JimmyHat

Well I was bored as hell today again, like everyday, and I was looking for more power out of the old RX. But I have NO money, so my resources are kinda limited. But I put my airpump back on and rigged a 19mm heater hose from the back of the pump to the inlet on the aircleaner. And I put another hose from the front part of the pump, to the front lower fender well, with a piece of cloth for a filter clamped on the end. I have a K&N and cut my aircleaner up so now its an open air. That thing is bad ***!!! rev it up to about 3000 and then let off, it makes a mean *** growling sound! Hell of alot better than my monza exhaust. But that airpump puts out alot of air! I was surprised. But now it has more HP, and thats always good to have. fruit:
I'll drink to that :1party:
If you are still running your stock aircleaner and you have no cats, or if you just have a crappy monza exhaust system that you cant stand to listen to, I strongly suggest you do that.

dbb280zx

I had thogh of this a while back when I took mine off but I had a train of thought that went something like this...
air being drawn through the carb venturies causes a vacuum where the fuel comes in from the bowls. The rate that the fuel comes in depends on the difference between the pressure in the venturies and the pressure in the bowls. This is why float level is so important in fuel mixture. Now theoretically, raising the pressure in the carb would lower the amount of fuel being drawn in. You may want to keep an eye on your spark plugs to see if your mixture is too lean (which I can promise you that it is if you did as you said) running lean will eventually destroy your engine.
This theory is why a supercharger is between the carb and the engine, sucking air through the carb not blowing air into it.
Dennis

JimmyHat

Yeah, I did think about that there would be too much air going in, but my engine already runs really rich. I put a MSD direct fire set up, and I looked at my plugs just a couple days ago, and they were new, and they have alot of carbon build up on them. But I will take you advice on that. But it was fun to experiment with though.

JimmyHat

What about ram air? that does kinda the same thing...forcing air into the carb. But I guess I'll just check the mixture then.

P.O.S. Racing

Jimmy what’s the status on your car? Are you going to get to keep it?

GSL-SE

im in the process of converting my 13B's old airpump into a supercharger for an snowmachine.

Jeff20B

iTrader: (13)

> I put a MSD direct fire set up, and I looked at my plugs just a couple days ago, and they were new, and they have alot of carbon build up on them. <

You and me both! I had done a fair bit of driving (and got a couple good loud backfires ) after hooking up an MSD direct fire ignition system, and when I looked at my plugs one day, they were covered with carbon. You know, I thought the MSD was supposed to burn carbon off plugs and be this wonderful aftermarket device for the rotary. Well, I thought wrong.

I switched my ignition to run dual leading ignitors and, almost like magic, my plugs are now perfect looking with a self cleaning ability. No carbon on the center electrode(just kinda brownish), with a hint of carbon on the grounds. My Trailing plugs looked the same as before, but my Leading plugs were simply impressive.

I haven't touched any adjustment screws or anything on the carb when going from the MSD to this new ignition system.

check out the article I wrote http://www.geocities.com/cd23c/dlidfis.html

So, if your plugs were carbon covered on a system that was probably running lean with the air pump hooked up, I hate to see what your plugs would look like on a normal intake system.

Oh yeah, I have done nothing but stop and go driving (no highway miles) and I floor it all the time. I have also not gotten a single backfire since removing the MSD.

JimmyHat

Whatz up POS? Yeah i dont know about the "Red Hot Chile Pepper" yet . I havn't gotten ahold of my mom yet. I think if I do want to keep the car, Im going to have to end up with something REAL cheap, like getting a....honda (aka rice burner). I know, I cant imagine, ME, driving a honda! It's going to be a discrace, but hey, anything for my RX, know what I mean? Hopefully I can find maybe a MR2, or Pontiac Fiero, or older model Supra or something. Sports cars are sure hard to come by in Lubbock tx. I need to get off my lazy *** and finish painting the bed on my '52 ford, so I can sell it! It's about $10k just sitting in my garage! You know all the mods I could do with that??!!! Im getting chills just thinking about it! But anyways, where is the mixture adjustment screw anyways on a 12A? And where is the fuel bowl? Laterz
Kyle

Northern 7

iTrader: (3)

20B

Bad plugs? Backfiring? I'm running a direct fire set up and I have none of these problem - are you sure it was the MSD? Were / are you using performance coils on the leading? I had some carbon problems (minor) until I stepped up to better coils - this may have been your problem
Thought I'd mention it before every one decides to scrap their MSD's

Felix Wankel

I never had a problem with mine either.

