What rpm chip should I be leaving with

I have a 4200 stall & using a 3200 chip in the 2 step to leave the line with. Does that seem about right?

As long as 3200 is hitting the tires hard enough to make the chassis work, I would think it would be fine. From a Bracket Racer perspective, I've always tried to launch at an RPM that is not on the ragged edge of spinning the tires but yet, still hits hard enough to consistantly work the suspension.

You just have to test to see what works the best for your particular setup. When I bracket raced the Maverick it stalled about 4500rpm but I left at idle (1100 rpm). It would sixty foot about 1.44 running 11.50. I know that wasn't the best et but I was deadly consistant and took home many trophies and big checks.

The two post above are 100% dead on.You have to make changes and see what happens.My mustang had
a mild steel head 460 running 10.80s and liked about 3800 But a friends vega we tried to slow down a little
to run SS went faster with a lower chip. seems like the cars travel and a lot of things come into play.
and we have a few guys dont run them at all/??

whatbumper wrote:You just have to test to see what works the best for your particular setup. When I bracket raced the Maverick it stalled about 4500rpm but I left at idle (1100 rpm). It would sixty foot about 1.44 running 11.50. I know that wasn't the best et but I was deadly consistant and took home many trophies and big checks.

What year Maverick was it? *wipes drool away* I'm going to be running a Mav at the High School Drags soon. Runs 14.35 seconds which isn't much, but all that we really care about is that it has some get up on the street for hot rodding. Which it has plenty of that, 2nd gear barks. My truck will probably bark going into 3rd.

Thanks for the help guys it is much appreciated as I need all the help I can get.

If the car won't repeat...change things until it will....less is usually more...although, some folk will disagree...

I had a well respected chassis guy tell me recently that lowering the rpm with a two step chip on the starting line would actually increase the amount of hit. His theory was that by holding the rpm down the torque multiplication of the converter would result in more torque being applied to the tire at least on the initial hit.

I am still trying to wrap my head around that but he is supposed to know what he is talking about.

dkp

bb429power wrote:

whatbumper wrote:You just have to test to see what works the best for your particular setup. When I bracket raced the Maverick it stalled about 4500rpm but I left at idle (1100 rpm). It would sixty foot about 1.44 running 11.50. I know that wasn't the best et but I was deadly consistent and took home many trophies and big checks.

What year Maverick was it? *wipes drool away* I'm going to be running a Mav at the High School Drags soon. Runs 14.35 seconds which isn't much, but all that we really care about is that it has some get up on the street for hot rodding. Which it has plenty of that, 2nd gear barks. My truck will probably bark going into 3rd.

It was a 1970 model. I liked it. It weighed 2620 with me sitting in it race ready. I had a little ole 302 in it that didn't make much horsepower but at that weight and it being a bracket car who cares, right? I wish I had some digital pics of the thing. I will try to scan some pics and post it. Very simple and consistent. A guy offered me more than it was worth so i sold it that day at the races. He raced it that day, won in the footbrake class, and then went home pulled the 302 and put an 18 degree headed sbc in it. After that he ran a 10.00 index class at his home track. Last I heard he is still running it just like that.

Someone said that a rule of thumb was to chip it 1000 rpm below stall. Now I dont know whose thumb that was but it seems to be a good starting point. My theory with mine is that the lower the chip, the harder it will hit when it reaches the converter stall. It has more momentum when it hits stall but it will be slightly slower on reaction. My Mustang 472 with PG liked 36-38 with the 5300 conv.

I personally think the "give it room" to hit the converter is an old wives tail. Your engine will not bog if it is at or slightly over peak torque rpm when the converter locks. I define a bog as loss of rpm and if your engine is stalled slightly over peak torque rpm it will not lose rpm because more torque is available behind it and it is also leaving on more hp .

If a car leaves faster with less rpm it is more than likely because of the suspension tuning or traction , or the converter is way way loose.

You just have to play with it, I've had mine all over the place with little change no matter where it was. With no chip flat on the converter it felt like the rearend was gonna fall out of it lol.

With the c4 we always chipped it 1000 rpm or so lower to take some strain off the little tranny.