1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

ATF is brewing as we speak

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Old 04-02-02 | 11:21 PM
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From: Troy,Mi
ATF is brewing as we speak

yep threw in 1 qt of atf today,
tommorrow morning i'll throw in another then wait about 12hrs after that to clear it out and fire it up.
i want to rotate my engine 120 degress so all the rotor tips get to soak nice.
probably gonna take some pics tommorrow,
or maybe i'll wait till day after tommorow so the pics are in the day light.
should be fun,
wish me luck on some high compression.
Old 04-02-02 | 11:28 PM
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OH MY GOD, YOU'VE HYDROLOCKED IT!!!!!!!!! THE ROTARY GODS WILL DESTROY YOUR ENGINE!!!!!!!!!! sorry, had to give you the treatment. wait till you get the mount saint helens cloud. you'll get a big ol' **** grin.
Old 04-02-02 | 11:28 PM
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good luck!
Old 04-02-02 | 11:30 PM
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yeah i did it before on my 1st owned 1st gen,
but never like this,
im taking it to the extreme,
with the last bit in the bottle i filled the carbie to the top as before with my old 1st gen,
hopefulley this helps out the carb as well,
once it back up and goin i'll be adding the mmo


IM INSANE
Old 04-02-02 | 11:33 PM
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From: Da Barrio!!!(Irving, Texas)
heheheee, I atf'ed mine about 5hrs ago. I drove it around for like 3 hrs, mostly spinning the dry rotted tires I have never appreiciated this car so much EVER, IT WAS FUN. I wired a switch to the fuel pump, and every time it started to flood, I would cut the pump, and rev the motor . Worked like a CHARM. Then I pulled in to my drive way, ready to park it, then it died. I then looked at the gas guage to see how much gas I used, and I had a HALF TANK when I left, but now it is DRY, EMPTY, GONE. So I guess its a trip to the gas station tommarow, loaded down with about 4 cans , oh well, it is worth it LATERZ, Andrew
Old 04-02-02 | 11:35 PM
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you is so crazy. since my tank lines are clogged, i just got my cloud for the little time we poured gas into the carb.
Old 04-02-02 | 11:38 PM
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is there ANY drawbacks to doing this like... once a month?
Old 04-02-02 | 11:42 PM
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thats a little extreme. maybe once every 20-30 thousand miles. the goal is to eat off carbon deposits and loosen up the seals. your talking about vacuuming once a day instead of once or twice a week.
Old 04-02-02 | 11:45 PM
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atf is basicly hi-octane fuel? it runs hot and fast?
Old 04-02-02 | 11:46 PM
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Originally posted by jeremy
thats a little extreme. maybe once every 20-30 thousand miles. the goal is to eat off carbon deposits and loosen up the seals. your talking about vacuuming once a day instead of once or twice a week.
no he's talking about vacuming 3-4 times a day

atf once a year is to extreme for me,
i say atf it,
then every year or so use mmo in your tank.
Old 04-03-02 | 12:15 AM
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hi...im a little new here...can someone please tell me what aft is?... thank you =D
Old 04-03-02 | 12:21 AM
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ATF = Automatic Transmission Fluid
Old 04-03-02 | 12:28 AM
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From: Jacksonville, FL
so...i just pour a bit into the carb, let it soak for about a day, then drive the hell outta it...sounds cool =D lol...but uhm...what if i have a manual tranny or does that not matter?
Old 04-03-02 | 12:29 AM
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From: Troy,Mi
Originally posted by RX785
hi...im a little new here...can someone please tell me what aft is?... thank you =D
heres for the newbie,


"atf treatment



man i cant wait till i up date my site and i can say
"just click on my sig"
Old 04-03-02 | 12:30 AM
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Originally posted by RX785
but uhm...what if i have a manual tranny or does that not matter?


Old 04-03-02 | 12:34 AM
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haha okay thanks....i might try this maybe over the weekend..
Old 04-03-02 | 12:36 AM
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disconnect the flux capacitor first.


sorry had to
Old 04-03-02 | 12:36 AM
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no problem,
dont forget to post your results and maybe some pics.
Old 04-03-02 | 12:37 AM
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Originally posted by jeremy
disconnect the flux capacitor first.


sorry had to
/\ POST WHOREING IN PROGRESS/\
Old 04-03-02 | 12:39 AM
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me? hehehe hahahaha
Old 04-03-02 | 12:42 AM
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im trying to hit 750 then im going to bed,
i so sick and tired of being a wanna be ******.

i hope 750 is where im something else,

it seems everyone in here is a wanna be ******.
i was more happy with insane burnout,

never the less im still trying to post usefull information.

