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My last time out I only got 2 runs, and got no bite, with my 60 ft times off by 0.3 to 0.8 sec. :mad: I am about to switch to the top hole on my Caltracs to get more consistency, especially when track conditions are poor. By all accounts this will hit the tire harder and I am wondering, how do I know when it is too much hit? What will happen? Will it pull rpm down when the converter flashes? If so, should I try more tire pressure? I am currently running 17-18 psi and leaving at about 1400 rpm, converter flashes at 3400. See this thread for more info on my setup:

http://www.stevesnovasite.com/forums/showthread.php?t=211251
 

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My last time out I only got 2 runs, and got no bite, with my 60 ft times off by 0.3 to 0.8 sec. :mad: I am about to switch to the top hole on my Caltracs to get more consistency, especially when track conditions are poor. By all accounts this will hit the tire harder and I am wondering, how do I know when it is too much hit? What will happen? Will it pull rpm down when the converter flashes? If so, should I try more tire pressure? I am currently running 17-18 psi and leaving at about 1400 rpm, converter flashes at 3400. See this thread for more info on my setup:

http://www.stevesnovasite.com/forums/showthread.php?t=211251
I run 10-12 psi 29.5 10.5 wide slick and I hit the tire real hard
 

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I use to leave at a dead idle and peg it on my last 71. No such thing as too much bite (my guess) as long as it's not wasting forward motion on wheelstands. If it bites too hard and there is a weak link, then you will find it. My old 71 would do a 1.65 at best loading the converter and flashing the converter at a dead idle it could get a 1.64.

My 72 hasn't been to the track yet(maybe springtime), but I will leave at a dead idle with it and see what it can do.

Air pressure is different for different cars, but I want to say mine worked really good with 17 psi and running Hoosier dot slicks. Car would pull the wheels about two inches.
 

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No such thing as too much bite (my guess) as long as it's not wasting forward motion on wheelstands.

If that is the result, I'll take it! :D Wasted motion pulling the wheels beats no motion spinning the tire. :yes: Gonna do the top hole and find the next weak link.
 

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"No such thing as too much bite (my guess)", pulled from my post up top and I do agree.:yes::yes::yes:

Probably don't want to tell a P/S that, as an example. A lower power car can deal with dead hooking and no tire spin sometimes but as the power goes up dead hooking can become an issue. Every combo is different
 

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For our deal, a dead hook might as well be the end of the pass. Yes, there is such a thing as too much traction. We WANT wheelspin and minimal wheels up. If we don't get wheelspin we have to either bump up power, and/or lower tire pressure to 5 lbs or less until we get the spin we want. I look at driveshaft speed at .1, .25, & .5 seconds into a run to see if we are achieving the numbers I want to see. If the numbers are too low we typically get tire shake...if they are too high, it may blow the tires off...there's a "sweet spot" where we have to be.
 

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really need info and video would help a lot. The front suspension is as important as the rear in a lower powered car, is it getting any transfer, is it hitting and unloading, etc.?

Yes you can hit the tire to hard, it kill's the sidewall and effects consistency, if its bad enough or after the sidewalls are dead it will wrinkle the slick so much it distorts the foot print. Without more info its hard to say but hitting it harder may fix your issue but it may also be a bandaid and far from optimal.
 

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Rephrase - No such thing as too much hit for a street-strip car.

Race car yes, pull timing, NOS controllers, less boost, chassis adjustment, etc..
 

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My last time out I only got 2 runs, and got no bite, with my 60 ft times off by 0.3 to 0.8 sec. :mad: I am about to switch to the top hole on my Caltracs to get more consistency, especially when track conditions are poor.

http://www.stevesnovasite.com/forums/showthread.php?t=211251
Bob, I wouldn't be too bummed out, the track conditions were really bad that day at the Mooneyes show.
I walked out to the starting line after the Camaro wrecked, and the prep was weak. I don't think that they sprayed the starting line at all.
My car spun badly on the one pass that I made that day. I ran the Nova with the same setup that I last ran at Bakerfield. At Bakersfield, the track was so good that I had to take hook out of the car.
My car works best with a little spin, about 1-3 tire revolutions on the launch. If it dead hooks, it smashes the rim into the track, and launches violently.

