View Full Version : EJ257 (STI motor) in my rx8?


risky business
04-15-2009, 09:31 PM
Possible?

I know next to nothing about most motor swaps, but I guess you gotta start somewhere. Does anyone have knowledge about these motors?

How would I mate it to a RWD system? I'm assuming of course, you couldn't fit the AWD system on an rx8, but i'm open to all ideas.



I'm at 82k miles on my orig engine and I figure it's going to die sometime, just thinking about the possibility of motor swaps, and I love those engines.

teknics
04-15-2009, 09:41 PM
im pretty sure subie motors are mounted the same as rotaries, ie no transaxle. if so you could probably get it to work at least ghettoly with a custom driveshaft along with the typical "change the whole engine and engine control system) type of swap. I know of a few rx7's with subie powertrains, i could see if i can dig them up and see what trans and such they use.

kevin.

Brettus
04-15-2009, 09:50 PM
I know next to nothing about most motor swaps, .

Then don't even think about it .....

Unless of course you are very mechanically minded and want to turn this kind of thing into a (very expensive and time consuming) hobby .....

PSTNLSS
04-15-2009, 10:48 PM
After watching this video

http://www.youtube.com/watch?v=3mHaiLfpOdo

I honestly think anything in this world is possible

Brettus
04-15-2009, 10:57 PM
/\ I'm pretty sure that is the one built here in NZ - I've seen it . Not as quick as it should be - must be issues getting it hooked up .

teknics
04-15-2009, 11:25 PM
anyone seen the clip of the twin vr6 vw jetta or golf or something? Youtube videos of it, awd, vr6 motor in front, vr6 in back. a launch video as proof, car is sick. they call it the unofficial w12 or some shit.

kevin.

risky business
04-15-2009, 11:48 PM
Then don't even think about it .....

Unless of course you are very mechanically minded and want to turn this kind of thing into a (very expensive and time consuming) hobby .....

I knew someone would say that when I typed that sentence. What you are saying is good advice, however I work in the mechanic field and am a very fast learner. I tend to do A LOT of research and planning before I step into something.

im pretty sure subie motors are mounted the same as rotaries, ie no transaxle. if so you could probably get it to work at least ghettoly with a custom driveshaft along with the typical "change the whole engine and engine control system) type of swap. I know of a few rx7's with subie powertrains, i could see if i can dig them up and see what trans and such they use.

kevin.

That sounds promising! If you could find anything it would be greatly appreciated!

risky business
04-16-2009, 12:12 AM
did some digging, doesn't look like it had a very promising outcome on the 7's


maybe i'm just dreaming here...

teknics
04-16-2009, 12:38 AM
did some digging, doesn't look like it had a very promising outcome on the 7's


maybe i'm just dreaming here...

if you dont want rotors go v8, nice ls1 will keep you happy. or buy a subaru?

kevin.

NACer4lyf
04-16-2009, 12:41 AM
or just save some money/time/frustration/money/time and just get a new engine for the car instead

dillsrotary
04-16-2009, 08:31 AM
Though I think it'll be a ton of work (and money), the sti motor with an aftermarket exhaust is one of the best sounding engines i've ever heard. It is very very unique.

teknics
04-16-2009, 10:05 AM
Though I think it'll be a ton of work (and money), the sti motor with an aftermarket exhaust is one of the best sounding engines i've ever heard. It is very very unique.

not too unique, its just a boxer engine. All the old mechanics i know think a subie with an exhaust is mifiring, its pretty funny, but an sti with a nice exhaust is definitely a beautiful exhaust note.

kevin.

dillsrotary
04-16-2009, 10:30 AM
^ Not unique in engine design, but very unique in sound once uncorked. Even a straight pipe porsche boxer doesn't have the "throaty" characteristic of the sub box, turbo or not. Probably something within the design that I am unaware of (valve placement, exhaust structure, etc.)

bose
04-16-2009, 11:10 AM
Subie's get their distinct rumble from having UN-equal length headers.

It's probably possible to do, but it will be incredibly expensive, difficult and time consuming. They plugs and coils are on the sides of the boxer, once it's in there how would you change them? But it would be pretty damned cool.

risky business
04-16-2009, 12:37 PM
if you dont want rotors go v8, nice ls1 will keep you happy. or buy a subaru?

kevin.

A: I love my rotary, but I wouldn't mind swapping in a piston motor if I liked it enough

B: meh, v8.... I don't know. It just seems like such a common thing. I feel like it's to popular of an idea. If I heard of some1 putting a v8 in an rx8 my thoughts would be "well, bound to happen sooner or later, people swap v8's into everything"

however swapping a boxer motor in is a very unique idea.

C: yes I could buy an sti I guess but. It's dumb to have that AND the 8. The only thing that I REALLY love about them IS the engine, I mean they can look alright, but my car looks better, they handle well, but so does mine.... so I was thinking about joining the 2 cars, best of both worlds.



I just like to entertain ideas of thought. Build different builds, price them out, plan how I would do them. It's kind of a hobby.

Most likely I will stick with a rotary in my car, but time will tell! Gotta wait for this engine to die first!

82k miles on orig engine baby!

Jedi54
04-16-2009, 12:51 PM
sell your car, buy a Subaru, problem solved.

teknics
04-16-2009, 01:05 PM
or build a kitcar with a subie motor.

a nice ariel atom with a subie motor probably has never been done...

kevin.

lepichichi
04-16-2009, 01:18 PM
with $$ ANYTHING IS POSSIBLE :) why not rebuild your engine and turbocharge it while you at it? or rebuild a 3rd gen rx7 engine :) or a 20B??? just ideas !