Sterling

I thought of that airpump thing a while back, as well. I took one apart, and it's truely a precision machine. It's a vane type pump, and has three fins. I filled it with BBs and then measured the volume. Did some math, and figured out that at 8K engine RPM, you'ld need two or three pumps to put out enough cfm. But that was to 'push'. Was'nt too sure it could be hooked up to 'suck-through', which is what you really need.
The thread I have all this math in, as well as a long discussion is called "Super v.s. Turbo" on Mazspeed.com. It's pretty old, so you'll have to do a search to find it.
The vanes in the air pumps are linen micarta, and there are carbon (Graphite) seals at the ends of each (total of 6 graphite square rods). I think I calculate in that thread just how fast the pump ever does go (ratio of the pump pully to the E-shaft pulley), and to push it any faster might risk breaking the pumps seals.
Then as far as a suck-through design, well first that's alot of fabbing, and then, I dunno if the fuel vapor would hurt the micarta vanes.

Then I wondered about a bigger air pump from a V8 something-or-other. Course if I were to go through all that trouble, I would try to get a supercharger from a Thunderbird and fab/modify it to work.

When all is said and done, it comes down to "aww ****...I'll just save my pennies for the Camden 7" !"
At least you know what the end result will be. As soft a a piece of that Graphite seal might be, I sure would'nt want it sucked into my engine if it broke!


BTW, though I did'nt go from an MSD, I did wire my ignition per Jeffs instructions, and the results are absolutely incredible. I have a stock ported 12A in my 85 with a Yaw carb and RB long primary header exhaust. Hooked up Jeffs dual leading igniter/coil direct fire system, and immediately (accidently) buried the tach on my first "try - it - out" run. There was nothing wrong with my ignition system prior, but it took effort to get to 8K.
I had nothing but Rx-7 parts in a pile, so I'm talkin' spliced plug wires, spliced exposed pick-up wires...a real friggin mess!
Only last night did I finally get a "make 'em yerself" plug wire kit, and I also rewired the pickups with shielded wire from one of the old Clarion radio connector cables.

We'll see in about 20 minutes when I take the "long way" to work! (Work is only 6 miles away, but the 'long way' I go is about twenty!!!:p )

jimmyv13

Sterling,
What is "Jeffs dual leading igniter/coil direct fire system"?
Could you explain it to me or direct me to a website or something? Thanks....

JoseReyes

Is this the site you were looking for?

http://www.geocities.com/cd23c/dlidfis.html

Jose

Jeff20B

iTrader: (13)

Yep, that's where the most recently revised version is at. Since it's on my own web page I can update it any time I need to, without the 10 minute limitations found here and at Mazspeed.

Northern 7, I was using the stock coils. They were meant to run in "kettering" mode, but still do work with a CD spark in parallel, more or less. My article mentions this.

Sterling, thanks for mentioning that you buried your tach needle without even trying . Word of mouth is always much better than anything I could tell anyone. Oh yeah, I first threw some wires together to get mine running, and it worked extremely well too. We'll never have that nasty 8000RPM bug that so many other people have had with their MSDs.

For the doubters out there, DLIDFIS is exactly the same as stock with only one more ignitor, and one more coil. It has the same (possibly 10,000RPM) limit as stock. If one of the Leading ignitors ever dies on you, just keep the old coil-to-cap wire handy in your car (like in a compartment behind the seats) and hook it up through the dizzy cap just like the old stock single fire setup and you will never be left stranded. Yes, move the Trailing wires back to the Trailing part of the cap first (duh).

