jasmine

I am only partly serious about this, but I am workin on a little bit of a sleeper car. I wonder if it would be possible to drop a new Renesis into an 87 RX-7. Is there room for it under the hood? Is the Renesis heavier or lighter? Will that result in necessary suspension mods, etc? Disregarding the ridiculous cost of such a venture, what considerations would be involved here?

And a more realistic question, is it anywhere near possible to get the kind of power out of the 13b as what comes from the Renesis? Other than Turbo, lighweight flywheel, LW pulleys, LW fan, better exhaust, and new computers, injection and so on, what mods can I make on the 13b to get maximum power, and what are the highest numbers possible? I have heard reports of 250hp on this engine, but I don't exactly believe that... that number just seems to defy the laws of physics. I am an old boxer engine specialist, and I admit I don't know much about the rotaries, so feel free to correct me on anything. I am impressed so far with my car, but I am skeptical of big numbers

Funkspectrum

iTrader: (5)

Um....the renesis swap can be done but it's pointless IMO....
The renesis just seems funky to me. I dunno if you need to or not, but I imagine that you'd need the gauge cluster, transmission, and all the under-hood BS of the RX8 in order for the swap to be complete. I just don't really trust the drive by wire thing....


I'd use a 13B-RE or a 13BT...

RETed

Oh no...
hehehehehehee?


-Ted

MrDirt

hahaha, it isnt even worth explaining anymore, is it, Ted?

jasmine

Is it really a drive-by-wire system? That is totally cool, but yeah, a little freaky. I don't trust it either

My point is that, to the guy in the Civic next me at the light, it would still look like a 20 year old RX-7! I'm wanting the people over in the next town to be like "hey, if you see a chick in an RX-7, DON'T race her!"

MrDirt

Just go with a 13BT swap. Ultimately, it will be cheaper. If you spend the same amount of money that you would [correctly] swapping in a renesis, the 13BT would be MUCH quicker.

arghx

iTrader: (3)

The Renesis is good for what it's supposed to be... a high-revving, emissions compliant rotary. It's much better than the old N/A's. But a 13BT has way more power potential in stock form.

jasmine

I am not anxious to do an engine-swap. It is a major PITA (see my other post on that topic). I am apparently not the only person to have this idea though

I know that with a piston engine you can seriously screw things up if you just slap in a turbo, but on this engine, can I simply add a turbo, or do I need a different engine? What is the difference between the turbo engine and the NA? Right now I have the NA, and it's pretty sweet all by itself, but it could always be better. Heck, I haven't even got a K&N filter in the thing yet, and it's way faster than my (lightly tuned) Subaru was. I haven't spent a dime on this car yet, except to fix the window, which was broken out by some thugs who stole the stereo right before I bought it. The previous owner did buy me a new window and we installed it over the weekend, but that wasn't really a performance enhancement, more of a winterization issue around here. Jasmine doesn't like to freeze her cute little butt off

lastphaseofthis

iTrader: (8)

or just wait for the turbo (and/or) supercharged renesis...

SparkienSuggah

the turbo motors have low compression rotors that help to keep the mixture cool during the first two phases of the otto cycle - this translates to "high boost low detonation".
na motors have higher compression rotors, thus cant take as much boost before the compression lights off the mixture prematurely (like your first boyfriend....)

the renesis is just a 13b w/ sideport exaust... it makes all its power through the multistage intake ports and sky high factory redline.

and why not trust drive by wire? its better than we are at controlling wheelspin (provided you install all the sensors...ugh)

rotarygod

iTrader: (1)

Ignoring whether there are better options out there for cheaper, yes it can be done. I personally love the Renesis. It's a far better engine than many think it is and it's definintely a better engine than the 13B n/a for many reasons. Obviously the biggest downside is cost.

