I have two s4 n/a engines both in decent condition but need rebuilding. I have enough parts between the two engines to make a 3 rotor block, minus the eccentric shaft. I understand I would need coils, a new ecu, some fuel pumping upgrades, along with a nice clutch and some stuff to keep this thing cool. I am looking to drift my rx7, and am shooting for around 450-500 horses. I also do not want to deal with turbos, so i will keep it N/A. Is this a possible goal, and is this practical? My other option is buying an eunos cosmos 20b which is also expensive and still having to buy an ecu etc. I could also build up the 13b but this is also an expensive route because along the way id still need a new ecu. Tell me your opinions, and no I dont want pistons in my rx7.

haha i forgot the R in rotor. o well.

 

Nothing from your 13Bs will be of use in a 3 rotor except for the rotors and housings. The 20B uses different irons with a different port configuration. Also there is a center "thick" iron that contains another bearing. These are getting more rare by the minute, so good luck finding one. Even if you did build some kind of hybrid 3 rotor with a 20B eccentric, thick iron, TII/NA end irons (which have different ports), NA housings, NA rotors, etc. you would have to build your own intake manifold because 20B stuff wouldn't fit.

If you want a three rotor and don't have a machine shop, then you need to buy a 20B. Don't waste time on the Cosmo ECU and harness, it won't work. You need a full standalone.

You're not going to make 500HP on a 20B NA unless it is a peripheral port and you are spinning it to 10K. Which will require balancing and a host of custom work.

You're flat out not going to make 400-500HP NA without a LOT of expense and custom work.

If you want that kind of power, the only "practical" way is via forced induction.

 

it is possible with enough money, but not practical. you are looking at ~$10,000 for the swap (at least) if you do most/all of the work yourself.

 

no, it isn't practical by any means. 2 rotors are fine.

 

if your looking into drift use your money for a good suspension set up. better 1.5 lsd, strong clutch and flywheel. aluminum drive shaft brakes and a roll bar. i personally wouldnt recommend a turbo for drift because it would make throttle control a bit more tricky. look drifting doesnt need 500bhp 200bhp is a good amount but remember any kind of racing has to do with balance. power-response-drivability-durability. balance is the key word.

 

You could build a Peripheral Port 3 Rotor using 13B parts. You still would need to modify an iron to accept another stationary gear and you would need to buy a short 3 Rotor eccentric shaft. Not to mention building a header for it, getting the right ECU, tunning, etc. Either way you go, getting to your 450-500whp goal is going to cost you a good bit of money. Turbo's are fine for drifitng as long as you select the right turbo and set it up properly.