I am getting ready to install a roll bar in my 240sx (I know not a Honda but this is the best forum for this question) and was wondering if doing the back bars like in this picture would be NHRA/NDRA legal, with the cross bar connecting at the strut towers on 6x6 plates of course.

 

You might want to look it up:
http://www.nhrasportcompact.co....html
but I'm pretty sure those rear downbars have to be welded to 6x6 plates of their own.

 

I hope thats OK Robbie cause that is exactly how mine is done. Our local NHRA guy was at MR2 performance when Mike was welding in my bar and he said it was fine

 

Thanks for the info guys, keep it coming!


Carey, got any pics?

 

im pretty sure it will be ok...i seen a few cars that run bars like that due to have their rear floors cut out and havin no place to weld 6x6 plates to the floor so they run a set up just like the one u have pictured....u should be ok...double check though

 

I got some pics on the indycarz forum. look under the build section I have a few pics there, just got the engine in this last weekend. Im getting stoked!!!

 

Car is looking awesome man! Bemis gave me a run down of everything your doing, gonna be wild! Do you have any pics of the cage?

 

I have a couple pics, what is your email I'll send them to you

 

O yeah, thanks for the positive comments about my car.....it outta be fun. Your car sounds sick as hell. Already been in the low 11's....thats awesome....on street tires????

How much power are those rearends good for? I've been thinking about doing the RWD conversion on my Scooby??

 

Thanks! That was on the new M/T street radials. People have pulled high 1.4 60's on stock axle and diff setups (lsd's of course). My email is t61civic@aol.com

 

Thats some awesome 60's. I hoping for the 1.7's maybe 1.6's on my street tires???? Pics are coming

 

I didn't 60' that btw lol. My best is a high 1.8 so far. Should be much lower next time out

 

Yeah....1.80 has been my best so far

 

The rear bars are supposed to be welded to the frame rails. The tech inspectors will usually give you a hard time even if you weld them to the strut bars.

Then again depending on how tech inspectors are in your area, they may not say anything to you. But according to NHRA rules, to the rear frame rails.

Jason

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SFWD 1934 &raquo;</TD></TR><TR><TD CLASS="quote">The rear bars are supposed to be welded to the frame rails. The tech inspectors will usually give you a hard time even if you weld them to the strut bars.

Then again depending on how tech inspectors are in your area, they may not say anything to you. But according to NHRA rules, to the rear frame rails.

Jason</TD></TR></TABLE>
what if u cut the rear frame rails out

 

They always seem to be a little more forgiving with full interior street cars

 

My main reason for wanting to do it this way is I will easily be able to tip the cage back to get a good weld on top of the hoop and also the sides of my rear strut towers are nice and smooth so the plates would jive up nicely. I'll probly post pics once the install gets going.

 

Big Tom:

If the rear frame rail have been removed, then you are telling me, or at least I am understanding it this way: You have esentially back halved the car. If that is the case, then you will join together with the rest of the roll cage. Then you will bend the tube and weld it in place.

Jason

 

I checked with my sources at NHRA in Glendora, and the tech guys said they don't have a problem with your set up.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Pro-Am 1934 &raquo;</TD></TR><TR><TD CLASS="quote">Big Tom:

If the rear frame rail have been removed, then you are telling me, or at least I am understanding it this way: You have esentially back halved the car. If that is the case, then you will join together with the rest of the roll cage. Then you will bend the tube and weld it in place.

Jason</TD></TR></TABLE>

i dont exactly understand what ur saying... but cutting frame rails or the floor out does not constitute a back-half

 

There are no "rear frame rails" in a unibody car, per the NHRA definition. That's why they specify that all the cage or bar attachment points have to have a 6x6 backing plate (or two, sandwiching the unibody, if it's bolted instead of welded). On cars with a true frame, the bars have to be welded or bolted directly to the frame rails.

We just put a bar into our project EK for an article in the September issue of OverRev. Steen Chassis did the work, and the diagonal back tubes are set up in exactly the same way as shown here - they tie in to a crossbar that extends between the two strut towers, and that crossbar is attached to the unibody on each end with welded 6x6 plates. If anybody knows how to build a safe and legal car, it's Gary Steen...

 

the 6x6 plates are not required for the bar linking the shock towers... at least thats what nhra tech has told me in the past...

i understand there are no "frame rails" by definition in a unibody... hence the "unibody." i was referring to the rails in the back of the car... whatever u want to call them

 

I did Arturbo's cage exactly like you're describing PNG. A 1.75 .083 crossbar welded to 6x6 plates on the strut towers, with the rear downbars connecting to this bar. It's passed tech a bunch of times, can't be too illegal! lol