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Re: rotary again

Posted: April 20th, 2009, 9:13 pm
by Nd4SpdSe
A transaxle of a FWD actually saves weight compared to a RWD system

Also, you can get 200bhp out of a ZE or BPT

Re: rotary again

Posted: April 20th, 2009, 10:04 pm
by onlytrueromeo
Ya, thats what Im saying. There is no way you'd be saving much weight if any. It'd be just for the "kool" factor of having rwd...which is nice, but I see no point in a n/a rotary...they're only worthwhile if you boost them...sooo much potential.

Re: rotary again

Posted: April 20th, 2009, 10:33 pm
by Nd4SpdSe
ACtually, you can make ALOT of power on an N/A rotary...Selecta picked up an FC that I asked him to look into for me and he was showing me how much power you can get out of one of those, upwards of 300hp belive it or not

Re: rotary again

Posted: April 20th, 2009, 10:35 pm
by RS_OBD'oh_2
my b6 will have more than 200whp very soon Then again you got guys out there like cjthor... he's sitting in/around 300hp

Re: rotary again

Posted: April 21st, 2009, 8:51 am
by onlytrueromeo
Well, I guess you are correct saying you can make power out of a n/a rotary - I misstated my point. You can make power n/a on any motor, but you need to build it, and most people think it's more worthwhile to turbo a car rather than do a full rebuild to extract every last bit of n/a power from an engine...I don't know how difficult this would be for a rotary, but I've seen the 10k+ pricetags for ZE's.

Where I see the power in a rotary is the QUICK revs, HIGH revs and turbo potential. I guess you could always go N/A first and step up to a turbo or nitrous setup. I would still suggest going megasquirt, upgraded fuel pump (will need a fuel cell anyway) and wideband when you install the motor.

Re: rotary again

Posted: April 21st, 2009, 11:43 am
by Robx1r
10k on a rotary would get you a quad rotar motor with roughly 500bhp and loads or torque

the cosmo 20 b is a triple rotor turbo which delivers 300 atw from the factory.
and on a normal engine you've to uprate so many differernt parts where as on a 13b there is 3 moving parts and i think 18 parts in total its nowhere near expsinve to tune a na rotary but the conseqquenses are greater if an error is made

Re: rotary again

Posted: April 21st, 2009, 11:47 am
by colinsmx3
I hope you have VER VERY deep pockets full of money! :welder:

Re: rotary again

Posted: April 21st, 2009, 12:17 pm
by onlytrueromeo
Yeah i know a 20b is more powerful, but I was talking 13b here because that is what you mentioned. I was under the impression that the crank alone for a 4rotor crankshaft was 3-4k alone (new). It'd sure be cool to have.


Good luck with whatever you do - I dont have any experience w/ rotaries so I cannot continue to comment...I just hope you budget at least 2x as much as you think this is going to cost.

Re: rotary again

Posted: April 21st, 2009, 2:19 pm
by Robx1r
can people tell my why they thing this is going to cost a fortune

Re: rotary again

Posted: April 21st, 2009, 3:52 pm
by onlytrueromeo
How much experience do you have welding? Do you have a press to bend metal if need be? Do you have a donor car?

Re: rotary again

Posted: April 21st, 2009, 4:12 pm
by colinsmx3
Robx1r wrote:can people tell my why they thing this is going to cost a fortune
We should'nt have to tell you... If you have done the research to do this then you can see why it will cost way more then you think! I have only seen this done once and the car was never completed... and I belive he said it costed him upwards of $15,000. to get it where it was... and the electrical was never done. It was on Ebay for a silly amount.

Re: rotary again

Posted: April 21st, 2009, 4:18 pm
by onlytrueromeo
That was w/ an rx7 rear end...this guy want's to do it w/ a miata rear end, which SHOULD fit better, but really we don't know. He also wants to go older possibly carbed I think to cut down on electrical (I would suggest FI over carbed). Electrical shouldn't be too bad as I've already said he should go with a standalone...just get the engine harness and splice into MS.

Cost will come when he realizes everything has to be custom! Unless he's a great fabricator or has alot of help, he will probably have some trouble!

Re: rotary again

Posted: April 21st, 2009, 8:43 pm
by Daveb
My buddy had an old RX-7 with a Chevy quadrjet carb on a rotary, It was a California Mod, It booted but sucked gas like crazy :lol:

Re: rotary again

Posted: April 21st, 2009, 9:23 pm
by Robx1r
i know i'm coming across as pedantic on this but ya'll need to open your minds when it come to modifying stop being afraid of what ya can do
i'm an auto electrician by trade so no matter which engine route i'll figure it out
and i've moderate fab skills and what i can see needing fab work is
the subframe to make mounts for the engine,
a tunnel gearbox mount
the rear axle mounts

is it just my ignorance or is that it?

i'll have to get the drivshaft made which will probably cost the most


and as for that other yoke from what i seen of it was trying to shoe horn an entire fd into an mx3 he was using all the fd running gear including the shocks subframe etc from what i remeber and tubbed the rear arches cos he wants to drag it

i'm not tubbing the rear
i'm not using rx7 running gear i'm using my existing coilovers
i dont know which box i'm going to use i've access to both mx5 and rx7 box's so i'll see which works best
as i said at the start of this thread i've more than enough time to do it if i wanted cheap and easy power i'll buy a klze or god forbid a different car but i dont i think that the mx3 should of being a rotary car and i'm gonna make it one (at least one of them)

Re: rotary again

Posted: April 21st, 2009, 10:04 pm
by onlytrueromeo
You will most likely need to modify the front subframe as well...but I cannot confirm this because I have not seen anyone put a rwd tranny in an mx3...it just makes sense.

I know for the AWD tranny the front subframe needs extensive cutting and rewelding new materials to hold the strength.

Also, you will need to remove the spare tire well, and reinforce the rear end of the car to support the new frame and power coming from the rear end.

A fuel cell will need to be secured in the back.

You may need to swap to a digital cluster unless the speedometer gear/cable setup in the tranny works w/ the mx3 cluster (digital clusters can be calibrated to whatever)

You will need a new suspension, and if you're doing all this work it'd be a shame to put in old parts. New ball joints, wheel bears, etc, add up quick.

The little things add up quickly. If you're cutting the center of the car out, do you plan to keep a back seat/carpet?

Will this car have an interior or be stripped for track only?