twint78

how about running no trailing whatsoever?

fastrotaries

i thought firing both lead and trailing at the same time was the way to go. Would this change with boost and RPM?

Evil Aviator

I think that running both off the same coil may be a bad idea because the trailing plug may pull too much current away from the leading plug. I think the best method is to run an aftermarket EMS and a separate coil for each plug like the racing 3-rotor and 4-rotor engines.

It would work just fine, but you would lose about 10% power without the trailing plug.

peejay

I lost about 20hp in a 120hp N/A by running without trailing. Went from calculated 120hp to calculated 100hp which corresponded to the factory stock 1/4mi times.

Well it was the other way around... I was only pulling stock times with an engine that had no business making only 100hp Then I reconnected the trailing timing and fixed the reason why I had it disconnected (I still owe ya one pp13bnos!) and all was well.

twint78

well i was going to take and fill both holes in leading and trailing,then make two holes side by side where the lead hole was.then run two leadings for each rotor.will this most definitely make up for the trailing?i think it would right?

DaleClark

iTrader: (55)

OK, dumb question time -

Besides an aftermarket fuel computer that shows the info on the screen, is there any way to find out what the timing advance, retard, and split is? As in, a gauge, a special timing light, whatever? I'm curious as well to find out what the stock ECU is doing at various loads and RPM's, but I'm not sure what the best way is to go about doing that.

Thanks,
Dale

Zach McAfee

Felix Wankel's original rotary engine (the real rotary engine) had the plugs in the rotor face.

You like apples? How bout them appples.

Who's in for a $1000 plug change?

rx7tt95

If I decide to lower the amount of split that I'm currently running, should I also consider changing my leading timing at all? Lower it a bit? Does running less split (or zero) create an increased potential for detonation on pump gas? I'm still fully sequential so perhaps more split at transition would be better? Just trying to be overly cautious:-)
Michel

rxrotary2_7

YEAH!! LMAO!!

peejay

No it would not.

The combustion chamber is very long. The reason there are two spark plugs is to do a better job of getting that big long chamber ignited. Putting two plugs side by side (besides being an incredible project - have you ever even seen a rotor housing before??) would be completely pointless, because it's not the width that is a problem so much as it is the length.

Besides, the bowl in the rotor for the most part "contains" the charge to the spark plug area so the majority of it is exposed to the initial flame. You wouldn't be able to get the spark plugs close enough together that they'd be exposed to the bowl.

rotorbrain

spark plugs that close together would also get very hot. that wouldnt be very good on the detonation factor. that area would be burning up. one also has to wonder who you would contract to put that precise layer of chrome on there too??

paul

nocab72

I did some additional split testing tonight. Gained about 18hp going from 12 degrees of split to 8. Measured using the Blitz PowerMeter. If I get another 18hp going down to 4, damn, that's nearly 40hp in split adjustment alone! whoohooo!

Dyno day coming up next weekend, so I'll verify these findings on the dyno.

K

RICE RACING

I think mainly cause it moves in relation to rotor direction +, as a "large" quantity of work is done by the leading plug due to design factors like even charge exposure and open path into the combustion chamber, unlike the trailing which cannot have such an open path due to design limits (loss of compression).

Inherently then even when both plugs are fired together, the leading plug gets a head start on the trailing, and realy the trailing is coming in on the final part of the combustion process, this is even more acentuated when you put a CDI on the leading plugs as CDI ignitions a much faster than transistorized ones.

Basically the limit of T&L is down to the acurate firing of you ignition computer or system, so long as the T does not fire before the L then there will be conflicting flame front, it is physically imposible due to the design of the plug clearnce volumes and their exposure to the combustion chamber.

As you know when you fire the T & L closer together in N/A or Forced Induction motor you get a mucher better more complete burn, which gives you more power in higher engine speeds, this is what I have found in my testing.

Good luck with it.

rotarygod

iTrader: (1)

I adjusted the timing split on my GSL-SE from the factory 15 degrees to 10 degrees. Noticable improvement in power. Average 1/4 mile times according to G-Tech were 1/4 second faster. Adjusted to 0 split and tried again. Car went slower than with 10 degree split. It felt weaker throughout the rpm range especially at low to mid rpms. I don't think ultimate top end power was decreased though. I'm definitely going to stay at 10 degrees for an n/a. Turbos are a different ballgame altogether. BDC alters his split according to different rpm and boost levels with great results. Never gets less than about 4 degrees split ever and goes about as high as 10 or so.

RETed

Oh come on, I know for a fact the Electromotive TECII absolutely cannot do this with a rotary engine unless they have come out with a new version of software that allows it to run just one magnetic pick-up.

As for the rest of the thread, Mazda R&D has already proved a "zero" split makes for more power, period.&nbsp There should be a FSAE paper on this - http://www.sae.org/



-Ted

RX794

Check again, I know it can.

rotarygod

iTrader: (1)

I personally couldn't give a rat's *** what Mazda's R&D says! I've already corrected/improved upon so many of their mistakes I just wait and see how I can fix their newest endeavours. Based on pictures ask me how I would improve their Renesis. I see a mistake already and no one has seen it in person taken apart yet. Admittedly half of their problems are due to cost cutting and emissions but even then they still have much room for improvement.

I don't think there is any problem with ultimate top end power with zero split. I do think it suffers at lower RPM's though. My decision on this is because I tried it.

RETed

Like I said before, does it require one mag pick-up or two?&nbsp Can't you answer a simple question like that?


-Ted

RETed

That's a really poor attitude.
Mazda developed bridge porting.
Mazda developed peripheral porting.
Hell, Mazda developed the engine.
Overlooking these FSAE papers that Mazda engineers have done is really eliminating a source of some very useful information.


-Ted

rotarygod

iTrader: (1)

I didn't quite mean it that way. What I was referring to is Mazda R&D's zero timing split opinion. I can't imagine Mazda has honestly claimed that it works better or if someone is trying to interpret for them. I suspect it is the latter. I've tried zero split and it is complete bullshit on an n/a at anything other than high rpm's.

FWIW NSU/Wankel developed the peripheral port. Come to think about it everyone who played around with the rotary developed the pp. Wankels first little engine had pp's. Mazda did develop bridge porting as a way to cheat because they couldn't use peripheral porting. Of course Mazda developed the rotary engine. They were the only ones to keep using it. I praise them for it. Imagine how much better the engine could be now if everyone had tried to develop it. You don't honestly think the Renesis is perfect do you? Mazda's R&D has many good engineers and they definitely deserve their credit. Like every major company out there they still don't do everything right. You interpreted my words wrong or maybe I just wasn't clear but I don't hate them. I hate the penny pinching lawyer/bankers that affect their designs.

Maxthe7man

On my own N/A, I found that my roughness and lack of power at lower RPMS was because the timing split wasn't there at idle, and low rpms, low load conditions, on an N/a, the timing split is part of the throttle tip in/accelaration programming running without split all the time makes it rough and jerky at low load..Max

RX794

Yes, use 4 Electromotive dual post coils in a wasted spark setup.

RETed

This is the typical configuration for a 13B/2 rotor set-up for the TEC-II.&nbsp Wasted spark in terms of grounding one side of the coil?

So what's the answer about the number of mag pick-ups?&nbsp One or two?


-Ted

RX794

One.

Flyrx7

iTrader: (1)

So, if the timing split is reduced on the Trailing, then isn't this effectively just advancing the timing? (Trailing firing before leading at a given rotor position/combustion chamber)I could see this adding more HP but at the risk of detenation (of course I'm sure you guys take this into account while tuning). Could you not get the same or similar results by leaving the stock split but advancing the overall timing? Interesting.

Frank