First off you don't need to use the factory ecu or drive by wire. You don't need drive by wire to make any other engine run. The Renesis is just another engine. Use a standalone and a conventional throttlebody and call it a day. It'll work fine. It would probably be easiest to use the stock intake manifold and just adapt a conventional throttle body to it. I'd even go so far as to adapt an S4 mechanical oil metering pump to it. You will need to fab up new motor mounts as they mount on the front rotor housing on the Renesis vs the intermediate housing of the 2nd gen. You also don't need to use the RX-8 transmission. It is the same bell housing bolt pattern so your tranny will bolt up. Use what you've got. Just use an aftermarket flywheel and clutch system designed for the car the tranny is intended for. It's real easy if you use a T-II tranny as the RX-8 flywheel is the same size and TII clutch parts will interchange with it. It wouldn't be nearly as hard as many people say it would but it will still require a little custom work. Shouldn't be that bad. Just get over the price. I'd love to see a Renesis powered 2nd gen. That would be a fun car.

rotarygod

iTrader: (1)

Actually most of it's power increase does not come from a skyhigh redline. It does make more power higher but that's not all. The Renesis has about 50% more exhaust port area than the last 13B. Even the port area isn't only responsible for the greater power. The biggest part is with the port timing. Timing is hugely important in determining power and more timing isn't necessarily better. Put all of this together and you've got your increase. The intake keeps it all nice and smooth throughout the powerband. The intake is also just far less restrictive.

RETed

I'm surprised you make such a claim?

PP exhaust port has "more aggressive" port timing.
This implies the PP exhaust port is better suited for top end power?
The Renesis MSP exhaust port might have more exhaust port area, but I doubt it would flow better than the PP exhaust port?

The MSP exhaust port is superior in terms of low-end power / torque and emissions, but there is no way it's better in terms of ultimate power output?

For reference...
http://www.thecarricos.com/ACRE/Docu...esis_paper.pdf


-Ted

jasmine

That really doesn't apply to my situation. I'm just interested in creating the fastest little RX-7 in this lonely part of Utah. There's only 3 in town that I know of, and those are all in bad shape. I'm a total "car chick" and I expect my machinery to be in top-notch condition. Gives me a lot to do with an older car like this, but I enjoy gettin dirty

I think I'm gonna stick with the regular 13B for a while and see what I can get out of it without a turbo. I'm also quite partial to superchargers over turbos, but I don't have a whole lot of experience with them.

MrDirt

As said before, you CAN turbo your N/A. I think there is a sticky at the top of the 2nd gen forum about doing it. Most people opt to swap in an entire TII driveline from a parts car, or just sourcing the parts from various places. If you really want a fast car, the N/A is not going to take you very far, short of several big/expensive modifications that will make the car a real pain-in-the-*** to drive. Swapping in a TII motor is not as hard as most unexperienced people would think.

spanish-road

my friend was driving a 84 rx7 with a frankie 13b n/a with big *** webber carbs, at 280hp, with a stock exhaust damn that was one hell of a fast car, the guy that built it was a roto-genius.

rotarygod

iTrader: (1)

Then what you are saying is that if we had 2 engines, a 13B and a Renesis and they had the same intake port area, compression ratio, etc, the 13B will make more power by sheer virtue of it's better flowing peripheral exhaust port? I'm going to go ahead and disagree with that one. But for the sake of argument let's just go out on a limb and say the 13B did make more ultimate power. It's not going to have the average power of the Renesis and it's also going to suffer in other ways such as part throttle performance, emissions, mileage, etc. I still stand by my statement. The Renesis is a better engine.

Turbo II-FB

jasmine if thats you in you avatar you llok like a guy with long hair

GundamExpo

Find the downloadable Renesis module if you can. If your interested in the motor it will feed your fire a little bit. The Renesis has a complicated adjustable geometry intake design, and I agree with whoever else said that it is where the motor makes most of its power. Mazda would not have equipped such a complicated design unless it served a purpose. The motor also has higher compression rotors. So I think its the intake and compression that gives it its extra umph.

I just had an interesting thought on ports. If you have ever taken apart a piston motor you know that the intake valves are significantly larger then the exhaust valves. The idea being that the exhaust has a lot higher pressure to push it though a small opening compared to the intake. On all the earlier 13Bs they had a gigantic exhaust port and small intake ports. Backwards from a piston motor. I wonder why they didn't side port the exhaust and peripheral port the intake?

rotorheaven7

One thing i did not see mentioned about the renisis is the rotors. They are alot lighter than the 13b which helps improve redline and overall power.

samperry007

For reference...
http://www.thecarricos.com/ACRE/Doc...nesis_paper.pdf


-Ted


Where do you find stuff like this?

sleeperfc

either sell the car and buy a tii, or...
Do a tii swap (13bt) with trans shatf and rearend, or...
Turbo your 6 port and break stuff.

Now it depends on the goal, if all you wanna do is beat a few hondas, maybe you should just get a 50 shot.

now if your looking to be king dingling on the street..... well thats not gonna happen with a s4 n/a fc.