NO RICE

A few weeks ago I got an '83 RX7 with a 12a in it. A friend of mine picked up a racing beat intake for me at a swap meet, he also gave me a 600 cfm Vacuum secondary Holley. I put that intake on 2 days ago, but I can't get the car to run smooth. It stumbles.

I have #62 jets in the front, plugged power valve, #8 metering plate in the back, pink accelerator pump cam and #37 squirters. There are two canisters on the distributor I conected them to the partial vacuum port on the holley, it looked like a vacuum advance. I plugged all the other ports

The car has a 2.25 inch exaust with magnaflow muffler and no cats... Everything else is stock.

What can I do make car not stumble.....

Thanks

DJ!

The best I been told is to do it on a dyno, but i don't know how~!

SilverRocket

I'm no expert, but I believe a 600 is waaayyy too big for a stock port 12A. I don't think you'll ever get it to run well.

A 600 is the right size for a street port 13B, I believe.

I think the right size holley for a stock 12A is 465cfm.

NO RICE

I've not been sitting around since the day I made that post.
I got the car to run right. I put an Edelbrock 600 on my mazda and the problem went away. It is the carburator that I use to pass emission tests on my firebird. ant it has slightly smaller jets in the front. Other than that is a stock carburator. The car does not stumble, it does not bog... and it does not run out umph!!! And it still get 20 mpg in the city vs 12 with holley. I think the stumble was due to the fact that carburator was set too lean. Edelbrock was set up for an engine 5 times the size of the wankle. I still plan on putting holley back on it, but not until I get gears and exaust...

mazdized

My Holley gets 16 mpg and 23 mph on my bridge port. What I do is to jet the primaries as lean as possible with out stubling at cruising speed so it gets good gas milage. The secondaries are jetted rich so it misfires at first, then leaning it out as the motor starts to pull strong and smooth. I use the smallest accelerator nozzle which is 25, then grind the cams to get best throttle response by just driving it and grinding it until it feels the best. I have set up a 600, 700,and 750 and they all worked good with over 20 mpg. on hi way. Vacum secodaries just don't seem to work well so I just pull the secodaries with the linkage on a vacum sec. carb. Ignition advance don't work well with a Holley in my opinion so i just set it to total advance. Inject oil above the throttle plate like a factory 12a carb. cause the oil injection won't work right if the lines see vacum at closed throttle.

pineapple racing

The off idle flat spot-the one you find if you turn the idle speed(or hold the throttle) at around 1500rpm is because the transfer circuit is too lean. It is very common on holleys esp. with big carbs on small engines. The real fix is not recomended for the average guy. It requires playing with the idle channel restriction and installing adjustable air bleeds on the idle circuit. Proper float level is very important. Without drilling out the vacuum passage to provide a big enough signal to operate the vac. sec. proper trans.to the secondaries will not happen. I will paraphrase every performance Holley carb book I have ever read and whole heartly believe:"DO NOT CONVERT A VACUUM SECONDARY CARB TO MANUAL. THERE IS NO ACC. PUMP SQUIRT TOO COVER UP A SUDDEN THROTTLE OPENING. This is very good advice except for a few racing applications.

813KR$

I have a Holley 600, sounds like 62 primaries are to big. Iam running 57's on the primaries and 62's on the secs.

turbo85

The holly 600 is perfect for just about any size motor.
It is not to big. iv'e used 650 double pump carbs on stock port 13b's. they have ran perfect. they just have to be tuned right.

Rotary7s

Dam you should of told me that abotu 3 yrs ago..

I have been runningmy Holley and had no problems besides fuel when turning,you need notched floats and extensions...But anyways.I dont mess vacume secondaries... I hate them,I would recommend a 1 in spacer,It will feel alot better.

FB II

all the holley's you guys are using; are they made by racing beat or specificly pre-set by a manufacturer for the rotary? i can get a 650 holley for cheap that's been rebuilt but it came off a boinger. will i have A LOT of trouble setting it up? or can it be done?

turbo85

it definitly can be done.i bought my 650 from summit racing.all you have to do is run your oil lines to the carb jet it and seal the metering pump.

FB II

FORK YEA! WOOHOOOOO! thx, which holley are you running turbo85?

turbo85

I'm using a 650 double pump.It works fine.A 600 is good also.It is the perfect size for just about any type of port from stock to a bridge port.

FB II

i have a large streetported 13b turbo. i'll try the 650. now i need a good bonnet! and not the k&n rip off junk!

Sammymatik

I got a nice bonnet!

Rotary7s

How does that lock down to the carb?

turbo85

MY BAD. NOT METERING PUMP, I MEANT TO SAY POWER VALVE.
IT'S BEEN A LONG DAY. SEAL THE POWER VALVE.

THE 650 WILL WORK GOOD AS LONG AS IT IS JETTED RIGHT. SPECIALLY IF YOUR GOING TURBO.

chinrx

what jets do you use for the 650.sorry for my ignorance but what do you mean for seal the power valve

813KR$

Pineapple Racing:I will paraphrase every performance Holley carb book I have ever read and whole heartly believe:"DO NOT CONVERT A VACUUM SECONDARY CARB TO MANUAL. THERE IS NO ACC. PUMP SQUIRT TOO COVER UP A SUDDEN THROTTLE OPENING. This is very good advice except for a few racing applications.

So will this kill apex seals? sounds like it to me? Could having the secs slightly open at idle then as the prim open the sec open with them, would that stop the sudden leaning effect of the sec suddenly opening? I dont want my new engine dead! I currently have the secs opening mec when the prim are 1/4 open.