jimlab

A lot of people seemed interested in the benefits of eliminating their trailing plugs after the anti-detonation "device" was publicized. However, the elimination of the trailing plugs will result in a loss of power (less fuel burned during the "power stroke") and increased emissions (more unburned fuel in the exhaust). You can try to compensate with tuning, but as I've said before, one step backward and one step forward doesn't really equal progress.

It is a fact that the rotary engine's combustion chamber shape is far from ideal. Another shortcoming is that the power stroke completes with fuel exiting the engine and burning in the exhaust even with both plugs firing. Fireballs may be fun for the kids, but all they really represent is wasted power. In order to make more power, you need to burn more fuel while it's still in the engine, where it can actually be put to use. Reason enough to keep the trailing plugs, if you ask me.

Fatman0203

I completly agree, so other than the negative I gave you, have you heard of anything else "bad" about the trailing spark plug?

jimlab

I don't think that's really an issue, or no more so than anything else "going wrong" in a rotary engine.

As much as people like to hype having "only 3 [major] moving parts", the large number of seals involved in trying to seal a rotary engine's combustion chambers is an imperfect system at best.

A piston typically has three seals (rings). The top ring is known as the fire ring or compression ring, and is intended to seal in pressure from the combustion process. The second and middle ring is also a typically referred to as a compression ring, and is a backup for the top ring. The bottom (and thickest) ring is the oil control ring, and its job is to allow oil into the piston to cool the dome and rings without letting it past into the combustion chamber.

Since all three are in series and the gaps in the rings which allow expansion are typically oriented on opposite sides of the piston (if not eliminated by using "gapless" rings like those made by Total Seal), they are very efficient at sealing in the combustion process. They're also very well protected by their location.

In the rotary, on the other hand, there are far too many seals to worry about and there are inevitably small gaps where they meet. In other words, there are plenty of ways that hot combustion gasses can leak and contaminate the intake charge in the next chamber without worrying about the pinhole of the trailing plug as the apex seal passes it. If it were that big a deal, I'd think you'd be more worried about the much larger leading plug openings.

Fatman0203

Yea I have a housing here Im thinking of selling if its in good cond (no dents or anything nasty) and I was surprised to see the size of the trailing plug hole, it was TINY. Hell even the leading is a bit small. Either way, I think this whole but plug is a bad idea but lets leave that topic alone.
Back to the MAF, do you think that us (as enthusiast) can actually set up such a system for the FD?

FDNewbie

iTrader: (10)

In line w/ what su_maverick said, the only drawback I see w/ the Wolf is not too many people are familiar w/ it, and just how many modifications can it handle, and precise tuning can it allow?

You said he ran it on stock twins, so we pretty much have an aftermarket ECU for stock sequentials, w/ a MAF. That's a huge jump.

I initially dismissed the PFC because when I looked @ the application chart, I didn't see the Toyota Supra under there. They do, however, make a PFC for the Skyline... but I don't know whether the Skyline has sequential or parallel twins...and I also don't know whether it uses an MAF sensor or not (I'd hope it does, for the incredible car it's hyped to be).

You can pretty much forget about Apexi making an add-on for us. I just don't see that happening, because I just don't think we've got that kind of pull (demand) to get something like that done.

About the trailing plugs, I had the same thought as Jim, that one step back followed by one step forward is no step at all...unless some other benefits are proved in the other thread.

jimlab

Like I said, I'm not as familiar with the Wolf 3D, but I know that Gotham Racing claims the ability to tune it, and it's a fairly simple but powerful system from what I've seen.

More info here...
http://www.wolfems.com.au/products/e...agement/wolf3d

From what? Stock? At the power levels we're talking about, you already have a sizable investment in modifications. What's the cost of an aftermarket engine management system and MAF sensor compared to the cost of replacing an engine?

No Japanese company is going to be easy to work with, but you're right that there isn't enough demand to make a change to an existing product. The key is finding a configurable product that will work with the least amount of effort.

