Fighting tire shake

I know I have a challenge on my hands but I have a 65 nova grudge car with a blown BBC making approximately 2200 hp, the car is a ladder bar car and is very heavy ( 3850lbs with me in it) , the car leaves initially pretty good with good wheel speed but gets out 30-50 ft and violently shakes the tires(33/15/15 MT). I've tried air pressure from 7-8-9 psi I've got Santhuff's double adjustable shocks on all four corners and had the extension set 2 from full tight on the rear it is smashing the tire pretty hard but on my data logger I'm seeing the convertor is only flashing to 5000 rpm and Im leaving on the two step @ 4000 rpm , I have three holes for the front of the ladder bar and currently it's in the middle hole with the lower bar pretty much level, now I know I'm asking a lot with such a heavy ladder bar car but I'm thinking my convertor is way too tight, let me know what you guys think? Thanks!

 

I'm sorry I forgot to mention it's a powerglide with 1.80 first gear and 4.56 rear

 

Rear extension 2 from full tight 10 on compression front is 7 from full tight 7 on compression and do you think my convertor is too tight mike?

 

pTC

 

It's a 10.5" weld together, if I remember lane at PTC called it one of their pro mod convertor said but it wasn't terribly expensive

 

Also I wanted to ask if anyone has ever used the tire shake box built by RPM and if so did it work??

 

I do have a data logger and I can record drive shaft RPM and I will take a look at it and get back , thanks mike, also I have some video that shows the tires all wadded up and distorted

 

We found we could modulate the launch power with enrichment to avoid tire shake. We used the high speed, set to open just after the hit, to lean out to the best power level for the run.

We had good success with different combination of main bypass and high speed jet sizes to increase the launch enrichment to soften the hit and still maintain a best power high end.

For example, a 0.040 inch high speed bypass with a proper main bypass brought up the power on the hit on our blown alc racecar.

A larger 0.050 inch high speed bypass with a proper (smaller) main bypass would kill a noticable amount of power in the launch, softening the hit, with the same high end power.

FYI: Our ProCalc calculator determined that the 0.040 inch high speed jet in our blown alc engine made an AFR difference of about 0.15 points between the low end and the high end. That smaller amount set up a high launch power.

The 0.050 inch high speed jet made a greater AFR difference of about 0.2 points which killed a noticable amount of horsepower at launch; then a kick in the back when the high speed opened. That is discussed in our fuel injection secrets book.

Even larger high speed jet sizes with the appropriate (smaller) main bypass can be set up for just about any AFR difference. The launch power can be softened with more enrichment to work better with the converter. The proper combination will maintain the best high end power.

It is really easy to modulate the launch power with enrichment (to soften the hit) by changing the launch AFR while maintaining the high end AFR for best power. That can be done simply by using the proper combination of main and high speed jet sizes with an opening poppet pressure just beyond the launch.

Our calculator was developed to do all that for different air densities, fuel splits, fuel distributions, blower overdrives, and different percentages of nitro, as well as blown or NA.

Bob Szabo
http://racecarbook.com
bob@racecarbook.com
Ca, USA (916) 419 6694

 

I do have a data logger and I can record drive shaft RPM and I will take a look at it and get back , thanks mike, also I have some video that shows the tires all wadded up and disto

 

Thanks will for your response as well, as far as a larger tire I can't go any taller without raising the back of the car and it already has a little rake to it and as far as wider I could probably squeeze an inch wider but as far as Mickey Thompson the next size is a 33/16/15 but the section width is actually like 2" wider and would rub on the frame and if I moved it out I would have to cut the quarter panel which I won't do but like mike said earlier I need to study my data logs carefully and try to figure what's going on, I was just thinking that what they claim typically causes tire shake on a clutch car is the clutch locking up to early which I think essentially the convertor is doing the same thing, just a fluid coupler instead of mechanical? I don't know and you guys probably do know but I've heard the convertor should stall ( flash)no less than 6000 ? Mine is only flashing to 5000 and the data logger shows it taking a full second to get to 6000 where is already shaking and I'll have too look again but I want to say it's barely making 20 lbs of boost but will make 38 lbs at 7900 rpm. But thanks again for all you and your knowledge, I appreciate all the help I can get!