MZR swap
 

okay, nobody get your feelings hurt...i know the 8 is all about rotary power and its uniqueness. Plus it's not like I'm thinking about doing this, I do not have even close to the time, skill, nor money to do this. but... what do you guys think about a 2.3 MZR engine swap from a speed3? would it be ridiculously expensive and hard? maybe a little easier because its same brand? would the engine bolt to the rx8 tranny? discuss.

Isn't that like almost the same HP? I know that you can get more power out of it than the RENE, but it kinda seems like a waste, why not just go ls1 if you are going to pull the rene, making big power out of a 4 banger is unreliable and a recipe for disaster.

the tranny wont bolt, and you need to make everything work. good luck:ylsuper:

No they dyno around 235whp/257tq to the ground, while to get around 250whp with the renny you gotta drop 10g's on the greddy kit or run nitrous which is more unreliable. Plus in the MZR you get the extra tq, and it would make a more reliable 300whp daily driver.

Yeah that's is not much of a difference for the jump to make a swap, and for the price of the swap I am pretty sure you could drop some thing better in, an fd motor perhaps.
There is no such thing as a reliable a turbo four cylinder daily driver.
And your comment about nitrous, I think is misinformed.

yeah I agree with the price being worth that much of a power difference. And the turbo four cylinder being reliable is a real thing, many lightly modified subaru's run 180k+ with regular maintenance. the mzr is too new to see if they will run for that long.

And I may not be a nitrous expert, but I have in fact run it myself. and it is pretty hard on your engine, maybe not worse that FI. but just as bad, maybe a little less.

If you did all the work yourself (meaning no outside labor costs), it would still cost at least as much as an FI kit would for the renesis. Considering the effort, I'd say it would be worth going FI renesis before doing a swap like that even if you knew for sure the renesis wouldn't last too long. It's so much work for a gain that can be had for less money and effort. It might be a good engine and produce gains rather easily, but if you're doing a swap, there are more worthwhile swaps to do.

I don't think anyone has had issues with nitrous on the renesis. While that doesn't prove it to be reliable, it shows that it's not a huge liability as you originally made it sound. I ran nitrous on my 8 and never had issues. I had about 60k miles on my 8 when I sold it and the engine ran strong as far as I could tell. Nitrous gets risky when you push the limits. The benefit of nitrous (in terms of reliability) is that you don't always have it there. There's an on off switch. With turbos, that's much harder to control. Sure, you can stay out of boost, but self control is difficult when you always have it right there to use. My current car has turbos and I almost always find myself pushing up to at least 10 psi a few times per drive... Once I hit that, it's hard to resist hitting 23 psi.

Well, for the same price as going FI I would think the extra effort would be worth the better reliability/power capability/and MPG. I'm just thinking out loud. I thought it would be cool to have the only swapped speed3 for an rx8, and it seems to be a reliable idea. and as far as nitrous, it is logical to think that someone would not run it as much with an on/off switch. But it was just way too fun for me, i was constantly hitting it just for fun(even though it was not run constantly). But as far as power comparison, a somewhat reliable nitrous or FI set up on a renny vs an MZR making approximately the same power stock (with the exception of the higher torque) and more reliable i would say. and I don't see how any other swap is any more difficult. yeah, you have the fd as a little easier option, but you're kinda in the same boat as far as reliability goes. Just wondering if someone will eventually give the MZR a shot, and see how difficult it actually is (plus a 4 banger weighs a lot less than say a V8 swap or i don't know...i've seen a couple 2jz's. but at least you maintain a lighter engine, and gain MPG).

Of course there are FAR cheaper/better ways to get the same power/reliability. I just thought it was an interesting swap.

Maybe you should drop a reliable diesel merc engine in it then, for that torque and reliability you crave :P

who said I was dropping anything into in my car? there's always gotta be some sarcastic post...

you wouldnt use the MZR. ITs not made to go longitudinally and the cost for result would be prohibitive. There are other MUCH better choices for swaps that would be easier to do and less costly for more gain.

I can understand some people wanting to do an engine swap in their 8, but swapping for that engine just doesn't make much sense to me. The gains you would get don't seem high enough to justify the time, money and all around hassle of doing an engine swap... If I was going to go to all that trouble, I'd wanna do it for an engine with significantly higher numbers that would give me a real noticeable difference in performance....

And the swapping an engine for the reliability doesn't make much sense to me..... The reliability trouble with the Renesis is that it has been known to fail with time. This is a problem because it means you have to get a new engine.... So it seems to me that you are buying a new engine and putting it in, so that you don't have to buy a new engine and put it in haha.

That's the thing I was trying to point out above (kind of). Even if you are going for power and reliability, it seems makes more sense to go for FI because it would still be easier to do an FI build and then replace the engine when necessary.

A V8 might not be as unique and heavier, but it at least puts out power to really justify that kind of effort. The gas mileage might not be on par with a turbo 4 cylinder, but (depending on the engine), I think you'd be surprised at the mileage you'd get.

Um, the MZR has proven to have it's own problems. Lot's of snapped rods in modded ones from what I've seen. Not to mention all of the other points mentioned above. The main being that it's designed to mount sideways.

The MZR is the same bird in the MX5. The swap would be dreadfully easy using an MX5 front subframe.

As far as durability and power production vs cost, to each his own. A strong MZR (L3 or LF engine) does require some pricey mods to make the power and to make it live with the power.

Paul.

Having tuned a gaggle of Speed6 and Speed3 cars, I can tell you that you will not produce much more peak power or torque than a well-tuned turbo Renesis and you will spend more money (in the conversion) and give up 3000 RPM or more in the process.

The DISI system is very limited and expensive (if not nearly impossible) to modify and has a very narrow tuning window.
There are a multitude of other difficulties - not impossibilities - involved. I just don't think it makes sense.

I have contemplated other motors in the RX-8, including the MZR and I discounted it.

Now, a well-built, turbo BP might be interesting. It is a conventional engine, already set-up for RWD and easily brought up to 400 HP by well-proven means.
If I don't do the other conversion that I am contemplating, the BP will be the route that I follow.

thanks Paul. forgot:(

I dealt with a guy who decided that he wanted to swap a BP Turbo into his RX8. After sufficient fabrication nightmare he had us build him an RX8 engine to go back in.

One of the big advantages with the LF, L3 over a BP is the exhaust routing on the R side of the vehicle just like the 13B (And all Mazda rotaries except the Premacy RE).

I think someone will make 600hp with a renesis this year.

Paul.

Hmm. I'm thinking his fabricator might have been a bit off their mark.


You will need to qualify that statement I'm afraid.

Interesting. If that wasn't a joke, it's not cool to say something like that and leave it unexplained.

well there is hope, continued researching it, and found out the ms6 rear diff is the same as the rx8's. there's at least one similarity. awd rx8 anyone? ;)

The last thing the RX8 needs is significantly more weight with no power gain.

The insides might be the same, but the outsides are quite different.

oh man, look what you did Paul ! Im about to go crazy. I mean it. :eek:

Yeah, and get 100 miles to the gallon. Uh huh. :rofl: