cagefreak

I own an S4 and I'm about to buy an S4 JDM motor to fully restore my beast. I plan to open track race(weekend warrior/freeway gladiator) and I want to know from the general 2nd Gen Group if the S4 motor has the potential to hold high horsepower numbers (350+) like the S5 can and last just as long. Everyone I've talked to, so far, has just told me to stop wasting my time and buy everything to facilitate a s5 swap in my s4 body. I believe I can get the S4 motor to last and pull 350hp with bpu++. Let me know what you think.

Planned horse power mods:
Denso 255lph fuel pump
720 secondaries
Greddy FMIC
BOV
TDO6 and Stainless steel manifold (external Wasgate)
KOYO radiator
Flex-a-lite fan
Profec B
RB DP and Presilencer
(some cat back of some sort)
S5 UIM and LIM
(stock apex seals/no internal work ie. porting)
pre-mix

Wompa164

iTrader: (4)

Whoever you talked to is stupid. I don't see any reason why S5 has any more potential than S4.

eoph

i don't c how s4 motor can't hold 350 hp. its still 13bt, its mainly the manifold that accounts for higher hp in the s5's

Mykl

I don't think your friends know what they're talking about.

1987RX7guy

iTrader: (3)

well your saying no porting. I would think a street port or just a polish would help out in the HP department. You should also think about a stand alone ems.

Ryde _Or_Die

You will at least need 2 more 720s for the primaries to get to 350hp. For your goal think more along the lines of moving your 720s to your primaries, get 1300 or 1600s for your secondaries and a standalone ECU. I didn't see any aftermarket ECU on your list, so make sure you get that in there since its one of the most expensive. There are also cheaper/better turbo options out there. Look into the 60-1s for your application. Seems to be right up your alley.

Other than that, quit worrying about S4/S5 ****. You can make 350hp on a S4 most definitely.

Avatar

there are plenty of worked s4 engines down here producing 350+. After a rebuild a s4 motor will last just as long as a s5.

BobbyRX

Maybe they were getting it confused with the 12A vs the 13B? I'm still learning here, but what do they do for oiling on Rotary engines? Is it like "full flow" where you bypass most of the stock oiling and dump the oil from the pump straight into the main galley like on other engines? What is the 3-window bearings? Is it like having 3 oiling holes or is it 3 groves? I'm interested in reliability mods, please. Thanks in advance!

cagefreak

Thanks for all the input. I was waiting for someone to tell me that I would need a stand alone. Kinda hoping I could pull those numbers out of my *** without going engine management.

Now that's solved. Can I get some review posts from E6k and Microtech owners. I would like to know the advantage and experiences people have been have with both. I know with the Microtech you can just swap the ECU out and it uses the factory harness. That to me sounds like a definite advantage.

Let me know what you guys think. Thanks again.

-Justin

BlackFC

The S5 motor may have a little more potential than the S4, but it is not any great amount. The S5 motor has lighter, higher compression rotors, and the castings for the block itself is a little bit stronger. You can run into problems with the dowells cracking in the S4 motor over 450bhp or so. The S5 can and does also crack, but it is stronger.

Your goal of 350rwhp is not so lofty as to warrant an upgrade if you have a S4 core that is in good shape or you can get one alot cheaper than a S5 core. For around the same money however, I would chose the S5 block everytime, if anything its just newer.

cagefreak

Anyone with a testimonial?? (E6K or Microtec)

BDoty311

Actually I would think that the S4 motor might be a better choice if you are going all out. But Why? Because the higher compression rotors limit the safe amount of boost you could run. And the S4 have a mechanical OMP, while the S5 is electrical which can cause some serious damage if it goes out.

Rizla+

I Totally agree with what BlackFC said.
The OMP is way out of the equation here cause he is planning on going Standalone....
Go take a look at this link, it is mostly comparing 13BT to the 13B-REW but there is also some explanations about the ameliorations done to the S5 engine over the S4.
http://members.rogers.com/sofronov/C...3BT13BREW.html