Derick Freese
Derick Freese Dork
10/1/11 11:09 p.m.

I'm posting this here due to the signal/noise ratio on the appropriate forums.

The question is pretty simple. How much power can be made with a naturally aspirated 13b? The plan is to use Mega Squirt for engine controls. I don't want to lose drivability, because I have plans with the engine that include a heavier vehicle than an RX7.

Mazdax605
Mazdax605 Dork
10/1/11 11:11 p.m.

4-port,or 6-port? Any plans for porting?

Derick Freese
Derick Freese Dork
10/1/11 11:19 p.m.

Maybe a street port, but the motors that are more available to me are 6 port motors.

Greg Voth
Greg Voth HalfDork
10/1/11 11:26 p.m.

You are probably looking at roughly 150 rwhp without a streetport. Up to 200 rwhp with a streetport but that would be pushing it.

I had a mild streetported 6 port 13B with 3rd gen rotor housings, RX-8 rotors, running off megasquirt. It made 160 rwhp (dyna-pak which reported reads a little lower). It had an S4 intake and the 5th and 6th ports removed.

If I were to do it over I would keep the ports and run a S5 intake. Also avoid running an aluminum flywheel and race clutch. It kills street ability with the little torque available.

Derick Freese
Derick Freese Dork
10/1/11 11:33 p.m.

Yeah, I'd be running a stock flywheel, but a heavier clutch.

I don't want to give anything away, but this would be mounted mid-ship.

Derick Freese
Derick Freese Dork
10/1/11 11:43 p.m.

What about porting the S4 intake? Is the S5 just cast in a better shape and the S4 isn't worth the trouble?

mr2peak
mr2peak GRM+ Memberand Reader
10/2/11 1:46 a.m.

2nd gen MR2?

Osterkraut
Osterkraut SuperDork
10/2/11 3:20 a.m.

My street-ported 13B put down 193hp to the wheels. Want to buy it? It's sitting in my parent's shed a little south of Ocala.

Derick Freese
Derick Freese Dork
10/2/11 7:41 a.m.

Osterkraut, that might be a possiblility. I have to check to see if it will work for the application with that long RX7 transmission.

Osterkraut
Osterkraut SuperDork
10/2/11 9:55 a.m.
Derick Freese wrote: Osterkraut, that might be a possiblility. I have to check to see if it will work for the application with that long RX7 transmission.

Don't forget you can mix and match transmission sections to build a really short one! Ask Josh about it.

Derick Freese
Derick Freese Dork
10/2/11 10:53 a.m.

A shortened transmission just might do. Do you want to be clued in on the emails we're sending back and forth?

Knurled
Knurled GRM+ Memberand Dork
10/3/11 11:49 a.m.
Derick Freese wrote: What about porting the S4 intake? Is the S5 just cast in a better shape and the S4 isn't worth the trouble?

The S4 intake has been proven time and again to make more power than the S5 unit.

But don't let this info get around, I like snapping up S4 intakes for cheap-to-free.

Osterkraut
Osterkraut SuperDork
10/3/11 12:32 p.m.
Derick Freese wrote: A shortened transmission just might do. Do you want to be clued in on the emails we're sending back and forth?

No, that'll only get me hankering for a good project. I'll cut you a deal on that 13B if you decide you want it (it won't be cheap, as it's a solid, low mile rebuilt long block, but it'll be a deal).

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