tire shake fixes??

top sportsman car 526 bbc 14-71 hi helix

this past weekend we went out testing out new setup with our 14-71. weather was pretty cold along with the track was cold. attempted 4 runs and went into pretty hard tire shake about 1/2 second into the run each time. ive talked with a few people much smarter than me, ive come up with a few possible things to try as we race the next 2 Saturdays to try and get it down the race track.

1st I was recommended to set up my 6 shooter/retard box off a digiset controller and pull about 5 degrees out for the first 2 seconds of the run. I do not have a leahy box so this is the only way we can come up with and will it even work to do that as well? right now with the promag 44 I am running 32 degrees of timing. would it be safe on the motor to drop it back to 29 or 30 degrees instead of fooling with the 6 shooter?

2nd, we have the 4 link ic set up at a 53 inches and 8" up. which leaves the bottom 4 link bar pretty flat. so without changing the whole set up, I was told to try changing the shock mounts and drop the car down and put an angle into the bottom bar to get more bite into the tire.
along with changing the angle of the 4 link bars, I also should stiffen the front struts to full stiff to keep the weight back.

everything makes sense to me as to why and what the recommendations are. can anyone give any input on there thoughts of this? or any other suggestions as to I am beginning to learn more and more about this car and the whole 4 link setup.

 

Was it spin shake or low wheel speed shake. What was your wheel speed at .5 sec?

 

If this is the same setup from last year lets say and everything was great last year. I'm gonna say it was power shake. Cold air equals a lot more hp for a blower and you prolly expected to get a little bit when it was prolly more like 100-150 hp more. You had more ws at the hit and put it over the edge at .5 when the rpms when higher and the hp really takes off. Prolly should of just took power out of it.

 

shake

If its a T/S car with a 6 shooter i'll assume converter driven.
I'm not a big believer in weak or low power shake situations for the average setup. IMO you are probably throwing too much at the tire for the conditions. I think your plan of attack is good. Keep in mind pulling base timing will slow the car all the way down track.
I'd recommend an 8973 or other timing control so you can make ramps and pull timing at problem areas of the run and feed it back in when you want.
The chevy will be fine even with half the timing dumped. Be careful of the phasing on the mag cap because it can misfire if you start pulling a lot out and don't compensate.
In my experience, 5 degrees out for 2 seconds with a healthy wedge will rattle your teeth out. I'd pull 10 for 2 seconds and see what happens.

 

wheel speed

for goodyear 34.5 tires what is a safe wheel speed at

.25-
.50-
.75 -
1.0-

thanks again

Butch

 

Yes this is a converter car. I do believe it shook from too much wheel speed. I put new tires on yesterday. The old ones had 20 runs on them. Hoosiers 33x16 co7. Also I was recomended to drop the shock mounts back down to put some angle into the bottom bar of the 4 link. As it sits now it is pretty level with the ground. Which I was told some bottom angle will help in any track. Also it is suppose to be a little warmer this weekend which should help. And if those 2 dont work I will try pulling timing out through a digiset until I can get a leahy box. I can get the ws numbers later tonight when I get home

 

rear gear is 4.11. I sent will the pictures of my graphs. I can email them to you too mike if that will help. I believe I stil have your email

 

hey mike, I emailed you pictures of 2 of the graphs from Saturday. my plan is to set up the retard and pull 5 degrees out for 2 seconds and let it back in. seeing as its a bracket car it should be fine to slow it down as qualifying will not be an issue. plus it sounds like its suppose to be about 8 to 10 degrees warmer than it was last weekend.