Why should I tune my carburetor?
A properly tuned carburetor is critical to the perfomance of a rotary engine. The engine will make the most power at an air fuel ratio of approximately 13 lbs. of air to 1 lb. of fuel. If the mixture supplied by the carburetor varies from this, the power output will drop considerably. To give you an example, one jet size can sometimes make a difference of ten or more horsepower. The ultimate goal in tuning your carburetor should be to supply the engine with the correct air fuel ratio throughout the powerband. Remember that average horsepower throughout the operating range is much more important than peak horsepower. Peak horsepower only tells you what the engine is doing at one rpm.


Getting down to details
An entire book could be written on the subject of carburetors, and since I seem to be getting a reputation for being rather long winded, I will try to describe the very basics of carburetor tuning. If you are using a carburetor that has adjustable air bleeds, (Weber, Mikuni, Dellorto, or one of my Nikki's) you have a fair amount of control over the shape of the fuel delivery curve.


Fuel Jets
When air flows through the venturi, a vacuum is created which draws fuel through the fuel jets. The fuel jet, or main jet, controls the fuel flow throughout the operating range, with the greatest effect at low to mid rpm. A larger fuel jet will deliver more fuel, making the mixture richer. A smaller fuel jet will deliver less fuel, making the mixture leaner.


Air Bleeds
The air bleeds, or air correction jets, control the mixture mostly at mid to high rpm. The air bleeds are best described as a controlled air leak in the main circuit. The air bleeds work by "bleeding off" this vacuum which draws fuel through the main jets. A larger air bleed will make the mixture leaner at high rpm by bleeding off more vacuum or "signal." A smaller air bleed will richen the high rpm mixture by bleeding off less signal.


Emulsion Tubes
The air from the air bleeds enters the main circuit through the emulsion tube. The emulsion tube has a series of small holes from top to bottom, and it is through these holes that air enters the main circuit. At low engine speeds, when fuel demand is low, these holes are submerged in fuel, and so no air can flow through them. As engine speed increases, the fuel level in the float bowl drops, uncovering these holes, and allowing air from the bleeds to enter the main circuit, thus leaning the mixture. As the engine speed increases further, the fuel level in the float bowl continues to drop. This uncovers even more of the holes in the emulsion tube, which makes the air bleed have a greater effect on the mixture.


Fuel Pressure
Changing the fuel pressure will vary the amount of float drop, and so it will vary the amount that the air bleeds control the mixture. If the fuel pressure is increased, there will be less float drop, and the mixture will be richer, because less of the holes in the emulsion tube will be uncovered. The opposite is true when the fuel pressure is decreased. The relationship between float drop, and fuel pressure is very critical, and so it is best to run your carburetor at the pressure specified by the manufacturer. Before tuning your carburetor, make sure that the float level is set properly. This varies with different manufacturers, so get the correct information, set the float level accordingly, and do not vary from this for any reason.


Remember The Rules
This may seem a bit confusing at first, but you can do well by simply remembering the following rules while you are tuning.

Smaller air bleed............richer high and mid rpm mixture.
Larger air bleed.............leaner high and mid rpm mixture.
Smaller fuel jet...............leaner low and mid rpm mixture.
Larger fuel jet................richer low and mid rpm mixture.


Tuning With An EGT Guage
The process of carburetor tuning is greatly simplified with an EGT guage. (Exhaust gas temperature guage.) You can buy an egt guage from Aircraft Spruce at 1-800-824-1930. They have a dual guage which costs $96.95, and a single guage package which costs 66.40. The part number for the single guage is 282-1 for the guage, and 712-2wk for the probe. The dual guage is sold complete with probes, and the part number is EG005. The probe should be installed about 24" from the exhaust port.

An egt does not tell you exactly what the mixture ratio is, but it does give you a pretty fair indication of what is happening inside of the engine. If the mixture is rich, the temperatures will be low, and if the mixture is lean the temperatures will be high. There is no exact number to aim for, as exhaust gas temperature is affected by many things. A typical race engine seems pretty happy at about 1650 to 1700 degrees farenheit, and turbo engines seem to run best with temperatures 150 to 200 degrees less. After installing your guage, make a run at full throttle in third gear, and monitor the temperatures throughout the rpm range. If for example, the guage reads 1400 at 4000 rpm, and creeps all the way up to 1850 at 8000 rpm, the engine is running rich at low rpm, and lean at high rpm. At some point in the range, the engine will feel strongest, and the temperature at that point should be your target, give or take maybe 100 degrees. It is normally best to correct the low rpm mixture first, and then correct the high speed mixture. The first step would be to decrease the fuel jet one size, make another run, and see what happens. If at this point, the temperature throughout the low and mid range is steady, and the high rpm still reads lean, decrease the air bleed and make another run. Contine making changes, and monitoring the results. This will involve a fair amount of trial and error, but after a few runs, you will get a feel for the effects of the jet changes, and the temperature that seems most appropriate for your engine. This is much easier than it sounds, and after a while you will begin to predict the effect of jet changes.


