he might have a 600 vacuum secondaries, only a 600 double pumper

would have linkage for the secondaries



might sound silly- but are you sure the carb is fully open at WOT?

 

the same size carb will always be down on power than the same size efi, becase the carb has to have a venturi. also efi can be tuned for a broader range, so it usually will make better power off peak than the carb

 

it seems that most of the people who modify NA RX7s always

go carb to keep it simple I guess



so that maybe that is the reason why its thought to make more

power?

 

Based on every class of motor racing I’ve ever seen, I would have to disagree. If EFI is allowed, any team with money immediately ditches the carburetor.

 

fuel injection is by far superior. power and tuning wise.



why do you think jegs has 3000 dollar injection systems for old skool chevys? it makes more power than carb.



carb is just simpler, not better. stick with fi.

 

its simple and usually larger, makes more power that way

 

I'll try to clarify - the "linkage" I meant to is really more of an actuator

rod coming from the secondary vacuum pod. Looking at a Holley, I also see that

if you unhook this to disable to secondaries, it is also necessary to wire the

secondary throttle shaft closed as there is no other spring. Then you just

drive an note any power loss. If you don't see any difference, the secondaries

weren't working to begin with.

The other secondary linkage present on a vacuum secondary carb is the lockout

that prevents the secondaries from opening before the primaries are open far

enough. You can stick a screw in this one and thus make it force the secondaries

to open (rather than just limiting when they can open). It's a rig, but

makes for a useful test. If the car now has more power, you've got a problem

such as a bad diaphragm (these get torn all the time when the vacuum pod

is reassembled from a spring change due to the cheap nature of the diaphragm).

 

holley's are too much trouble, get a demon or edelbrock. not too much more, and loads better.

 

why not peek in the carb, open the throttle all the way and see if there

is gas coming out of the secondaries?

 

Engine needs to be under a load for the secondaries to really open. In neutral

they will barely move at all. They may open visibly if you rev the crap out

of it.