Send it to Sterling. Im sure he could work some magick on it.

 

I have been reading the forum for more then a year and have yet to see anyone say they know what is needed. It is always "stuff has to be done send it to XXXX to get it done" But if someone is making their money doing it then I guess they would not want to tell.

 

and I guarantee he'll explain in detail exactly what he did to it.

 

Him and Carl are not doing turbo mods yet. Last I read.

 

I believe that is correct but hypothetically speaking, if Carl or Sterling did do turbo Nikki work I am quite sure they would be forthright in explaining their deliverable.

 

it took me a year to figure out how to boost a nikki, on low boost that is, another 2 years to get high boost figured out and the cat went 10.40 et @18 psi with a nikki so i do know what im doing with nikki carbs.... now after all the time i spent learning on my car, (experimenting, leaning out motors, blowing up, wasting money) you want me to explain exactly how to boost prep a nikki?!!!

 

Vendor secrets, okay, I'll buy that. Being as experienced as you are, perhaps you could contribute to the discussion by giving some general non-Nikki specific things that would need to be done to a carb for this application. That would be interesting to read.

 

Not accusing you. Propority information is how money is made. If I run a business to live on, I would not tell eather.

 

Yeah, if it's that proprietary you're damn right I wouldn't give away the recipe. As an example I don't see Racing Beat coming on this board selling or telling members how they make their stuff either. Racing Beat's damn smart that way. But I digress......

 

I don't know exactly what has to be done yet.

-But I gaurantee you this-
When I finally figure it out, I will have NO PROBLEM sharing my information.
I freely share information about mods both here and on my website (as pathetic as the site still is )

-I feel it's my quality craftsmanship that will set my products apart from others', not some "shhh! -It's a secret" bullshit.
I will stand behind my product, and I'll always offer a money back gaurantee when I can.

-With some people, your lucky if you get the product in the first place, let alone your money back.


Robert, you're starting to really **** me off.
Personally, I think you should deflate your big head so that you can get it out of your *******.
You should be alot more humble around here than you are.

And wipe that ******* note off your avatar before you get yer stupid *** booted off again. It's antagonistic for one thing, and IMO you sure as **** ought not be so proud of a pissed-off customer as to wear a reminder on on your posts like some kind of "badge of victory".

...then again, it kinda suits you; a reminder for us all.

 

im not tring to make anybody mad, and i definaty dont have a big head

maybee when i go 8 sec. with my 12a but until then, im just working at the shack.....

oh yah and as far as the turbo nikki mods go the bottom line is i have done it and you have not... and there is alot more to a turbo preped nikki than you will ever know.....i think i have earned that.... and the note in my avitar is to remind people than i hold no hard feelings toward him and his friend will recive more than he paid for , thats a promise.....flawless 93 engine parts are hard to come by cheap but i will make good on my part, i always do.....

 

I've prepped 4 holleys for boost, hopefully some of the info is the same for nikkis. This information will all be about holley's, to tell you the truth I know next to nothing about nikki's. So if any of the modifications transfer between the carbs, good, if not then this is still some good info if anybody wants to modify a holley.

The first thing you need to worry about is the floats cracking or crushing under pressure. Holley makes some nitrophyl floats just for that, so it isn't a problem. It is also possible to fill the brass floats with some sort of expanding foam, just remember that this decreases some of their boyancy (big problem with weber IDA's from what i've read).

Mechanical secondaries are needed along with a larger accelerator pump shot. Good thing sterling is around with that write-up

Next, the bowls will be pressurized, and the higher pressure inside the floats is going to want to squeeze out to the lower pressure atmospheric air. On a holley you fix this by milling the carburetor main body so it is truely flat (you can also use a flat file), this way there are no raised portions or indindations and it makes for a pretty nice seal.

The choke horn must be milled off, the linkage removed, and the choke holes filled with epoxy or jbweld.

That is basically everything you need to do with a holley to make it stable under boost, then it is on to the tuning...I'll give a little info on that also.

Simply jetting up for correct a/f ratios while on boost will get you there, but the carb will always run rich while off boost. That isn't much of a problem for some people (drag racers etc...), but for those who need good gas mileage there are ways to cure that problem.