FDNewbie

iTrader: (10)

Gotham tunes 'em? PERFECT =)

Sorry...poor wording on my part. What I meant by "that's a huge jump" is that's a very big step forward from wondering if a) we can get a system that runs a MAF sensor, and can read it, b) that works on rotaries, and c) that can run the sequential twins. When you mentioned the Wolf ECU, that pretty much took care of all 3 problems. It's used on rotaries, and specifically on rotaries that use an MAF sensor, and it was on sequential twins. So it's like we started w/ many questions, and all of a sudden we jumped to a very viable option/solution!

Speaking of tuners, when you said Wolf, it jogged my memory, and I just double checked.

T & R Racing in NY (http://www.rx7s.com/) runs Haltech, PFC, TEC, and Wolf 3D on their 7s. Check it out (http://www.rx7s.com/tandrracing/team/team.htm) They have two 7s running the Wolf 3D. One's a 3rd gen, and the 2nd gen is a Turbo II that ran an 11.3. Pretty impressive...

su_maverick

So it seems that we have reached the Wolf as the base ECU for the MAF conversion. Basing this on the idea that the wolf will be successful, what else do we need to do to get this to work....what MAF? where to connect? do we need custom intake hoses or just go with an aftermarket intake? etc....
you see where I am going.

Rhode_Dog

there are tones of differn't sensors you could choose of other cars i am thinking, like the Z32 MAF (common upgrade for the skyline folks), or the one off the Z06 or SVT cobra which are fucken huge.

take a looksie

http://www.dejontool.com/Fuel.htm

a rather popular upgrade with ol 3Si crew.

Rhode_Dog

i remember reading in one of these MAF talk threads about placement of the sensor itself, without getting in the way of the BOV( venting causing rich mixture)

look at the placement on this

FDNewbie

iTrader: (10)

Still no word from Stephen...hmmm

su_maverick

Dammit, because of this F*%&$ thread I cant sleep. I have been searching all over the web for anything useful on this.

BTW: I am familiar with the 3kGT upgrade, I have one of those as well

FDNewbie

iTrader: (10)

huh? wanna explain??

su_maverick

I upgraded the MAF on my 3000GT

3si.org member # 1873

FDNewbie

iTrader: (10)

Ahhh...gotcha. You had a VR4??? BALLER! LOL

su_maverick

ahem, correction....have....my friend should be picker her up in a week or so.

su_maverick

BTW, what is the pricing on the Wolf? havent found that around

FDNewbie

iTrader: (10)

How you gonna say you wish you had dough like me, and you got a VR4? Those things are MONEY.

I dunno how much the Wolf 3D is...I don't believe I've ever seen a price for it before.

jspecracer7

20B used a MAP sensor. Almost 99% certain.

jimlab

There's information on price as well as more information on the unit here...
http://www.scuderiaciriani.com/rx7/computer.html#WOL

Make that 99.9%.

su_maverick

so now the question becomes, who is going to guinea pig this? I would but funds are tight right now, Ive already spent 3g's in june/july so we would have to wait a couple weeks on mine.

FDNewbie

iTrader: (10)

Ummm...again, this isn't me being ****, just trying to be clear. Jspecracer, did you mean to say MAP or MAF sensor?

And Jim, were you humoring him about the MAP sensor (which we all know it would have), or were you saying yes to the 20B having an MAF sensor? Because if you look below, it looked like you said they did NOT have them...

Now my other question is based on whether or not the 20B has a MAF sensor. If it DOES, what engine management systems can you use on 20Bs? (If it doesn't, well, forget it...)

jimlab

Well, someone needs to contact Wolf and/or do some more research...

Brochures:
http://www.wolfems.com.au/products/e...sion4brochures

Installation manual:
http://www.wolfems.com.au/products/e...nstallshortcut

User guide:
http://www.wolfems.com.au/products/e...rguideshortcut

FDNewbie

iTrader: (10)

Jim,

Sure...a lot of reading needs to be done about the Wolf. But my question was whether the 20B runs a MAF sensor system or not....because if it does, wouldn't that open up the possibility for other ECUs?

I'd like to know ALL the options available before delving into just one...

jimlab

I believe he meant no MAF, MAP only.

It was meant to be humorous. 100% would have been funnier, though.

You can find answers to your questions about the 20B in the 20B forum... or find someone who can answer them for you.