hey guys, i know this is a honda forum and i was innitially turned off by the apperances forum *cringe* but the road race forum seems to be an extremly intelligible place. This is going to be for a 1995 nissan 240sx. Anyhow i am going to a roll bar fabrication shop tomorrow and was looking for some advice. What i want to do is get as close as a race cage setup as possible behind the rear seats. Currently this is my daily driver and i do not want to be wearing a helmet every time i need to go to the grocery store so i dont want to get anything infront of the seats. Maybe i would get the remainder of the pipe welded on in the front if i get more into track and/or get a new DD. but for now i need somwhere to mount my 5 point and would like some added rollover protection as well. What kind of design would you guys suggest? what i am thinking of making a bar similar to the autopower race bar with additional bracing.


now what i am kindof hung up on is the diagonal cross braces. I was thinking one bar running from bottom, front left to top, front right (facing the car). Now do you guys think it would be better to run an additional diagonal bar from the top, front left to bottom, rear right, and have them staggered, OR should i opt to not put in that first bar i said, and instead run it from top, front right to bottom, rear left, an X brace if you will. I can draw a picture if that didnt make sense to anybody. also do you think it would be smart to have a pipe welded between my struts while its in the shop? or should i just stick with a traditional strut brace. i guess the welded pipe might be kindof ghetto and less flashy, but it seems to serve the same purpose in my mind.

any feedback would be great guys, thanks!

 

I think i know what you're getting at, and yes i think its worthwhile...... i'll post a pic of what i had built for me last year - pretty nice piece, although its sitting in the garage

 

which design do you think is best? the first one i described with 2 staggered bars, or the second one with an X bar?

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Buttcrack &raquo;</TD></TR><TR><TD CLASS="quote">which design do you think is best? the first one i described with 2 staggered bars, or the second one with an X bar?</TD></TR></TABLE>

Well, without getting too technical (and over my head as well), you only need to accomplish two things with a roll bar. First, you have to keep the main hoop from tweaking side to side. Second, you have to keep the main hoop from moving forward or backward. If you can accomplish these two things, you're good to go no matter how you do it. If it were me, I would run the diagonal from behind the driver's head down to the passenger floor, all within the main hoop. This bar should be straight...no bends. You can then wrap a harness bar around the back of this brace if you wish. Then the job of the rear supports doens't have to be keeping the main hoop from tweaking, they just have to keep it vertical-ish. Not knowing the 240 interior or sub frame all that well, I can't tell you if you should go to the shock towers/fenders or to the floor. However, if you have a quality shop doing your work, you can combine your idea and run the rear supports to the shock towers and then have a bar between the stock towers, all part of the same mounting plate (search this forum for "cage" and you'll see plenty of pics and ideas). And, if you later decide you want that additional cross brace on the rear supports, you can always add it. A word of warning, however. Since most of us compete, most of us have rule books we must follow. So, if you ever plan to compete you should be aware that some roll bar designs are not legal for events like Solo I or II.

 

Keep all of the bars triangulating the main hoop in the same plane - so you can't see any of them looking at it from the side. Two diagonals is probably overkill, frankly...

It's also probably worth the additional research time and minimal cost increase to have whatever gets built actually meet common road racing rules - probably 1.75 OD x .095" wall thickness but DON'T take my word for it. The advantage here is that you are spending money on something that might have a future, should you or someone else decide to go the next step.

K

 

I forgot to take pics today. I'll do it tomorrow.

RJ