StavFC

As title, I have ran it on piston engine cars in the past with great sucess, but I dont really know if it will work on rotaries, so thought best ask.

"anti lag" as in start line launch control certainly works, but thats a whole other thing to proper anti lag.

How I had it was when switched on and throttle position was sensed to be less than 2-3deg, it activated, hugely retarded the ign (approx 30deg IIRC), increased the fueling hugely, and opened a large throttle bypass.
The result of this was the revs dropped as usual (though little/no engine braking), but the boost stayed up, between 23 and 29 psi on my setup when slowing for a corner etc, even though 30psi was my peak boost.
Obviously it made a huge amount of bangs and flames and heat, but forgeting noise and heat issues, it did its job, ie INSTANT and i mean feeling like a 10litre n/a engine style instant, performance at all revs.

Due to the rotary engine design, not to mention the leading and trailing plugs situation, im not knowlegable enough on rotary engines/electronics to know if exactly the same thing will work on a rotary (with the right managment of course).

Will it? The only real thing I miss from any previous cars is the ALS systems, so any info appreciated.

maac0953

if those noises you heard were knocking then you would blow up a rotary like nothing.
and heat issues need to be worked out with these motors cause there already enough heat produced so cooling is key with rotary's.

StavFC

No knocking, that would kill anything if you could hear it clearly, rotary or not.

The noise rapidfire bangs and flames from the exhaust due to most of the combustion happening with the exhaust valves open or indeed in the manifold/turbo/exhaust. Same as startline anti-lag or launch control (ie a 2step).

Heat is mostly in the exhaust/turbo/manifold, and a little more in the exhaust side of the engine, but not enough that you see water/oil temps rise.

Heat etc is not a concern of me, im well versed in running proper ALS on a car and the problems I just need to know if proper anti-lag is possible with a rotary engine and ignition design.

zaridar

iTrader: (3)

probably end up warping or burning through your exhaust... especially over time.. regular rotary exhaust is about 400deg F hotter then Piston engines... also probably have overheating issues...

Funkspectrum

iTrader: (5)

maybe coupled with alky injection?

StavFC

Like I said, heat is of no concern to me, and with ALS on heat is immense after a while even on a piston engine as most the burn is done in the exhaust/turbo when activated, used to regularly see over 2000degF EGT regardless.
I have no problems with the issue of having to counteract that, been doing that for years, its simply one of the major issues, but one I understand, unlike rotaries, lol.

I simply need to know if its physically possible (due to the unique rotary engine/ignition design) to do it, due to the main factor is the need to be able to massively retard the timing so its ignited with the exhaust valves open etc.

The more I think about it, the more I think tis impossible as the plugs are in a different place to where the exhaust ports are.

How does 2step/LaunchControl work on a rotary? As they are commonly used in drag racing? Is it a simple ignition cut rev limiter, or is the ignition and fuelling adjusted too, as it is on many piston 2steps. If anyone can at least give me details on how that works on a rotary that would help me on my quest...

C. Ludwig

iTrader: (27)

Yes it can be done, yes it has been done, yes it's hard on components. Very common in drag racing. In a launch mode it can be done with a simple rev limiter and/or timing and fuel adjustments. Rally mode is more complex but the idea is the same. Retard the timing and dump extra fuel so you create heat in the exhaust.

StavFC

Sounds promising then.

In the mode I want, that I have always used in the past, the ignition is so hugely retarded that despite huge amounts of air still entering the engine via the throttle bypass when slowing for a corner, the revs still drop like they normally, I dont want the car to push on like a stuck open throttle with it activated.
I presume that is possible still with the rotary setup? Didnt know if there was a limitation to how much is possible due to the four stroke process going on in seperate chambers so to speak on a rotary.

classicauto

iTrader: (3)

I'm not aware of anyone who's done it on a rally car with a rotary, but as Ludwig said its very common in drag racing for the launch. I have tried it in my car when I ran a Haltech.....could make 10psi sitting still on the line. Pulled about 28* advance out, and added 22%-25% fuel IIRC, i could have the numbers backwards

As far as I can tell there's not much of a "limitation" to waht its capable of outside of the hardware you're doing it to. But the main problem you'll run into if you do this alot (which you would be in a rally situation) is going to be torching turbine wheels. And depending on which type of apex seals you run, you'll also risk warping them over extended periods of anti-lag operation.

IMO Its super hard on the engine, and it kicks the supreme **** out of the turbo.

StavFC

Its a funny thing, in rally use on long sustained stages it is REALLY hard on the turbo etc, but rally stages are generally 10-20min long.
I have found in practice over the years that for other uses where you are on the throttle more and driving hard for less sustained periods (ie sprints, hillclimbs, drifting, etc, often 1min30 or so and at least 50% on throttle where ALS isnt activated), its a lot less harsh as although the temps still are ridiculous and causes issues, it is not for sustained periods.

Anyhow, as you say, its commonly used on the startline, but then it is used combined with ignition cut and is held at say, 5000rpm, for use on the move like I would need it the revs would have to drop back down as if the throttle wasnt open, and thats what I was not too sure is possible on a rotary, BUT it seems like it probably is.

Thing is, I kinda expected it to be not something many have tried, as its of no use in drag racing etc (with a dog box and maybe full throttle gearchange lag is no issue in the powerband), and far from common on the road, but was hoping somebody had used it and could share their experiences just to confirm it deffo works ok.

I still have the ideal valve and remote holder (off a Escort WRC car actually), just need to make sure its deffo going to be possible before I start the hard work...!

Uncle Hungry

iTrader: (2)

In drag racing it's called a two step.

StavFC

As has been mentioned various times, but that is for launching only, has no effect once on the move and off throttle (or more to the point, decelerating).
What I want is "proper" anti-lag, ie for on the move when off throttle and decelerating, and as it works differently (to some extent) when on the move compared to a 2step, I need to find out if that deffo works on a wankel before I waste a fortune trying...

Uncle Hungry

iTrader: (2)

Oh. I didnt see that post the first time.

StavFC

So can anyone let me know exactly how (on the fuel and ign front) a 2step works on a rotary?

Just from how my mind is working, its impossible for the spark plugs to spark when the exhaust port of "open", which is whats needed for proper on the move anti-lag to work.

2step is easier as can just have total ignition cut for some of the revolutions, but not sure if thats possible for what I want to do, its certainly not how it works on piston engines anyhow.

zaridar

iTrader: (3)

i believe there is a few degrees of eccentric shaft rotation where the leading plug is in the same chamber as the "exhuast" chamber ie. exhaust port is open. if the ignition is retarded enough the flame front inside the chamber will still be burning when the exhaust port open regardless. This is why people say you cant retard your ignition too much or you will have too hight of egts.

StavFC

Aaah, interesting reply, and a VERY good point. If thats the case I would say its certainly possible.

ljrotary

RX7_Nut13B posted a wiring diagram for a traditional 2-step here

https://www.rx7club.com/power-fc-forum-47/2-step-pfc-818960/

Don't know whether it can be modified to do what you want.