Blake

I never had a problem starting a Peripheral Port 13B with Weber 51IDA, stock distributor ignition and 11.5 race plugs, even stone cold. I can't imagine a harder setup to start. Most rotaries will fire right up with only the trailing ignition! How did I learn that? My MSD died and the car still ran great, lacking only a bit of "oomph" and throttle response. Bypassed the MSD and the problem was solved. Even when it was working, I never noticed all these great benefits being touted here. It started the same, idled the same, accelerated the same. The only difference was that it proved unreliable. If any of you really want to objectively tell if there is a qualitative difference, teach a friend how to bypass the box (or whatever system you are using) and have them randomly connect and disconnect it without telling you...a blind "taste test", if you will. Also, be sure your stock setup is operating at 100% (new cap and rotor, new plugs, good condition plug wires, etc). A healthy stock setup is pretty damn good, IMO. If you don't have friends, as I suspect some of you do not (just kidding! ), run with the MSD or whatever, then disconnect it for a day. The butt dyno is easily fooled when "upgrading"; not so much when "downgrading".

Funny upgrade story: back when I invested serious money into my custom cold air intake setup for my 2nd gen GTU-S (bonez filter, custom fiberglass box, KSP fresh air headlight cover, gutted FTP lens, etc) I swore it was waaaay faster. Seriously, I was gung ho over cold air. Once, I was being tailgated by a real ******* while trapped behind a very slow car on a two-lane (one each direction) somewhat curvy road with few passing zones and lots of oncoming traffic. When I finally got my opportunity, I blasted around the slow car and ran full out, redlining every gear including fourth briefly. Several minutes later, the ******* finally caught up after I got caught in more traffic. Redline in 4th gear was 138 mph! Wow, that seemed amazing performance, particularly because the road was not completely straight and level. Proof that the cold air system worked. Not really...a week later, I noticed my clutch slipping in 5th, then 4th, then 3rd. Yes, I redlined 4th gear, but the car was not going anywhere near 138mph even though in the excitement it felt as if it were. Under the conditions, I was not watching the speedo; just the more important tachometer. D'oh! I changed the clutch and dynoed the car at exactly 1hp above my previous run without the cold air setup. Of course, a cold air setup won't give you all the benefits on a dyno run, but having reverted back for the sake of testing on the street, the performance drop was negligible. The lesson: butt dynos SUCK! As enthusiasts, we are so biased about our "upgrades" that we will notice a beneficial change for just about any mod. BTW, that clutch was the best upgrade I *ever* made! Just a RB street/strip unit and initially I was not very impressed (probably because I was still adjusting to the heavier pedal), but after driving it daily for a while, I drove another 2nd gen with a brand new stock clutch and was SHOCKED how sloppy the engagement was.

Mods are fun, even if not totally worthwhile in terms of cost/benefit. If nothing else, we learn more about our cars and sacrifice some knuckle-blood to the rotor gods -- their favorite kind. But the least we can do is pass on our experiences so that others can make an honest decision if they want to walk the same path. I'm not trying to discourage anybody; just offer information. Make your own decisions. What I have a problem with are people who take "faith" in mods and treat those with dissimilar experiences as heretics. Notice I said "experiences". I have no love for theoreticians, as you may have noticed.

Anyway, no matter what gets said here, I'm just going to ignore the thread further and hope others do the same. If I ever run into Purple82, I'll buy him a beer and Im sure we can manage to have a rational, friendly discussion even if we continue to disagree. Same offer to Mar3. The internet seems to turn things into pissing matches when there is even slight disagreement. Most people I have arguments with on the internet turn out to be really nice people in real life and our positions are not so far off as we imagined.

purple82

Sounds good to me.

Jeff20B

iTrader: (13)

Well you're Jesus to Rob's God-like rotary prowess, so shut-a you face! lol

A friend and I tore down a rotten pineapple recently which has B11EGVs in it and a stock dizzy etc. I bet its previous owner learned how to start it 'correctly' with those plugs.

Oh, and Blake, no amount of ignition mod bashing coming from you will ever make me think twice about how cool the FC-like sound of DLIDFIS is.

