Pablo

iTrader: (1)

I installed a lighter airvalve in my 1405 and had a problem with not having enough fuel when I matted it due to the air valve opening too quickly

The pump shot cant really cover this because its not designed to deliver a ton of fuel for that last 30% or so of throttle travel, it comes out at an even rate (actually, probably less at the end)

so i started looking at the secondary transition system, if you pull off the secondary booster youll find the small brass peice that lets fuel in as the valve is opening and you can also trace it back to a small airbleed with a brass insert on the side.

I wanted a quicker reacting setup so I just plugged the airbleed today.

I havent been able to do datalogging but SOTP data along with my WBo2 readout show a definate improvement on secondary opening, its not perfect yet but definately way less lag once those secondaries open.

Im probably going to drill out the shooter size one step bigger tomorrow and see what happens.

ill post wbo2 datalogs before and after so you can see what I mean.

305sbc

iTrader: (3)

That will do it, but just log and make sure you don't go richer on the top end.

Carbs will still always respond better with a smoother application of the throttle.

Do you still have the check-valve/ball installed under the squirter nozzle?

Pablo

iTrader: (1)

yes i still have the check ball and all, the accel pump is working fine.

I ended up taking off the secondary booster and tracing things back to a feed tube for the aux secondary transition circuit. The feed tube had an opening of .035, the actual nozzle in the booster is much larger so I determined the feed tube to be the greatest restriction. I drilled it out to .045 and re assembled it along with the plugged airbleeds.

I also stepped down the nozzle size on my accel pump shooter and everything improved markedly

It still sucks compared to fuel injection, if the secondaries open there is still a lean and a bog.

I think for a manual transmission car the carburetor should be a double pumper or it should have fuel injection.

on another note, today i ran at the track with a K&N stub stack and no aircleaner, my mph was down, I looked at my datalogs and i was WAY LEAN, like 14.7

the stub stack apparently does a good job of getting airflow through that carb ill tell you that much. I wasnt able to rejet in time to get a run in with enough fuel. I may go tomorrow and give it a shot.

mcgruff1

Hey I just got my motor running again with the secondary air valve removed. It gets up much better, but if you nail the gas the car will almost stall out before getting going due to the lean spot. Do you have any ideas on what to do? Its also running leaner in the secondaries without the airvalve.