i've been playing with 2nd gen rx7's for while now....i have yet to play with a n/a s5.

well i just bought my first one and had some questions......now before everybody says "search"... its currently not working........

so i'd like to start modifying it....but...was wondering about the secondary ports.

how do i tell if the VDI is working? how do i tell if the 5th and 6th ports are working.

do the 5th and 6th ports work on vacuum like the s4?

i have a header for it, and im just planning on doing bolt on's and using the s-afcll.

any answer's or tips would be awesome.

 

if you have a vdi problem you'll have a noticeable heistation around ~6500rpm, theres couple write ups on how to fix it and if thats actually the problem. If you have a shop manuel it (i have haynes and the benchbook for my s5) will tell you how to fix the problem.

The 5th and 6th ports are electronically opened IIRC and arnt nearly as problematic as the ones on s4s

 

You mean auxilary ports. NA engines have two primary ports and two secondary ports like the Turbos, plus two auxilary ports, hence the name Six-Port Induction (6PI).

See the FSM.

Neither S4 or S5 system works on vacuum. The S4 uses exhaust backpressure, which is an imprecise method that loses its effectiveness when you start modding the exhaust (less backpressure = later opening). The S5 uses pressure from the air pump that's switched via ECU-controlled solenoids, which is far more accurate and not affected by exhaust mods.

I strongly recommend you read the section in the FSM that covers the VDI and 6PI systems. You will better understand how they work if you do.

 

FYI: The GXL was not offered in '91, just the base model RX-7 Coupe with or without option package A and/or B.

 

i just figure it was a gxl type mofel, since its fully loaded with the 4 piston brakes, 15" wheels and such. sorry

if i wanted to remove the air pump, how would keep the 5th and 6th ports working?

what is the FSM?

thanks for the replys guys

 

oh yeah and how well does the s-afcll work, is the a better alternative other then going haltech?

is there a performance chip for the s5? should i go chip+safcll?


any tips on mods....please feel free to add your imput.

thanks

 

FSM = Factory Service Manual. Links to download are available in the FAQ.

If you remove the air pump, you will lose your 5th and 6th ports. Just leave the airpump in place.

The S-AFCII is a fuel controller that messes with the signal from the AFM to fool the ECU to add or delete fuel. It cannot be compared to a true standalone like the Haltech. If you can tune (or know someone who can) the S-AFC, then it's a worthwhile upgrade. You can gain a lot by leaning the car out.

 

awesome thanks