My Carb issues
 

I have the same problem as one of the other guys here.. My carb seems to be running very rich at meduim/high throttle high load.. between 2500 and 4000 rpm's it seems as if it is missing, i really can't tell because i'm so new to rotaries.. I installed an aftermarket leading coil this week and put in a full tank of fresh 93 but it still seems to be running a bit quirky... I replaced the plugs with an autolite part to see if that would help "should i not have used autolites?" it didn't do much.

I supposedly have a 550 cfm holley from MazdaTrix but i can't seem to find any way of identifiing it.. any help? I didn't see any 550 cfm holleys for a street port 12a on mazdaTrix's website

I'm wondering if it isn't a 460cfm like they describe on their website. but then again by putting on a 550 could this be too much fuel for my 12a

Like i said it has a street port with RB intake manifold and SP headers "those things are huge" and a full dual 2 5/8 header back with no cat I wish it wasn't soo loud, i can't hear my tires spinning over the exhaust..

NONONONONO!!!!! Use the lowest octane gas you can find, and don't ever put autolites in your car! Get some NGKs in there right away, and check your timing.....:)

Are you seriuos about the gas?? why?

the rich 93 gas doesnt burn as fast as the 87 octane so your rotary cant burn it all up thus leaving carbon deposits! Save yourself some money and put the lowest octane u can find in there!

how do you know it's rich? often if it's a little rich it runs very smooth still... bucking and quirky sounds lean.

Well since you looked at RB's website you know that they sell only a 465 for the 12A's. Either you were mislead or its not a true RB Holley, which if its not could be your problem since they mod them to work on a rotary. Also our cars dont need anything more than 87 octane gas. Could be alot of things causing the problem. Has the car sat for any lenght of time?

Yeah the car sat for a good 6 months before i got it.. I'm pretty sure it a true Rb holley, supposedly the salesman there told the previous owner that you get a bit more horsepower from the 550 and even more for the 600.. I know the previous owner didn't know too much about cars in general, let alone rotaries, but his cousin who helped him put the motor in has had a couple first gens.. dunno.. I will be getting it dynoed and running a wideband soon to see how stoic it is.

FBII its not really bucking bad its very subtle like someone is pulling the ebrake off and on very lightly.

the main reason i think its running rich is because it burns my eyes at idle.. i've tried to lean it out some but the car just dies. what is a reasonable idle rpm with the rb and street port?
right not its idleing around 750 maybe this is too low and causing me to richen it too much to maintain idle?

rich at idle doesn't mean rich accross the board... it it feels weak and slightly stumbles then it sounds lean to me. mine did exactly that and watching the wideband i notcied i needed to jet up. these cars idle best and drive the best around the 12:1 afr territory.

good to see you are getting a wideband... this will tell all :D get a jet kit from holley.

Timing?

Timing was a bit off.. and seems the two coil wires were switched.. got it back to factory timing and i am going to advance to 24/16 today and try this. thqanks for the help guys.

It seems the previous owner messed up a few things in the swap to the new sp 12a.

he had the vacuum line attached to the trailing disty advance actuator.. moved it to the leading..

coil wires to disty were backwards omfg.. fixed
Timing was... well don't know since the wires were switched.. fixed... back to 0/20


It seems it needs a bit of advance as it now sputters first gear.

low end torque is greatly increased now, idles really clean.

now time to start tuning the carb.. uh oh time for some dyno runs $$$$$$


Oh I need to know what to look for on my holley... I can't find a part# that corresponds to anything in the holley catalogue.
Are all holley jets universal?
how about the vacuum secondary onset springs?
or can i convert vac scondaries to mechanical?

I am in the same boat as you. I had a Holley installed that was supposed to me a RB, but it isn't. It has an R3559 stamped on the top and Holley doesn't even have that List number on their website. I do have a local Holley dealer though. I am going by there today and I will find out about the jet kits.

There should be a vacuum line going to each of the advance units on the dizzy. If you only have one line, you can get a T fitting to split it between the two.

Thanks alot for the info kentetsu... The car is running great now. just found out that I'm supposed to be premixing the gas as the previous owner removed the oil injection thingy.. I don't think he even knew that he had to premix the gas and he put 20 k on the rebuilt sp motor... uh oh hope everything is ok in there.

i thought the factory manual recomended 91 octane? then again i havent read it in a long time..

On the airhorn theres a small number stamped into it. Thats the carb model number. From what I know they are grouped into families. If its a 4150 or 4160 model (like what RB sells) then the standard Holley jets will fit, as will the vac sec spring kit and the AP cam kits. Other families like the 2bbls, and Dominators use different air bleeds, but not sure on the jets. Anyway most likely you have one that standard jets will fit. I think even my 3310 had standard Holley jets in it.

I love this car... when the scondaries open it like i'm running boost.. I wonder if i can convert the vacuum secondaries to mechanical.

yes you can do it with the "screw trick". initially you may have a bog when opening them under load... it's from a massive quick lean spot. you can compensate this with a bigger squirter tower and a more aggressive pump cam (pink is awesome).

its better to use 87 octane? i thought the manual recomended of at least 91 octane (page 1-4 for '82) its better to use 87 because it burns quicker than 91 instead of burning slower thus not burning more carbons than 87 would? midgrade? which is better disregarding gas prices.

yes, as said save the money because you are just wasting it by purchasing anything higher than 87 octane for your n/a rotary.

thanks for the reply FB_II! what about your turbocharged 12A? you use premium right.. otherwise your engine will detonate i believe.. also you have convinced me to build or at least drive a turbo 12A before i die!

lol, yea i definately only use 93 octance pump gas. with boost it becomes a totally different story because then you have detonation to worry about :D

I have a similar problem... A mech. talked me into letting him install a Holley and RB intake on my stock 12a, that he just happend to have lying around. It ran okay but not great. I have been following this thread, and decided to get a buddy to check my timing. It was off. We set it and the car runs much better now. We did the "screw" trick and I like it for the most part but I do have the "bog" now. The same buddy said that my Holley is indeed a RB modded one but a very old one. It has R3559 stamped on the top. My problem now is that I cannot find a reference on Holley's website for ordering parts.

BTW thanks for sharing this advise... Now I'm off to google "Squirt tower" and "pump cam" and figure out what the heck they are!