Crush

Hey, I am kinda new to RX7's, so I was wondering what is the difference between the s4 and s5? Pics would help, also anything different engine wise?

rico05

About 20hp for starters. Are you lookin at n/a's or TIIs?

Crush

N/A's

rico05

Ok, the S4 is lighter, but the S5 has more stock hp (factory: S4 143hp, S5 160hp.) The S5 has different side mouldings and front lip. The interiors are the same, except for the shift ****, gauges, and the S5 (at least the american ones) have power assisted seat belts. The S5 LSD has 4.10 gears, and the S4 has 4.33. The S5 has a taller 5th gear (I *think*). The intake manifolds are different. The auxillary port intake system is actuated via backpressure in the S4, via air pump in the S5. That is about all the general stuff. Now different models have different options, but I am decently sure that is the big stuff. Mark, Jason, Ted...correct anything that is wrong please!!

vaughnc

here's your pics.

The S5 (1989 - 1991) looks a bit more modern and has more OEM HP. The NAs (non turbos) make a great daily driver. My favorite models are the convertible, GTU-S, and GXL. The Turbo II is the platform if your looking to make MASSIVE HP reliably (ie 350-450hp).

Here's a welcome package that explains more. Let us know if you have more questions.

-- vaughnc

--------------------------------------------------------------------------------------------

Hey welcome to the forum.

The best thing about the rx-7s is the car is 100% designed as a TRUE sports car - not a

"sports coupe" or "sports sendan."

The Turbo II is a SUPERCAR and is the tuners DREAM CAR. Mazda designed the car with 450HP in mind but detuned to 200/180 ft-lbs torque. What that means is you can GO NUTS designing a porsche killer for little $$$.

The rotary engine is PERFECT for a sports car. Mazda designed the rx-7 to take 130% advantage of it. That means you get lightweight HIGH OUTPUT performance, UNLIMITED REVING (there's nothing to break), small engine means sweet aerodynamics = low drag. Handlign is the BEST part of the rotary experience. The chassis has rear steer like some porsches, so you can kick some serious butt around the corners. The car handles & drives so well - it inspires you to push the car beyond what you think it's capable of

Best of all, the rx-7s have an international following from tuners, manufacturers, and enthusiest. That means you have a wide selection of performance upgrades, accessories, bodykits, coffeytable books, toy models, and knowlegable people.

a few pictures:

Crush

Thats exactly what I wanted to know. Thanks

vaughnc

SoloIIdrift

*buzzer*

Actually the S4 and S5 N/A cars with LSD had the same gear ratio, 4.10, but use a different style of LSD. The S4 uses a clutch pack style LSD (mechanical clutch locks diff), while the S5 uses a viscous style LSD (fluid that heats up and locks the diff)

The 4.33 gears in the rear end were only in the GTUs N/A which is limited editon and not the normal GTU cars.

Other than that spot-on info

Crush

I got another question. I am planning on buying an RX7 with a blown motor, would the s5 engine fit into the s4 without any mods?

wpgrexx

probably not, at the very least, new wiring harnesses and ecu

rico05

Um yes. The motor itself will bolt right in. You can even use the same motor mounts. However, you will need to replace thefuel/emissions computer, also known as the ECU. Thanks Solo, I knew I would screw something up!!

BlackRx7

damn vaughnc whos engine bay pics are those those are totaly awsome

biorotary

with the engine swap from s4 to s5 you'll have to replace the front engine cover (s4: machanical oil metering pump, s5: electrical omp) on the s5 with the s4 one, injectors, and other various engine sensors if you don't want to replace the wiring harnesses (notice i said harnesses and not harness) and ecu...

basically, you'll have to strip just about everything off the s5 block and put the s4 stuff back on the s5 block...

NZConvertible

If it had come from the factory with over 400hp and could reach 200mph, they maybe. But it didn’t, so it isn’t. Not even close. Except for the undersized wastegate, very low boost/fuel cut, untunable ECU, low resistance to detonation... That’s not how manufacturers do things. The car was engineered to make 200hp for a long time. As a consequence it is able to handle 450hp for a short time. Except the flywheel and clutch, not to mention the engine’s bearings and stationary gears...

Don’t get me wrong here, I love RX-7’s and rotaries in general. I’m just not so blinded by that love to ignore simple engineering realities.

Snrub

iTrader: (1)

I was reading the Brian Long book and he had an interesting quote about the first TII: "The planners had originally set a target of 170bhp for this unit, but causes all sorts of headaches when they then upped it to 180 at the last minuite in order to remain competitive with comteporary Toyota and Nissan outputs." It goes on to say that the twin scroll turbo easily saved the day.

To the real point of this thread: Personally I'd go with whichever works out better. If you can get a good S5 for approximately the same money as a similar S4, then get the S5. Much of the time S5s are too hard to find or are overpriced compared to S4s. These are the reasons I have a S4. I'd be happy to trade my car plus $500 for an similar S5, but it ain't gonna happen!