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I have a tube chassis S-10 that I bracket race and sometimes index race with. Attempting to try and get the chassis dialed in and looking for some advice.

The truck weighs in at 2361 on the starting line.

Weight's are

LF = 751
RF = 673
LR = 486
RR = 451

Front 60.32%
Rear 39.68%

4 link is set at 61.7" out and 5.27" up
CG = 16.83" and 65.15" out

Strange SA strut front suspension
Strange DA rear coil-overs with new 110# springs

The rear shocks are currently at the middle of both settings and the front is at full loose.

Engine is a NA SBC, turbo 400 with a brake, 9" with 3.89 gears
Slicks are Hoosier 29.5x11.50w.
2 step was at 4000 rpm. Converter goes to 6000 on the hit... and drops back to 6100-6150 rpm with the transmission actually shifting at 7000 rpm per the logger.

The slicks seem to like a very long burnout... the video with the longer burnout (labeled 3rd pass) went a 1.290 60' spinning, the other video (labeled final pass) with slightly less burnout went a 1.304 60'... both at 8 psi.






The data logger shows it spinning for over the first second of each pass... then spinning slightly at the second gear shift. This track didn't have any track prep the night I went. They had last prepped two weeks earlier... and had rain a few days in between.



Jeff
 

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Your weight bias is way heavy on the nose. I would hang a 100 lb weight bar in the rear to balance it out a bit and see how that helps the car. loosen the rear shocks a bit to help with initial bite.
second recommendation would be to put a glide in it and a bit more rear gear. This would also help some on the weight issue.
3 rd would be lower the leave rpm to about 3200. That light of a car should not need that much launch RPM especially with a small tire
 

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Your weight bias is way heavy on the nose. I would hang a 100 lb weight bar in the rear to balance it out a bit and see how that helps the car. loosen the rear shocks a bit to help with initial bite.
second recommendation would be to put a glide in it and a bit more rear gear. This would also help some on the weight issue.
3 rd would be lower the leave rpm to about 3200. That light of a car should not need that much launch RPM especially with a small tire

Yep... it's definitely nose heavy.

I ran more gear last season with a smaller engine. Current engine makes more power so I went to the 3.89 gears so I don't trap at too high of a rpm. Right now it's trapping at 7100 rpm at 143.66 mph in the quarter.
A glide is out. I'd have to spend too much to build a glide, then a new shifter, new JW bell-housing, new trans mount and have the driveshaft redone. I realize the 400 is heavy, high rotating mass, and probably too steep of a first gear... but it's strong and works.
I'll try playing with launch rpm and shock settings this coming weekend when I get back out for some test hits.

Currently my best 1/8 mile pass is:

1.286 60'
5.780 1/8
120.57 mph

All settings were the same as stated above, except the slicks were at 9 psi instead of the current 8 psi setting. Data logger showed driveshaft rpm up and down for the first 1.134 seconds on that pass until it finally hooked and went.




Jeff
 

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for as light as it is you have to much SLR, hunt for a 2.10 gearset for the 400 your motor cant keep up the gear it has ,a 2.10 will be a big improvement,our vega only weighs 2445, it has a 2.08 first and its been 7.80 @174 its 52-48 F to B weight shortin you CG to like 45 it will help with traction off the line
 

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for as light as it is you have to much SLR, hunt for a 2.10 gearset for the 400 your motor cant keep up the gear it has ,a 2.10 will be a big improvement,our vega only weighs 2445, it has a 2.08 first and its been 7.80 @174 its 52-48 F to B weight shortin you CG to like 45 it will help with traction off the line

I can drop my upper bars down 1 hole at the frame and be right at 49.5" out. I tried that a couple years ago with a different engine setup. If the track had any type of traction available it shook the tires. The current engine makes much more power.

I'll try the 4 link where it is this weekend to see what adjusting the shocks and launch rpm can do. If it won't work, I'll drop the bars down and retry it at 49.5" out.

Thanks for the input guys.




Jeff
 
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