bikeordie092

iTrader: (2)

ok.. so i have an fb with the 12a, annnnnndddd... im thinking about diving into a turbo build, but i dont want to go nuts with it... im thinking only 6-7lbs, fabricating my manifold and downpipe. I want to do a blowthru, and if possible i want to keep my nikki. the wallet stays pretty skinny, so this needs to be a bit of a "budget build"

one of my buddies has some kind of "tiny" turbo, i think he said off like a 3000gt or something, its a mitsubishi of some sort, that he would let go pretty cheap. im thinking a small turbo would be perfect, because of less lag and the fact that i dont want much boost.

now for the questions, lol...
if this turbo isnt a good option, what would be?
with low boost is a bov really needed?
can i use the stock fuel pump?
how much hp does an intercooler add on average?

im sure ill have more questions, as im new to turbos... this is all i can think of for now lol

Qingdao

iTrader: (3)

N/A 13B You'll find enough power in one and they are cheap and LOTS of parts avalibility. Thats your option.



If you don't have money or experience then turbo isn't a good option.

bikeordie092

iTrader: (2)

i would, if only i didnt already have 2 12a's lol... i am experienced when it comes to fabrication, i just havent had the experience with turbos yet, as all the people where i live want their "all motor 500hp 350" lol..

i know how to fab the mani and downpipe and all that, and ive done quite a bit of research on how turbo chargers work, just need a few questions answered lol

LizardFC

iTrader: (1)

Small world. I'm building a Nikki blowthrough 12a right now. I would recommend getting a hold of a stock TII turbo or a similar aftermarket unit. A "tiny" turbo might not flow well enough on either side for a rotary. The manifold and hat are probably the hardest parts since they need to be custom-made. You'll need to do a lot of modification to the carb, add a larger return line to the tank, upgrade the pump and add a boost-referenced regulator. You'll need oil feed and return lines, which will require drilling and tapping your front cover or swapping a 13B cover. Don't forget a wideband 02 and boost gauge. You'll want an intercooler, which will require a battery relocation if you mount it up front.

You can find a more detailed laundry list on some recent threads. Just search "blowthrough turbo" in the first gen section. It's a tough project, probably harder than just swapping a 13B, but a good blowthrough will yield more power than an N/A 13B.

bikeordie092

iTrader: (2)

I would think blowthrough would be easier than drawthrough simply for the fact that you don't have to fab up some kinda mount for a carb elsewhere, not to mention a way to hook up the tubing to the existing mani... plus I like blowthru better anyway, wayyy less risk of blowing stuff up lol

PercentSevenC

A stock TII turbo would be cheap, or you could look for a used T04B or something for more power.

No. I would suggest one because cars with no BOV sound stupid and the eBay knockoff ones are dirt cheap, but it's your call.

No. You need an EFI pump (Walbro 255 is overkill, but they're as cheap as anything else), a bigger return line, and a boost-referenced FPR (Mallory 4309 or similar).

Impossible to answer because it depends on too many things. The density increase of dropping 180F air to 110F (just making up some numbers here) is 12.3%, but you can also bump up the timing with cooler air, etc. Just use one. Don't make the same mistake I did. First-gens have a massive amount of room to easily mount a big intercooler, so take advantage of it.

ArmyOfOne

iTrader: (12)

I would start by trying to find a gslse fuel tank, larger feed and return. You can use a gslse fuel pump as well with a Mallory 4309 or modify a holley dead head regulator to function as a return style. If you are just running low boost, use a TII intercooler and mount it up front and run your tubing.

As far as the hat goes, find mild steel in the correct size to fit around the carb inlet and make angled cuts (lobster style) and reduce the diameter until it can connect to the tube. If you are going to do it getting the best bang for your buck, you need to fab a lot of stuff yourself. Maybe even find an old school 13B Nikki to help with inlet size and fuel delivery.

Jeff20B

iTrader: (13)

Never really a 13B Nikki. It's 12A Nikki or 13B Hitachi.

ArmyOfOne

iTrader: (12)

Thanks for the correction Jeff20B.

bikeordie092

iTrader: (2)

well, i just found a t3t4 today for $80 that is supposed to be good. so, let me see if i know what all i need...

