Launch advice please

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BracketNova
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Launch advice please

#1 Post by BracketNova » Sun Jun 23, 2013 9:55 pm

Looks to me like my new combo is crushing my stiff sidewall slicks. This was at 12 PSI. I don't know if I should air it up and try to hit it harder to get it to hook, or move the Caltracs to the bottom hole and start there? Thoughts?

4.88 gear, 28" tire, Trans Brake, 90/10 shocks up front w/ 6 cyl springs, CE 3-ways in the rear (but I am unsure where they are set) Calvert split monos. This vid was leaving at 4400 on a 5800 stall. On the last combo I always left from 4400.

What RPM should I be trying to leave at? Is there any general starting points?

This was a 1.5081 60', the run before when I left from 4000 (first run with the new combo) was a 1.4726
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

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'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

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John_Heard
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Re: Launch advice please

#2 Post by John_Heard » Mon Jun 24, 2013 8:19 am

I don't think it's crushing it at all. I'd drop the launch RPM down to 3400 - 3500 or so and see how it likes it there. Your first pass at lower RPM was a better 60', maybe lower yet would be helpful.

luv454
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Joined: Fri Apr 24, 2009 4:28 pm

Re: Launch advice please

#3 Post by luv454 » Mon Jun 24, 2013 12:09 pm

Is that the M/T 28 10.5 S rear tire?
I think you could play with air pressure maybe go up 1lb at a time until it spins then back it up. That may give you the quickest et. So I've been told but I run a 30x9 radial slick on my car.
I think leaving at a lower rpm hits the convertor harder may be why it is quicker.
I've thought about running that tire on my car to gain a little rpm on the top end. How does it hook and how many passes can you get from them?

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BracketNova
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Re: Launch advice please

#4 Post by BracketNova » Mon Jun 24, 2013 9:40 pm

Thanks John, I've never hit a tire that hard before. Can I hit it harder? Lower the launch RPM...that doesn't sound like fun :roll: Not sure why I am so determined to leave at a lot of RPM.

Luv - yes 28-10.5 S they have about 40-50 passes on them. Some people throw em away at 20 passes. This is my first set so I can't speak to how long they last with moderate power.

Here's the 4000 RPM launch. Sorry back wheel is hard to see.
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

Check out my website...
http://www.findmoneyraces.com


'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

User avatar
John_Heard
Site Admin
Posts: 5683
Joined: Thu May 12, 2005 11:20 am
Location: Resume Speed, Kansas
Contact:

Re: Launch advice please

#5 Post by John_Heard » Mon Jun 24, 2013 10:05 pm

Might also try a pass with the front shocks a bit tighter on the extension and see if it likes that as well.

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BracketNova
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Re: Launch advice please

#6 Post by BracketNova » Mon Jun 24, 2013 10:34 pm

Interesting you say that...I also used to have three ways on the front and put some 90/10s a friend had barely used on it for this year. I might take my old shocks to the track with me and swap them - I think they were set tighter. I'd just like to see an even load on the tire. It looks to me to be too aggressive and then it unloads and spins.
"I always compare drag racing to lighting $100 bills on fire, only it's more expensive." - Craig W.

Check out my website...
http://www.findmoneyraces.com


'71 Nova E85
6.69 @ 100.2 MPH 9/6/14
1.4257 60'
1700' DA

13:1 439 BBC
3330 lbs

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