por9146gt

Hi there, could we get some advice on the size of the accelerator bleed valve on our 46 webers on a 906 spec 2.0 engine. accel pump volume seems high, have to be careful not to flood engine, while starting , and acceleration is slow,ie it takes a while for it to get up and go even at 5000 rpm or a little higher. it feels smooth, but does not have the acceleration while in formation when the green flag drops, the gearing is good and when it is going then it does well. exhaust is good with bypass installed. thanks and have a great weekend.

Steve Weiner-Rennsport Systems

Hi:

Those C-6 spec 46's should have 050 pump jets in them, yes?

One big problem I always run across is that people tend to have too much fuel quantity per stroke of acceleration enrichment that makes for a flat spot when the throttle is opened. Large venturies make this effect worse,...

Since we know that "Lean is Mean", one needs to use the minimal amount of fuel to prevent the bog when the throttle is suddenly opened and this is usually a trial-and-error process. Patience is rewarded,.......

Lastly, I cannot possibly stress how much the exhaust system affects jetting, throttle response, and mid-range torque. Headers that are too short, no crossover pipe, and the wrong muffler make ALL the difference in the world in situations like yours. I'll not reveal secrets here to protect my clientel, but you can read between the lines,....

por9146gt

"One big problem I always run across is that people tend to have too much fuel quantity per stroke of acceleration enrichment that makes for a flat spot when the throttle is opened. Large venturies make this effect worse",...

Hi Steve,
Yup you got it. I will try and make my .40 bleed valves larger to .6 or .7 to reduce the amount pumped into the engine. What about the adjustment on the accel rod? I hate to tigthen those too much, something is wrong about doing that.

Steve Weiner-Rennsport Systems

I'd agree,......sometimes we reduce the pump jets or enlarge bleeds to lean it out. In lieu of having smaller jets, adjust the accel rods as required,...

por9146gt

Thanks for the input, one more question if I may, I have the volume to about 4 ml, what is the true function of the accel pump rod, does it have to do with timing the injection to the opening of the throttles in any way, or does it just control volume of injection or the length of time of the injection....By the way, you helped us out in 04 getting the bugs out of this colorado car.

Steve Weiner-Rennsport Systems

The threaded rod controls the volume of the pump shot as well as the length of time,....

Glad to hear that I was able to offer something constructive.