question for the 10 sec guys
Thread Starter
Drifting
Joined: Oct 2000
Posts: 1,396
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From: Sacramento CA
question for the 10 sec guys
Hey I am thinking about sticking 4:11's in my open road car in the off season and doing some drag racing. I was told that if you break into the 10's you can't have independent rear susp. Is this true?
Thanks,
Jeffy'
Thanks,
Jeffy'
Elite Torch Red Member
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From: Exit 89 GSP,Lakewood,NJ The Land Of Mojo
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Re: question for the 10 sec guys (Jeffyvette)
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
Re: question for the 10 sec guys (Mr Mojo)
Mojo, i believe you are referring to the rules for under 10 sec. I beieve the safety requirements are the same from under 12 to 10.000. basically a 5 point roll bar, fire jacket, and 5 point harness, plus minor misc stuff.
They changed the rule on the IRS, used to require a solid axle, but a couple of years ago they changed that, so the IRS is also good until you go in the nines.
They changed the rule on the IRS, used to require a solid axle, but a couple of years ago they changed that, so the IRS is also good until you go in the nines.
Melting Slicks
Joined: Jul 1999
Posts: 2,875
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From: Olive Branch (Memphis suburb) MS
Cruise-In II Veteran
Re: question for the 10 sec guys (Jeffyvette)
Damn, in a car that only weights 2620 lb, puts down 588 hp, and uses a good set of tires you'll be in the nines. :eek:
Race Director
Joined: Sep 2000
Posts: 17,298
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From: The Top of Utah
Re: question for the 10 sec guys (ralph)
They changed the rule on the IRS, used to require a solid axle, but a couple of years ago they changed that, so the IRS is also good until you go in the nines.
The rule is a little more complicated than that. A car with IRS, 2000 pounds or more, running 10.99, must change to a solid axle if it doesn't have both upper and lower control arms. This means, C3's, and not C4's. The C4 can retain the IRS for any weight or ET, but must be fitted with half shaft loops at 10.99. I hope this doesn't make matters worse. Good luck, and...
RACE ON!!!
Drifting
Joined: Feb 2002
Posts: 1,952
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From: Little Rock Arkansas
Re: question for the 10 sec guys (CFI-EFI)
I had a long discussion with Wesley Roberson who used to be the main tech official for NHRA and is now the Rules God for PRO/Edelbrock Muscle Car series at Memphis two years ago...At the time I was running low 10's in my '90... NHRA has very little written rules on IRS cars and what was written WAS changed as CFI correctly points out above... The C4 cars are allowed to 9.00 because of their "positive retention IRS assembly;" meaning that the wheels aren't going to come out of the car like they would on earlier Vettes' IRS rears. You are required to run retention loops for the halfshafts for spectator safety, however. Cars running 13.99 or quicker on drag slicks must have a driveshaft safety loop, cars running from 11.99 to 10.00 must have a 5 point roll cage with a door bar intersecting the driver's position between the shoulder and elbow. 10 point cages can be certified to 7.50... I have to add an additional roof loop and down bars to my 6 point cage in order to be legal for what the car now runs (high 9's)... But the IRS will remain...
-Jeb
-Jeb
Le Mans Master
Joined: Feb 1999
Posts: 6,172
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From: somers, ny
Re: question for the 10 sec guys (jburnett)
Ok, i guess i oversimplified it a bit :bb
I got news for the tech team tho. I wouldn't feel so confident about wheel retention on C4s. When i busted a spindle, the only thing holding the wheel on was the caliper :crazy:
[Modified by ralph, 6:55 PM 9/29/2003]
I got news for the tech team tho. I wouldn't feel so confident about wheel retention on C4s. When i busted a spindle, the only thing holding the wheel on was the caliper :crazy:
[Modified by ralph, 6:55 PM 9/29/2003]
Thread Starter
Drifting
Joined: Oct 2000
Posts: 1,396
Likes: 0
From: Sacramento CA
Re: question for the 10 sec guys (jburnett)
I have the big time cage, I have the drive shaft loop, at what ET do the half shaft loops come in? I have everything else.
Thanks,
Jeffy'
Thanks,
Jeffy'
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Race Director
Joined: Sep 2000
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From: The Top of Utah
Re: question for the 10 sec guys (Jeffyvette)
I have the big time cage, I have the drive shaft loop, at what ET do the half shaft loops come in? I have everything else.
Thanks,
Jeffy'
Thanks,
Jeffy'
RACE ON!!!
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: question for the 10 sec guys (ralph)
Ralph when you broke your spindle (I broke 15 of them before I "fixed" them) your wheel still would not come off... The rear wheel bearing is bolted to the rear knuckle which is in turn bolted to the frame via the control arms and the shock assembly... On a C3 if you broke the spindle (which is attached directly to the wheel bearing and wheel and merely rides in the knuckle) you WOULD lose a wheel... The only way the wheel is coming out of a C4 is IF: 1) you shear the wheel bearing past the retention bolts (the three big-azz bolts that go into the knuckle) 2) if you break the knuckle itself.
This is why the NHRA views the C4 axle assembly differently than they do all the other IRS systems used on previous Vettes. If I can get ahold of Wesley again (I'm going to the PRO finals in Memphis this weekend) I'll get a dead nuts ruling from him on this...
-Jeb
This is why the NHRA views the C4 axle assembly differently than they do all the other IRS systems used on previous Vettes. If I can get ahold of Wesley again (I'm going to the PRO finals in Memphis this weekend) I'll get a dead nuts ruling from him on this...
-Jeb
Le Mans Master
Joined: Feb 1999
Posts: 6,172
Likes: 11
From: somers, ny
Re: question for the 10 sec guys (jburnett)
Jeb, mine actually pushed the bearing apart, separating the bearings from the race. The spindle sheared on a sharpe angle so it acted like a cam, pushing the bearing apart. Actually the bearing was still hanging on but i credit that to the caliper. The wheel had about 30deg negative camber. Fortunately for me the car only moved about ten feet.
My buddy has a 70 vette he runs in Stock eliminator. He runs mid tens and has 1/2 shaft loops about midway if memory serves me. Tom Diff also made him halfshafts that are about 6-8 inches in diameter!
My buddy has a 70 vette he runs in Stock eliminator. He runs mid tens and has 1/2 shaft loops about midway if memory serves me. Tom Diff also made him halfshafts that are about 6-8 inches in diameter!
Drifting
Joined: Feb 2002
Posts: 1,952
Likes: 2
From: Little Rock Arkansas
Re: question for the 10 sec guys (ralph)
Ok...You're one of those rare situations I mentioned where it happened...Freaky! Tom's makes some good stuff; I used a lot of his stuff in the past on C3 cars. An entire TD rear end assembly in an Eliminator 68 BBC car I used to run...
-Jeb
-Jeb