What do you mean annual I've never heard annual aux venturi's, and google yeilded no results.

 

it was a much bigger number than you'd have thought, they had time slips too. i wanna say it was running mis 13's with the pulley and 2.5" exhaust.

 

So what are your carb specs currently?

 

48ida
4.5 aux vent
43mm choke
f-8 e-tube
220 mains
120 a/c
120 idle jet holder
70f10 idle jet
and it's still waaaaaayyyyy too rich!!

but an IDA is a different animal than your dco.
I'd suggest 4.5 aux vent 42-44mm chokes
210 main 130ac
f-8 etube
65f9 idle jets

On another note i just ordered some f-2 and f-3 etubes to try out. i still don't think I've found the right ones. I'm going to get 200whp and 20mpg that's my goal. CARBURETED!!

 

are you guys getting the rx8 plugs from Mazda?

 

i actually got them from someone local, but best price is usually sparkplugs.com

 

according to sparkplugs.com, your reach measurements are a little off.

the stock NGK FB plugs have a reach of 19.5mm, not 20.6, the stock RX8 leading plug is 21mm, and both the stock FC plugs are 21.5mm.

that said, i've never measure myself.

 

What suprises me about this whole thing is your hp went up so much when your afrs approached those that are are generally used for turbo engines. I would have thought that when you got into the 12.5:1 range the net hp would have gone down, not up. I suspect your hp is higher than mine in the widebody with the 1/2 sp, 1/2 bp 12A. For me, that's truely disappointing but great for you.

The 2nd gen guys have been trying to hit the 200 hp mark with their 6-port NAs with very little success, even with standalone ecus. Your #s say a lot for carbs, but then you no longer have the restrictive afm that holds back the 2nd gens. I wonder what you could do with a Lake Cities intake mani and dual 40 mm side draft Webers. I may know someone that has the manifold, not sure if he has the carbs to go with it. Can't remember if the mani is for a 12A or 13B., but it might be something to look into.

 

Nice numbers! What octane fuel were you running? Why not just throw the old 50hp nitrous setup on? Why settle for 200 go for 250!


Every engine is differnt! They all seem to want different amounts of fuel/air for there own peak power numbers. I've made more power at 10.5:1 than 11.5:1+ on some of my turbo engines. Some even likes high 12's for peak power. Sounds like Hyper4mance2k just got lucky and found himself a "freak" motor. I'm sure if he could replicate his combo on another 13b he'd have quite a few interested buyers.

As far as the FC air metering unit being a restriction Why not just run a cheap Mega squirt systam and base the tune off speed density? That would completly remove all the intake restriction. Also I think a big reason the FC's have trouble hitting the 200 WHP mark is drivetrain weight/loss. I've seen alot of 210-220 NA 13b's on engine dyno's. The FB drivetrain has lighter/smaller parts making them wasier to turn...and break!

I still can't believe the trouble U NA guys go through for 200whp! I'll stick with pistons and turbos. Still....awesome numbers! I'm impressed!

 

If it had Nitrous it would no longer be NA, and he'd be flirting with diasaster.

Another thing to note-200whp NA will feel alot different than 200whp on a turbo. Honestly, I'm not a big fan of turbo'd cars. You can get amazing numbers, sure, but what it really comes down to is the feel, IMO. A buddy of mine has a WRX @ 22psi and over 300whp. Honestly, when he throws his foot on the floor it feels weak up until the turbo spools up, which takes far too long.

 

annular, my bad. popular with holley. very hard to find for weber ida. you want the one that is a straight bar going across, that way there is less obstruction for air to go around.

 

Either way the Rx-8 plugs are shorter and not a concern. In the NA section guys are getting 200whp on stock port 6 ports, but that seems to be the limit of EFI, even stand alone. There are a few guys getting 210-230 whp on standalone street ports. I actually made the same HP at 13:1 and 12:5 so i just kept it rich for safty sake since I was running so much advance. Most guys are making peak HP NA at 12.8:1. More first gen guys should be reading over in the NA section. There is some cool **** goings on over there.

Brad are these what you're talking about?
http://www.cbperformance.com/Jan2000.asp

 

Just called CB and they have a kit for 2 IDF carbs for $135... They don't make anything for the IDA or know where to get it. Looks like a great idea thought. i wonder why Jaycee and gene breg don't do it when they modify 48ida to 51 IDA's... It replaces the aux and main choke with one long choke to improve flow and fuel atomization.
Here's a good thread on it as well.
http://www.speedtalk.com/forum/viewt...01f9ee77937530

 

Yessssssssss.......

