how much would you have to mod the carb to do this? Like fuel wise? Bigger primaries and secondaries? I saw that you added a RRFPR as well. Just curious cause i want to do something like this as well.

 

I don't have anything against them, I was just a little weary of their reputation on the various forums as well as ebay feedback. But I got my carb hat and it looks like a quality part so I'm happy. The shipping was a bit delayed but nothing ridiculous. I'm not ready to put it on yet anyway.

So I had an idea last night that I'm curious about. It's a possible solution to the exhaust and intake manifold problem. Everyone says that a TII turbo and manifold won't clear the stock 12a intake manifold. I noticed there is an old school 12a manifold for sale locally. After looking at the pictures of it, I'm wondering if it will clear the TII turbo. It seems a lot slimmer but I can't be sure without looking at it in person. If it cleared, that would save me the trouble of having to have a manifold made or an adapter for the stock TII manifold.

 

Slightly bigger primaries and much bigger secondaries, since you'll be hitting positive boost numbers when the secondaries are open. RRFPR is essential to add substantially more fuel along with the air that the turbo is adding. Sounds like you're on the right track if you want to go this route - read up as much as you can before you start spending money and turning wrenches

 

A rising rate regulator (or boost referenced, if that's what you wanna call it) isn't really the mechanism for adding extra fuel to the mixture in a carburetor, even in positive pressure situations. The carb's jetting and airflow is responsible for that. The rising rate regulator really just keeps the float bowls from dropping in level faster than they should (or from running dry). That's why it's boost referenced at 1:1. It kind of makes float bowls act as if there isn't positive pressure.

Now the regulator keeping the float bowls filled higher at high load (boost) than they might normally be under full load at NA could technically be a means of enriching the mixture a bit under boost. That's because more holes on the emulsion tubes are exposed as the level drops, and that leans the mixture.

Sorry I don't mean to be rude or nit pick. I just feel that understanding that can help blow-through carb tuners.

 

I'll tell you right now and save you the trouble: it still won't fit. Even my RB sidedraft LIM, which is much narrower than any stock carb intake manifold, required a spacer (about 1/4" if I remember right, and I also ground down the turbine housing a bit).

 

Yeah, my explanation was a bit oversimplified. Thanks for going into specifics on that. It's not rude, it's just good info

Thanks, that's exactly the answer I was looking for. You saved me trouble and some money I guess it's just better to have an exhaust manifold made. It's no big deal, I just have to find a good shop around here that will do it right. If they want too much money then I'm just going to buy a welder and make it myself.

 

https://www.rx7club.com/1st-generation-specific-1979-1985-18/start-well-something-awesome-707542/page2/

Good thread for you Lizard.

 

I've about worn the search button out in the first gen section lately but I haven't run across that thread... thanks, you're the man.