3sgte swap into an rx8 Options

[Malhar95]

[Story]
My other car is a mazda rx8, sooner or later i know its going to need a new motor. And i'm not at that level of learning and understanding everything about a rotary to build one(or get one built and manage it correctly), so i was thinking out swapping a piston engine into it (getting it done by a shop ofcourse, maybe ATS or DDperformance, but havent decided yet).

My first option was a LS swap, because its 'murica and we like v8s.
But then i would prefer toyota since im more familiar with them...so i thought about 1jz/2jz. I know theyve been done to million rx7s and few 8s, so there are some off the shelf partially ready swap kits for those.

But im not looking for that much power, maybe 300 whp for now, and later upto 500 once im used to power.
so that being said, i figured a 3sgte would be a good candidate since its EASILY capable of that power, im familiar with it. And its also going to be smaller, so less weight going towards the front, so closer to stock handling (comparing to ls and jz) and lighter too.
[question]
But i havent been able to find any swaps similar. Im trying to find a transmission that is going to work with rwd. from what ive read, the 1jz mounts to the stock transmission on the rx8, so is the 3sgte and JZ have similar bolting points? If so i can just use the stock one.
Also, any suggestions of how to tackle the exhaust problem, the 3sgte exhaust side faces the driver side, so its opposite to both the stock 13b and JZ, so the turbo might not fit. I was thinking of doing a semi-rear mount turbo if thats an issue.

last question, i read alot about people running two seperate ECUs to run different engine. how does that work?

does one tell the engine what to do and the other the dash?

If you guys find any builds simliar to this or have seen it in person. i would really appreciate some suggestions/tips
Also i know "anything is possible if u have money" that being said, i was quoted 11k for a LS1 swap out the door.
so im hoping to spend equal if not less for this swap.

[Bitter]

You can do an LS swap for much much less. 5.3's are super common in the junk yards now, crank out the power you want, can crank out the power you will want later (with some assisted aspiration), and the off the shelf mounting kits are available from many many vendors, some probably better than others. 5.3 engine parts are WAY easier to obtain than 3S-GTE parts too, walk into any Autozone, Pepboys, or O'Rileys and order up stuff for a later model Sierra or Suburban.

One magazine cranked out 1000 hp from a 5.3 with just a cam and turbo's bolted on and some relaxed ring gaps...from a motor pulled from the junk yard for several hours on the dyno. The LS will weigh about the same or less and instant torque is much more fun.

[1994Celica]

Id go ls. There's more info and a better aftermarket for them. Or Id just rebuild the rotary because I love rotaries despite their faults.

[Malhar95]

I understand ls is very common and the the benifits of parts and mechanics being everywhere, but then I would really choose the JZ over those. Both motors are capable of same power with as easy work done.

But if the 3s is possible I would prefer that. Lighter and not as long. And 3s is capable of upto 800whp if done right. And I doubt I would handle that kind of power anytime soon. I think 300-400 would be more than enough for me now. And a 3s with a good bottom end and higher boost could get me there. Later I could improve the head and increase power. And after all that, turbo upgrades are fun.

And all that from a 4 banger is just a cherry on top. Lol

But if all fails ls might be my only option cuz of cost.

[Bitter]

A complete LS1 weighs 430lbs.
A complete 3S-GTE weighs 421lbs.

An engine that cranks out 300whp+ in STOCK form is going to be more reliable than one that must be modified to produce 100whp more than in it's stock form. Not only that, you've got way more head room to increase the power without loosing reliability since you're straying far less from stock configuration. I think you're blinding yourself to a great engine choice with your fanboi-ism and desire to be 'unique'. There's a reason the LSx swap is so popular, it's a great choice!

Even a Toyota V6 is a better choice HP/Lb taken into consideration. 2GR-FE is 1.3hp/lb and weighs LESS than a 3S-GTE and makes MORE power in stock form. 259lbs

A bare RX8 rotary weighs 210lbs, however I believe all the engine accessories and fluids add about 70lbs, so figure 280-290lbs complete weight I guess. Bare engine means no intake, exhaust manifolds, or fluids, complete engine means ready to drop in and run.

This post has been edited by Bitter: Jul 19, 2014 - 10:47 PM

[Malhar95]

A complete LS1 weighs 430lbs.
A complete 3S-GTE weighs 421lbs.

An engine that cranks out 300whp+ in STOCK form is going to be more reliable than one that must be modified to produce 100whp more than in it's stock form. Not only that, you've got way more head room to increase the power without loosing reliability since you're straying far less from stock configuration. I think you're blinding yourself to a great engine choice with your fanboi-ism and desire to be 'unique'. There's a reason the LSx swap is so popular, it's a great choice!

Even a Toyota V6 is a better choice HP/Lb taken into consideration. 2GR-FE is 1.3hp/lb and weighs LESS than a 3S-GTE and makes MORE power in stock form. 259lbs

A bare RX8 rotary weighs 210lbs, however I believe all the engine accessories and fluids add about 70lbs, so figure 280-290lbs complete weight I guess. Bare engine means no intake, exhaust manifolds, or fluids, complete engine means ready to drop in and run.

Ah, I wasn't aware of that. I was under the impression it's less.

But I still would have a wieght distribution advantage since it would be closer to the middle of the car.
And yeah, I'm guilty of being biased because of my "love" for the 3s and toyota. But doing something not everyone has was also a factor.

As far as the ls swap goes, not a lot of people have actually successfully completed the swap with proper documentation.
Yeah, th kit is like 3500-4k with everything included, and the engine/trans/ecu combo could be found for another 3k high side.

And then custom fabrication and labor would run be another 3-4k
So not bad.
But then most people have issued with steering and the dash not getting proper data.
YES, I would have to deal with the same problems with the 3s too.
That being said, I'm not sure myself what I want to do now. Lol.

[Bitter]

Yea, you're pretty much boned when it comes to the dash/data buss issues unless you ca piggyback the stock ECM to feed that stuff but you'll still be throwing a CEL in the stock PCM. You'll have to wire the Mazda PCM to be able to run the dash but NOT command the CEL which if it's all through serial data is going to be impossible.


Le sigh, 3 rotor swap...GO!

[mkernz22]

The 3s weighs 400lbs?...
I could pick my 5s up with two people and the same goes for the 1mz.
I highly doubt the 3s weighs 400lbs.

[Bitter]

430lbs with turbo, manifolds, fluids. Lifting 200lbs a person isn't unreasonable at all, the 5S would weigh less than a 3S-GTE since the 5s has no turbo and a lighter weight manifold.

[Smaay]

I would NOT put a 3S-GTE in an RX8. Its not a cost effective engine. you said yourself you only want 300 something, well a stock 2JZ will do that. then turn up the boost when you are ready for more power. Just because my Supra makes 1000 HP does not mean I run it there all the time. I turn it way down. ill make 600 for normal driving and thats stupid fast.

I would also consider a Toyota V6 option. since the 2GR has RWD applications, finding a transmission that will bolt up shouldn't be an issue.