Going rich coming off the 2 step

[littlemanjoe]

When I let go of the brake and the car comes off the two step, the O2's show way rich. They go down to 9ish or 10ish then go up to 12's towards the bottom of second gear.

Is this normal or is there a way to lean out the carbs a touch at the launch?

My car has Holleys on it.

Thanks,
Mike
A/SA

[1700camaro]

Originally Posted by littlemanjoe

When I let go of the brake and the car comes off the two step, the O2's show way rich. They go down to 9ish or 10ish then go up to 12's towards the bottom of second gear.

Is this normal or is there a way to lean out the carbs a touch at the launch?

My car has Holleys on it.

Thanks,
Mike
A/SA

What are the O2's showing while on the two-step?

[littlemanjoe]

Originally Posted by 1700camaro

What are the O2's showing while on the two-step?

They show lean on the 2-step.

[1700camaro]

I have the same issues on/coming off the two-step.

I wish I could help you with your tune on your carb. I use a Holley TBI & have done some tuning to help with the situation & it paid off with some pretty good gains in the 60'.

When we 1st started with our new combo 2 years ago, TBI & a ProCharger. We had crappy 1.45 60's & we saw the O2 issues in the data logs.

While our TBI functions differently than a carb. I added fuel to the table while on the two-step. My 1st change got us 1.35 60's. We have continued to make changes in that area & have gotten into the 1.2x 60's.

Our data logs still show lean on the limiter & fat coming off. It has significantly improved both on & coming off the limiter. Still trying to work the issue.

[pmrphil]

Fuel level control would be the place to start

[Larry Hill]

You might try some whistles in the carbs.

[Ben Holt]

O2's will be lean on 2 step (especially if they are just in each collector) because holes are misfiring. Then it will usually show fat when feet are swapped because of the load change on the engine and velocity going into carbs. Some combos are fine this way. Some like to be changed around. If numbers down track are rich, try leaning it down until it slows down. If numbers down track are decent, it's squirters, pumps, bleeds, floats,etc

[pmrphil]

Squirters and pumps cannot affect readings after your foot is on the floor on the chip, unless you leave while still moving your foot.

[Ben Holt]

Not everyone in Stock leaves on the floor......I don't know exactly what the OP has for a combo....I'm just saying there are a lot of things to adjust, depending on the combo

[littlemanjoe]

Originally Posted by pmrphil

Squirters and pumps cannot affect readings after your foot is on the floor on the chip, unless you leave while still moving your foot.

I stage the car and then smash the gas to the floor while obviously holding the brake. When it's time to launch the car, I release the brake.

So squirters and pumps are not in play for me.