corvette track update....

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Hitchcock
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corvette track update....

#1 Post by Hitchcock » Mon Oct 03, 2016 11:27 am

Okay gang, I took the Vette to Topeka on 9-24, and found out it really likes wheelies! I made 4 passes while I was there. We were just there to run 1/8 mile and I was launching it fairly hard. Running 11.40's at like 80 something mph. Then on my 3rd pass I just said screw it, and let it have it. I had gone from 10 to 12 psi on the tires, and was hooking very well. This time it spun on the hit, and 60' 1.40 something, bumped the rev limiter on the 1-2, and rode the limiter for about 2 seconds across the stripe. Went 6.50 something to the 1/8 @ 111.25 mph and, 10.15 @ 132. Next pass, lowered the tires back to 10 PSI and raised the rev limiter from 7200-7400. Went 1.34 60', and botched the shift, and went from 1st to 3rd went 6.50 something to the 1/8 at 109, and 10.05 @ 136. And it ripped a tub out and broke a chunk out of the body on that pass. So we were done.

Fast forward 1 week. Dad was nice enough to get me some new slicks that didn't rub. So I went from a 31.5 X 12.5 W to (31.9 X 13.5 actual) to a 29.5 X 11.5 W (30 X 13 actual). And headed to our local track. We set the tires to 10.5 and got to work, and started hot lapping the car as we had 1 hour before they closed the lanes. Big thanks to Kansas International Dragway, for letting us in at all!!!

Made 3 passes, first pass, it spun off the line and went 1.40 something 60' and humped the crap out of the limiter and went 10.11 at like 132. About what I expected. Second pass, kind of the same thing, 1.40 something 60' but I made a clean shift on the 1-2 and holy crap!!!!!! 115.8 to the 1/8 mile, and 9.66 @ 132 putting the MSD rev limiter to the test for 300 feet! HOLY CRAP!!!!! I thought for sure it was a mistake, so I rolled right back into the staging lanes, and gave the car about 20 minutes to cool off. Let the tires down to I think 8 psi, and asked them the give the starting line a little spray to see if I could duplicate the 1.34 I had in topeka. Told the ol girl I loved her and clocked back in. I was rewarded with a stout wheels up launch and a 1.32 60' pulled 114.3 to the 1/8 at 6.14 and at 1000" was 129 mph. Crossed the line at 130.5 at 9.65! :shock: :shock: :shock: :shock:
The trans was a little warm at 180 on the last pass, so I think that's where the mph went. So trying to math out if I need a 4.30 or 4.56 gear, to run it out the back door. I'm sure it will lose a little to the 660 mark with a taller gear. but now I'm hungry for a 9.30 pass. We have not played with timing, shocks, plugs, jets or anything. So I'm pretty sure I can scrounge 3 tenths out of the poor little motor. But holy crap, I was shocked at what it did!!!!

Image

10.05 in Topeka
https://www.youtube.com/watch?v=DsbT4saJcCY


9.65 in Wichita...
https://www.facebook.com/apache.racing. ... 647469816/
Last edited by Hitchcock on Tue Oct 04, 2016 8:38 am, edited 1 time in total.
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

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wikd69
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Re: corvette track update....

#2 Post by wikd69 » Mon Oct 03, 2016 11:29 pm

Holy crap indeed !!! Man, that thing is a beast !!! It sure sounds like there is a lot more there - tune things a little different, play with the suspension a bit and tweak the pre-loads, and you should be ripping down the track even faster and meaner. Man, that is an awesome showing for that sweet ride, congrats :)
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

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wikd69
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Re: corvette track update....

#3 Post by wikd69 » Mon Oct 03, 2016 11:31 pm

Btw, I run those same Hoosiers - 29.5 x 11.5W - hook city :)
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

bracketchev1221
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Re: corvette track update....

#4 Post by bracketchev1221 » Tue Oct 04, 2016 6:48 am

Looking over the incrementals, it looks like the car is running right where it is supposed to. Even a full power 1/8 mile time of 6.14, shows a 9.639. The car is not losing much on the top end with the speed drop. You may see about 137-138 speed at the 1/4, but it won't drop ET a whole lot. Also you can see the speed was higher at the 1/8 on the pass where it spun the tires compared to when it hooked. That is a tell tale sign of tire spin. MPH will always be higher when the tires spin because it gives the engine a running start at the powerband. So, the 1.32 60' pass is pretty much a good representation of what the car can run. And I don't think 1.32 is far off for anything. I think it is pretty good for a 9.60 car.

