why is boost prepping a nikki such a secret? the people that want to make an insanely fast car arent going to bother with the nikki anyway probably. The ones who just want to be turbo'd want to do it as cheap as possible. I would pay someone something just to tell me how to do it, since i want to do all the work myself. I read how to do it to a holley 600dp and it doesnt seem hard to do at all. I know i could do everything, but i think there is just one step that i dont know. I would pay to know it, and keep it a secret.

 

x2. been searching and keep hitting walls.

 

contact Bad83

 

the problem is no one has done a write up on it and a company like atkins could make money off of just sell a kit with instructions sence robert has it down with the nikki i would say have a group buy for parts and instructions get intrest and buyers then contact him.

 

If you found out the secret of boost prepping then secret ninjas from the ancient society of old school rotary turbos will dispose of you!

 

Id go down happy, with a fast car.... Hahaha

 

The market for performance improvements to the first gens has dwindled substantially over the past few years.

Hell, even Mazda abandoned them and quit making 12a housings.

 

Someone needs to just do whatever it is they think might work and document it in a thread. I'm sure with all the different input this section has to offer as a whole & a bit of patience it can be figured out.

 

Has anyone put a hat on a stock Nikki with the basic mods to seal the top of the carb.... with a wideband and see what happens!?

 

I'm not too familiar with the Nikki myself, nor do I have one handy to examine, but I'd imagine that the principles are the same as boost-prepping a Holley. Convert to mechanical secondaries and seal off anything that could leak.

 

^ thats what i was thinking. i looked at the "how to prep a holley DP" article and i dont see what would be different with the nikki. Up the jets, drill the ap jet bigger, dont use extra gaskets in the ap diaphram, remove all the extra **** off the nikki, plug all vac holes that are unused, solid floats, convert to mech secondaries, lengthen the ap arm... what else? seal everything, remove choke... what am i missing?!?

 

up jet sizes to approx, 135ish primary and 260ish sec for 10psi. I know im close, i just need to try it. I feel like there is something im missing, or more people would would do this. Everything that ive stated doesnt seem like it would be hard to do at all.

 

From what I understand you don't just need to seal it up. I haven't boost prepped a nikki, but I've worked with boost prepped webers and dellortos.

It does need to be sealed, but it also needs to behave as if it is not pressurized compared to the outside air pressure.

If you could develop a theoretical giant hat that covered the whole carb, fuel tank, fuel pump and lines, you wouldn't need to do anything different at all to the carb besides jetting.

Now you can shrink the theoretical hat to cover just the entire carb when you add a rising rate fuel pressure regulator (RRFPR). Now the RRFPR doesn't "push" in extra fuel to enrich the mixture, it just makes the fuel come in like normal. so the system behaves like their is no pressurized air. the boost would make the fuel flow slow until eventually it pushed it backwards, the RRFPR simply keeps that from happening, keeping flow like normal. The proper jetting is what enriches the mixture.

You need the look at the carb and remember that it needs to "think" it's not pressurized. It needs to "think" that some how when you step on the throttle, the whole vehicle is magically going into an area where the air is thicker and more pressurized then just one atmosphere.

For example if the jets are sealed off from the boost pressure, like in a dellorto, JUST SEALING UP EVERYTHING WILL NOT WORK. There needs to be a path for the boost pressure to reach them so it will operate correctly.

I believe this MIGHT be the case with the nikki. The air horn (top piece) looks like it seals off the venturis from the jets. So you might need to drill in the right places to let the fuel bowl and jets "see" boost, so they "think" that the compressed air is everywhere, like a beautiful, thick, turbocharged atmosphere.

This has me curious, so I'm gonna look at my old nikkis. But if anyone want to take a peek at my boost prepped dellorto and weber IDA, I'll post pics. It might clarify what I stumbled through describing above.

 

i see what you mean, it looks like if you try to put boost through the nikki, the fuel would get pushed back into the bowl through the jet. The top of the bowl looks like it needs to see pressure too. i think. lol

 

You don't drill out the accelator pump unless you need a bigger pump shot.

You drill out the power valve circuit on a Holley and you completely modify the power valve to work with no vacuum to positive vacuum. No power valve on Nikki/qjet/edelbrock carbs.

It SHOULD be closer to prepping a qjet or edelbrock. Holley is a way different, much simpler carb.

 

guys... as said before... send it to Robert... for $100 it's done... then if you're REALLY curious, take it apart and see what he did.. then you can be the next boost-prepped Nikki Guru.

 

If I did that I wouldn't I've the satisfaction of doing it myself. Not to mention I'd spend $100 on something I dont need to spend money on. I have everything to do it.. I just need to figure it out.

 

I though all you needed to do was seal off the vacuum lines not used and one of these (I'm sure there a couple other steps but for the most part that was it)

 

If I did that I wouldn't I've the satisfaction of doing it myself. Not to mention I'd spend $100 on something I dont need to spend money on. I have everything to do it.. I just need to figure it out.

 

^^ no.

 

^^ didn't say I was right

 

I got a "boost prepped" OER (basically weber) sidedraft from robert. When i put boost to it it leaked everywhere!!! I just sealed off everything that was leaking. As long as you allow pressurized are from the intake to reach all areas of the carb, as you stated, it should be good. Well also sealing everything that may leak...

if you dont want to pay for someone to do it you might have to resort to paying to experiment on one...

 

THE PRIMARY JETS DO NOT NEED TO BE CHANGED. You can buy main jets for a Harley Mikuni carb that will fit the Nikki secondary jet location. The Mikuni jets are sized differentlly then the Nikki jets. Use the 200 Harley Mikuni jets. Good for 10-12 pounds of boost. They will cost you about 5-8 bucks a pair. The choke flap and shaft have to be removed. Holes sealed up with JB Weld. All vacuum ports removed and sealed. Secondary mod of course. You can use the stock floats. When you get done, it should look like this.

http://smg.photobucket.com/albums/v6...view=slideshow


There it is guys. Let's see how long this stays up before being deleted.

 

???? Why would this be deleted ????

 

^^ awesome! thank you so much!!