Bog at the line

Hello

I´m getting a hard bog at the starting line since I got traction, I used to run regular radials and now hoosier´s drag radials.

The car is doing the same ET (11.8) but after it hooks it gets a bog that stops it from pulling up steadly. I makes a jump then almost dies... I run some different combo, since here is Brazil and our gas is a E25 (25% ethanol). I´m also adding 20% methanol, that wake things up a bit. The car has a 302 .040 with stock ported heads, vitor jr and a 850DP holley. Also I have a aluminium flywheel, that I´m not willing to trade it.

The holley runs with 30cc/50cc pumps, 75/88 jets. I have a datalogger that clearly shows that after the start it gets lean and then goes nice where it should be the rest of the run.

I´ll try next race different pump cams (colors) and even 50cc front.

Just for test I left one run at 2000rpms and it run an excellent 1.7s without bogging, showing the car has to do a 1.6 at least. Any ideas will be welcome.

Here is a picture of the launch with the street radias.

Sounds like you need jet extensions on the rear jets.

Originally Posted by mustang42782

Sounds like you need jet extensions on the rear jets.

That would be my guess as well..

I agree with the others, Rear jet extensions

I don't know anything about the fuel your running, but the aluminium flywheel you have, is hurting your 60' also.

If jet extensions don't help try a bigger squirter size on the front. 30cc pump is fine and pump cam should be fine. Converter may also be to tight. What is the stall and flash RPM? What size cam? Duration @ .050. Not enough gear? When it hooks like that it pulls the motor down and if theres not enought fuel, converter or gear, It will stumble. Could be something else, but thoses 3 are the most likely.

I haven´t tought about rear jet extensions, but that´s a valid try! I run a 4spd, centerforce dualfriction, 246@.050 .504" mechanical cam, 3.92 gears and

I agree with the others... try the ext's.

Cool car and a 4 speed!

Originally Posted by akv8

I haven´t tought about rear jet extensions, but that´s a valid try! I run a 4spd, centerforce dualfriction, 246@.050 .504" mechanical cam, 3.92 gears and

Is it a street car? if not put some gear in it...you must only cross at what maybe 5000 rpm?

And yes very cool car...

I agree with the rest. We had the same problem, jet extensions and raising the 2-step chip a few hundred rpms cleared it up.

You may have too big a gap between your primary and secondary jets.