Torque Converter Flash Point

I think my torque converter is wrong for my car. The car is a 135" hard tail altered with a 511" hemi on 20% nitro. On straight alcohol the converter worked OK. It is a Coan 10" spragless mega-converter. At the hit it is flashing to 7200 rpm and the car wants to haze the tires around 60' all the way to the stripe. My thoughts are that it should probably flash to around 4500-5000 rpms. The extra torque with the nitro I think is driving through the converter and not loading the motor enough causing it to break the tires loose. Will do you remember what the converter flashed to in the FC? I know I need to change it some, but I am not sure how much. This converter worked perfectly in our old 270" dragster, and the altered just can not load the tires near as much. Thanks for the advice!

 

If you want to load the motor I would do it with the 1st gear ratio or the diff, if you are making enough power to blaze the tires 60 ft out I doubt that a tighter converter will solve the problem, some retard might slow the wheel speed down enough to get it moving as well.

 

When we switched from injected alcohol to injected 50% nitro, the converter flashed real high and we drove through it, tightened it to 4000, much better. we will probably try 3500 or 3000 after we finish tuning the fuel/timing. btw, we do not use the transbrake. When I experimented with 20%, I never saw too much difference in tune up but that was a small inch big block injected, not big inch blown, so I do don't have blown nitro/auto trans experience.
frank

 

Jack, Are you still running a 3 speed?

 

We still have the 3 speed Lencodrive in the car.

Dragcars, I am thinking my car is doing the same thing driving through the converter. I have a different converter in the car for this weekend, so maybe I can confirm that is my problem.

Thanks!

 

What size tire are you running and what was the stall speed the converter was built to?

 

I'm running 34.5x17x16 M/T tires and I run them at 6lbs. The converter was built to 6700 for our old dragster.

 

Jack, if you're running this weekend, try leaving in second gear, or whichever gives your the smaller split if your not running the same in both packs. This will essentially make it a 2 speed and load the motor harder. With the nitro, you should have more torque and not necessarily need the 1st gear. The best part is this modification costs nothing!!

 

Thanks again to everyone who replied. The lower stall converter worked to calm the car down. It ran a 4.15 at 149 with a broken throttle cable at 500 foot. This converter flashed to 6000 where as the other one flashed to 7200.