-exhaust mani(fab)
-carb hat(fab)
-return style FPR
-efi fuel pump
-bov and flange/adapter thingy
-boost controller
-intercooler, piping and couplers
-oil cooler
-boost gauge
-wideband O2 sensor and gauge
-oil temp gauge

i believe i can get everything pretty cheap, like under $400.. we shall see lol

Jmthegerm66

iTrader: (1)

ive got a boost prepped nikki and the regulator. the carb was set up for blow through.
ill sell it if you want it. pm me or reply to post.

zaridar

iTrader: (3)

Not wholly true... With some slight mods you can do a front mount and keep battery up front... I guess it's relocated but only about 2 inches... I did it..

bikeordie092

iTrader: (2)

just wondering, what all must be done to "boost prep" a nikki?

LizardFC

iTrader: (1)

If you can do it, more power to ya! I wanted to relocate mine anyway. You could also get a smaller battery like a Braille or Odyssey for more room. Did you have to move the coolant reservoir? I just bolted mine to the strut tower.

You have to seal everything off, as the inside of the carb will be pressurized under boost. So every opening to the outside must be sealed in some way. I haven't gotten to this part yet, but it'll be my next step after I install the new fuel pump. It looks like the tricky part is the throttle shafts. I read that you can mill a groove in each side where the shaft passes through the wall of the body and sandwich an o-ring in there.

The main fuel jets will also need to be hogged out or swapped for larger jets. I would step up the primaries a little, and the secondaries a lot. How much is up to trial and error. Tuning! I would definitely do the accel pump mod at this time. Increase the capacity, bore the jet and nozzle, and increase the duration via the linkage. You don't want that typical lean spike right as you're building boost.

coldy13

You can do the front mount IC without moving the battery at all. Actually, I have a good IC and all the piping to do it and I wouldn't want much for it. There's just enough room between the sway bar and front crosstube to fit a 2" pipe through the gap. Looks like everyone else has your other questions answered, you can search through my older posts if you want more info, I'm getting tired of typing it out all the time

bikeordie092

iTrader: (2)

where is a good place to get a rebuild kit for a nikki? i have at least 1 extra if not 2 laying in pieces in a box lol.. i would like to "boost prep" one of those and just put it on the car when i get ready for it. oh yeah and where in knox are u? i live in maryville and dont have any rx7 friends lol

LizardFC

iTrader: (1)

Black Dragon carries it: 1979-85 RX7 12A Carburetor Repair Kit > Black Dragon Automotive > Carburetor Repair Kit For 1979-85 RX7 12A

I got my last GP Sorensen kit at Advance for like 40 bucks, so that's a pretty good deal. Looks like it has everything the other kits have.

I'm in West Knox near Cedar Bluff. There's quite a few of us around Knoxville, did you ever find our group on Facebook?

bikeordie092

iTrader: (2)

i work at autozone, and we list 2 different kits, but im not sure which one to get...

and yes i found it and tried to join, but i dont think i was ever accepted lol.. if u dont have anything to do on tuesdays and thursdays im in a car club and those are the nights of our meets... feel free to come out, if u wana look us up its illegal illusions, just like the page on facebook and they post when and where we will meet.. im there almost every time.

LizardFC

iTrader: (1)

It's probably the 79-80 kit and the 81-85 kit. AFAIK they contain the same parts, but if you order from there I'd say go with the 81-85.

The guy who does the approvals for our club is probably asleep at the wheel. PM me your e-mail or name you use on facebook and I'll send you an invite.

bikeordie092

iTrader: (2)

well, i got my turbo the other day, has anyone heard of turbosh?? its a .50 trim t3t4, and it seems that the serial no. yields no results on google.

K-Tune

iTrader: (26)

Sounds like a Chinese copycat turbo.

Jeff20B

iTrader: (13)

Give us the wheel sizes. Take the housings off, measure the large and small diameters. Is the turbine housing divided? What outlet size is it? What A/R is it? What is the cold side like? 2.5" inlet with a 2" outlet? Or bigger? What A/R? Water cooled CHRA?

bikeordie092

iTrader: (2)

ill have to do that, but i do have one other question, oil feed. where does it come from? i know you can tap the front cover for the drain. i will soon have a build thread, since i lost the front rotor last week... stupid "rebuilt" motor.......

coldy13

One of these is the best way Mazda RX-2 : Oil Pedestal (Version 2)

or you can put in a T fitting at the oil pressure sensor

LizardFC

iTrader: (1)

I have that one and it's a nice part. The only thing I don't like about it is that the outlets are on the driver's side so you have to route your feed line around it. Not a big deal though.

Sorry to hear your motor took a dump. Must've been a rebuild issue because factory 12a's are tough little buggers. Good luck getting it going again.