Filosi723

I've had an account on here for some time but have never really used RX7club to its full potential and now I need assistance of people of great knowledge about my RX-7.

I have a 87' TII with around 112k miles on it and I recently lost compression on my rear rotor. I was having a cracking popping sound in boost before she went and I think it was detonation.

Power Mods are:

-Fuel pump rewire
-FD fuel pump
-750cc secondary injectors
-Rtek 1.7 ECU
-Hallman pro boost controller aroud 11psi
-Wide band O2 and boost gauge
-Corksport intake pipe
-Cone filter adapter
-Racingbeat tubo back exhaust

I ran really rich at idle and WOT. From my prior research the setup I had above was safe and I hope it was just old age my engine blew and not my own doing.
If these mods seem bad please let me know.


After removing and dissembling everything I found that I really need two rotors and two housings for my S4 (according to my Rotary Aviation DVD. The rear is definitely gone and the front housing has groves I can catch my nail on, plus the front rotor has an indentation on it).

So now I am kinda caught in what I should do next.

I have done some research and have found that I might be able to use S5 TII rotors and housings, or FD rotors and housings. Is this true? Will it work with my almost stock ECU (Rtek 1.7)?

I guess main question is should I spend the money and buy new S4 rotors and housings or should I try to find a set of nice S5 or S6 rotors and housings and counter weight?

During the rebuild I plan to street port and most likely run a upgraded BNR turbo with a front mount setup and most likely will need a different ECU upgrade+injectors. Searching for around a somewhat reliable 300whp.

I'm just looking for ideas, options and pricing. The S4 rotors and housing seem to be harder to come by and would it just be more beneficial to go with a high compression setup?

And I am aware that these answers lurk in this form somewhere but I suck at using the search on the forum.

Any assistance that anyone could provide would be greatly appreciated.
If this is more advanced thread stuff sorry again just please let me know.

Thank You!!!

diabolical1

iTrader: (3)

NEW stuff? well, damn, baller.

seriously though, I think I read that all S4 engine parts have been superseded by the S5 equivalents now anyway, so I don't think you could buy NEW S4 even if you were so inclined.

that said, just buy a good used rotating assembly. the rotor housings might be worth getting new, but even they can be had used in great condition (but used prices have been rising though).

when the engine assembled, focus your attention to aged fuel injectors and

Filosi723

Will S5 turbo internals work with my S4 ECU? Does the change in compression matter to the ECU?

diabolical1

iTrader: (3)

I doubt it. years ago, a friend of mine ran 9.4s in his T2 on the stock ECU. keep in mind, i'll be the first to admit i'm not THAT ECU-savvy (in terms of functional details), but i think there's wiggle room built into it to handle the bump in compression, which may likely amount to changes in the curve as opposed absolute values.


wow! total brain fart here. LOL. i don't remember the rest of my thought. sorry.

Filosi723

So now where can I get a full rotating assembly for a S5 turbo 13b? Or just rotors, housings, and a counter weight?

I'd like to do it myself but I would entertain the idea of buying a streetported short block from a company.

diabolical1

iTrader: (3)

you can check the classified (general or regional) for the parts. there's also a few vendors that usually stocks parts. if you choose to do it yourself, then check those options.

however, you have quite a few options to have an engine built for you, but do your research anyway. i can't think of any "local" to Syracuse though. about the closest i can think of are a couple shops in New Jersey.