kil kare 5-17-12

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05-17-2012, 10:48 PM
Jake

kil kare 5-17-12

was anyone at the kil kare test and tune tonight? I was having some trouble figuring out how to launch with my new IRS, and was hoping some of you more experienced guys may have been watching. I was in the green vert that was wheel hopping pretty badly.

drag racing is not the primary goal of this car, but I'd like to know if it's simply something I'm doing wrong, or an easy adjustment that may be needed.

the IRS has full urethane/delrin/aluminium bushings, with a diff brace as well. the only things I could think of other than driver error may be a need for a higher spring rate and stiffer shock, and a softer tire. I have a decent amount of racing experience in this car with a SRA, but have no idea what tuning may be required to dial in the new set up.

thanks for any help you guys can provide.

-Jake.
05-17-2012, 11:30 PM
evil8

Lookup solid axle swap.
05-17-2012, 11:39 PM
four6trix

I showed up late tonight. Didn't get to see you run though. I was just doing more hanging out and eating tonight LOL. When my car was up on the lift at Dayton Perf. we realized that my IRS already had the brace and some of the upgraded urethane bushings as well.

I'm still playing around with mine trying to get that launch down. I've probably put about 15 passes on my car so far and have NAILED the launch once. It took off like a bat outta hell. Every other time, I get some wheel spin/hop and have to back out of it.

I know for a fact that I need to get a nice set of DR's, and that should help a lot. IMO so far, it's just a fine science with these things. You have to find the right RPM's to let out at, then feather that clutch out just right. Best of luck man. I should have my X-pipe bolted in this weekend (hopefully before the cruise) and I'll get back to running again next Thurs!
05-18-2012, 01:37 AM
Rick93coupe

Quote:

Originally Posted by Jake

was anyone at the kil kare test and tune tonight? I was having some trouble figuring out how to launch with my new IRS, and was hoping some of you more experienced guys may have been watching. I was in the green vert that was wheel hopping pretty badly.

drag racing is not the primary goal of this car, but I'd like to know if it's simply something I'm doing wrong, or an easy adjustment that may be needed.

the IRS has full urethane/delrin/aluminium bushings, with a diff brace as well. the only things I could think of other than driver error may be a need for a higher spring rate and stiffer shock, and a softer tire. I have a decent amount of racing experience in this car with a SRA, but have no idea what tuning may be required to dial in the new set up.

thanks for any help you guys can provide.

-Jake.

I was there spectating but I don't remember seeing your car?
05-18-2012, 11:35 AM
rtvickers

Quote:

Originally Posted by evil8

Lookup solid axle swap.

^^^^^^^^^^X2
05-18-2012, 06:26 PM
Jake

Quote:

Originally Posted by evil8

Lookup solid axle swap.

Quote:

Originally Posted by rtvickers

^^^^^^^^^^X2

I just got the IRS in! as I said, drag racing isn't my focus, I'd just like to improve where I can.

Quote:

Originally Posted by four6trix

I showed up late tonight. Didn't get to see you run though. I was just doing more hanging out and eating tonight LOL. When my car was up on the lift at Dayton Perf. we realized that my IRS already had the brace and some of the upgraded urethane bushings as well.

I'm still playing around with mine trying to get that launch down. I've probably put about 15 passes on my car so far and have NAILED the launch once. It took off like a bat outta hell. Every other time, I get some wheel spin/hop and have to back out of it.

I know for a fact that I need to get a nice set of DR's, and that should help a lot. IMO so far, it's just a fine science with these things. You have to find the right RPM's to let out at, then feather that clutch out just right. Best of luck man. I should have my X-pipe bolted in this weekend (hopefully before the cruise) and I'll get back to running again next Thurs!

I'm thinking that the tire will have a big impact as well. we'll definitely talk strategy at the cruise!

Quote:

Originally Posted by Rick93coupe

I was there spectating but I don't remember seeing your car?

I was there from 5 till 7:30 or 8. dark green vert with a tan top that makes more noise than grandma falling down the stairs.... I only managed to get 4 or 5 runs in.

I tried dumping the clutch a couple times, and those both resulted in massive hop with 2.3 60's and a 15.3 and a 15.7 because I felt hop, and promptly shifted into second. both of these runs I trapped right around 87.

from there I decided to try and feather the clutch, which gave me a 15.2 at 92 mph. realized that might be the way to go, and launched at around 2k the next run, which gave me my best 60 time ever of 2.0, and a 1/4 of 14.9 at 93, which is just a tenth and an mph off my best with the live axle. this run I still had slight wheel hop in the first two gears which made me give a slight pause.

I know there is a little bit left in there if I can manage to launch well. with a best of 14.9 with 3.27's, I was hoping to see some improvement with the 3.73s. not to mention the IRS hooks better than the live axle ever did on the street.
05-23-2012, 06:24 PM
Jake

"With a manual transmission, and a suspension design that experiences wheel hop, you also need to consider dampening the shock loads. The easiest way to do that is run a bias ply drag slick, or Mickey Thompson has a bias ply ET Drag tire which is DOT legal. The sidewalls of radial tires are extremely stiff, and provide minimal damping of shock loads from wheel hop. Bias ply tires, by comparison, have soft sidewalls which significantly dampen shock loads.

On supercharged thunderbirds with IRS and M5R2 manual transmissions (350 to 500ft/lbs of torque at 3200rpm), the switch from drag radials to bias ply drag tires resulted in an significant drop in the incidence of snapped axle shafts, and ended the failures of transmission tail shaft housings. Along with driver training, stop trying to drive through wheel hop, most axle shaft failures are a thing of the past. A 28" tire on a 16" wheel seems to work best."

found this on corner-carvers. it pretty much supports what I was thinking. I'm curious if there are ways of doing this while on a street tire though? would a different spring/shock combo be able to benefit me?