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-   -   Critque this launch. (https://classracer.com/classforum/showthread.php?t=43849)

L79racer 10-15-2012 04:30 PM

Critque this launch.
 
Is the nose going up too fast too soon? I've been getting a lot of red lights and was trying to figure out if its just me or the car snatching the wheels out of the lights.Thanks in advance. I've been running 10.50 index all year under part throttle with good lights. Now I'm running full throttle and my lights suck.

http://s807.beta.photobucket.com/use...13ac2.mp4.html

Another view

http://s807.beta.photobucket.com/use...02dbe.mp4.html

Ed Wright 10-15-2012 05:43 PM

Re: Critque this launch.
 
Certainly nothing dramatic there. It's going forward before the tires come off the ground, it's not snatching the tires out of the lights. Looks like a pretty smooth launch. Don't know why it would screw up your lights. Looks very easy to drive. At least you can see where your going. :-)

jim hensley 10-15-2012 05:57 PM

Re: Critque this launch.
 
Looks like in the side view video you spun the tires about 1 rotation.

FED 387 10-15-2012 06:08 PM

Re: Critque this launch.
 
side view some slip --view from the right rear looked better no slip noticeable

L79racer 10-15-2012 06:38 PM

Re: Critque this launch.
 
Quote:

Originally Posted by Ed Wright (Post 352058)
Certainly nothing dramatic there. It's going forward before the tires come off the ground, it's not snatching the tires out of the lights. Looks like a pretty smooth launch. Don't know why it would screw up your lights. Looks very easy to drive. At least you can see where your going. :-)

Well I Guess its just me. I'll have to adjust to running more power.

Videos are of two differnt passes.

Bob Don 10-15-2012 07:11 PM

Re: Critque this launch.
 
Try a larger diameter front tire or let a little air out your front. This will give you a bigger bulge at the bottom of the front tire and allow you a little more time in the front beam before redlighting.

L79racer 10-15-2012 07:17 PM

Re: Critque this launch.
 
Quote:

Originally Posted by Bob Don (Post 352073)
Try a larger diameter front tire or let a little air out your front. This will give you a bigger bulge at the bottom of the front tire and allow you a little more time in the front beam before redlighting.

I usually run 33lbs in the front. What should I drop it to?

Ed Wright 10-15-2012 07:23 PM

Re: Critque this launch.
 
Letting air out of the rears make more difference in my lights than out of the front.

Adger Smith 10-15-2012 08:25 PM

Re: Critque this launch.
 
Side view, too much rotation on the hit. Inconsistant for bracket style racing, great for max et over dead hook.
side view : better hook on the hit. like Ed said car going forward before the front end lifted out of the lights.. In the back the tire side wall has too much bulge. that is making sidewall "work" too hard. Notice how the tire kind of "wallows around after the initial hit. wheel width needs to be matched to the tire or I would get a stiffer sidewall tire with matching wheel size. Then when the front end comes down you have massive toe /bump steer. that slows the car down. I guess i could do it frame by frame and get a few more ideas of what is going on. Hope that helps.

FED 387 10-15-2012 08:29 PM

Re: Critque this launch.
 
28ish see what happens ----if it improves maybe down a 1/2 pound at a time until its consistent---otherwise go up a 1/2 pound from 28 keep playing with it---just do maybe 330 foot or less launches til ya get it right--- all yer concerned with is the launch no point running it a 1/8 or more

L79racer 10-15-2012 11:26 PM

Re: Critque this launch.
 
Quote:

Originally Posted by Adger Smith (Post 352094)
Side view, too much rotation on the hit. Inconsistant for bracket style racing, great for max et over dead hook.
side view : better hook on the hit. like Ed said car going forward before the front end lifted out of the lights.. In the back the tire side wall has too much bulge. that is making sidewall "work" too hard. Notice how the tire kind of "wallows around after the initial hit. wheel width needs to be matched to the tire or I would get a stiffer sidewall tire with matching wheel size. Then when the front end comes down you have massive toe /bump steer. that slows the car down. I guess i could do it frame by frame and get a few more ideas of what is going on. Hope that helps.

