RX7 rotor in RX8 housing
 

hi.....
anyone now is it possible to use rx7 rotor in the rx8 housing. because i had blown my engine 2 times (apex seal problem). currently i'm using greddy turbo with 0.4 bar with e-manage. my friend told that his friend had using rx7 rotor in rx8 housing for almost 2years without blow (after blown 3 times using OEM rx8 part). now i'm planning to put rx7 rotor in the rx8 housing with super seal rx7 2mm apex seal with racing corner seal. any advice?

dont take my word for it but I dont think you can just throw in a rotor from a different engine other than teh 13b msp


hopefully someone more knowledgeable will chime in

My advice is you find someone that has experience building & tuning turbo Renesis motors. Your post clearly indicates you do not know what your doing.

Without some modifications by an SKILLED rotary engine builder putting RX-7 rotors in a Renesis will not work long. If he was to get the seals modified to work in a Renesis he would still need a custom tune because of the lower compression the RX-7 rotors have. The threads below cover this topic. But the OP problems are due to poor tuning and selection of parts and he needs find competent help on that first before he entertains building a FrankenRenesis.

https://www.rx8club.com/rx-8-discussion-3/rx-8-rotor-rx-7-rotor-89607/
https://www.rx8club.com/series-i-major-horsepower-upgrades-93/rx-7-5th-gen-rotors-118830/
https://www.rx8club.com/series-i-major-horsepower-upgrades-93/cracked-front-housing-119714/

I don't personally think that the rotors or the compression ratio is the problem. You're only going to blow up a motor if it detonates, or you're running more boost pressure than the apex seal itself can withstand (not likely).

I would say all you need is more adequate cooling, maybe a higher octane gas, and a better tune. There's really no reason to be blowing that many engines unless something in the setup is just wrong.

Do we have to have multiple threads on the same subject?

This separate forum thing isn't very well thought out

and learn to Search before you post n00b

"The rotors themselves are the same physical size. There are some diferences with the seals though. The Renesis rotors have a cutoff seal in between the side seals and the oil control rings that the 13B's do not have. The shape and size of the seals is also different between rotors. Due to this fact the RX-8 rotor can be used in an RX-7 but not the other way around. You'll just have to trust me on that one. The casting thickness of the RX-8 rotors is also thinner than the 13B which makes them less strong but lighter. I'm not sure where you can get any dimensional drawings. I'll start digging"

ROTARYGOD posted this in a different thread

I thought they were balanced differently.

i had a same problem with you.....or..u can call me

i had seen one mechanic who expert with the rotary engine. he told me to modify the rx8 rotor (to deepen the grove for putting OEM rx7 apex seal). anyone who done this before? any advice?

You can modify the rx8 rotors to fit the older seals.
The problem is that you blew 2 engines and will blow a modified one as well without the right installation and tune.
From your words it isn't an engine problem, rather an install one.

You don't even know wtf you are doing.

6 psi and it blown up? that sounds like stock map, so yeah,

top using stock E-Manage map Genius

Fix it up and find a good e-Manage Tunner to TUNE it.

No don't use RX-7 rotors in a Renesis.

The problem isn't the apex seals. It's the fact that you have a Greddy turbo tuned with an e-manage.

hey, you are a fktard, renesis engine is fine by itself. Learn to get it tuned and boosted right.



ACTUALLY, GO FOR IT!

You are both right and wrong.
Cam from Pettit can machine the Renesis type cutoff seals into 7 rotors, for use in a Renesis, you also must use the 7 style engine balance weights.

I have 9 to 1 compression rotors with about 6K miles on them, I did reduce my rev limit to 8500 rpm though, in fear of the heavier rotors...

Good so far. :D:

The Greddy timing maps are bad, that's why you blew up your motor. See this thread for my revised maps: https://www.rx8club.com/series-i-engine-tuning-forum-63/beware-emanage-ultimate-timing-maps-greddy-kit-193496/

Hi
i have 2005 Mazda rx8 and my car need rotary Housing. if anyone have Rotary Housing good condition please text me.
thanks everyone
my emil adders is ELD051@YAHOO.COM:o:

THIS! This is why I love this forum! Everyone talking about different weights of the rotors, and someone chimes in to remind you not to forget about the counterweights! Thank you!

yeah, because they only supply these modified rotors with an engine rebuild that includes balancing the rotating assembly

but all these years later most of those past people in this thread you’re trying to communicate with are gone.
.

Hey guys what if you wanted to put higher boost into the renny, I know the REW is the better engine for this. BUT, what if you blocked off the side exhaust ports using devcon or some thing and used GSL-SE rotor housing for use of the pp exhaust and then modded the rx7 rotors to fit.

If everything was balanced correctly. could you not push the same sort of power through the renny and it would last the same as a REW ?? If one had access to machining equipment etc and did not haft to fork out loads of coin to make it all fit, and they had a bunch of renneys laying around in the shop like for example MEUWWWAAAAA

What would then be the weak point in the engine if a build like this was done ?

Just off the top of my head, prolly the Devcon epoxy that temporarily fills the side ports?

Ad hominem again, Team.

Try and reel the old vitriol in a bit?

let me help you out; start here:

https://www.rx8club.com/series-i-maj...2/#post4933175

Correct, however there could be other ways to block them off.

I see to some people have made poor attempts to create valves in the exhaust to open and close the PP.

But my question still stands. what becomes the weak point in the engine if you using rx7 rotors and block off the side ports. I know there is a weak point at the front of the engine which cracks at the dal but studding the block and adding an extra dal pin would solve this issue i think.

Thanks for your replay but this dont help me. I am trying to understand if you are to use rx7 rotors and block off the side ports what then becomes the weak point in the engine ??