_crazy_crazy_

hi all ,
i just bought and rx7 s4 n/a .. and i have been searching for the main differences between the s4 and s5 i've read that the s5 has the redline at 8000 while the s4 at 7000 .. I'm thinking of doing the change to the s5 admission and the tb mod what do i have to do to reach the 8000 rpm ? will it worth it ? and what else do you advise me to do ?



thanks in advance rotor heads

Turbonut

iTrader: (1)

Each rotor in the S5 is about 1/2 lb lighter than the S4 which certainly helps with the 8000 limit, and also the compression ratios are different between the two 9.7 to 9.4. Should of bought a S5 if you wanted the high rpm.

ericgrau

iTrader: (1)

You need the S5 VDI intake and the lighter, better balanced rotors like s5 rotors. IIRC it takes a little fab work to get the VDI onto an S4. While the VDI doesn't affect max rpm, it provides power at higher rpms so there's not much point without it.

The higher compression ratio on the s5 rotors is just an added bonus.

_crazy_crazy_

well i guess that i'll do the vdi mod and in a few months i'll rebuild the engine and try to find the s5 rotors and streetport it , by the way is the s5 instrument panel interchangeable with s4 ?

2_3D_SC

Most folks around here would probably tell you to forget about this kind of swap. I would like to this swap my self but don't have the money or the time, mostly time.

to get the 8000rpm redline you will need to change the ecu and the engine wiring harness and possibly the dash harness and instrument cluster.

other differences are:
S5 uses electric OMP vs mechanical (different front cover also)
S5 has two TPS sensors
you may need to change fuel injectors as well.

HTH

_crazy_crazy_

well i tried but the s5 wasn't sold over here in fact there must be like 15 rx7 n/a and turbo in the whole country .. it was a lucky find this one it was in a garage for a couples of years and it is in fact an import from over there it came from California in 1994 and it has been sitting in a dusty garage/barn for the last 6/7 years .

i'm in the disassembly part right now all interior has been removed so i can restore (and i do mean restore because even mazda official dealer here has a hard time geting parts and they are unbelievable expensive lol ) and the streetport is out of the question we have annual inspections to the cars and the car can get reproved by even an headlight change ...

well because i'm in a roll one quick question me and my friends usually drive in mountain roads, normally it's a friend of mine mx3 that wins our little competitions except when a certain r5 turbo appears but i ain't even trying to go against him do you think that my rx7 n/a s4 can win against his mx3 v6 ?

Thundercatzzz

how much could you do a swap for? s4 n/a to s5 n/a and what are the benefits...?