ITSWILL

iTrader: (12)

I know there are guys out there running serious nitrous setups on 13Bs, unfortunately it is hard to get good info. Hopefully someone in the know can chime in here.

The base engine is a half bridge S4 13b that will be running a JW intake and a Holley. Fuel pump is a Walbro 255 and regulator is a Aeromotive job.

For ignition I will be running an FB distributor with an MSD. I have heard of people not running trailing when using nitrous, is this just BS?

I have an NOS mini for nitrous control, where do people set their window switches to turn on nitrous?

I have built nitrous V8s in the past and I imagine a lot of things translate like pulling one ignition degree per 25hp and 1 step colder spark plug for every 100 shot or so.

The nitrous will be a wet kit with 2 nozzles near the outer ports or possibly a carb spacer plate, which is generally preferred?

What kind of things do people do to the engine internals. It there anything I should be doing to impact intake or exhaust port timing that is specific to nitrous? How about side seal and apex seal clearance? I imagine they are run a little looser but does anyone have any spec they use?

krazy4

You can definitely run a lot of nitrous through a rotary motor if it's tuned correctly.
Just be conservative on the timing and air/fuel ratio and work up slowly.

A nitrous nozzle per intake runner is the best. A plate will work though.

I would turn the nitrous on above 4,000rpm. Higher is even better.

Hopefully someone else can chime in on clearances for the seals.

rotorholic

iTrader: (53)

I ran a 200 shot of nos, more like 150 shot with a different chart NOS supplied me with, mine was on the pedal and would just floor it and even 2 step it, biggest secret with any rotary engine with making things work is a quality build of the block,

I ran factory seals with a standard bridge port. Do your research on what's the best engine rebuild parts available today to seal the engine good and don't use worn out housings.

krazy4

I've heard some nitrous guys like the RA seals.

Skeese

iTrader: (11)

Interested to see how this turns out. I've always wanted to learn more about tuning nitrous on a rotary but as the OP mentioned there isn't squat about it online.

I've talked about using a baby shot to juice my turbo into spool should this next setup have more lag than Im hoping for, but I don't know enough about it to gauge how effective that would be.

Skeese

Gilgamesh

I guess you would have to call up some of the old school rotary drag racers before turbos were really popular.

Then again I really dont know who these guys are other than videos some have posted on their social media accounts like Abel Ibarra and Goopy.

Skeese

iTrader: (11)

Eh, in my experience people like that won't talk to you unless you are paying them and even then they don't want to share tech info but rather just do it themselves. I'll likely just start as small as possible and error on the side of too much fuel and retarded timing and work the results forward from there. We shall see

Skeese

krazy4

Just start small, keep the air fuel ratios good and read the plugs. You'll be fine.

Rotary motors love nitrous contrary to popular belief.

Judge Ito posted about nitrous back in the day on this forum. He had a low 9 second nitrous car. No turbo.
Look for his posts.

chainreaction

I ran up to 150 hp shot through a pate system with a stock 12a for 6 years before I finally shattered a plug and took out the apex seals. I started out with a very conservative 38 Hp shot. At that point I simply upsized the jets a couple of sizes and hit the button manually after the rpm's got up around 6,000, left the power for the fuel solenoid unplugged. At around 75 hp I cut the jets back to my prior size and started using the gas side of the plate. At 100 hp I had to add a timing controller to be able to take some timing out. Ran the best around 125 hp, at 150 hp, it started getting finicky, but was still turning the stock motor up to a touch over 10,000 rpm's.

I now run a Wankle Works full bridge-port 12a.Current tune up:
Running C10 race fuel with Amsoil Dominator 2 stroke oil mixed at 10 oz per 5 gallonsHave 4 coils mounted firing all at once. Timing is locked at 18 degrees. I turn the power on, retard 4 degrees to start, then retard an additional 4 degrees before running.Fuel pressure is at 6.5 psi.It pulls 12-14" of vaccum at idle (idle at 2400-2600 rpm's), it now has a 10.5 power valve in it. 700 Holley-HP 4-barrel, RB ported intake, straight pipe exhaust 30" pipes at 2 1/4" heavy wall, Primary side has .070 jets and a .028 squirter, black cam with a 50cc accelerator pump, the secondary side has .076 jets and a .025 squirter, red cam with a 25cc accelerator pump. Hitting the nitrous manually after the tach hits 6-7000 rpm's. turns up to 11,800 rpm'sThis combination has gotten me the best throttle response. If I turn the idle up to about 4,000 rpm's there is no stumble. Launching at 5,200 rpm's, Running motor only, the plugs show just a tad rich. I currently have the nitrous tuned for a 100hp shot.

chainreaction

I have reached out to a number of the top shops in the country with questions. You have to remember, my car is a bit unique and many of those guys have followed what I am doing for years. One example: I found out the digital MSD boxes do not communicate with the CAS from the 2nd gen Mazda's. I ran an older analogue unit for years and "upgraded" (to a nightmare) The MSD was trying to fire the plugs every 120 degrees of timing.... I was able to talk through what was going on and come up with a solution, Ie: MSD digital timing controller.
I have called Atkins Rotary, Rotary Performance, Racing Beat and a few others and have had no problem picking the minds of the owners.. Just remember and respect the fact that they have business interests to look out for and aren't in business to give their hard earned trade secrets away.
The stock motor:
The BP motor:

ITSWILL

iTrader: (12)

This is great information. Thanks for the input.

AuthoritySucks

iTrader: (7)

great info brothers

mazda1200

iTrader: (1)

yes is good