Pavement

Hello all,
My name is Jeff and I own a 1987 Nissan 200SX SE. Its a boxy 2dr hatch back w/ the N/A V6 out of the same vintage 300ZX. It also carries the front suspension out of the 280ZX and the rear form the 84-86 300ZX. If you'd like you can read more about them @ www.club-s12.org In any case. My V6 is nice and all but it not cutting it right now for me and as rare as my car is I would still like something different. I have always been fasinated w/ rotories and have wanted one for some time but I wasn't sure if I wanted the maintance. Lately I have had this wield hair leading me back to them though. Do to a fairly small engine bay we are limited in what we can swap in (pretty much just 4cyl's)and I don't wish to be another SR20. So I'm here...

I am looking @ a 13B w/ DCOE carbs, 13B w/ EFI, and 13B w/ single turbo. The carb'd engine I think would be the easiest to get in (no computer mess) but I'm not sure what kinna power it would make. My car is pretty light so I really don't need 1000HP, just a good amount. I think the rotory will lighten things up a bit more too (my V6 is a pig). my goal is 200-300HP keeping things as light and compact as possible (thus no TT). I would love to hit 13's but anythign is better than 16.7 so... tell me what you think. My engine need to be replaced any way (16.7??? stock should be 15.6) any and all info is helpful. feel free to send it to me direct too. I'm not sure how often I'll be able to check in here. thanx for your help
[jeff]

Evil Aviator

Is this a race car or street car? A non-turbo 13B has a difficult time making over 200hp and still maintaining streetable noise levels. A pro-built, full-race, non-turbo 13B will make over 300hp at ear-shattering noise levels. If you are building a street car, you will need forced induction to make a good solid 200-300hp.

Don't write off the TT engine. The 13B-TT (aka 13B-REW) has the best block, and it's compact except for the intercooler plumbing. It is rated at 255hp stock, and you can get a good used J-Spec engine for about $2,000 USD.
http://www.nippon-motors.com/mazda.htm

Pavement

Well, my car is gutted and after the conversion I will be working on tubing part of the frame but I'd like to keep it streetable and prefer the car not sound like a hurricane. I thought I had read some were that a late model 13B (one w/ higher comp) w/ a holley 4b or DCOE (obviously w/ custom intake) and a good header could make 200HP. But I don't know what kinna power ea engine makes stock or what kinna work it'll take to get them up and going. THats y I posted this. I am looking for tech info. WHich eninge and transmitions are the best (yrs or seriel #'s)and so on. How much does ea engine weigh bare. THe only things I know for sure are... there will be NO A/C, I will be using a steel or chromoly flywheel, ACT or Exedy clutch, and a UR pulley set. Oh, ya the most I can run is a 4.11 rear, stock is 3.90 but the swap is not hard. What tire size would you suggest w/ either rearend? Waht size exhaust do you suggest with ea egine type? If I were going to carb a 13b would u use a DCOE or a 4 barrel? I know that either turbo engine would make far more power but like I said I am looking for clean, simple, and light. I have a lot of time to figure this all out, so no rush. I know this is a weird request but thanx for any and all help. later
[jeff]

Evil Aviator

Hehehe, my cars are like that, too. Both are gutted with full roll cages. I put a Racing Beat "Street Port" exhaust on the 1Gen to keep the noise down (gained 2 hp but lost 4 lb-ft tq vs. the loud race exhaust), and I chose to go with a turbocharger on the 2Gen because turbine wheel can soak up 50% of the noise. I have some friends who made track-only cars, and they were not in the least bit happy driving their cars only a few times a year, especially after all the work and expense.

Sure, but that's at the very bottom of the 200-300hp that you quoted earlier. You could probably make it up to 230hp or so at the flywheel and still keep it marginally street legal, but that's pretty much going to be your limit.

OK, first of all, you should order a Racing Beat catalog, which is full of all kinds of helpful performance tips. While fuel injection is far superior, and standalone engine management systems are now competitively priced vs. carb kits, I understand if you want to stick with a carburetor because that is all you know how to tune. Racing Beat is the leader in carb kits. Since you mentioned Holley, take special note of their modified Holley carb. The catalog will also answer your exhaust questions.
http://www.racingbeat.com/

Common American engines in a nutshell:

12A - Severe lack of torque, but it's small, light, and cheap. This is a fun engine for lightweight cars (under 2,400 lbs). It has a carburetor in stock form. Found on 1985 and earlier RX-7's.

13BT (aka 13B 4-port) - The stock 13BT comes with a turbocharger, but the block lends itself well to high-performance non-turbo engines. See the "Porting" links later in my post. This was standard on all TurboII RX-7's (1987-1992). See this site for special changes in the 1989-on models:
http://2ndgenrx7.freeservers.com/2ndgen.html

13B (aka 13B NA, 13B NT, 13B 6-port) - This non-turbo engine has 2 extra intake ports that are staged to raise low-end torque. This is the standard engine for all non-turbo RX-7's from 1986-on, and was an option for the 1984-85 RX-7. All 13B engines are fuel injected in stock form. See this site for special changes in the 1989-on models:
http://2ndgenrx7.freeservers.com/2ndgen.html

13B-REW (aka 13B TT) - Arguably the best block of the bunch, it comes standard with a sequential twin turbo (which works just fine non-sequenced if you don't want to deal with the sequencing issues). I am not aware of any carb kits specifically for this block, but there are numerous turbo kits.

Porting (similar to piston engine valvetrain performance mods)
http://home.iprimus.com.au/bluey3/portsPage/ports.htm
http://www.mazdatrix.com/faq/porting.htm

Approximate rotor weights and compression raitos. Ligher rotors allow for higher rpm potential. The 13B rotors are interchangeable if the proper counterbalances and flywheels are used.
http://www.mazdatrix.com/faq/rotorwgt.htm

Transmissions:
http://www.mazdatrix.com/g1.htm
Basically, if you have up to 200hp, the 1981-on non-turbo transmissions will work fine if you are not drag racing. Otherwise, I would recommend the heavier 1987-1992 TurboII transmission. The 1993+ transmissions have the same gearing and strength as earlier turbo transmissions, but the clutch works in an opposite manner. The 1980 and earlier transmissions are weak.

The tire size and differential gearing are going to depend on your transmission ratio and driving preference. If it helps any, the 86-on RX-7's generally have 3.909 for the 4-speed auto tranny, 4.10 for the manual 5-speed, and a special non-turbo performance model had a 4.30 differential. The 3.90 RX-7's have poor acceleration, so your 4.11 rear end idea sounds good. Stock tire circumferences on the 86-on RX-7's ranged from 76" on the non-turbo base model to just a hair over 78" on the turbo models.

MaTT_FoULk

Damn! Evil Aviator is the man.

Evil Aviator

Well, the "M" is circled on my flight physical, so I must be the man.

Please feel free to post any opposing opinions or other insights so that Pavement doesn't get a polarized view of the rotary world from yours truly. If everybody thought like me, we would all be in a lot of trouble.

Jeff20B

iTrader: (13)

I can add to your evil info, A.

There were '74-'78 13Bs that came stock with a carb for American models (REPU, RX-4, CD Cosmo). A little more torque than a 12A, but still not that much compared to forced induction. Porting these older engines yields lots more HP. Torque is increased and moved higher in the RPM range at the expence of some low end torque.

Speaking of 13Bs, you didn't mention JC Cosmo engines (I know, Japan only). The '13BRE' is also a really good one and can give an FD engine a run for its money (with proper attention to exhaust ports etc).

20B.