Is it possible to gather all the best parts from S4 and S5 engine? I have read before that S4 has better plates and S5 has better rotors. Anyways, this is on N/A engine with street port and I'll start to get these parts if any one can guide me on this rebuild.

 

Yes, you can mix and match. But if this is your first engine, I suggest sticking with a stock setup.

You'll run into issues when mixing and matching that can be very annoying. For example, if you use S5 plates with an S4 intake, the intake won't fit. Then you have to go to an S5 intake. So if you've used S5 rotors, S5 plates, S5 intake, you may have well just started with an S5 engine.

However a very popular upgrade is S5 rotors (and matching counterweight) on the S4 engine.

 

Thanks! So all I need is a pair of S5 rotors into S4 block? also the corresponding counter weight.

 

Aaron. You say it's popular to uses5 rotors on a s4 engine? What's the benefit? Also you said s5 plates WON'T work with s4 intake. Does that mean the same the other way around? s4 plates and s5 intake. What do you mean by matching counter weight? From a s5?

 

S5 rotors are higher compression than S4s. The front counterweight and flywheel (or auto rear counterweight) must match the rotors (S4 w/ S4, S5 w/ S5). S5 NA rotors for example, are lighter than S4 NAs and thus need different counterweights.

 

what about s5t2 rotors in an s4na? would have to use the same series e-shaft too with the rotors?

 

E-shafts are identical for all FC engines, S4/S5 NA/TII.

S5T2 Rotors would be a downgrade in a S4 NA because they would be lower compression.

 

thanks man. i didn't know that. i made the mistake of buying a s5t2 without knowing before hand about s4 and s5. so i'm trying to figure out how to still use it without getting rid of. plus my s4 na most likely has a blown coolant seal so i wanna see if can piece together a good NA from the two and maybe use the t2 tranny.

 

To clarify:

S4 TII rotors, 8.5:1 compression ratio
S4 NA rotors, 9.4:1
S5 TII rotors, 9.0:1
S5 NA rotors, 9.7:1

 

I don't mean to hijack this thread but just out of curiosity i have heard that gsl-se had the highest compression is this true?

 

No, internally the 13b in a GSL-SE is just about the same as an S4 NA. The rotors are 9.4:1.

The highest compression rotors available are renesis rotors, which are 10.0:1.

 

You may be confusing highest compression with highest weight. GSL-SE are the heaviest rotors.

 

how interchangeable are rotor housings, side plates, etc.?

 

might be easier to go with a v-8

 

NO!!!!!!! You put a v-8 in an Rx-7 and you just make it another car. The rotary is what defines the it. I would never consider it. Now maybe build a 4 rotor and put it in a vette. Haha.

 

what about an engine with this:

s5t2 rotor housings
s4na side plates
s5na rotors
s4na intake manifold/intake
s4na exhaust header (or will it not mate with s5t2 housings)

 

I think will be fine, but you will have to block off the upper coolant passage in the housings.

 

why is that? sorry if that may sound dumb, but idk a whole lot about this part.

 

This is another car! You're defeating the whole purpose of the rotary engine, which has less moving parts to a more complex piston. I had my rotor over revved several times during mountain pass and didn't had an issue of bent valves etc.

 

Watch this video to see what he's talking about: http://www.rebuildingrotaryengines.c...g_modification

The turbo housings have openings to allow coolant to flow through the intake manifold to the turbo. NA housings have freeze plugs pressed into the openings, so you would need to press some in.

 

is it possible to take those plugs out?

 

Sure, but that'd only be necessary if you're builiding a turbo engine with NA housings.

 

My engine water seal blew up yesterday! Now I have few questions. Since I do have S5 rotors going into S4 block. Do I need to order the S5 rebuild kit? The car is equip with RB light weight steel flywheel with Automatic rear counter weight. Should I change the rear counter weight specifically for the S5? Font counter weight is on my list, what else do I need to do this rebuild? And yes the world's popular porting is on the list as well!

 

I forgot to ask! Where is the cheapest place to order a rebuild kit?

 

actually i lesser known fact/ chevy DID make a vette with a rotary in it. the are way ahead of you. although it was never made into production chevy made one. look it up. i saw it on that 100 cars you must drive or something liek that. it was the one onwankers and wankels. quite interesting show