Tuning With An Oxygen Sensor
An egt guage is a great tool for tuning full throttle mixture, but it is not at all helpful for tuning idle and cruise mixture. An oxygen sensor, or lambda sensor can be used to properly tune the carburetor for gas mileage and driveability. An O2 sensor works by sampling the amount of oxygen present in the exhaust gasses. An oxygen sensor responds much quicker than an egt guage, and its output is extremely accurate at mixtures of 14.7:1 and leaner. At mixtures richer than that, the output becomes temperature dependant and loses its accuracy. While all of the O2 sensors on the market have a display that reads from about 16:1 to 12.5:1, they simply cannot be relied upon at richer mixtures. My own dyno testing has shown that a difference between 11:1 and 13:1 is almost un noticeable in the output of the sensor. While full power is achieved at a ratio of 13:1, optimum gas mileage and emissions output occur at a mixture of 14.7:1. Now that you know how jet changes affect the mixture, you can monitor the output of your sensor and change idle, and fuel jets to achieve optimum mixture at idle and cruise. All high quality carburetors have adjustable idle jets, and my modified Nikki's also have an idle restrictor jet. The idle circuit continues to supply fuel to the engine at cruise, or any time the throttle blades are only slightly opened. After installing the unit, simply drive the car as you wold during normal driving, and monitor the output of the sensor. If the mixture is richer than 14.7:1, simply decrease the size of the idle jet. You can also increase your fuel mileage by making the mixture lean under light acceleration. The engine will make slightly less power during light acceleration, but gas mileage will improve. Full power mixture can then be tuned with the egt guage. If you have both units installed in your vehicle, you can tune your carburetor to work nearly as well as the best injection units.


Accelerator Pump Tuning
The purpose of the accelerator pump is to richen the mixture during rapid throttle opening. When the throttle is opened quickly, the pressure in the manifold rises, and causes some of the fuel to drop out of suspension. Since fuel can only burn if it is atomized, the engine will experience a lean condition, and stumble before acceleration. The accelerator pump squirts a small amount of fuel into the airstream to correct this. If you have an O2 sensor, the mixture during throttle opening can be monitored and adjusted accordingly. In reading the sensor, you should aim for a relatively rich mixture during this period. The accelerator pump has a greater effect on throttle response that any other part of the carburetor. If you do not have a sensor, you can arrive at the correct "pump shot" experimentally. Most carburetors allow for accelerator pump tuning, but the methods vary a great deal from one manufacturer to another. Your best bet is to consult the manufacturer to determine what parts you need. (cams, bypass jets, and squirter nozzles)
What , No EGT?
Don't worry, you can still tune you carb, it will just take a little longer! The first thing to do is change to a smaller fuel jet. Drive the car, and pay close attention to the low rpm power. If the power is worse, you should change to a jet one size bigger than what you originally had, and test the results. If this also make less low speed power, the original fuel jet was correct. If it makes more power, keep going bigger until the car makes less power, then go back to the previous size. In other words, make a change, and keep going in that direction until you see no further increases in power. Once the fuel jet is dialed in, do the same with the air bleeds until the engine makes the best power throughout the entire operating range.
Final Notes
It is likely that once you near the optimum combination of fuel and air jets that changing either jet will affect the entire operating range. At this point, you should get out the stopwatch, and do some "jet juggling" until you get the best acceleration times in one gear. Do not try to time yourself going through the gears. Your times will be affected by wheelspin, and the speed of your shifts.

No one can tell you exactly what works best for your application. You can tune your caburetor with a bit of patience, and brainpower. After a while, this will become easy, and you will be glad that you learned how. If you have any questions, feel free to send me a message. Don't forget, your not a real gearhead until you can tune your own carburetor!
Old 04-03-02 | 12:55 AM
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it would have been a lot easier just to post the link to that web site.. you still would have gotten the post credit.

v8kilr: i am just hopping to hit tripple sixes tonight, strictly for amusment purposes.
Old 04-03-02 | 12:58 AM
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From: Troy,Mi
Originally posted by riffraff
it would have been a lot easier just to post the link to that web site.. you still would have gotten the post credit.

v8kilr: i am just hopping to hit tripple sixes tonight, strictly for amusment purposes.
yeah i hit that the other night,

i was gonna leave it for a while but i just wanna not a wanna be
Old 04-03-02 | 01:00 AM
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welp.. looks like both of us are not going to hit our goal tonight.
Old 04-03-02 | 01:03 AM
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Originally posted by SuperPhly
atf is basicly hi-octane fuel? it runs hot and fast?
Uhm no, not quite. ATF contains cleaning agents that are useful for cleaning carbon deposits out of combustion chambers. This means that it's useful for restoring compression, fixing engines that are carbon-locked or have stuck apex-seals and also for starting flooded engines.


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