83gslRX-7

when you say "This will use more fuel than stock even when driven conservatively, which is why original vacuum operated secondary box and original fuel jets are returned along with installation instructions. " on the partly moded carb how bad is it? im looking into doing this but my 7 is my daily driver and i dont want to fill her up everytime i go to work...

Sterling

I dunno.

None of these mods is new. This is all old school ****. I've just developed a few different approaches. I have not yet tested the "Partial Mod." carb for MPG. I've had similar mods on a stock Nikki before, but I don't recall what the MPG was.
I just know it uses more fuel. (Common sense will tell you that.)

We're at the very beginning stages of modding carbs. Questions like yours is precisely why we appreciate feedback from our customers. Frankly, I can't take the time out to slap on a partial mod and drive four tanks of fuel out to get an MPG. I will if I have to, but I'm hoping that customer feedback will help with details like that.

As an aside, I do recieve alot of questions concerning fuel consumption. However, I don't recall too many posts here where people ask about the fuel consumption of a Holley, Weber, etc. It makes me wonder if people understand that the modifications we do to these stock carbs really does make them into performance carbs.
If you don't see even the Partial Mod. Nikki as a performance carb, then you will be disappointed at the fuel consumption.

The Sterling Carb on my DD gets 12.5 MPG. I'm jetted fat for power, and I've never jetted it for economy, so I cannot gaurantee what I don't know. But it's the most heavily modded carb I've done, so I can gaurantee that you won't get less than that!~

I'm working on a vacuum box mod that will allow the user to be able to change the vacuum needed for the secondaries to open. It's very simple...It's a valve that bleeds off signal to the vacuum diaphragm. I'll put the lightest possible spring inside, and simply by opening the tiny needle valve, you'll be able to have the same effect as installing a stiffer spring. It needs to be tested to be certain it'll work.
But a special accelerator pump linkage will have to be developed for quick, precalibrated adjustment so the carb does'nt dog from too much shot when you "tighten the spring" in the box.
...and it has to be doable for cheap, and easily installed by those that have our modded carbs already without this feature.

See?...I'm thinkin' aboutcha.

83gslRX-7

you have been pmed!

Sterling

I would think so, but not having done it myself, I can't say for certain.

slashdawg00110

sterling - I saw in another thread a recommendation to upgrade from the stock fuel pump and add a pressure regulator even when using an un-modded carb. I think you may have been the poster. Can you explain why I'd be advised to do this?

Sterling

This is probably advice I gave to someone who was going to put slightly larger jets in his stock carb.

The stock pumps on our sevens are at least 19 years old now. They are of piston design, and are small capacity to begin with, and can't be expected to perform as they did 2 decades ago.

Making the secondaries mechanical also creates a necessity for a better pump.

If your fuel pump is marginal, you will run lean at WOT.

slashdawg00110

Thanks. I'll add that to my list of things to do.

rmayton

ahem,

has anyone thought about a better intake for the nikki or is it not needed?

Rx7carl

It's needed and in the pipeline (if I gave out the flow numbers for the stocker youd probably pass out), . Making an entirely new one is a bit too much in the $$$ at this point, but I am working on some stuff for the stock intake.

Sterling

...in my Beavis voice, "Bring it. Heheheheh heheheh."

(Thought you were gonna stump us, huh? )

rotorysuzuki

how do these mods work for off road performance I race my samurai and am currently putting in a 12a from a 79 and want as much as possible out of it but dont want it to quit on steep hill climbs or off camber sitiuations

Rx7carl

Cant say for high angle off road from experience (never rallied), but it is a performance carb, built from the stock carb that was designed to run on a rotary, unlike other carbs.

Sterling

You would have to be tilted at approximately at OVER 45* to the right (drivers side up) in order to starve both primary circuits for fuel.

You're far more likely to starve the primary circuits in a Nikki going fast around left curves while racing on asphalt because centrifical force throws the fuel all to the right side in the carb. (which is why we install baffles)

It should'nt be a concern unless you are rock climbing, in which case I would think there are few carbed engines.

mar3

iTrader: (8)

You've got the mill and lathe stuff, right? How about a extension plate for the secondary pot and a new hat with a plate that can go back and forth via a threaded rod? Then use a long spring inside than sits on the plate...by adjusting the rod, you determine spring rate...some BGs and Holleys use this idea, I'm pretty sure....it's been so long since I tore into a Nikki, I can't even remember for sure if the vac secondary pot has the spring on the hat side, but if it does, this would be simpler, I would think...

It's late, I'm upstairs and too lazy to go into the garage to get the haynes, so disregard my rambling if the spring is internalized...

Sterling

I think signal bleeding will prove to be a very easy and consistant way of changing the carburetors characteristics.

I'll let everyone know how it turns out.

Metallic_rock

Hey, just thought I'd throw this in.... I still have my stock fuel pump with a clean fuel filter... never had to upgrade the pump. Haven't had any problems yet.

Sterling

I advise upgrading the pump.

Metallic_rock

Who knows, maybe mine was upgraded before me... I haven't actually looked at it.

Upgrading is Strongly advised if you have the orriginal pump.

I have a 13b hybrid that was installed before I got it, so who knows what they did to my fuel pump. There are so many odd things about this car. I have 2 oil coolers, as an example. I have the beehive and the SE oil coolers.

hornbm

I am using a GSL-SE pump with regulator on my weber. It does work, however I am having some fuel dilvery issues. My pressure is too low, so I gotta adjust it. I just havent had time to **** with it in a bit.

RXTbone

Can I just state how ******* pissed off I am at myself for not researching the pricing on Sterling's rebuild?

I just spent $350 a few months ago for a stock rebuild!

So, let's say that I fall into a little cash and want a Sterling carb - what kind of HP am I looking at with simply a stockport, full RB single pipe exhaust - with the addition of your Sterling Carb?

Also, is the "is a Sterling carb waiting to come out" pic of the actual modified Nikki?

This thread is turning into a "infothread". All we need now is the pretty showgirl twising her hand over your carb in a presentating fashion...

Rx7carl

In the neighborhood of 170hp. Which is a pretty respectable neighborhood.

Yes, that a picture of an actual Sterling carb.

If you find me that spokesmodel, I'll give you a discount on the carb.

Sterling

Just click on the picture.

Sterling

They're looking even better now that we plate the linkages.

These flow 450 cfm.

Unsupa

iTrader: (2)

rawr. i want me one.. hopefully i'll have the money saved up within the next month..

i know you said 12.5 mpg on the modded carb, but was that highway or city driving? my stock carb is only gettin me 16 on the highway, so it's not much of a concern, just wondering.

Sterling

I said 12.5 on MINE.
-You can rejet your Sterling Carb to whatever performance-economy comprimise that suits you.

You can jet the secondaries rich and lean out the midrange, so that you can cruise lean, and then open her up for passing power, if you want to.

I myself live on squirrly rural roads, and love to have midrange power. So I just jet gluttonously rich throughout.

However before going on long hauls, I'll jet down the carb for better economy.

That's the beauty of full-out, absolute tuneability.

And Bahh to vacuum secondaries.
Once you learn to feel when they open through the spring in the pedal, you'll be able to drive with your foot off 'em when you want.

If you choose to jet like the above example, then you would feel the secondaries open up when the car surges.

-But for all out performance, you can jet so that the transition is as smooth as can be.

Just read the texts on my site.
They explain how it all works, and then you'll realize how the Sterling Carb can be curtailed to meet whatever your needs happpen to be, and can be changed at any time!

Click the signature picture, and then click the big one that comes up.