Thanks for your input. The car usually dead hooks with no tire spin. I have been running the car in the corvette challenge and have been the 10.50 index champ for the past two years. I have been leaving the line at a lower rpm and using a mechanical throttle stop to keep it at 10.50. Its been deadly consistent that way. This was a track rental with friends that I was going for best ET. As for rims. They are 8.5 wide with a 29x10 slick with tubes. A wider rim will not fit on the car so I would have to go with a 29x9 slick. The bump steer is something I need to look into as to how to correct it. Any tips on that? Should I start tightening front shocks and keep tightening them as long as I dont get wheel spin? Here is the challenge race with it leaving softer.

http://www.youtube.com/watch?v=Hh5Y8...ature=youtu.be

L79racer 10-15-2012 11:31 PM

Re: Critque this launch.
 
Quote:

Originally Posted by FED 387 (Post 352096)
28ish see what happens ----if it improves maybe down a 1/2 pound at a time until its consistent---otherwise go up a 1/2 pound from 28 keep playing with it---just do maybe 330 foot or less launches til ya get it right--- all yer concerned with is the launch no point running it a 1/8 or more

Thanks, I'll try it out.

FED 387 10-16-2012 12:13 AM

Re: Critque this launch.
 
the reason I say 28 is going down a 1/2 or pound ya wont really know or notice if ya did the right thing---go down an extreme amount like the 28 ish see if it likes it---if it does then go up a 1/2 or down a 1/2 see waht happens---ya can always go back to the 33 setting---way too much front tire wobble when it sets down need to correct that scuffing off a lot of time there--rims do look narrow for the tire maybe try a narrower tire on those same rims ---borrow a set to try-might try to up the rear tire pressure a bit see if it likes it---see ya have license plates on it is this a street car too??? might have something to do with the suspension----lotsa things going on there---front wobble/tire spin/wrong size tire-rim combo hafta sort one thing at a time out---if you want consistency 10.50 or whatever keep doing whatever yer doing if it runs the number dont change it---if ya wanna improve yer performance and go quicker ya need to change some things---if it runs 10.50 all day and the 60 changes from 1.30 to 1.45 as long as yer in front and go 10.50 who cares---

L79racer 10-16-2012 12:42 AM

Re: Critque this launch.
 
Quote:

Originally Posted by FED 387 (Post 352141)
the reason I say 28 is going down a 1/2 or pound ya wont really know or notice if ya did the right thing---go down an extreme amount like the 28 ish see if it likes it---if it does then go up a 1/2 or down a 1/2 see waht happens---ya can always go back to the 33 setting---way too much front tire wobble when it sets down need to correct that scuffing off a lot of time there--rims do look narrow for the tire maybe try a narrower tire on those same rims ---borrow a set to try-might try to up the rear tire pressure a bit see if it likes it---see ya have license plates on it is this a street car too??? might have something to do with the suspension----lotsa things going on there---front wobble/tire spin/wrong size tire-rim combo hafta sort one thing at a time out---if you want consistency 10.50 or whatever keep doing whatever yer doing if it runs the number dont change it---if ya wanna improve yer performance and go quicker ya need to change some things---if it runs 10.50 all day and the 60 changes from 1.30 to 1.45 as long as yer in front and go 10.50 who cares---

I'll try fixing the front wobble. I just found a bumpsteer kit for it. yes its a street car with stock front suspension. Its just a pump gas small block. Best so far is a 9.92 at over 134.

http://s807.beta.photobucket.com/use...05671.mp4.html

Dave Gantz 10-16-2012 08:26 AM

Re: Critque this launch.
 
Make sure you're just barely rolling into the stage beam. You may be deeper than you think. It's sometimes hard to tell from inside the car just how far you're in. A helper on the line can give you an idea of how far you're rolling in, compared to how far you THINK you're in.


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