I shift at 7200, stall will be 6500 this year. It is 6200 now and I launch at 5400. Converter guys say that is too high and so do many racers – they prefer 4200 to 4800. Is there and advantage to launching lower? Is it more consistent? I use to launch lower and don’t remember much difference. What does everyone do and why?

Door Car or Dragster?

Altered

The largest advantage with a lower launch RPM is keeping the front tire on the ground through the beam on the launch for more consistent RT and ET.

This is most likely why it's been recommended to you by your converter guy.

Honestly, not many people have experience with an altered so I'd say whatever works best for you. Iphone slo mo video is amazing to help in this day and age.

Best of luck,
SL...

I leave at 3800 ...if I leave off the converter 5800 the car is on the bars for 150ft. The lower rpm also takes a marginal track out of the equation.

In my opinion a car is more consistent when the converter is allowed to do its job and flash the way it is intended to. Leaving to close to where you convertor flashes will not let it do its job. 5400 is too high

5400 is to high in IMO. 3800-4400 depending on track cond.

We've always ran 5000 launch. I tried 4400, it changed nothing. so I put it back to 5000 bc it is very consistent there. This is in a dragster.

Thanks everyone for the input. My car doesn’t have an issue with pulling the wheels out of the beams and the reason I went to a higher launch is I felt it hit the tire harder. I guess I will need to do some testing when I get the new looser converter.

quote:

Originally posted by Quick Dawg:
Thanks everyone for the input. My car doesn’t have an issue with pulling the wheels out of the beams and the reason I went to a higher launch is I felt it hit the tire harder. I guess I will need to do some testing when I get the new looser converter.

Any data to back that up or you just think its hitting it harder. Seems to me with setting it so high there is not much flash left when it does leaves.

Brian – Good question. If you consider results data then I do believe so. I run MT 3074S and they were responding to more air pressure – less in the box and better 60’s – so I thought I would try more RPM’s at the launch – went from 4500 to 5000 – again better 60’s and my reaction spread seemed to be tighter, so I went up a little more on the launch RPM’s since I seemed to have hit my limit on air pressure. I will admit at that point I didn’t notice any difference one way or the other.

quote:

Originally posted by gxp7903:
We've always ran 5000 launch. I tried 4400, it changed nothing. so I put it back to 5000 bc it is very consistent there. This is in a dragster.

I’ve been between 4200 and 5200 in my dragster and it doesn’t change anything except for the time in the delay box. Higher rpm breaks the beam faster but the 60s aren’t any better for me. No matter what the launch rpm is the engine goes right to the converter flash as soon as the tbrake releases.

I agree. I think my 60" improvement was due to air pressure not launch RPM's. I do get a little dip in RPM's right after TB release hence I am going to a looser converter this year. Everyone seems to think a looser converter is more forgiving and more consistent. I'll give it a try, if it doesn't work, I can always put the old one back in. Again, thanks for all the input.

I'm spraying a healthy dose of nitrous right off the line in my TS car so the converter is fairly tight, but I set my launch RPM at 4000 and haven't changed it in 8 years. Converter flashes to around 6200-6500 and i adjust the launch setup with shock adjustments and timing curve changes. Running the Narrow Hoosier 34.5 tire