The power valve opens on a holley at a designated vacuum number (I am not sure if nikkis have anything similar to power valves, but oh well). There are different power valve ratings for different amounts of vacuum. So at idle and light cruise (around 18inHg) the power valve will remain closed and you will simply be driving around using the main jets. Once the throttle opens enough the vac will drop and the power valve will bypass fuel to richen up the mixture. This good part about this is you only get the rich mixture when under heavy load (lets say 6.5 inHg all they way through the positive boost range) so you can actually tune for boost using the power valve. Granted, you will need to jet up between 4 and 8 sizes both primary and secondary, you can richen your mixture by simply drilling the PVCR (power valve channel restrictions) 1/32-1/16th of an inch at a time.

Well I'm not sure about nikki's, but that is how i go about holleys. Maybe i'll do an actual writeup one day with pictures and everything, for anybody wanting to blow through a holley.

-Marques

 

i always removed the powervalve on holley carbs because under boost they blow out...

holley carbs are way different than nikki carbs in many ways....

worst part is the huge secondairy bog that cant be eliminated due to there only being 1 pump squirter on the primaries and not on the secondaries....
if you use a holley doublepumper though you can eliminate that problem 4 squirters instead of 2

 

Yeah I don't like the 4160's much. That was my first blowthrough carb and i wasn't pleased. The 4150 double pumpers are great. I've boosted up to 1 bar and i've never had a powervalve blowout, maybe i'm lucky.

 

I'm planning on boosting my stock nikki to about 8psi. If no one is sharing info my then (2-3 months from now) I promise a full detail of everything needed to modify the stock Nikki. Personally, I think you're better off getting a different carb for anything over 8-10 psi. I'm just trying to score some cheap power out of my daily driver, so I'm not going overboard or all out on parts.

 

yah i totaly agree, if you need help ...E-mail me llllll

 

guess i kind of opened up a can worms on this one. still not even some pointers though?

 

Well you have to read between the lines. So far we have

The floats need to be tested to see if they can handle the pressure. If not then they must be filled with foam to strengthen them. Holleys need to be filled cause they are cheap brass.

All the AP needs a bigger shot, and the Secs need to be made mechanical.

As far as the bodies go, the Nikki's are very well made and I dont think that milling will be necessary. Face it, Holleys arent the best mfg carb out there. Even professional Holley carb guys mill them even for N/A engines. They just arent made to great tolerances.

I'll add that the throttle shafts may need to be sealed, but I havent pressurized one yet so thats just something to think about.

Those are the issues I'd look at first. And Robert, no one is asking you to tell us exactly how to perform the mods step by step, just what needs to be done. It's not rocket science. Just knowing the carb, the major issues become obvious. In my post Id guess I hit all the major pitfalls. Cool it down alright?

 

rx7carl thanx u really cleared some things up for me, the maine thing i am worrying about is the tuneing, like where do i get jets?

 

jets for a nikki? Mazdatrix has them. Also you can use Holley 10-32 airbleeds as they will fit (but youll have to do the metric conversion and use a holley jet chart). But youll also need to modify the main airbleeds like we do for our modded carbs.

 

hay thanx, really good info i will look in to that!

 

How much boost can a freshly rebuilt street port 12a handle?

 

This is kind of a grey area for me too. I know how you strengthen a piston engine for higher boost, but what about a rotary. Really the only things are the apex seals, side seals, and any other seals either on the rotor or around it. I would guess you upgrade these to a stronger material.

 

^the stock seals and motor in general are strong enough for moderate boost levels. I've seen 10 psi and more on a stock 12a. Some 12a turbo low compression rotors wouldn't hurt though.

 

ok a little up date, so far i have converted to mech secs, put a bigger shot on the ap, also removed the booster supports, and polished the boosters(i think thats what there called). also removed the choke and sealed it, removed the shutter valve on the intake man, and sealed the holes left over. now it going to be n/a (60-1 on its way too)till i get used to tunning this thing, just wondering where i should start with the jet sizeing? its stock port.