is it true that a nikki carb with the mechanical secondaries mod will be very difficult to use as a dalily driven car?....i was told that the secondaries begin to open the second you start opening the throttle. i thought they only opened when you get maybe 1/3 way open on the throttle. won't this mod affect gas mileage tremendously even when you're not hard on it?

 

they open 1/3 trust me and i dont think itl be hash on daily driven
i dont know for sure but ill guess it will affect milleage seeing on vaccum they dont open much

 

its even farther than 1/3 of the way down on the throttle, they really don't open unless you floor it, which is how it should be. As for gas mileage I'm still getting ~20 and I like to run it hard. Do the mod you'll be happy with it, just be prepared to have it feel awkward at first, you'll have to learn how to make it smooth.

 

True that! I have mine ziptied for now and it opens at about 3/4 throttle. I usually don't start easing into WOT until about 3500-4000. As you go from 3/4-WOT you feel the power increase as you push the pedal. Very cool

 

I did it and it's very noticeable when the secondaries kick in. You'll feel it with your foot. Once you notice you'll adjust your driving style to accomodate it.

If you don't like it the mod is easy to undo.

 

thank you! this is the way i figured it was

my knowitall buddy says otherwise, but i have to pretend like i think he's right since he's helping me out so much with my car....

there you go mike.....(for **** sakes mike) lol

 

make it mech and turn the linkage it will explain its self if he still bitches

 

I have yet to see a good illustration of how to do the mod, the pics I've seen really don't show the mod very well, anybody got a carb on the worktable that can do a before/after shot showing how it's done?
That would be great.

 

the carb i want to use on my car is completely stripped. the only hookups are throttle cable, fuel lines, and brake booster line. i bought it this way. problem is the throttle only goes half way, and that's it. the secondaries don't open. practically all the linkages are missing. anyways i plan on having it rebuilt, and i have a stock nikki unmolested i can take parts from but i would like to see pics too jsut to find out what is wrong with this thing.

 

i can give you a now shot honestly not rocket sincesejust a matter off wireing two linkages together tight

edit im sorry flash makin it all blury heres some pics but i dont think they will help much ill post some tomorro

 

I don't have any emissions on my carb, so don't let the spring and the bare look confuse you. This picture was taken directly under the air filter, passenger side, rear side of the carb. There are two shafts coming out the back, the bigger one towards the driver side is your primary butterfly shaft and the small one on the passenger side is the secondary butterfly shaft.

Okay, now that we established where the secondaries are, take a look at the picture and Identify the metal piece that the clip of my zip tie is resting against. That arm has to move with the other arm on the spring loaded shaft on for the secondaries. Just connect the two arms on that shaft togeather and there ya go!

 

forgot to attach image

 

what i have learned from this

my carb is already modded for mechanical secondaries (i just threw this thing on a new motor i haven't even run yet so that's why i didn't know) the previous owner said he thought the mod was done, but told me it wasn't done properly\

my secondarie butterfly valves/linkage is completely stuck. the secondaries do not open at all. i've even tried pushing them through the top of the carb with a screwdriver and they aren't budging at all.

now i know why my carb throttle only goes half way. because when it gets to thje part for the secondaries to open, they don't open....which also means the primaries are only about 3/4 open

is this a common thging for them to bind up? or am i screwed?

 

You guys salt your roads right? Rust hurts!

 

ummmmm yeah

sterling!!! am i screwed?

 

Dude, use some initiative. Get in there, find out what's wrong and fix it. My bet is the linkage has been modified incorrectly causing it to bing up.

 

Mine was completely stuck also before I did the mod. Spray some penetrating fluid on either end of the shaft and let it sit for a little while, spray some more and try to work it loose without breaking/bending anything

 

I've got a sterling with mech secs and it is the absolute best to drive in any conditions. With the secondaries under the direct control of your foot, *you* choose when they open (you can actually feel the difference in the pedal between "primaries only" and "secondaries too").

When I press down on the pedal, it goes between 1/3 to 1/2 the way down and then I hit a light resistance. With a sensitive foot, you know that resistance is the little link between the primaries and secondaries going tight. Then you can push past it (once you're high enough in revs) to open them up and take advantage.

Takes about 1min to learn the basics and be able to drive it full time. (Takes forever to find that "sweet spot" where kicking in the secondaries just right gives you the best "oomph"... but that's what makes it fun).

Whenever other people drive my car I just tell them:
"Drive it like a normal car, but you'll notice a resistance halfway down the pedal. Dont' push past it until 4k and you'll be fine"

Nobody ever has problems driving it.

You just have to remember, you can't suddenly SLAM the throttle to the floor anymore. If you do, all 4 barrels open at the same time, and if you're at low revs there won't be enough velocity to pull the fuel out and atomize it. So your car will get all air, no gas, and choke out.

Jon

 

Wow, this is officially the most ghetto modified thing I've ever seen. I've worked on holley carbs( both vacuum and mech) and have never seen anything closely resembling this garbage. I say if you want it, do it right, buy a holley and make a plate to fit the manifold, or keep it vacuum, as there is clearly nothing to gain by this other than hampered acceleration at lower RPM.

ghetto, I had to say it again its that bad.

 

^ Yeah, You arent really gaining anything by doing this. Other than making your car a pain to drive. I see no advantages of anysort by doing this other than lowering economy, and making the car less user friendly.

 

What's ghetto about it? I really don't think you have any idea what you're talking about.

 

^ I think he is referring to the zip tie......

 

And the wire. What is the point of doing it, unless you have a turbo, in which case the vacuum wouldn't open the secondaries.

Lets look at the ghetto parts of it in detail.

1) press the throttle, the wire has slack, so it might not open the secondaries right away, unless you wound the wire really tight (mad type yo),or it doesn't open at all( as such in nick1's case).
2) if the secondaries DO open, they open when the slack in the wire is gone, and the secondary plates now move with the pirmary, at a rate of...... hhmmmm...well, you would have to measure the radius of the linkage to find out the ratio between the primary and secondary linkages.
3)Assuming you've got this far, your pirmary plates are now open. but, there was slack to start of with, so where do the secondary plates go to? Doubt they would open all the way, or by everyones math, they would be 1/3 unopened, impeeding airflow, and losing power.
4) As your shifting mad quik yo, you snap the wire which you ghetto'd on, and you lose your street cred. damn, should have bought the civic.

 

lol uh oh, now i pissed off mike

sorry buddy

i don't know for sure about all the facts, but i do like the simplicity of the mech. secondaries. i have yet to actually drive a car with them, but as per the writeup on it by sterling, if it is done right, the primary and secondary butterflies will both be standing straight up and down at WOT.

either way, i still have the problem of my secondaries being stuck...i'll try to get em loose and go from there, then see just how much crap i have to add to the carb to make the vacum secondaries work. if its too much, im going with mechanical

 

if the guy had teared it apart maybe he might have not screwd the butterflys in right they have bout a 1mm gab i had to play around till i got them center but try the penertrating spray first i would say to do this as a very last resort i meant very last as its abit of a **** around