I am still new at the rx7 . but why do they put larger cc inj. as sec. and smaller cc. as the pri. and not the other way around. Are the sec. for the top in or long haul?

 

stock 7's came with the same size in all 4 holes.

As the words would indicate...primary is the first, and secondary is, well, secondary. Secondaries come on-line (on the stock ECU) around 3500-3800rpm, depending on load.

The reason people put smaller primaries in is because huge secondaries would be pouring gas into the motor at idle, smaller primaries can run the engine at low loads/speeds more efficiently.

 

So another way to save gas is not to rev past 3500 so the secondarys dont cut on, and if you make the secondary inj. larger the more load the motor can handle at higher rev.

 

In another thread someone said that bridge porting makes the car unstreetable. What do they mean by this?

 

When the secondaries come on, the injector duty is split 50/50 between the primary/secondary (stock motor). So, there's really no difference in gas mileage except for the fact that you're running at a higher rpm if your secondaries are coming on.

With a bridgeport, your powerband shifts upward. Basically, you have "no" power under a certain rpm depending on the bridge (ex. 4000 rpm). Have fun with that on the street...

 

No sh*t

 

It also has a high idle and can have partial throttle driving issues. It can be driven on the street, a numbe rof people have done it. Its just more challenging and not very practical.