tweaking an edelbrock carb for autocross

so, I've signed up to go to the test and tune autocross day down at maxton next Sunday. figured it would be a good day to get to know my car as it sits, before i start making suspension changes that it may or may not need.

i do, however, know that my 750 edelbrock performer carb is going to need dialed in. reading through all my carter tuning stuff, throttle response and turning are never really mentioned. i know with holleys, if you're pulling some good lateral G's, you need some special floats. what float setting should i be running in the eddy? how about throttle response? right now, its pretty soggy and boggy. i know that my metering rods and step up springs need some tweaking, and that is in order this week. but what else?

in other words, what general tune up should i do to this thing for autocross/motor sports usage?

thanks Michael

pull your exhaust, weld in an O2 sensor bung, buy a wideband with datalogging capability, test and tune on the street if need be, dial it in, voila. If you want to tune it for serious use, be serious in your method, if you just want a street-runnable fast and easy tune, dial it till it runs well enough, alter timing, get driving...

The Ed/Carter carbs have side floats. I ran an Ed 750 on my Barracuda for several years, but didn't autocross with it on there. Took it to an autocross school with a Demon on it. Has an Ed 800 AVS now. Hopefully I'll get to autocross it later this year.

My buddy ran the Ed 750 on his Dart at the same school. For the most part didn't have any problems. It did get starved for fuel at one point later in the day and stalled briefly. Might have been from the floats, might have been vapor lock from hot lapping in the August heat.

Check your fuel pressure. The Edelbrocks like lower pressure, like 5 PSI.

The Ed carbs tend to need a little more pump shot. Try increasing it by adjusting the linkage. If that's not enough you might need to either drill out the squirters or get the kit with larger squirters from Edelbrock. I put the larger squirters on my 800. Throttle response is pretty crisp now.

The 750 Eds also like a little higher float level than the factory spec. That's something to experiment with.

Edelbrock also offers an "off-road" kit for the float needles. It's a spring loaded set used by the 4x4 crowd. I have a set but haven't tried them yet. They should dampen the float movements. Might be useful in an autocross situation.

Raze wrote: pull your exhaust, weld in an O2 sensor bung, buy a wideband with datalogging capability, test and tune on the street if need be, dial it in, voila. If you want to tune it for serious use, be serious in your method, if you just want a street-runnable fast and easy tune, dial it till it runs well enough, alter timing, get driving...

Exactly!

This carb is SUPER tuneable. This means that it is possible to make it work extremely well (or berkeley it up big time!)

We used a wideband to tune ours for our lemons car. We read 12.5 across the board with no stumbles or bumbles. The only issue we have is the changing conditions throughout the race. Obviously, a carb is not going to "adapt" to increased heat, humidity, etc...

The tuning kit is necessary!

The float setup is front to back on these carbs, not side to side. Therefore you have to worry more about floats on accelerations and decelerations than you do in corners.

I hope this helps!

Rob