deagle50ae

Hello all. I am curious... i'm told that the NA 14B's run quite rich in stock form which is great for saftey, but bad for performance as you all know.

I'm wondering how much the fuel can be leaned out or timing advanced for better performance on the N/A and what kinds of gains could be expected from a safe tune?

I've searched around a bit and just can't find what I am looking for.

I'm new to rotaries... not new to cars.
used to run a BPU '93 3000GT VR4 @ 1bar

speedturn

iTrader: (1)

Who told you to lean out your rotary to make more performance? Rich is good for power on rotaries; race rotaries will loose power with A/F ratio higher than 13.

Shoot for an A/F ratio in the mid to high 12's for max power.

Set leading spark advance at 24 deg BTDC at wide open throttle above 4000 rpm

Black91n/a

An A/F of high 12's to 13 is leaned out for a stock NA 13B with mods.

There's a lot of debate on what's best for power and so on, but around 13 is good for power, with some safety. 14/7 or a little higher is good for light throttle cruizing.

deagle50ae

what would you recomend using for fuel correction?

also, I didnt know rich is good for rotary performance... I assume this is because the design of the rotary allows for a longer burn?

what do they run in stock form? (FC S5)

Nihilanthic

Its rich because the BSFC is high, and becuase mazda tuned it to be as safe as it could be, and the ECM technology of the 80s kinda sucked compared to now.

People who go with a megasquirt, etc often gain a lot in the way of gas mileage (leaning out part throttle cruise conditions) and getting the RIGHT AFR for WOT. Too rich isnt good for power, and too lean can cause engine damage. It all depends on how much load and just the tune of the motor.

Rotaries have a high BSFC for a lot of reasons, so it like a lil more than most motors, but no its not because of a longer burn... its due to lower efficiency.

Honestly If I were you Id go Megasquirt and get it on a dyno or just do lots of WOT street runs (safely, of course!) and log it to tune in the best ratio you can get. SAFC could help some, but I just dont like the idea of a piggyback that costs the same as a full blown EFI :P.

And yeah, at part throttle, dont be afraid to go lean of stoichometric. As long as you log and use sensors when tuning you can get some good mpg and better responce without swimming in gasoline that isnt needed. Just dont get stingy at full load. And of course with a turbo safety is more important than the perfect AFR unless you're using racegas or other fuels.

Then again, if you have to ask, uh... you could always get dyno time and a guy to tune for you and play it safe

Black91n/a

There's really no plug and play system for the S5 NA (I'm in the same boat). There is a plug and play Megasquirt in development right now, and there's a Rtek 2.0 under development. Other than those you'll need $1500+ to get something like a Microteck, Haltech, Wolf or whatever, plus making an adaptor or re-wiring the car. Not cheap or easy.

For me the Rtek seems like a better solution, as it'll retain all the stock drivability and so on, but will offer full correction for fuel, adjustable ignition for both leading and trailing, datalogging, and more, plus they're working on adding an AFM delete option to a future release of it. It offers all the adjustability that most people want without having to deal with all the other paramaters.

The Megasquirt is a more powerful engine management option (more options), but that means that there's more to set up and tune, and there's more chances of getting it wrong. The plug and play ones should be pretty well tuned right out of the box, and they'll give you support though.

Right now I'm leaning towards getting the Rtek when it's released with the AFM delete if that's not too far off.