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BTW, if anyone really really wants a quiet exhaust, I have the original 12a setup from 85. Car had 25k miles on it when I pulled it off 3 years ago. Doubt I'll be going back to stock, but I kept it just in case. It's slow.
Not meant as any kind of racist remark. My BIL is a Puerto Rican rotary bracket racer. He says that my car won't run is because it h as s a choke, and that I need a 600cfm racing Holley. But, he doesnt have any carbed cars, and doesnt know how carbs Or chokes work. He pays someone to tune his FI turbo motors with a laptop.
He has a 12a alcohol turbo (80mm in / 135mm exh) in a starlet. Fastest 1/4 mile time is 8.9 @155 but he has to feather it 1/2 way down the track because he doesnt have his next license.
I have a carb'd non ported 12A street car, that I want to drive on the street anytime there isn't salt on the road.. I need a medium sized carb with a choke.
Last edited by Maxwedge; Mar 22, 2019 at 08:08 PM.
what holley do u hav ? played with jetting ? pics of throttle plate lookin down ... ones that RB sells are garbage..... 390 4150 hp with no choke .. that's all i ever used and will kick the **** out of all others.... make them idle perfect at 8
It was a RB 465cfm (1848/4160), stock jetting. Throttle bores match intake runners (1.5"). Everything clean and rebuilt to RB specs Runs very lean. Nikki and Eddy run fine so I know it's the carb, not the ignition/engine.
I looked at that 390 but how do you start it on a freezing cold day in a parking lot? Pull the air cleaner and put a rag or carb hat on it? That's what the race guys here with the 600 HP Holleys are telling me but I don't want that trouble. I'm not standing in the rain outside a movie theater working on my engine trying to get it started. That's what chokes are for.
Does mazdacomp still sell those lavarock mufflers?
i could be totally full of it or just 10 years out of date but the long primarily header, collected early with a good collector into 3" seems to be what most of the race shops will recommend for max power.
I'm pretty sure Dave lemon ran something like that and didn't go over the axle, it was routed across to the driver's side and out the driver's rear.
There was a guy on here, hyper something or the other that did some testing and posted about his results. I'd search for his posts, they seemed on point.
Also, what the hell, racing beats site says they still sell the good ole power pulse muffled system. I'd call them and quality weather it's been updated or not. There is another post on this recently and it appears completely different.
anyway,after feeling like i lost a bunch of power all of a sudden, i noticed that my fuel filter next to my carb was almost dry for some reason, if i turned it off and let the pump run for a bit it would fill up, id let it get to about halfway and stat it, sure enough the level of gas would start to lower until it was dryish on the inside, i could still see fuel still trickling into it.
so i went down to orieles and got a different filter with less volume in it for the fuel to sit below the exit port., it seemed to help? of course that could be my imagination, so to do some more tests i took the car a bit out of town to a deserted area and did a couple of 0-60 runs. i got around 12-12.5 seconds. (my tires are old and crappy. probably didnt help) but, that was with it going slightly down hill since i dont know of anywhere else that isnt the freeway for that speed. seems slowish considering i had a slight downhill? dont they get around 11 (if you good i guess) seconds at stock? for what its worth i did a compression check before i "feel like i lost power" and i was gettoung around 90 normalized across both rotors and all faces. dead even.
augh. might just be slow cause old. and stock.
which is what brings me back to the question i asked initially but slightly different.
im thinking about getting rid of the rats nest and when i do that, the thermal reactor. (aka massive heat generator) has to go right? if i were to get these Disassembled Road Race Header Kit for 74-85 12A - Racing Beat
when i do this do i need to A get a tune (stupid question, im guessing i do) B need anyhting else to to mate it to the stock exhuast where the headers exit? exra piping? or is it going to come out at about the right spot? hell since im there.
There is no power gains to unlock by deleting the rats nest itself. You'll make more power with the header, which means you'll be removing the air pump and valve, making a few of the rats nest solenoids obsolete, but you can still keep the purge valve, shutter valve solenoid, a/c solenoid if so equipped, and the two vacuum advance solenoids which help with smooth off throttle deceleration. That stuff isn't holding you back unless you have vacuum leaks. Best approach is to remove, clean up, and replace all the hoses and bench test the solenoids, then reinstall.
instead of just replacing stuff, you might want to do some testing. and as a for instance, if your fuel pump is weak/tired then adding an exhaust will just make it worse.
i would suggest testing the fuel pump. you need a stop watch and a container with markings on the side. if you pull the hose off, and put it in the container, a good stock pump will do more than 1400cc/minute. if you put a gauge on it and deadhead it, it will do about 2.75psi. if your pump does not meet the specs, you need to look at the filters, and then the pump itself.
next thing to look at is the ignition, i like to just replace the cap and rotor and plugs. i check the wires, new is around 8k ohms, the more resistance you have, the less ignition power you have. NGK wires are good, but some other brands have too much resistance right out of the box, and should not be used.
