Hey everybody,

I own a stock 1980 Series 1 RX-7 with a 12A engine that I plan on modifying after I finish an engine rebuild. I would like to make about 160 hp at the flywheel (130 hp at the rear wheels).

I'm going to use Racing Beat streetport templates (product no.'s 22202 and 22210) and a Racing Beat exhaust system (no. 16410), and the stock Nikki carburetor.

I spoke to a Racing Beat representative on the phone, and he said that the stock Nikki carb was insufficent for 160 hp. I looked at the 48 IDA Weber (no. 16601) on Racing Beat's site, but the item description says that it has no choke and that cold starts may become difficult. But I've also seen people post on these forums about making 160 fwhp on a stock carb.

The Racing Beat rep said that with an aftermarket carb, a streetport, and a Racing Beat exhaust (no. 16410), I could make a conservative 150 fwhp. When I askes the RB rep about their streetport exhaust (no. 16422), the rep said that gains would be minimal (about 5 fwhp).

So my questions are: to make 160 naturally-aspirated fwhp, do I need an aftermarket carb? Do I need aftermarket headers? Do I need aftermarket fuel system components? And, if anybody has made similar mods to their RX-7, could they post dyno sheets and parts lists?

Thanks!

 

its been a while, but the Pro7 cars, which were stock engine, stock carb, stock exhaust manifold, with a 2.5" system would do 112-116hp
add a header to that and you'd be right around 125hp.

i'm not sure what the street port would do, possible it doesn't help until you put a header on it
and then to get more than that you do need to do something with the carb. if you actually look through the venturis with the carb off the car though, you can see that there are lots of screws and thing poking out into the airflow
if you can find it Paul Yaw used to have a page about his super header, which was ~150hp, i think at the flywheel, although its been a long time

you could also do some of the other tuning stuff, like an efan instead of the mechanical one, better ignition, etc

 

The amount of work required to let a Niki make that kind of power is very time consuming and without a flow bench will be a boatload of trial and error for you I'd think. I've done some work on my own flow bench years ago to try and help a client with a similar goal and while possible, the amount of money they would have had to compensate for my time was eclipsed by how easily (and how much more gains there are to be had) with an IDA.

There's also the option down the line of being able to run IDA style EFI down the line once you step into an IDA if you decide you can't live without cold start amenities and the like.

 

welcome to the board.

for starters, you will need a proper exhaust system that begins with a header. i don't see a path to 160 (with a 12A) without one.

on the intake side, aftermarket is the way to go. your choices are Holley or Weber, and Weber is probably the more sensible road. after you've done the porting you said you plan to do, you should be in great shape.

 

Go with the Ida Weber. The lack of choke is not a big deal if the carb is jetted right. Two pumps of the accelerater and hit the starter. All it takes to start. I think with 13b street ported it's possible to get 160 HP very easily.

 

You don't need to port a 12A to make that kind of power. RB SP exhaust and header, remove the entire rats nest, better ignition system, modified nikki or various aftermarket carbs, higher flow fuel pump, and electric fan. I had a RB Dellorto DHLA 48 that put down 134 whp back in the day with that configuration. I have since switched to a hogged out nikki and it revs better and feels about the same but never dynoed it. Now I'm putting the Dellorto back on to prepare for another project where I will use it on an engine swap (thats why I saw this post).