Oh the agony of decision! V8 or Renesis? It burns...
 

For those of you who have not noticed/read/cared at all about my obnoxious build thread that keeps popping up, I am in the process of bringing an old dead GSL back to canyon killer status, and while my suspension is taking over a month to ship from billy because he is short strut tops (I'm waiting man...) I have some time to consider my next move in what to order. I know I'll be grabbing some stainless brake lines and new pads at a bare minimum at some point, and seats and so on, but my powertrain decision will be the basis of almost every other big purchase and the car's direction.

I really like the 5.0 and I know how they work, and that they make good power and will fit and make a glorious noise, but after looking at the renesis 13B I see that the price difference between a 302 built to where I want it (alu heads for weight and a total refresh/mod to about 300-350 horse) and a Renesis with bolt ons is not that big.

Tl;dr version: What engine will I use? Deciding factors:

1. Will the Renesis let me use the R&P conversion?
2. How much fabrication will be needed to fit a Renesis?
3. How much N/A power potential is in a Renesis?
4. Can I live with the fact that the car will ultimately be slower and not sound as epic?

Mods feel free to move the thread or call me a freak of nature, but I thought the good folks of the FB thread would be able to shed more light.

Renesis, because RX stands for Rotary Experiment.

I somehow think of putting a rotary engine in an RX7 as pretty standard, and not so experimental.

go with the renesis shant be too much!

Renesis, an RX does not have a soul if it does not have a rotary

Just think... You'd be the only Renesis Powered FB in all of North America. And you could always add a turbo later if you needed more power.

5.0 has been done to death. Also take a serious note at how many V8 Rx-7 projects are always for sale. Because they suck.

honestly from what ive read the reni engine is better as a paper weight than an engine. if you got the money to dump why not go LSx? youll be starting at 350 or so hp so no reason to even dump any cash into it. that is unless you want to play with the big boys.

but honestly its all covered going ls. so no issues with that. but every single person on this site will just cry like babies for me telling you this

Because it's wrong, pointless and perverted and will make flyboy end up in HELL!

Or in a Chevy dealer trying to buy parts, which in many ways is worse. Provided he can find one that is open.

True statement.

thats a stupid question stay with the rotors the weight of a first gen with the power of the Renesis will make it own and not weigh it down at the same time. ohh and v8s suck ass

funniest thing i've read in days, rotfl!!!

its actually a very good engine. its extremely efficient (as far as rotaries go) and its very reliable. the issues with the engine are due to lack of internal oiling. premixing is an excellent way to preserve the engine for many many years. as an RX-8 owner i can tell everyone that i'm more than pleased with the renesis and as a 13 year rotary owner, i can say that the renesis is an excellent rotary and is well suited to the RX-8 as well as an FB.

100% true been seeing alot of v87s for sale on craigslist.
If i had the money i would buy them and de-bastardize them:lol:

I like your thinking, maybe I should learn to get over my dislike of Chebby engines and just suck it up for the inherent advantages. Honestly it is so very nice out of the box...

And yes they will :egrin:, but soul means as much to me as a dead cat, I'm looking at the criteria above.

I used to have an RX8 and I would be fine with premixing, it's power potential without resorting to a turbo I'm worried about.

Yes it does, it's like a tiny japanese mustang as is, might as well finish the job! :lol:

Ok guys and gals perhaps I should try to have this moved to the tech section? I mean if anyone knows approximately what it takes I would greatly appreciate it, not that I don't appreciate being told I'm clearly nuts :)

230hp is about all you will get out of a renesis without a turbo.
I say, go buy a 20b. There are waaaaay more v8 FB's than 20b FBs. And 20b FB's haul much more ass than a fat stone-age v8. I've seen N/A 20B's get 400+ HP.

1. sure, the v8 might not though.
2. put 12A front cover on it, or add the front cover mount to the rx8 front cover, and its in the car. unlike the v8.
3. this might be the hard part, 230 wheel hp? its rotary HP though. the rx8 makes 90% of peak torque from like 2000 to 8500 rpm, the v8 can't touch that, add some curves in there, and when the v8 guy has to shift, and he does twice, you'll be GONE....
4. the renisis actually sounds pretty awesome... i know its opinion, but v8's only sound cool when there is a full field of 60's trans am cars coming over the hill at laguna, and the ground is shaking, other than that they kind of sound like toilets flushing....

5. if you want a good LSx swap candidate, look to the 7 series volvo. my friend did one, its the easiest swap ever, and its like the perfect home for that engine....

oh and if you want a shock, start pricing out LSx parts... $300 water pump? the a/c delco one is made in china? pass...

If I had a boatload of cash a 20B would be way cool, but they're heavier, I would rather go with a "stone age" V8 because it'll do me 400 horse at half the price.

Do you know for a fact (or at least solidly think so) that I could front mount the Renesis? If you could back this up at all I would be VERY tempted to do it, I realize after a bit of thought that the same approximate peak numbers could be reached by adding a supercharger, and while they're way expensive I could learn to wring the car out in the meantime and get it sorted. Thank you for a well thought out answer :icon_tup: I'll have to look into the design differences.

You can get 20b's for $3,000... Built LSx engines are like 5,000.

But I can get an LS1 with the same or better power and the same or better weight for 2k with a tranny thrown in if i look hard enough.

And 5.0 Small blocks are about 400 bucks, so again about the same, the only reason I'm considering the Renesis is because it revs to the moon stock, is light as can be, not too expensive, and can be supercharged relatively easily if not cheaply, plus it has that slick six speed attached to it. I will not use a turbo engine. I just don't like turbos.

either add two aluminum blocks like this guy http://page11.auctions.yahoo.co.jp/jp/auction/n68926921
you don't have to change the oil pan, so that might be better.

it also would be possible to fab up something that adapts to the stock rx8 mount points...

or maybe even put the 12a front cover on it

I've heard rumor that Racing Beat is experimenting with tweaking Renesis engines...

They have porting templates and ECU reflashes for same already available. And there was a shrink-wrapped Renesis sitting in their lobby for a couple months that has mysteriously disappeared.

Wait a minute, I was under the impression that Mazda's Racing RX8 was pushing about 300 + NA?

Now then, a good V8 can make gobs of power on the cheap. The issue is going to be cost vs. weight, where if you want an all aluminum small block 5.0 with all the goodies to stay as close to stock weight, it'll probably start piling up in cost.

I personally believe an RX7 should have Rotary Engine, otherwise go buy a Miata. What makes these cars unique is how much they do with so little; low weight and low powered engine, often ends up being a fun ride.

That said, I also believe that people are entitled to what ever they want to do and or try. The Renesis will be a unique engine swap and will require a good amount of fabrication and creativity since it hasn't been done many times and very little documentation exists. If you want easy, cheap power; (without going turbo) go with the V8. You want to try some unique that will test your skills, ingenuity, and at the end of the day leave you amazed that you made it work? Tread in the unknown.

Good luck in what ever you decide, hopefully we'll be able to help you out with either choice.

-Paul

Side note: Hasn't anyone thought about doing a VR6 or W12 swap?

the grand am cars are running a 3 rotor peripheral port which mazda sold as 450hp@8500rpms.

the lower classes are running the stock engines, which still do pretty well, i've seen em run the 25 hours of thinderhill.

another plus to the Renesis is you can upgrade to the six speed too and thats a really good thing