I'm just wondering how the power difference is achieved between the series 4 (fc1031) and the series 5 (FC1032). Did Mazda simply increase the boost or have they made changes elsewhere?

 

The s4 has a lower compression motor and comes with a max of about 7 psi boost. The s5 on the other hand has a higher compression motor and comes with about 8.5 psi boost. Hope this answers your question.

 

also you dont have the circle tails, and it has black side moldings no matter what color the exterior is. Rims are diffrents, mirrors, rear spoiler, front bumper, and the gauge cluster. Hope this is enough for ya. S5 is the way to go but the S4 is still a beauty!

 

Is it worth replacing the Series 4 with the series 5 engine or just mod the series 4

 

The s5 has also beter turbo housing... i also think they have a better drive line... also the s5 ecu doesent have as many buggs as the s4...

 

It is totally worth replacin the s4 motor with an s5 five motor. If you go with the s5 you get 205 hp at the flywheel. Also when you do the same mods to the s5 as the s4 you get more power.

 

I'm sorry but i'm kinda new with Rx-7s but i would figure that the S4 would be better. First off, would a lower compression engine be better for higher boost? And isn't there any upgrade turbo kits for the TII? HKS? Trust? I'm looking to buy a TII but i want it to keep up with my MKIV...well sorta.
BJ

 

Blah blah...My s4 is every bit as powerful as any s5 with the same mods.

 

plus the S4 is lighter and has better looking tailights and no squirrel belt


Justin

 

I really dont know what you are talking about

I dont have the belts, and I DO have the best looking taillights....

...of course, I have a European/JDM TII

As for the S4 having the same power as the S5......how's that even possible ? They start with 20HP difference from the word "GO". Same mods should lead to same -if not even bigger- difference in power output

 

i like the S4 lights better

Justin

 

http://2ndgenrx7.freeservers.com/page1.html

 

i use to like the s4 lights.. then the s5 came out in late summer of 88.. and i realized the difference.. haha

 

s5 has lighter rotors

 

which engine does the 10th anniversary edition have? s4 or s5? please excuse my newbieness...

 

with an s4, if you are making a lot of power you have to worry more about craching the rearmost housing where the oil filter is. this is not as big of a problem with the s5 motor.

my $.02

dave
87 TII (series V conversion)

 

S4 (1988)

 

The difference is small, 9.0:1 vs. 8.5:1 (6%), so it’s really not an issue. Higher compression gives better torque and drivability off-boost anyway. Yeah but they have huge price tags attached to them. If you’re planning on keeping the stock turbo and maybe upgrading it, the S5 one is much better.

 

No way!! the s5 lights dominate the s4 lights IMO

 

all this s4 And s5 bullshit, the perfect match is s4 motor s5 looking body,and a big turbo ,NUFF SAID.

 

If your a fan of the old T-Bird tail lights, then then you would be a fan of S5 taillights.

But, this observation has been a spark to flameing before.......

 

uuummmmm, I didnt say that I actually HAVE an S5