Hello all!
I have recently purchased an '81 RX-7 that i am trying to get more power out of. I have a few questions about certian parts.
1. Do I need a presilencer if i do not run a cat? I was just going to run a header, and then run an inline muffler to a turn out on the passenger side. Moroso has a nice inline muffler.
2. Has anyone had their carbs worked on by YawPower.com? I think a guy named Sterling does this? Is he good? does it add a lot of HP?
3. I've searched everywhere on this site about carbed nitrous. Is anyone running a plate system? what kind of carb do we have ( i know its a 4 barrel, but is it a spread bore or square or custom?) would a fogger tapped into the intake runner work better?
4. I have the chance to grab a free 13b from a 74 RX-4, will this bolt up into my car without to much hassle?, could i use the same externals?

Thank you very much for all of your input!

 

Define "need". It helps with lowering the noise. Rotary exhaust is louder than piston. I have the Racing Beat streetport exhaust with a 12A (presilencers on both ports), and it's as loud as I would want it for street application. Your rice tolerance may vary.

-dave

 

2. Sterling or rx7carl. PM them. combined with a full exhaust system, a well tuned modded Nikki adds about 50 hp.

 

One avaerage muffler made for a cylinder car will burn up - but not before your ears bleed.

 

1. No you dont have to run a presilencer, but it is going to be much louder without it.

2. Your referring to two different carb modifiers, if it were me, id send my carb off to sterling. http://www.sterlingmetalworks.com/racing_index.html

3. kettleman on this forum runs a plate system, but he has a different intake, probably the racing beat holley intake, (im not sure though). The nikki is not compatible with spreadbore or square. So it sounds like you should either go with the racing beat holley setup, or just tap the jet into you intake runner. http://www.racingbeat.com

4. I have that same engine in my 83 gsl, although the conversion was not done by me. From what ive heard it is the easiest way to get a 13b into a 1st gen. I think the front cover has the spots for the motor mount bracket, so i think everthing should bolt up ok. The engine will bolt to the tranny fine. For the externals (im assuming you mean intake and exhaust manifolds?) they aren't interchangeable.

So my recommendation is to drop the 13b into the car, then get the racing beat holley 600 for it, get your plate system, get some headers....sounds like a sweet setup, (almost copying mine exactly ). I have a plate system on the way after tax returns

 

The RX-4's 13-B header will not clear the FB/SA's firewall due to its design. so it will require some creativeness. BTW, that Rotary engineering header. Not sure on the RB brand.

 

i have the racing beat header on my car, and im pretty sure theres no modification done to get it to fit on the 13b

 

You are correct, sir ! I have the same header and exhaust in the 13B as I had on the 12A.

 

There is no way to install a 13-B header to a 12-A or vice versa without cutting the flange in the engine or the rear.

 

Great guys, this is the stuff i need. I was looking at the DLIDFIS threads, how hard is that? I was reading it and was a bit confused, maybe i should read it again. oh and i ordered a moroso disk muffler to put on my header, since my header didn't come with a flange of any kind. I guess i'll see how loud that is. I mean, im used to a glasspack chevy truck, but i don't like the tinny (sp?) sound that i get from all of my friends honda's! thats a bum about the nitrous, but a fogger can be hidden (he he).Yeah, im still unsure about the 13b, its been sitting there for about 3-5 years, and i might get to rebuild it in class, but my teacher doesn't want me too. and im currently not in a situation where i have a garage. who knows! cool ok, well have a good day everyone, im gonna go pull some seats out of a brand new Jeep!

 

Hey Jack, Where in Co are you exactly? If you need some pointers or places to find parts let me know.

 

Right know im in Greeley, but i frequent boulder (Go CU)and thornton, as that is where my friends and family are. I go to a u-pull-it here in greeley, they usually have 3-4 first gens and 2-3 2nd gens but it depends. Yeah, im doin the automotive program at AIMs up here, i love the program but the town stinks(literaly!) I see your in longmont, well have to get together sometime this summer (im WAY to busy this semester to even try and get stuff done). but what other places are there to get parts? I will probably need help with this DLIDFIS once i get all of the parts, in a month or so...

 

My 79 had straight pipes, no pre-silencer, and EVERYONE heard me coming. The Boulder Police didn't like it much either and told me if I was going to be taking the car to Illinois, I "had better get going before the engine has a chance to cool off". (it was 11:30 pm)

 

Yeah, its loud alright, I ended up getting a cherry bomb at the last minute, but that didn't help much. I am going to try and get a tunable muffler tip to quiet it down until i can get money for a muffler shop to go into a nice muffler. Ok but know i have less powere at low RPMs until my secondaries kick in, do i need to rejet the carb?

 

IMO yaw does a good carb mod/rebuild