whofarzed

I am going to rebuild one of my parts cars carbs to put on my 85 rx7. I have a 84 and a 79 parts car so which carb would be better (performance wise) to rebuild? Also, isn't the 79 intake manifold better then the 84-85? Would it bolt right up to my engine or is it not worth the extra hassle? (I have a header and no rats nest)I already have both my parts cars carbs off and the 79 intake manifold is removed.

Also, I was wondering how many people have done Sterlings mechanical secondaries mod and if they liked the results?


Thanks.

jr69187

on the note of sterlings mod. Try it you will love it. I did it to my old 12 a and it was great. Have not done it to the new one but soon I will have some time to do it to it. But i liked it.

dan

jeremy

iTrader: (1)

79. it supposedly has larger openings and automizes the mixture better.

Directfreak

iTrader: (2)

And a lot of plugs to plug.

Directfreak

iTrader: (2)

Don't know the accuracy of this, but FYI.

jeremy

iTrader: (1)

well, that is solved by using the 79 nikki. less **** on it anyway.

mperformance

i have both carbs 79 and 85 completely intercheangeble...no validity to that.

the 79 intake is by far superior to the newer more restrictive type

Barwick

from what I understand, racers use the '79 (and '80 I think) manifolds over any others. There's a bunch of little quirks they use to get power out of the race cars legally.

whofarzed

So the the 79 intake will bolt up to my engine? If it does with no problems then I will rebuild the 84 carb (it is cleaner) and use the 79 intake. Are the carbs similar performance wise?

whofarzed

I just looked at racing beats website and the two gaskets do look different, has someone here used the 79 intake on a 84-85 car? If so how did you make it fit?

peejay

The '79-80 manifold WILL bolt right up to any 12A. However if you put it on a '81-85 engine, it will leave the air injection port below the center two intake ports open to atmosphere, and it will act as a huge exhaust leak. You need to have a small tab of aluminum welded on tothe manifold, then have the manifold face machined flat.

The '79-80 manifold is better because it's symmetrical. The '81-85 setup has the same arrangement as '79-80 for the #1 rotor, however the #2 rotor has a much different arangement to accomodate the shutter valve. The runner volumes are far out of whack relative to each other which is a Bad Thing. If you remove the shutter valve shaft it makes things even worse.

I spent LOTS of time (at least 30-40 hours) and JB Weld modifying an '83 manifold to work like the '79-80 setup, haven't installed it yet and I don't know if I ever will. But it's a thing of absolute beauty

whofarzed

Looking at the gasket pictures at racing beat, wouldn't the air injection port be abouve the two intake ports? I am guessing it is that square looking port.

peejay

You're looking at the gasket upside down.

whofarzed

also, since I will not be running any emissions, what vacume lines can I plug. (I know on my 85 I have the ac&cv blockoff plate and some other small blockoff plate that I forget what it was called)
Also, what is that thing that screws into the 79 manifold (kind of looks like how the carb heater(i think thats the carb heater anyways) looks like on my 85) can this opening, along with others be pluged?

paposwing14

I have a 12A with that intake on it and it make a difference on the top end i also have directfire ignition and that puppy runs three times better than when i got it stock! i am worrking on a 79 intake and im trying to get the primary exits opened some more hopfully that will work , !

peejay

NOOOOO! Don't open up the primary exits, you will ruin the manifold!

RotorMotorDriver

iTrader: (1)

In rebutal to what DirectFreak posted earlier...I personally have and an 83 carb on an 84 intake manifold and had the car running. As a matter of fact, thats what Im using right now on my 83. So its an 83 GSL, with an 84 GS engine, 84 intake, 83 carb, 84 clutch, and 83 tranny. It works.

~T.J.

PS -
I realize he said 84 wont fit on 83, but that means an 83 shouldnt fit on an 84, but it does. Thus proving this entire statement false .

whofarzed

someone have the answer for this?

also, since I will not be running any emissions, what vacume lines or etc. can I plug. (I know on my 85 I have the ac&cv blockoff plate and some other small blockoff plate that I forget what it was called)
Also, what is that thing that screws into the 79 manifold (kind of looks like how the carb heater(i think thats the carb heater anyways(or maybe something to do with the choke) looks like on my 85) can this opening, along with others be pluged?

MIKE-P-28

iTrader: (1)

I thought that all carbs would bolt to the manifolds, I had an 85 on several different years before, I dont remmeber any problems? But anyways, that was a long time ago...

MIKE-P-28

iTrader: (1)

Is it on the passenger side of the car (carb)? If its a round little thing with 4 phillips screws then its probally your secondary throttle linkage and return diaphram. I think Id be leaving that on there... Unless you wanna mod is slower

whofarzed

no it screws into the '79 manifold and has a hose coming off it(I just mentioned the carb because it looked similar to the thing on the carb that has a wire coming off it (on the drivers side)