Now that my transmission should be getting back this week and the car should be making some good power, I want to strengthen the chassis up a bit. I was going to buy UMI's 3pt SFCs, but to be track legal, I'm going to need at least a roll bar. If the rules are still the same as the 02-03 seasons, I should be okay to 10.00 with a 6pt or 8pt roll bar (stock chassis, nothing cut up). Looking to run low-mid 11's on motor and another second or so faster with the direct port.

The car will by no means be set up oriented to drag-only. I know when it comes to drag/handling, you can't really have your cake and eat it too. I'm more or less looking for well handling car that will be "able" to drag. I know one of Sam's other customers cut 1.7x 60's on Koni SAs (which I now have), which is perfectly acceptable to me.

Suspension so far..
-poly-ended LCAs
-rod-ended aluminum PHB
-Koni SAs all around with lower perch and hose mods and stock springs
-24mm rear swaybar with poly links and mounts (will more than likely be changing to a 21mm this week)

I plan on changing the body-side bushings on the LCAs to rubber and replacing the PHB with a steel one with a poly/rubber bushing combination as well. Not a big fan of the extra noise I've gotten from the rear with the rod ends and poly stuff, and I don't really trust the stiffness of the aluminum bar. Aside from chassis stiffening, the next suspension piece I'm looking into is a UMI chassis mounted torque arm with driveshaft safety loop.

Is a 6pt roll bar going to give me the same kind of stiffness as having the 3pt SFCs? Is there going to be much benefit of installing the SFCs once I have the roll bar in?

 

Also interested. Can anyone speak from experience?

 

Just remember if you try to sell the car later down the road it will be a lot harder to do so with a jungle gym in it.

 

UNLESS...the buyer wants a jungle gym

 

kids love jungle gyms!

 

While I agree, if the car is going to be legal to run at a track at all, I'm going to need more than SFCs anyways, unless I feel like hitting the brakes after the 1/8...which we all know is also against track rules.

I plan on getting a rollbar. I'm just curious as to whether a 6pt roll bar will make my car as stiff as having 3pt SFCs. I know full cages offer the most chassis rigidity obviously, but a 6pt is by no means a full cage either.

I'd like to avoid a full cage though because the halo will have to hang too low to clear my T-tops. As cool as I think that would look to see the cage bars across the t-top areas when they are out, it'd be almost impossible to deal with them there. As I said, assuming the rules haven't changed much since 02-03 for cages/bars, I should be good to 10.00, while adding better protection for road racing/street driving.

I would imagine that a rollbar would help torsional rigidity moreso than even a set of 3pt SFCs based on how they are tied together, but that's just my thinking. Only went through one semester of M.E. stuff, and I'd like to hear something out of experience as well.

And then if we're on this topic. Am I better off having the rear bars go to the wheel wells or the end of the rear framerails? I'd imagine the bars to above the fuel tank would be the worst, and the bars to the framerails would probably be the best, but at the same time, the bars will have to be longer to do that and I'd imagine they will lose some of their anti-torsional support the longer they are. Unless I were to do something like have the rear bars run back to the end of the frame rails and somewhere along that bar have each of those tie into the wheel well area as well.

EDIT: I care a lot about the torsional rigidity in the event that I get into more serious road racing events and such, not to mention the added safety.

 

If you end up open tracking the car you might want to look into a cage thats made from DOM steel instead of ERW. I know what you mean, im one of the people that would rather have the roll bar (cant attatch a harness to subframes) but im debating on getting rid of the car so thats where that thought came from, lol.

 

Does anybody else have any input? Any of the hardcore RR/AX guys?

 

TTT. This is my dilema as well. I want to stiffen the car but I don't want rollbars and subframes. Will the rollbar be enough to keep the frame straight?

