When I floor the throttle only the smaller butterflies open on the carb. The larger, secondarys don't open at all. Is this normal? It seems to have good power.

 

i am no mechanic but id say they are stuck... check em out, try lubin em a bit, but keep the lube outa the wholes ... id imagine

 

They move freely when I push on them from the top down. Are they supposed to move when the engine is not on? Are they operated bt the throttle linkage or by some other means? I hear people talk about a mech secondary modification.

 

The secondaries wont open unless the engine is under load. You will NOT see them open while the car is satnding still (unless your on a dyno).

 

Out of the factory, the Rx-7 has vacuum actuated secondaries that will open when there is a signal. If the car isn't running, then only the primaries will open. If the secondaries are mechanical, then all four barrels should be wide open when your foot hits the floor. If they don't, check the linkage because something could be stuck or broken.

 

the mechanical sencondaries conversion was the best mod i've done to my old carby 12a.with this mod you can control when the secondaries will come in life.
there is going to be a point while pressing the pedal,at about 50% throttle,where it's sense become stiffer.that gives you the signal that this is the point where secondaries opens.

 

Where's a good place to get the mechanical setup?

B

 

Its a mod you do yourself. Check out sterlings writeup in the archieves, its very detailed on how to do the mod. Its very simple, you'll be glad you did it.

 

oh yea, after you've read through sterlings writeup, check out my site it has some pics of the mod, it might help clear some things up. www.slegers.com/sites/sean

 

Thanks for the advice. I will try out the mech mod.

 

ok i have my secondaries on mechanical..... and i have my timing advanced but.. my mechanic still left the vaccum advance on? should this be removed?

 

can you "unmechanical" your carb? I mean going back to vaccum activated secondaries if I don't like mechanical?

 

Glad until you go to the gas pump LOL

 

yes, its very easy to undo

 

No it should be fine as long as your total ignition advance isint too high.

24L 16T @RPM > 4000 per Paul Yaw

 

What is the "idle" setting then?

 

Well if you have no vac or centrifigual advance, like mine, then its the same. Read pauls ign article, its very informative.