I think with your car, you can make some changes to tire pressure, shock settings, launch rpm, changes to the Cal tracks, to experiment with hook. I think that the worst that will happen on your car with too much hook,is that it will bog on the launch.

I think that your car is well set up, and that you've got the right idea.





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Discussion Starter #13
Update

Made it to the track last night after moving the Caltracs to the upper hole and rear shocks set at 9 (stiff). As Bill noted, the track conditions have been dismal lately and last night wasn't much better. The good news is my 60 fts were more consistent: 1.88, 1.80, 1.85, with the shock set at 7 on the last run. The bad news is I am still about 2/10 off where I was a year ago at the same track. Looking at my datalogger, I am convinced the tire is now hooking, then unloading. In fact on the last run it "chattered" badly but I stayed in it and almost matched et of the second run. The datalogger clearly shows the tire unloading twice within 1.0 second from launch. Another racer (much heavier car) told me he also had chatter last night, and I have had it many times with Caltracs set in the lower hole and softer shock settings. I am guessing it is the tire unloading. If so, do I soften the shock more to counter it? I did not have a chance to try that last night, without waiting in line for another hour and a 1.5 hour drive to get home. :( Any other ideas of where to go from here?
 

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Here ya go Bob. Heres some videos of us last night at Irwindale. Don't know if you can see whats going on or not. Good times though :D:yes:

 

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A couple of things...My car 60' the best when I left off idle. When you get up against the converter in a foot brake car you preload the suspension. I noticed in the video that the rear suspension was not separating from the body much; this could be due to the tight shock setting. How much front end travel do you have, what kind of springs and shocks?

Have you guys noticed the 60' time difference between the two lanes there?
 

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Here ya go Bob. Heres some videos of us last night at Irwindale. Don't know if you can see whats going on or not. Good times though :D:yes:
Ya, had a good time in spite of the track down time. Good video, thanks for posting. I have looked at our race over and over to see anything that might show the tire chatter. Even looked at it frame by frame, could not see anything but the front end coming up and staying up through the 60 ft marker, nothing at the back tire. Maybe in daylight I could see more, but nothing on this vid. The one thing I did notice was you had 1/2 car length on me very quick and it seemed like I started to hook near the 60 ft and start to close the gap. It was a close race! :yes:
 

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A couple of things...My car 60' the best when I left off idle. When you get up against the converter in a foot brake car you preload the suspension. I noticed in the video that the rear suspension was not separating from the body much; this could be due to the tight shock setting. How much front end travel do you have, what kind of springs and shocks?

Have you guys noticed the 60' time difference between the two lanes there?
Lou, good to hear from you! :yes: Hope to see you again at the track soon. I have 5" of front travel, Moroso trick springs with Calvert 90/10 front, Calvert split monos with Rancho 9-way rear. I will be going to a softer shock setting next time out. I have been leaving at 1200-1400.
 

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Lou, good to hear from you! :yes: Hope to see you again at the track soon. I have 5" of front travel, Moroso trick springs with Calvert 90/10 front, Calvert split monos with Rancho 9-way rear. I will be going to a softer shock setting next time out. I have been leaving at 1200-1400.
A softer shock setting will most likely make it worse. The higher the shock setting on the Ranchos the better it keeps the tire planted!:yes: I have spent many T-n-T messing with the shocks to figure out what works with these. You are also chasing your tail with a cool track, drag radials need track temp and decent prep!:yes: How old are your rear tires?
 

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Lou, good to hear from you! :yes: Hope to see you again at the track soon. I have 5" of front travel, Moroso trick springs with Calvert 90/10 front, Calvert split monos with Rancho 9-way rear. I will be going to a softer shock setting next time out. I have been leaving at 1200-1400.
Like stated and I also mentioned on my old 71, if you haven't left on a dead idle then try. As long as the engine doesn't bog and plenty of timing give it a go. Converter flashes higher.

That was a close run between you two guys. :yes:
 

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You are also chasing your tail with a cool track, drag radials need track temp and decent prep!:yes: How old are your rear tires?
Eddie, you may be right about chasing my tail, but I had a 1.67 60 ft almost exactly a year ago at the same track with about the same air temp. Tires are less than one year old with about 40 runs. The track prep is the wild card, but seems to be very poor lately.
 
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