 

i decided to put a 6pt cage in my 95 Z28 instead of SFC's. i went with an NHRA legal weld in cage from fbodymotorsports.com and my car was really stiffened up after insalling the cage. and as far as getting in and out and the cage getting in the way ti is not too bad. i don't ahve swing out bars and i still daily drive the car. and the hoop doesn't get in the way of the t-tops, but you lose your back seats. and as far as install time i did it over a weekend and about 12 hours of work but i hit a few snags that if i had to do it again i could go quicker. i hope that info helps.... oh and driving a caged car in the street every day gets a lot of looks from other car guys which is always fun. esp if ur car is fast enough to need the cage

 

Yeah, I know a 6pt won't get in the way of T-tops. I was saying I'd love to have a full cage, but then the halo bars will get in the way. Thanks for the input on it stiffening up your car. That's what I'm looking to hear. Now to decide which 6pt I'm buying.. lol

 

RE: extra noise, this is from the rod-ends on your LCAs. Having a double rod-end PHB will not cause any more road noise, this I know from experience. I've read other threads of folks complain about the noise when they replace their LCA's with rod-ended ones.

 

LCAs are poly-ended, not rod-ended. With that said, I will still probably be replacing the PHB with a steel adjustable poly version. If anybody wants to trade, PM me

 

All depends on how the roll bar is installed and where the attachment points are.

Bolt-in bars are a universal "one size fits most" contraption. Recommend staying away from them, unless you weld them in after installation.

A custom 4-point with fabbed and welded in 2-point SFCs may be a better way to go. If you really think you'll need the extra 2 attachment points in the rollbar (i.e., the down bars into the footwells) they can be attached to the same point as the front of the SFC, which will tie the rollbar and SFCs together at both ends of the SFC. This will increase chassis rigidity more so over the 3-point SFC alone, and allow for proper attachment of safety harness (which you'll need if you get into the 10's IIRC).

Main hoop should rise as high as possible to ensure adequate headroom clearance. Most bolt-in roll bars won't do that, and end up blocking some or most of rearward vision.

As an aside, my rod-ended PHB does make noise. It can be reduced by ziptying some heater hose around the metal collar bushing on either side of the rod end.

 

Thanks for the tip on the rod end trick, I'll see how that works.

I like the idea of the 6-pt tying into the SFCs. I just wasn't sure if I would need SFCs as well. I'm going to need the two sidebars though to be legal at the track I'm pretty sure. I could be wrong though.

I just ordered my UMI tunnel-mounted torque arm today, so that will be going in when it gets here. As soon as I have that paid off, I will probably be ordering a rollbar from Wolf. Was looking at the Competition Engineering kit, but Young at BYUNSPEED told me to skip that and just go to a Wolf setup. I'll see what I can afford and work it out.

 

I have a comp eng weld in 8pt bar. DON NOT get it. I wish every time I drive my car that I would have waited a little longer for the kit and pony up the extra 100 bucks and buy the wolf kit. The comp kit is a universal kit, unlike the wolf where it is built to the car.

 

DC, verify your track's/sanctioning body's rules before get the roll bar installed. May save you money in the long run. I would hate to see you get a bar that is not legal or structurally correct (or both - yikes!). Verify minimum number of attachment points for the class or expected ET you will be running, along with other safety requirements.

FYI, I was recommending custom 2-point SFCs that work in conjunction with the roll bar. The bolt-in SFCs may not be able to be welded to the roll bar in the right places (where the main hoop comes into the floor behind the driver/front passenger seat, for instance).

Picture it this way - the SFCs are like a piece of paper, and the rollbar welded to the SFCs are like a box. It is much easier to twist the piece of paper holding either end than the box.

If your rules allow it, the 3-point bolt-in/weld-in SFCs will help out. If they don't, get some 2-point SFCs that will work with your roll bar kit (tie into the main hoop and the down bars in the front). Also, look around for a chassis shop in your area. You might be able to get them to fab and install the bar and SFCs. May cost more, but safety shouldn't be scrimped on. JMHO.

 

Any updates?

I was thinking of building my own 4 pt rollbar but actually tie it into the car where the main hoop would not be seen, but the 2 bars to the rear would. The rear bars will also be tied into the cars unibody chassis at multiple points. With all the bars actually welded to the car all around it should give maximum rigidity (in at least the back half of the car anyway).

I don't have to be legal for any tracks, BTW.