I had old school racer tell me that once you get into the 1.3xx 60'ft you needed to have a roll cage put in to keep from twisting your frame up. I have sub frame connectors in. My lowest 60'ft is 1.44, my question is, is this true? I know for safety I need it I understand that and its coming this winter just trying to see what I can get out of it as is.

 

It will usually dimple the rear quarters first. I wouldn't worry about twisting the frame too much at that level.

 

Well I don't want it to do that either lol, so at what point will it dimple the quarters and what point will it twist the frame, thanks

 

Thats hard to say because every car leaves a little different. If the car has a anti roll bar and is tied down well and not wheel standing I dont see any problems at low 1.3x. You shouldn't be looking at doing a cage for just this reason though as I'm sure you know.

 

IMO if your planning on going faster a cage can be done for the future. Otherwise a Roll bar should keep your car pretty safe for a while.

 

I went many 1.30/1.32 60's on the rear tires, carried the fronts well past the 60' clocks with no problems. When this track went NHRA I had to have the certified cage to run nines. Made no difference I could see. I had been told stories about tee tops popping out, etc. Nothing happened.

 

Sounds good, thanks for the info.
The front is coming up but only a couple inches.

 

yeah I don't see it a HAVE TO HAVE to cut 1.3 60s... an anti roll will help though.

my buddie consistantly runs 1.28s in a stock bottom end na ls3 powered hard top car and doesnt have anything more than an antiroll and subframe connectors. Car still seems solid.

 

One of my old 4th gens started twisting going low 1.6s. It started a wrinkle in the firewall in the area where the clutch master cylinder would be. Over the course of a couple years it got worse and eventually the car wouldn't hook anymore. You'd adjust stuff in the suspension, new tires, different tire pressures, launch rpm, and get it working, and the car would work good for a few passes then refuse to work anymore. That wrinkle started in the floor pan next to the subframe and spread up through the firewall. The car was never wrecked.

 

That is strange. You wouldn't think 60's that slow would bother anything. Wonder what was wrong with it for it to start that?

 

I wouldn't have thought so either if it hadn't happened to me. It was a virgin car... hadn't been in any bad wreck or anything.

I remember when I first saw it in the floor when it was a small crease, thought it was a weird place for one to be and wondered if it was factory, but didn't think so. Then it kept growing and spreading up through the firewall.

 

Door gaps will start to change too.

 

I could see door gaps changing, but cause they are on my little fox car. But the wrinkling the floor and fire wall seems very strange. I've never seen a chassis do that with out being in a collision or something major.
A cage certainly helps for this problem and the anti roll bar is the best thing to put on to keep from twisting the car.

 

Many 1.30 60's, my T-top car didn't change door gaps either.