It's a completely redundant ignition system. Compare that to your short duration MSD dependant setup. Poor RX-Midget had his MSD go out on him. I certainly don't ever want that to happen to me, or any of you guys.

Jeff20B

iTrader: (13)

About the backfiring, I used to get lots of backfires with the old stock ignition sytem, then I still got them with PMDFIS and they stayed pretty much the same with MSD DFIS. Now with DLIDFIS and even harder driving, I have not gotten a single backfire. I have kept my timing "tuned" properly throughout all my ignition experiments. But I never touched anything on my carb. The cleaner plugs are a result of better combustion.

Here is a think (brain intensive) section for you all to ponder. Yo, Felix, gitcher brain over here! This is kind of a true/false section.

Please read these and correct any which you think are wrong.

The MSD has a different amount of advance/retard compensation than the stock J109 ignitors do.

The compensation of the 6A and 6AL is not adjustable by the user.

The Leading/Trailing timing split does drift at high RPM with an MSD on your Leading and a stock ignitor on your Trailing.

The Leading/Trailing timing split never drifts with J109 ignitors.

When the MSD dies on you, it'll leave you stranded unless you try running your Trailing spark into your Leading plugs. That'll work, but it'll be less advanced than the Leading was and may be hard to start.

The MSD CD spark is high voltage and low amperage. Hooking it in parallel to two coils reduces the amps even more. This gives you an even colder spark than if it was not hooked in parallel.

The MSD CD spark is short in duration at the RPMs where a rotary is supposed to run at normaly. They say 3000RPM, but that is misleading. I think it counts input pulses per minute, not output coil pulses. It would need to know how many cylinders you have in order to know when to go from multispark mode to single spark mode.

Note: all those were meant to be true. If you found one to be false, please write about your reasons and post them here.

Thanks!

Jeff20B

iTrader: (13)

jimmyv13,
You're using Accel Super Coils? how many? 2? How and where did you fit them? I compared one to my 3-coil bundle in my REPU and the square top of the super coil took up as much room as 3 coils did. Scary!

V8kilr

well thats true but did you know you could turbocharge a carbed rotary?its true you can even get the video that has this done from racingbeat.and the turbo goes after the carb not in between.but what im wandering is if the noise he is hearing is from not getting enough air?do you think that little pump can push enough to add hp to the engine?if so why in 20 something years hasnt anyone else thought of this?

JimmyHat

I really dont know what the hell the air pump thing is doing, but its not that complicated. All I have is a rigged 4in aircleaner hooked up to a 7up can near the front of the car. Then a hose going from the can to the inlet in the front of the air pump, and then a hose going from the back of the airpump to the original aircleaner where the old airpump hose used to go. All its doing is blowing more air into the carb. I dont see how its any different like in a ram air or something. If the engine isnt using all the air being blown into it, wouldn't some of it just blow out threw the filter. I cut the cleaner assembly into an open air. Hell I dont know. All I know is that from 2500 to about 5500, there's more power than before. Im probably wrong, you guys are alot smarter than me. And about that MSD, I never knew you could run a dual leading ignitor. Whenever I find another ignitor, sence mine went out, Im going to have to try that. I have a 6A and 3 blaster2 coils, and it still backfires some when you're down shifting, but its kinda quiet and not as bad as when I was running original. I like it. Its good enough for me.

Jozay721

has anone else tried this??, i know its a very old thread but i was just looking through and found this. thisis very intersting, could this really damage ur engine???If not im going tohave to give this a shot, although i like my engine without the air pump.

gsterror

Look, Sterling without a Sterling carb

steve84GS TII

Dont waste your time.
Youd have as much luck running one of those bilge pump electric turbos off of Ebay. As stated earlier in the thread,the output of the airpump is FAR less than the CFM needs of the engine, at speed.....

Huh,......kinda an anti-climactic 2000th post...oh,well......

Jozay721

o ok,thanks dudes, i just wanted to know, cuz i like to get as much as i can out of my rex, but i thought it wouldnt be worth it, it still is kinda cool though.