I don't know if any one can answer this but what can rotarys handle HP wise before blowning a hole in the rotor?
or snaping the e shaft?
or blowing apart the housings?
and can we try and give the limits for each series of motor (S4,S5,rew)

 

Zenki FC - 400hp
Kouki FC - 500hp
FD - 600hp

This is the rule of thumb I stick to.&nbsp The rotors and rotor housing don't fail.&nbsp It's the dowel mount bosses that crack or the water jacket groove fails.


-Ted

 

What's the difference betwixt the two FC blocks? Is that 87-88 vs. 89-90? Thanks.

 

Yes, Zenki FC blocks are the S4 (86-88) blocks and the Kouki FC blocks are the S5 (89+). RETed just wants to be difficult j/k

 

What factors are included in those numbers? 3mm seals? Reinforced dowel pins?

 

Are these stock motors?

 

I just relized I spelled handle wrong

 

We got the idea.

 

Bringing one back from the dead...

I thought the only difference between the S4 and S5 blocks was internal. What else is different? Is it the dowels? Can S5 blocks run mechanical OMP (sic)?

Help before my engine goes away for a rebuild!

 

nudge

 

it depends who you choose to listen to.......

i know of a Series 5 motor making 830HP with no extra dowels, running 2mm seals.

there are a number of guys out there making 500HP on series 4 blocks with no troubles.

i personally believe that cracking plates is due to detonation at anything under 650ish HP weather it be S4/S5 or FD engine block.

 

Tension bolt bosses in the front end plate are supposed to be stronger on the Kouki engines.



-Ted

 

That is true.&nbsp I know of guys running only 300hp on Zenki blocks that have cracked the dowels on the back plate - oil leaks between the housings.

Like I always do, I always estimate on the conservative side.&nbsp Hey, we can't all be supertuners, and I guarantee you're going to detonate at least once.&nbsp Hell, I'll admit that I detonated my engine more than I have wanted to - not sissy "popcorn" detonation but NASTY hammer-on-metal-pipe detonation over a dozen times!&nbsp My motor is still together, and I've torn it down and found no damage.&nbsp Granted, I'm not even close to a 400hp monster...



-Ted

 

by any chance are the guys making 300HP who are crackingplates - do they run 3mm apex seals?

if the do, be they believe you NEED extra dowels to run over 15psi boost too - sounds like 95% of New Zealand rotary guys if ya ask me hahaha

 

What are dowels?

 

the two locating DOWELS which hold the rotor housing in the right place in relation to the end and centre plates.

Some people believe that you need to add extra ones down the combustion side of the housing to prevent the housing from "walking" sideways when you are running upped boost, but testing from a number of places has shown this is due to detonation and not from running high boost

 

Can a Kouki be substituted for a Zenki easily? or does that get into ECU , Accessory ( a/c, ps,alt ) and Exhaust compatibility issues?

 

yes but the kouki makes more hp so you will probley need a fuel controler to up the fuel. and the kouki intake flows more air.

 

Sorry , will do a search for it