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Hitchcock
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Re: corvette track update....

#5 Post by Hitchcock » Tue Oct 04, 2016 7:30 am

Yeah I'm pretty pleased with it right now. But I'm dying to get some tuning done to see how much there is left in it. I'm hoping to ring it out for a 9.30
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

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Re: corvette track update....

#6 Post by John_Heard » Tue Oct 04, 2016 10:25 am

Man tough to hear about the wheel tub carnage, that sucks. Sounds like everything else is working pretty darn good though! Bet your excited to finally get to race it!

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wikd69
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Re: corvette track update....

#7 Post by wikd69 » Tue Oct 04, 2016 3:38 pm

By the way (again)... You're faster than my camaro with the blown 427. Good work, bud :)
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

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Hitchcock
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Re: corvette track update....

#8 Post by Hitchcock » Tue Oct 04, 2016 3:40 pm

Oh yeah, I'm on cloud 9 right now. The wheel tub carnage was really not as bad as it looked. Because of my trade I am actually pretty good with sheet metal. So I was able to get that repaired and looking good in a couple hours. And Dad is a pretty good body and paint man, so the body damage is mostly fixed. It need to be painted in that spot, but the car needs painted so bad anyway, it doesn't really bother me. I mean, at least there is not a chunk missing out of the quarter panel anymore.
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

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wikd69
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Re: corvette track update....

#9 Post by wikd69 » Tue Oct 04, 2016 5:08 pm

I didn't seen any of the carnage in your wheel tubs... Did the slicks you had before grow at rpm and grab the sheetmetal ? I've seen that happen before and it's not pretty :(
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

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Hitchcock
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Re: corvette track update....

#10 Post by Hitchcock » Tue Oct 04, 2016 9:47 pm

Harry, I'm pretty sure that's what happened. I didn't know anything was wrong unturned I turned onto the return road.
Last edited by Hitchcock on Wed Oct 05, 2016 10:34 pm, edited 1 time in total.
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

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wikd69
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Re: corvette track update....

#11 Post by wikd69 » Wed Oct 05, 2016 3:02 pm

Man, way lucky that didn't eat a slick at speed... I can't imagine what it would be like to have a slick explosively deflate under power at speed. Yuck.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

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Hitchcock
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Re: corvette track update....

#12 Post by Hitchcock » Wed Oct 05, 2016 7:19 pm

Harry, what tires do you race on and what is your finish line rpm?
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

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wikd69
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Re: corvette track update....

#13 Post by wikd69 » Wed Oct 05, 2016 9:32 pm

I run the heavy series Mickey Thomson 3.5 x 15's up front, and Hoosier 29.5 x 11.5W in the back... I usually run about 9 lbs in the slicks... I'm running double adjustables in the back so I can dial in the hook pretty much to match the track conditions. Mine has always been really good at hooking and running like it's on rails. Of course that was with the 850 hp motor. This new build is gonna make a whole bunch more so who knows what it'll be like when I finally get back to the track.

As to finish line RPM I'd have to guess - I've not really paid attention to it - was always a bit pre-occupied at watching my life pass before my eyes crossing the stripe lol...

I'm running a standard gear TH400 and 4.10 gears, so at 140 mph I was probably up close to 7K crossing the stripe...

http://www.wallaceracing.com/calc-gear-tire-rpm-mph.php

Try this link out (and the other racing calculators that Wallace has on their site). This will tell you a bunch - it's how I settled on the 4.10 gears I'm running. With my gearing and mid-7K shift point, I should be good all the way up to about 160 mph, though I'll never get that fast with this street ride.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

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wikd69
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Re: corvette track update....

#14 Post by wikd69 » Wed Oct 05, 2016 9:43 pm

Gotta tell ya, the photo above is the first time I'd seen your ride finished. That is one bad hama-jama and has an absolute stone cold bad-ass look to it. Good job in putting that together brother.
1969 ProStreet Camaro RS Best 9.75@139 1.46 60'
Blown 427 BBC, TH400 w/Brake, Back-Half Ladderbar
Narrowed 12-Bolt, 4.10 Gears, Spool, Moser 33 Spline

http://www.marsh-racing.com/harrys_camaro-1.htm

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Hitchcock
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Joined: Fri Sep 12, 2008 6:57 pm
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Re: corvette track update....

#15 Post by Hitchcock » Wed Oct 05, 2016 10:36 pm

Thanks. Here's one of my favorites...

Image
73 Vette, moly back half
Pump gas 496
Two Pro Systems 950's
Chance 6000 converter

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