lithe951

There's a good chance I'm going to be building a race engine in very short order and I'm looking for advice. FWIW I know rotaries pretty well, been away for a few years though. Here are the rules I have to follow:

1. The only rule is little/no money
2. See rule #1

So I'm going to build up a 12A n/a engine, looking for the best possible output in a road-racing engine, so high-end is great, power out of the corners even better. My first question, can I do a full bridge port without getting into high $ stuff? Odds are good I won't be able to replace apex seals and I'll be stuck with a modded Nikki/stock intake. A header is possible if I can find one dirt-cheap so is it even worth trying a bridge, or will I be better off with a street port? Thanks!

Mark

ultimatejay

iTrader: (1)

The Nikki will never flow enough to support a bridgeport, so stick with a streetport and use oem seals. If your really tight you can use some used seals and just buy a gasket kit. Just make sure the used seals are within Mazda specs

IanS

iTrader: (4)

Sterling himself said that he is extremely confident that the Sterling Nikki carb will be just fine on a half bridge (wouldnt try it with a stock nikki thats simply stripped down though). Although of course when you end up with a bridge or half bridge you may end up wanting to get hardened stat gears, etc since the powerband is moved up quite a bit. Streetport may still be best option though so you dont end up buying a whole bunch of extra stuff and therefore requiring a much longer break in period.

lithe951

That was my concern that the stock Nikki wouldn't flow enough, even with some improvements...I won't pretend to know enough about them to get the to flow like Sterling does. And buying one is out of the budget.

I suppose I should mention we're building a car for the 24 Hours of LeMons running in SC in July, so the budget is REALLY tight.

FWIW I nearly bought an '84 GS last night with 235k on it. It ran well, engine pulled great and drove pretty good too. But the second time we jump started it (stone-dead battery) there was a HUGE arc on the positive terminal and from that point...nothing. The positive cable was corroded and weak and I think it blew the coil. Turned over (mostly) fine, had fuel, but no spark. Unfortunately the racing budget doesn't allow much room for fixing problems so I had to back out. Any leads on a super-cheap, but running/driving car?

Sterling

Some of your rotary competition is using a Sterling carb. Some other of your rotary competition chose not to. (FYI)
I can offer a "less than esthetically pleasing" model for less, built with part that are too weathered to be used for carbs that need a good finish. This is what I did with one LeMons customer.

j9fd3s

iTrader: (3)

back in the early 80's in the imsa RS class they were running "stock" carbs on a full bridge, its not ideal, but it did work.

PDF

There is nothing wrong with a nikki carb! They're very well designed and much more refined than a Holley or IDA. Theres a few basic tricks to them and when done properly they work well. I've got one on my daily driven peripheral port and it does the job nicely. The only downside is it take much longer to tune a nikki than an IDA because of jet access.

lithe951

I like the Nikki a lot, had a modified one on my last autox'er and it ran great and made excellent power. Sterling, you're getting a pm.

btw...a daily driven peripheral? wow, I'm impressed...I need one of those.