Joking aside, DLIDFIS can pay for itself quickly due to no longer having to buy a new set of caps and rotors every now and then. I don't know if it's the wet weather up in the Pacific NW or what, but typical aluminum contacts inside the cap tend to corrode quickly up here. If you tell me to go out and buy a more expensive cap with brass contacts, well, I was the original poor man in the Poor Man's Direct Fire Ignition System which eventually became DLIDFIS, so you're wasting keystrokes. I haven't purchased a new cap and rotor set since '97 when I first hooked up an FB dizzy in my REPU. Wow, has it been that long?

Blake

I'll buy you a beer too, Jeff. And, since you're local, that might actually happen sooner rather than later. I'd like to hear that DLFDIBSTCDHW...er, what's it called again? I've got nothing against direct fire and I suppose if you save money, that may make it worthwhile regardelss of performance. I've just never had a problem with the stock system, including needing to change the cap and rotor very frequently...but maybe that's just me. Ideally, I'd like to replace the whole deal with a CAS and microprocessor controlled programmable ignition, because timing is everything as far as I'm concerned. Too many projects, though! First, I have to finish my microprossesor controlled, datalogging and graphing DIY rotary engine compression checker...SHHHHH, it's a secret.

Kenku

Well, cool... that's not my personal experience, LIS. And again, I don't claim to be any sort of guru with years of experience... it's just what I've found on my car in (yes) back to back tests. It's more than possible there's some other problem that the MSD box is masking (I wouldn't be surprised if the jets controlling low-rpm mixtures are off) but on my setup it seems to make a difference in starting.

Heh heh, this is damned true. At least on here it hasn't degenerated into people yelling expletives at each other... that happens irritatingly often on some other forums I frequent.

Jeff20B

iTrader: (13)

I believe Portland is pretty wet too, right? Anyway, if you can imagine an FC with an R5 mild ported 13B with a dizzy which has the mechanical advance of a GSL-SE, and the particular make of Hitachi carb that come on the old R5s, that's what DLIDFIS sounds like on my REPU. The exhaust is kinda loud and unique-sounding as well, which makes for easier listening, if you're into that sort of thing.

Anyway, that late firing leading spark per rotor face is obviously doing something to change the engine's exhaust note from a putt-putt 1st gen-like sound to more of a smoother 2nd gen type of sound. The only way that's physically possible is that it's actually igniting more fuel than a stock FB ignition system can by itself. What does that mean to you and me? Less caps and rotors to buy as trailing can fire through a less than perfectly clean set of contacts without a loss in performance.

Speaking of controlling timing with a CAS and a microprocessor, I'm going to look into using MegaSquirt to control three ignition channels on the X outputs. This is mainly to provide the late leading sparks to my 20B that my modded dizzy can already provide (much more accurately of course), but it can also be used on a 12A or 13B I suppose. Since leading normally does 99% of the work (on a stock FB cap 'n rotor system), I won't lose sleep over not trying to develope a trailing ignition system. I'd rather focus my efforts on sparking the leading plugs twice per rotor face regardless of the number of rotors in the engine (one, two and three for example) as the benefits outway the loss of trailing sparking through those tiny stock holes. In other words, if I have a choice between running an unshrouded late leading spark vs a trailing spark to ignitie the squish zone, I'd pick the former every time. Butt dyno testing as well as real dyno testing influenced my descision.

This next part is total speculation, but I think the Pac Performance RX-3 had a late leading ignition system on its turbocharged 20B with powerglide tranny back in '00 or so. The exhaust note sounds kinda like my 20B when I was test firing it. All other 20Bs sound different. Of course they both had raspy exhaust notes too, due to very little muffling. I'll know more as soon as my engine is running. The exhaust system in 90% complete and shouldn't be too quiet.

purple82

I think I can better explain the phenomena than I did with the car analogy.

Typically, people with an understanding of physics look at fluid flows as solid body motions where a “wall” of water pushes it’s way along a channel. The wall must stay perpendicular to the channel, thus forcing the outer side of the fluid to move faster around a turn than the inside.

