soslowgtp

But can't you use that room for more timing & boost therefore producing more power ? I know that the higher compression 12 a will produce more power at the same boost & timing, but won't the 12at let you crank up the boost more, and with proper tuning produce more power ? Or are rotaries just better at handeling boost & high compression better than piston engines and not allow much room for more boost and timing even with the lower compression ?

j9fd3s

iTrader: (3)

given detonation free fuel (ie c16) the higher comp motor will always make more power.

in the real world with pump gas there is a point where the lower comp motor will, in theory, make better power because you can run more agressively on the tune (leaner, more timing etc). also you have a greater fudge factor with the lower compression, and if you get a bad tank of gas it might save your motor.

its one of these combonation/comprimise things.

id use the 9.4 rotors myself, and less psi.

FB II

hmm, i think i have another way of looking at things.... now first, don't get me wrong, i like low compression rotors but my choice is the 9.4:1 for sure i just feel that for a street car with good power you shouldn't "need" to run 16 - 20 psi to get the same you would at 12 - 15psi on a stock compression 12a

either way you really can't go wrong for power. just gotta be sure to pay attention to your tuning on both, but more severe on the higher compression. i just look at it this way... it forces me to always be in check. i don't want to slack on my tuning becuase i think the lower compression can take more abuse. i dunno... i haven't had any issues except wheel spin

soslowgtp

I'll probably go with rebuilding my 12a and streetporting it, switching to EFI and adding a turbo. It just seemed like everyone hated the 12at for no real reason. I don't want to have to run more then 15lbs of boost to make good power. Now I just need to decide whether to keep the dizzy or go full ecu.... Thanks for the help

j9fd3s

iTrader: (3)

the reason to hate the 12at are three fold.

1. its made of parts you cant easily get here in the us (said rotors are a good example...)
2. it needs an ecu to work (unless you get lucky), and if you're gonna do that you can just as easily do a 13bt, which you can get parts for at at mazda dealer
3. it doesnt make that much power stock, it needs an intercooler, bigger turbo etc etc

adding insult of course is that a 13bt swap is the same money.....

FB II

E X A C T L Y well said mr. j9fd3s

wheaton

hey check out this site im not sure if it will help but i tried http://www.rotaryshack.com/Products/...sp?intView=100

FB II

yes. those are turbos.

soslowgtp

1. Very Ture
2. to switch to EFI I will need some type of ecu, and I want to keep it 12a
3. correct me if I'm wrong 12a is rated 100hp 12at is rated 160.... either one would ONLY be a starting point, I wouldn't be content with 160. But it doesn't seem like a terible starting point compared to rebuilding a 100hp motor.

I think I've mentioned this a few times but I don't want to go 13b, I want to keep it 12a

FB II

yes, the 12aT is 160 flywheel power W/ the turbo. a standard 12a will be atleast 160REAR WHEEL POWER w/ the turbo at the same boost level. mine had like 160,000 miles and was destroying people. actually tonite we just beat a turbo S2000 on the highway in my friends 12a gsl w/ turbo that i just finished tuning. stock motor, well over 100,000 miles that was in the car the day it left the factory porting will make it just that much better... video is going up tomorrow. YAYY!!!

sorry i had to spread the good news. hahaha 12a's with turbos are the jam!

soslowgtp

Great stuff.... I love messing with people, holding even as the slam on the gas, then just push it to the floor and fly off...... fun stuff, esp in a 4dr grandma car.

I'm gonna go with a custom turbo setup on my 12a probly, just becuse I want the power band to be lower and easier to manage.... not a turbo that spools up @ 3500 and makes the car feel like it just got rearended by a semi

vipernicus42

iTrader: (4)

The stock 12aT didn't come with an FMIC. Assuming you got a good block, you could pop it in, rig a cheap megasquirt or something and have a cool, simple, and not prohibitively expensive base for starting a turbo setup. Yes, it'd probably cost more than a 13bt in the end, yes parts are hard to find, but rarity is one of the things that makes our cars appealing!

I'd love to have a stock 12aT in my car, but not for power or affordability. I'd have it so that people at rotary meets would say "Dude! That's a J-Spec 12aT! Where the fork did you get one of those?"

Not that I'd leave it completely stock for long

Jon

boyee

iTrader: (3)

doesnt really have to do with turbocharging a 12A but it does explain a lot about heat of the combustion cycle mentioned earlier: http://www.tprmag.com/issue/11/11_rotary_1.shtml thought it was pretty interesting.. read it a while ago and just remembered when i was thinking back about heat/pinging topic earlier in this thread.. hope this helps

j9fd3s

iTrader: (3)

2. the 12at is efi already....
3. basically the 12at engine is the same as a usa 12a except is got different rotors in it, and its got a metering oil system like a gsl-se/fc with oil injectors in the rotor housings. so without the turbo the 12at is just another 100hp 12a motor...

soslowgtp

I know, but the 12a does not..... I will need an ECU to control a 12at OR an ECU to control a custom EFI system on my 12a

That is very true, although the 12at w/o a turbo probly make more like 85hp..... but again, for me it would be about the same price to rebuild not including adding EFI or a turbo as to swap a 12at. the money I would spend on adding a turbo and EFI to a 12a could be spent on upgrading what is already on the 12at.....

Node

iTrader: (1)

I wouldnt use the stock ECU from the 12AT unless the thing was some period reproduction and going into a museum.

I'd go w/ at least megasquirt if not a more spendy form of management

The s4 t2 ecu is a handful as is, im sure the 12at is TEN times worse with no english manuals and nobody w/ experience not to mention its prehistoric like barbara bush