nick1

well i finally got around to begin pulling the motor from my gsl, thanks to the help of forum member DufourMike...thanks buddy!!!

anyways, we pulled the carb, and there is some type of butterfly (i think that's what they're called) valve that looks like it maybe cuts fuel to the rear rotor??? what is this? i was surprised to see it.

only thing i can think of is maybe it is there to help cut down on backfiring maybe during de-acceleration?

i was sooo surprised how much CRAP we pulled out of the engine bay. i am going no emissions at all, which basically consists of half of everything in the engine bay. lol including an entire wiring harness on the passenger side of the car...GONE! haha

so...anyone know what this valve is? it is totally stuck, won't move at all. it seems to run off vacume pressure

nick

FB II

take it out. it's worthless to you and restricts airflow. WOOT

Dan_s_young

iTrader: (1)

Agreed I cut mine out, kind of ghettoed it but then a couple weeks later I decided to go for the weber and a REAL intake manifold...

Also what I was reading about this butterfly before is it actually can screw up your idle. It actually seemed to make a difference when I removed it, but then again I may just be crazy...

Kentetsu

It's purpose is to lean the mixture during deceleration I believe. Some take it out, some repair them (they tend to get stuck closed), some say that if you remove it then it will mess up the flow of the carb. If you look at the throats you will notice that the one with the valve in it is slightly larger than the one toward the front. This is to make up for the restriction of the valve in the open position, so if you remove it then half your motor will run richer than the other half (please, someone correct me if I'm mistaken). What I did was just remove the small screws holding the flap itself into the shaft (make damn sure you don't drop them in ), figuring that the shaft would still provide the necessary restriction and keep things on an even keel.

FB II

nope, take it out. only helps.. and when you boost your nikki, it reaaaally becomes a restriction.

nick1

so i guess if its stuck in the open posision its all good

does anyone know for sure what it is?

FB II

shutter valve, keeps the car (with all stock emissions still on) from backfiring on decelleration. worthless

Kentetsu

No, no, no. The purpose is to lean the mixture during deceleration to reduce your overall effect on the ozone layer and global warming. The reduction in backfiring is just a side effect of leaning the mixture. I know that I got that much right! lol. Just messing with you FB II.

Kentetsu

I had read in another thread, where someone was asking if they should disable the valve or if they should remove it. Sterling replied that he should not remove the valve due to what I mentioned above. I'm 99.9% sure that I'm remembering this correctly, but if I'm wrong may Sterling strike me down with a bolt of lightning.

FB II

well, it's not a matter of correct or wrong, but i am speaking from actual experience on 3 different nikki setups. i always remove this butterfly only to see no side effects, only easier to shoot flames hahaha. lots of people go beyond just taking it out and will hog out the entire manifold (what i'm currently doing for my turbo nikki setup) and get great results. you will not hurt the performance of your nikki in ANY way by removing this. all setups have run beautifully after removing it... but they also ran good before. like i said, no affects at all. just assurance that it won't become a block in the intake path. oh and i have a wideband to aid me in my results. if one wants to be safe about it then wire it to stay open all the time, i just know that with boost (granted we're not talking about that) it can still be forced shut. that's why i just go all the way with it.

Kentetsu

Cool, I wanted to completely remove mine too but couldn't get something to come loose so I just removed the flap and left the shaft. Gives me something to do after the snow starts flying.