based on what I see on the net than on personal experience.

 

Are Hotchkis STB not as strong as BMR or similar 1-piece units? The Hotchkis has hinges on it and not a solid piece, this can't be as strong as a one-peice, because it would still allow flex, right?

 

check out my cardomain page in my sig. i installed the BMR STB and it is a high quality piece. definitely stiffened up the front of my car a great deal. i have yet to have the BMR SFCs welded but they appear to be very high quality

 

Hmmm, can subframe connectors really be called subframe connectors if they don't tie the subframes together?

 

I have LGMotorsports SFC's, they're very beefy, apparently they sit higher than the BMR's once installed. I also opted for the optional v-braces, which bolt from the SFC's to the tunnel brace bolts. I don't know if the v-braces would be legal for your endeavor. The LGM SFC's would work for you just fine, I love what it did for my handling, I had Don Lorentzen in Orange County CA do the installation, he really liked the way LGM designed them.
They're not cheap though.

 

My SFCs are by Competition Engineering...VERY high quality. I actually like them better than some of the more popular brands because they are a boxed design that tucks right up under the body, unlike some that hang down like 2 inches and can be seen from outside the car.....that looks ghetto IMO

 

That's how it seems to me. I don't see how it can be as stiff as a one piece STB.

 

I think I'd spend my money and time elsewhere.

While yes, subframe connectors DO make a difference, in the class I run in, they're illegal. They don't directly help a car handle better, just improves the "feel" and precision. I used them years ago on my 2nd gen Firebird and they helped BUT I was running in a prepared class too.

STB, I have one, can't tell you if it made ANY difference at all. Probably not much though, but it's legal for me and everything I can do within the rules, I need to do.

There are numerous things I would do first before those you mentioned. Sway bars, springs, and shocks would be my first investment. Do the things that make the most dramatic difference then start with the items that maybe make a difference but much smaller.

 

I disagree with that approach. The guy said he wants to run SM, where sfcs are legal.

He'll spend time setting up his car and learning to drive it. That effort will be better spent on a car with a solid chassis. Otherwise he'll be setting up and learning to drivie around the problems of chassis flexibility.

Not to mention the possibility of bending things a little or loosening up welded and glued joints.

I'd make the chassis solid, and then mod it.