Tire Shake and Powerglides

Got back from the Patch last nite with a less than stellar test session on our Nostalgia A/F car. 225" 46"out BBC/powerglide w/1.66 low, 4:30, 2750 launch chip on 2 step. Unable to get the new american made #1503 goodyears(31x14), I opted to buy some Hoosiers and M/T's (both 32x14)and see if I could make them work. Friday nite track was junk and smoked the tires (M/T w/5.75lbs) after 1 revolution, wheels up! Saturday... put on the Hoosiers, lowered air psi to 5.50 and had moderate shake, peddle it and ran it thru 7.119 @197 (first pass on all new motor) Next.. hoosiers w/5.75lbs moderate shake again.. no real change. Next went back to the M/T w/5.25lbs, car hooked hard, on the wheelie bar very hard, wheels up then shake. So for my last trick, I figuired, to get the tire to slip, I'd raise the launch rpm 250, add 8% blower and raise tire psi to 6 and put 12lbs on the nose. And... it shook again, only sooner, but it split quick, .364r/t(not deep). I had been normally @ .452-.475 all day. My question is: Is the powerglide part of my problem? Not being able to slip the clutch and let the tire grow smoothly? Any of you guys that run a glide and have incountered this have any suggestions or cures? When I ran the 31x14 goodyears prior to this past weekend I used to haze them, hence no shake... but also no decent 60'Is it possible I need to move the motor back out to 48" (especially seeing how the engine is now 100lbs lighter w/alum block) Or should I just give in, sell my glide(s) and buy a clutch so I have adjustability. Thanks...Jim Lange hitecca@aol.com

 

ok... i'm just gonna throw in my 2 cents here. For starters, stick with the glide unless you have plenty of $$, time and hair to spare, cause you'll end up spending it, wasting it, and pulling it out (in that respective order). There is no reason you need to abandon the glide idea, especially if you want to have minimal between rounds maintainence.

For two years i tuned my buddy's little alcohol car with a powerglide/solid chassis combo.... so i think i can kinda relate to your situation. It took a little trial and error but the car definitely had a "sweet spot" and we stayed in that sweet spot using about 3/4 of a pound of air, 25# ballast, and 100 launch RPM to keep the car happy (shake free).

My biggest question is this. On the last pass that you described... if the car had run well and improved... which of your adjustments would have been the "magic fix". You would have had no idea. My advice would be to be very methodical and patient while trying to fix the problem.... make 1 and only ONE change on each pass. When you make progress.... then simply try to repeat it... THEN move on to tackle the next issue. Let your driver know... "we're learning here and if it even acts funny.. click it". It took us quite a few passes on our car to get to this point. But come race time we were never in left field... it was always a matter of those few little adjustments and staying on top of the engine maintainence.

Currently I'm on a pro-mod team... I do the clutch maintainence at the track and it's a whole new learning curve and infinite set of variables that get thrown into the equation when you go to a can/lenco set up. While the glide is less "tune-able"... it's also one less variable to change from run to run.

One last thing and I'll go away... I noticed that you swapped tires between the runs... just keep in mind that tire for tire is not apples for apples... they have totally different attitudes. Especially when you throw the name Hoosier in the mix. I have zero experience with the M/T... but we've run the GY's and the Hoosiers on the pro-mod car. You can damn near spin the good years till they smoke and still drive the car down the track without any shake. But for some reason, even when they are spinning on a greasy track, the Hoosiers are VERY GRABBY.... and they will shake like a MF. They are absolutely a fast tire... but you have to have the combination 110% perfect or they are gonna shake their ass off.

 

Ok I lied..one other thing. Sounds like a pretty hot motor set up... who did your glide work? Thanks Sean.... bpyromedic@aol.com

 

Hey Hitecca:
Any updates you can provide from this thread?
It was several years ago but wondering how it ended up.

 

On our dragster we found with a glide and Hoosiers tires do not like a lot of air. We put anything over 4.5 lbs it will yank the front tires off the ground hard. We have seem to find 4.25 to 4 lbs was the magic number. We launch at 4200 bbc try lowering the air next time out. It can’t hurt to try. Hope it helps you.

 

So running a blown RED with powerglide, have ran both a 3196 MT and the Hoosier 1500 slick, they like different things. With the MT it wants to dead hook so I would run 6 psi of air, and pull some timing starting at .01 seconds through 1.5 seconds and it would do good. With the Hoosiers they want some wheel speed, I run 4.5 psi and hit the tires hard not pulling time for .05 seconds. If I were to run the slicks the other way it would shake (one due to not enough wheel speed, one due to too much)

 

While its different animal. WIth our funny car I found that adding power(clutch in this case) would most of the time get us aways from shake. Adding blower IMO was move in right direction, Unfortunately as stated earlier you forgot rule one. Unless its a last ditch effort to get into field.YOU ALWAYS DO ONE MOVE AT A TIME. You may have made correct move and then countered it with a wrong one we will never know.

A benefit of adding power. You can drive a spinning car, but driving a shaking one is real bitch. Plus spinning rarely breaks parts.