This view of fluid flow is incorrect, basically because it neglects the ability for the fluid particles to move relative to each other, and because it neglects the forces that particles of fluid can exert on each other.

As a fluid goes around a corner, the particles on the outer side of the corner of fluid press on the inner particles as they try to make their way around. The most inside particles are compressed between the inner surface and the next particles out. This creates a “squirting” effect of the particle, like pressing a wet pumpkin seed between your fingers. This is the shear force effect of the fluid particles on each other. This force is neglected by the bernoulli equation, incidently.

In the example that you cited, the shear force effect is much less pronounced because the force on the fluid on the inside of the bend is relieved by the separated water at the inside of the bend. It is known, however, that the flow around a corner that I described above is what causes a meandering river to meander further. The pressure difference between the inside and outside of the bend sets up a weak secondary flow in the water from the outside of the bend to the inside, causing the deposit of sand at the inside of the bend.

I ran a couple more simulations, trying to model the secondary ports geometry approximately. Although there are geometries that can SLIGHTLY improve flow by restricting the slight expansion/compression that can be caused by the corner flow, for the most part, adding anything to the inside of the port actually hurts the mass flow of air through the port. I can share some screen shots with you if you’re interested.

joeyrotors

all or you guy dont know any thing

Roundabout

iTrader: (8)

Ban hammer?

Rx-7Doctor

iTrader: (13)

I had not actually read this whole thread until now. Blake,Jeff,Purple, all you guys owe me a beer for making my brain actually have to work to digest all of the technical data,lol.

I can say this though about the 2nd gen coil usage.

I was averaging 25.6 -26.5 combo city/highway driving with the 2nd gen coil and a max of 29.1 highway on my Se stock port with base mods.
I removed the coil and reinstalled the stock one. The mileage dumped down to 22.9. This was with a 100 mile run with only 8 miles of it intown driving.
No noticeable power increase but better starting and improved idle.
The question is. If I purchased a new stock coil and removed the 2nd gen coil, Would the mileage stay the same?
I don't know. However, a buddy of mine has one of the Jacobs Ultra coils that come with the ignition kits. The coil weighs about 5 lbs,lol.
I am thinking about running that coil and see if my mileage stays the same as the 2nd gen results have been.

locopr1

Let us know if you run that experiment doctor! I was considering the upgrade on your previous post on the fuel economy improvements alone. But Blake's points bring up a question in my mind. Is the improvements observed with the 2nd gen coil upgrade thingy due to a better "spark" and "combustion" it provides, which inherently means the stock system was poorly designed or lacking by Mazda, OR is the improvement noticed due to a wornout/defective stock system that is just being restored to an adequate level by the upgrade?

As Blake says, if theory and reality conflict, throw out theory. In this case, a stronger spark should not make a difference once you have reached the threshhold of an adequate spark. MAny credible people have enjoyed the benefit of the dizzy setups, so there is something to this. So I guess the real question comes down to did Mazda create an adequtely "hot" spark in the first gens in the first place? It would seem to be a terrible oversite on Mazda's part if this is the case. Particularly since this affects the reason the US model first gens were not as powerful as the JDM version: emmissons and fuel economy.

Here is one part that I cant understand though. How can this setup at the same time burn the same about of fuel better, thus creating more energy for the same amount of fuel, which would account for better gas mileage, but NOT create more HP, which is a measure of energy, at any given range? As has been expressed, the improvements seem to be confined to idling, starting, and low rpms, so maybe the stock system is flawed at the bottom end and more than adequate at the top end? BUT this would even be more of a glaring oversight of MAZDA!!!!!!!

I LOVE THESE THOUGHT EXPERIMENTS!!! Not on either side of the argument just yet for the record. But my cheap *** would love to find out it really does add a few MPGs!!!!!!!!!!!

Jeff20B

iTrader: (13)

I reread most of this thread. Skipping over the arguments helped get through it quickly.

