motor swap NA 13b/rx8 internals Vs. T2
 

So my suspension is coming together nicely. motor work is the next thing to start planning out. I have an '85 GSL 5spd. My original intent was to go T2 swap, to that end I already have a T2 trans (not in the car).
goals are:

1. 300+ hp to the wheels (in our cars this should be more than enough to best most cars on the street?)
2. No loss of torque from a stock 12a (I'd like more if I can)
3. reliability

I'm thinking now that I could reach these goals with a 13b with large ports running a good carb (not decided on the unit yet) good exhaust, RX8 rotating assembly balanced and clearanced for high rpm. I think this set up would be more reliable than the t2 setup? also lighter weight?

Can I reach my goal this way? I would prefer the simplicity of non turbo.

if I run NA what porting would you use to meat my goals

this lil goal of yours has been done 3000 times in so many different ways and combinations that this isn't new news to any of us...Do you what you got to do and have fun with it...Start posting pics...lol..

S5 engine street ported boosted w/6ports

would be a kick.

Nononono, he said reliability.

I know how to get the horse power and more. I know a lot of people are making this kind of HP and more. BUT what about a good TORQUE curve and RELIABILITY with NO boost.
I figure that I can port out a normal 12a or 13b make gobs of power at an unrealistic rpm and lose any simbalance of mpg. I or I could go T2 swap have better low end (not great) lose reliability ad complexity and cost.
Or maybe do 13b with large port (how big before I lose lowend useibility?) with RX8 rotors to gegain some of the bottom end (higher compression) and retain a little fuel milage, again higher compression. lighter weight e-shaft balanced ect.
would it work for my goals what could I expect. I don't see many (if any) running this combo. I see alot of questions about swaping in the whole RX8 engine (not what I want to do).

the whole rx8 engine isnt that worth it at all idont think ive read

with a large port there goes your gas... and low end....

Rotary <3 turbo, if tuned right you can has rotors n turbos, I've always wanted to have a low boost, quick spooling setup tuned on the safe side of things

A 6 port engine will give you better low end & high end w/proper porting (im sure you can see that) so for you i'd say you need a 6port to begin with cause you want torq and power...

The rx8 rotors + balancing is going to run you more than a t2 swap am i wrong? I thought balancing was like 800 dollars

300 at the wheels is not gonna happen with a streetported NA 13B. You could peripheral port it, and have crap drivability, or you could boost it and deal with the issues related to that. Or you could get a 20B and port that. A healthy streetport on a 20B should get you near 300 WHP.

300+ RWHP is pretty much not going to happen without boost or a good size shot of N20.

You are probably looking at a big bridge or peri-port to get anywhere close, and you still may be a good distance from your mark. Even a full blown PP race motor from Mazdatrix is "only" pushing about 310HP (to the flywheel).

http://www.mazdatrix.com/r-20.htm

With a TII, the turbo will provide the extra torque that you are looking for. You could get yourself an S5 TII engine, maybe start off stock (about 200HP or so to the flywheel) or do a street port if you are going to be rebuilding it. As you get things working well, you can upgrade the turbo, increase boost, add better intercooler, etc. to meet your goals.

You have to be realistic on the tradeoffs between power and reliability. You are basically asking for over 2x what a stock NA 13b puts out and over a 50% increase over a stock S5 TII.

If you are dead set in getting these numbers and staying NA, then you may have to consider a 20b. You are looking at a good chunk of change to do that. You can get your 300HP from an NA 20b, but even then, you won't be getting those level without quite a few mods. Good torque and should be fairly reliable. MPGs won't be great, though.

Another option would be a blowthrogh setup of some sort if you didn't want to use EFI. Still going to be work to get to 300+ RWHP.

As they say: "fast, cheap, reliable - pick two" holds very true and for us rotary owners, we usually only get to pick one. :lol:

looks like I might have to stick with my original plan of a T2. Its a long term goal. I'm working out the suspension now (almost done there). what scares me about the T2 swap I I'm basically on my own here and I see all the cost horror stories about going WAY over budget. also worry about my tuning wrong getting detonation and wasting all my time/money.

Thanks for the responses.

1. 300hp in a 2500lbs car is fast! without the turbo the car can be a lighter but power will be in the 180-200hp range unless you go with some giant port that needs a loud exhaust. how much lighter you go depends on how hot and uncomfortable you're willing to make the car.

2. stock 12a has the least torque of anything, so that isn't a big deal.

3. NA is very easy to make reliable, turbo needs more thought put into the combination, it needs more plumbing, more parts, more money etc etc. if you're smart about a turbo setup, it'll be plenty reliable.

+1 for the NA 20B. I have a 300+ RWHP single turbo Cosmo engine, and it's lots of fun. But all things considered, I think I'd have been just as happy with a street ported 20B. I also think it would cost a little less, especially when you factor in the blown engine that set me back a bunch of $$$ (this isn't trivial because many turbo owners blow an engine during the "learning process").

20Bs aren't cheap, but then neither are turbo setups.