TheWulf
04-16-2009, 01:27 PM
they handle well, but so does mine....

The 8 won't handle as well with an STi motor in it. You'll throw off the weight distribution by a nice amount.

chiketkd
04-16-2009, 02:09 PM
im pretty sure subie motors are mounted the same as rotaries, ie no transaxle.
You are correct. The front diff sits in the trans, so since the OP isn't trying to make his RX-8 AWD, this might be a doable swap. However, it will cost money and require custom fabrication (bell housing, etc.)
The 8 won't handle as well with an STi motor in it. You'll throw off the weight distribution by a nice amount.
Meh...it won't throw the balance off too much. Remember the EJ25 is a 4 cyl engine with a very low CoG due to the boxer engine.

To the OP, if considering this swap, I'd just go with the EJ25 out of an '06+ WRX or '04+ Forester XT. Identical block to the STi, just different cams & pistons.

White_Shadows
04-16-2009, 03:08 PM
I'm with the whole I LOVE THE SOUND OF A SCOOBY!, but alas, I got the rotary for it is unique. The 20b has been done a few times, but not that many. You won't be made fun of, and it'll still sound cool as hell and hmmm wouldn't it be faster???

delhi
04-16-2009, 04:01 PM
wouldn't the TMIC + flat-4 becomes too tall for the low hood of the rx-8? I love boxer engine sounds. Great to work with. You can try it. But I think without the rotary, an rx-8 cannot be an rx-8 but an mx-8 at best.

risky business
04-16-2009, 04:26 PM
with $$ ANYTHING IS POSSIBLE :) why not rebuild your engine and turbocharge it while you at it? or rebuild a 3rd gen rx7 engine :) or a 20B??? just ideas !

the sti motor is way more reliable then either of those options.

I'm with the whole I LOVE THE SOUND OF A SCOOBY!, but alas, I got the rotary for it is unique. The 20b has been done a few times, but not that many. You won't be made fun of, and it'll still sound cool as hell and hmmm wouldn't it be faster???

your right, I don't think I would be made fun of.... But the gas mileage is terrible on the 20b...(I know some1 will now say "if your concerned about gas mileage, you can't afford a swap!)

well to that person, obviously i DON'T care about gas mileage, or I would not have gotten an rx8 when premium was $4.50 a gallon.

The reliability is really more of a factor.

I wouldn't expect a turbo'd renesis to last more then 20-30k, whereas I could count on the EJ257 to last quite a long while





sell your car, buy a Subaru, problem solved.

I seem to either hate your posts, or love them jedi.
wtf kind of response is this..... I guess someone would say it.
The subie looks like a brick, is uncomfortable and.... well i'm not getting rid of my rx8, so why not put the one thing I like about the subie IN my rx8?

things aren't always as cut and dry as "sell your car and buy X"
I am NOT one of those teenagers posting about how to make their rx8 be fast then a mustang or evo. that is the correct answer for that type of thread, not this one.

If you can't offer helpful information or insight, please don't crap in my threads

/rant

Brettus
04-16-2009, 04:46 PM
go check our cr333's thread
I think he started that build about a year ago - when he finally gets it going he will have same power as before but it will be "reliable" .
What a joke

Rootski
04-16-2009, 05:15 PM
Is it possible? Sure, anything is possible with enough time and money. But it's far more difficult, expensive, and probably unreliable option than getting a replacement Renesis.

EDIT: risky business, I didn't read the post where you mention reliability before I posted mine. The idea that any engine swapped into any other car is going to be more reliable than the stock setup is pretty laughable. Sure, the engine itself might have a history of being more reliable, but once you move, fabricate, or replace all the tertiary components needed to make it work, ESPECIALLY if you have no experience in swapping engines, you're left with a frankenstein-ish mess of components from different companies in a custom layout that no one in the world but the installer or a few seldom crack mechanics could possibly diagnose. There's only one reason to swap an engine: because you want to. You'll gain nothing from it except the weight and power characteristics of the new engine and suffer losses everywhere else. There's a reason engine swaps are so rare in daily-driven cars. Turboing the Renesis is a much cheaper and easier option to get the results you are looking for. Yes, it's less reliable, but reliability will suffer no matter how you go about gaining power. But people here understand and deal with turbo systems.

TrochoidMagic
04-19-2009, 05:52 PM
^^ i don't know of a better way to say that.

i'd have to be with you on this one. swaps always compromise a ideal vehicle specific geometry somewhere... this is NOT always about CG's and PMOI's.

i'd have seen in person a V8 ls1 swap in a FC in my friends shop machine tune in gardena ca., and although i complimented on his efforts, i still told him it was a waste of an FC.

the shop specializes in 240's and 240sx' swaps.... so obviously the car was naturally used for drifting, where fine balance of a vehicle isn't well looked into, only concerns were of raw power to induce oversteer...

nothing against the subie's bro, just not my cup of tea. hope you find a better foundation...
IMO, honda motor swaps tend to work in uniformity very well... but isn't unique as its been done a thousands of times over due to vtec. but thats not to blame because the car is staged to do so...

F8S RX8
04-25-2009, 03:19 AM
Best swap for the RX8 I personally think is the 13b-rew with single turbo. Talk to Robert from Rotary Shack, even though he is in Cali he can give you a good explanation why.

alfy28
05-21-2009, 10:01 AM
sell your car, buy a Subaru, problem solved.
:lol: a good way to start the morning. :)