The S5 T2 still runs. It turns out the reason why the idle didn't improve on the old S4 6 port engine after the DLIDFIS install is because I goofed on the W and G wires (my first time with HEI and I didn't move the distributor so no need to check it with a light and all that...). The S5 engine ran the same when it was first fired up so I checked the timing and sure enough. It was off. A simple change in pickup polarity and it idles nice and smooth.

It wouldn't have helped the S4 NA engine though. That thing has bad internals. It was a shoddy rebuild from a garage specialising in asian cars. We'll tear it down eventually to see just how bad it is. Looking through the exhaust ports, you can see missing chrome. Suspect bad side seals too.

Since this thread was written, I've succesfully modded the MegaSquirt to output a late leading trigger signal to three J-109 ignitors and Diamond coils (thanks James for the code tweak). I could eventually upgrade to GM HEI or FC stuff if the J-109s prove to be too weak for boost. For now though, it's staying NA because it is an early engine and I don't want to break it.

As for the engine sound, it sounded a lot smoother with a full exhaust system, but still had that nice 20B exhaust note. The late leading sparks did make it sound a little different from most 20Bs I've heard, but not enough to notice unless you really listen. But who can resist. 20Bs always sound good.

The exhaust system was too small and too quiet for me. The next system will consist of 2.5" pipe (just right for high velocity and three rotors) and two Borlas. We all know now that Borla mufflers suit rotary exhaust characteristics very well, and last longer than Magnaflow. Racing Beat components cost more, last forever etc, but since this is all kind of untested, I don't want to spend very much on it. Plus if I go with a turbo I'll have to redo the whole system anyway.

I'm going to try late leading in the form of DLIDFIS on a 12A next. It currently is in an FB with stock ignition. It's not that bad, but it certainly doesn't fire up as quickly as the large ported R5 13B in the GLC with two GM HEIs on leading. To compare apples to apples, the 13B is coming out and the 12A is going in. A rather absurd way to test, yes, but I'm only interested in starting and idle quality, which makes the chassis part of the equation irrelevant. The 12A already flies at mid to high RPM in the FB, so I'm not worried about that, and the GLC is lighter and will have a better ignition system and exhaust, so I'm sure it will improve up there too. Big whoop. If it fires up quicker and idles smoother, I'll be a happy camper.

locopr1

Jeff, nice descriptions, but we need pictures!!! And even better some sounds of that 20B!!! YOUTUBE!

Jeff20B

iTrader: (13)

Did you just call me a tube?


lol I know what you're talking about. I'll leave the video stuff up to PercentSevenC. I'm the audio guy. I have some audio clips of the 20B with the complete exhaust system around here somewhere.

Jeff20B

iTrader: (13)

Ok here are two clips from before the MegaSquirt. I got it running on a dizzy modded for late leading on a 3 rotor with a carb and just an open header. It revs quicker and sounds meaner than the Pac Performance RX-3. Teehee.

The mic is several feet away from the engine in this first clip. If you listen carefully you can actually hear the echo off the neighborhood at the end.

The second clip finds the mic 25 feet away from the engine, inside a garage with the door closed. Listen to how quiet the starter is now, yet how loud the engine still is. That's loud!

Note these are zipped MP3 files.

Jeff20B

iTrader: (13)

Here it is with the MS and the full exhaust.

The third clip is an oscilating idle because the MS is not tuned yet.

Fourth clip is firing up when partially warm.

Fifth clip is just a little driving away from the mic.

glewsRx

iTrader: (1)

that purple fella was kinda a dick.

purple82

Yeah, man, what a jacka$$.

glewsRx

iTrader: (1)

Was he behind me that entire time?

Rx-7Doctor

iTrader: (13)

^ don't you hate it when that happens,lol.

objautomotive

.

Hyper4mance2k

iTrader: (40)

Why the fudge did you bump this? If anyone was wondering dlidfs showed no power gain since the links to the dyno sheets are dead.

Dr Rx

Wow i actually sat down and took the time to read all of this. It's quite a good read actually.

purple82

Blake and I often didn't see eye to eye, but I enjoyed going back and forth with him. RIP man.

cmanns

Wow I read a 4yr old thread.