Don Terrill’s Speed-Talk

Hey Everyone! I am in the middle of building a 82-92 S10 to race at my local track and I have a couple question regarding the IHRA legal cab and roll bar mounting. This will not be for any specific class mostly just a test and tune/grudge car. Maybe down the road some sort of drag radial class but for now just fun. I say IHRA cause that is the rules my track goes by. I don't plan on running it past the 10.0 sec or 130 mph range anytime soon which from when I read through the rule book it seems like 130 mph and 9.99 a lot of things chassis wise need to change. I got a 6pt roll bar setup with the truck. I was told by the owner of the local track that the cage has to be welded to the floor of the cab onto a 6" x 6" x 1/4" plate. Is this true? Also can I reuse the existing cabs four corner mounting locations? The one mount looks like it took a hit so I was thinking about cutting off the mount and replace them with some solid steel spacers so its mounted solid to the frame. Is there anything anyone here would suggest I do differently? I have never undertaken a project like this before so I am all ears. Will one bolt in each corner be good enough? Is there a certain size I should put in? Thanks for your input!

Welcome to the site!

I cannot directly answer your question, but I can tell you what happens to an S10 if it hits the ditch. In high school, I sold my cousin an S10 V8. He put it in the ditch full speed. All six cab mounts (core support too) tore through the frame, the cab pivoted on the steering shaft 90 degrees and the rotation was stopped by the B&M shifter cable.

Make it safe.

crazyman wrote:Welcome to the site!

I cannot directly answer your question, but I can tell you what happens to an S10 if it hits the ditch. In high school, I sold my cousin an S10 V8. He put it in the ditch full speed. All six cab mounts (core support too) tore through the frame, the cab pivoted on the steering shaft 90 degrees and the rotation was stopped by the B&M shifter cable.

Make it safe.

Wow. I hope he was okay from it. Yeah I figured since this is my first time building something to go at that fast of a speed I want to get in touch with other people who know what is the correct safe thing to do so incase worse comes to worse I will have a better chance walking away from it.

I don't know what IHRA rules say but with the S10 having a full frame, I would want the cage attached to that, not to floor plates regardless of whether the body mounts were solid or not.

ZIGGY wrote:I don't know what IHRA rules say but with the S10 having a full frame, I would want the cage attached to that, not to floor plates regardless of whether the body mounts were solid or not.

So you would drill holes through the floor and drop the cage down to that and then weld the cage right to the frame?

I don't know IHRA rules but NHRA says that if it has a full frame the bar must be welded to the frame. Not to the body, and not bolted in, welded to the frame. You need a 5 point bar to go 10.0 to 11.49; that's a hoop over the driver's head with a shoulder high cross brace, two braces running to the back and a door bar on the driver's door from hoop to the floor by the driver's feet. The door bar can swivel for easier access or be welded solid, and most guys put a door bar on the passenger side too. You need a five point harness attached to the cross bar and the floor, a fire jacket, gloves, certified helmet and I'm sure some other details I've forgotten (driveshaft loop, long enough wheel studs and open end lugnuts, ...).

First thing to do is buy a rule book and read it. Then go talk to the guy who does the tech inspections at your track, because no matter what you read or what we say, his word is law. Most every tech guy I've talked with was happy to help because if it is right the first time eveyone's job is easier.

Just found this....
http://d27vj430nutdmd.cloudfront.net/12 ... 6979.1.pdf
I will read through and figure out from there. Thanks for all the input so far!

page 98. "All cars with an OEM frame must have roll bar welded to frame."

zildjian4life218 wrote:Just found this....
http://d27vj430nutdmd.cloudfront.net/12 ... 6979.1.pdf
I will read through and figure out from there. Thanks for all the input so far!

cool, thanks.

Even though you are running an IHRA track, in my opinion you should build your truck to satisfy both IHRA and NHRA rules. It won't cost a dime more but will make your truck easier to sell someday if it can be certified by either sanctioning body.

Those frames are kinda narrow, so you might have to
add some rectangle tube outriggers, welded to the frame.

Thanks for the input on the outriggers. The previous owner had the cage mounted to the floor on 6"x6" 1/4" plate so I will probably get an outrigger kit from these guys http://www.autoweldchassis.com/rbc.ivnu. I will need it because of the height issue too since the cage was setup to go off the floor I now need to bring a mount from the frame to above the floor to get as much height out of the cage as possible. Im a little over 6'3" so I need all the height I can get. In the next couple weekends I will be cutting out the floor and building the subframe that the aluminum sheet metal floor will attach too. Hopefully I will snag some pictures to post so you guys can critique my work and provide some input for other interested.

also I am going to be redoing the floor and firewall. What do you guys prefer steel or aluminum? I like the idea of Aluminum being lighter and wont rust but its definitely more expensive and I won't be able to weld it and forced to use rivets or something. Is it worth the couple extra pounds it saves.