 

ive had 2 fc's with afc type things in em, and just with the butt dyno, the big power gain was going from 11:1 to 12.5:1, going leaner to like 13:1 wasn't too noticeable, and since i had a cat, i just left it at like 12.5.

if you're actually ON a dyno and looking for max power, this might be different

 

Hyper,

1st of all thank you for taking the time to post this thread and for experimenting with the exhaust system to show the potential of your system.

Did you happen to notice if the tubing size is larger on the RE header versus the RB one?

Also I have the standard RB header/presilencer set up and was thinking about replacing the presilecer with their universal 3 inch one as seen here-

http://mazdatrix.com/r-8.htm

In your opinion do you feel that the stock RB presliencer is too restrictive and holding back potential HP?

 

The RE header used 2"od .125" tubes for the primaries. which is 1-7/8" ID. I know the RB RR header is the same and I believe all the street headers are the same. Yes the presilencer is a major problem. Though I think the biggest problem is at the collector. RB headers collect 2 x 1-7/8" ID pipes into one 2" id pipe, and it's 2"id all the way out the back of the car. There is nowhere for the exhaust to go. I say if you can weld, cut off their collector and weld on a decent one. You want it to collect at 2", but then the exhaust needs to expand after the collector to actually scavange the exhaust. That's why all their actually racing exhaust setups collect at 2 inches then use a megaphone to expand into 4" http://www.racingbeat.com/resultset....rtNumber=16119

The center section from ISC uses a similar process, but collects the 1-7/8" runners into 3" and then expands into a 4" chamber where it's lower pressure. Hense the name expansion chamber it expands from 3" to 4" the exhaust scavanges in there. Then it collects back into 3" and out the back of the car it goes. There really isn't a simple, cheap fix to their exhasut problem. You need to get ridof their collector and run bigger exhaust out the back of the car. Check out Megs exhaust for CHEAP copllectors and megaphones to design and build your own system. If you want to do things a little cheaper. Cut off the RB collector weld on a good one from megs that collects 1.875 id into 2" then immediatly after that weld on a 2" to 3" come then weld in a 3" id presilenceer and just do what ever 3" exhaust suites you after that. You'll net way better numbers than you are now. Now you won't get the cool TQ curve of the expansion chamber or quite make the same numbers, but you'll save yourself $500 in the process.

Megs: http://www.coneeng.com/index.html

This thread although a boor at first has a lot of good exhaust talk in it. I had some dumb questions through my first reads. I asked a lot of questions I already knew the answer to. My girlfriend tells me that I do it all the time and it pisses her off. lol...
https://www.rx7club.com/naturally-aspirated-performance-forum-220/highest-power-challenge-2-rotor-13b-non-bridge-non-peri-712131/

 

Thank you very much for the feedback.

 

So who wants to tell me whats going to be the best exhaust for my car, stock 86 this will be the first major mod. 314k miles, and K&N is about the only thing unusual

 

Wrong section bud, and 'best' exhaust is all about perspective.

 

Actually, on a 2 rotor, since they fire 180 degrees apart, it's not as bottlenecked as you think. When one chamber is evacuating, the other isn't. 2" all the way is ok for many applications, but not for all, as you've proven with your setup.

Hey, Percent's new setup will be 2" all the way. I wonder how it will compare to his current manifold setup (also with 2" all the way).

 

Sorry jeff, but you're wrong there. Yes the exhaust events are 180* apart, but there isn't a pause between exhaust events per rotor. you're not waiting for for intake, compression, and power strokes before you get the exhasut stroke. Remember all 3 faces of the rotor are working at the same time. There is not a big enough lapse in between one rotors exhaust pulses to just fit in another exhaust stroke. 2" isn't close to enough room for all the exhaust gasses to merge. just watch this video.
Will a car drive with a 2" exhasut? yes, but I gaurentee you can't make more than 140 ftlbs of torque na with it. and there's no way to make peak tq past 5500 rpm with it.
remember HP=TQxRPM/5252
http://www.youtube.com/watch?v=WmAxCTTn-NA

 

Great results. just wanted to share some itell I recently built a motor for a friends 85 GSL_SE it is has a S-4 motor with a mild street port it with a racing beat dual street exhaust system. He put out 196 to the rear wheels with a 650 double pumper carb. I always used the racing beat exhaust system they do work. A bit costly but they do work. Feel free to call me I can give you some ideas 845 406-2142 DVS RoTaRy

 

LOL! You quoted the lowest HP pic... I made 189 with my exhaust. remember I run a GSL-SE engine with a tiny tiny port. He's got higher compression rotors, lighter weight rotors, lighter e-shaft, 10* more intake timing from the factory (s4 had more timing than s3), and he only made 7 more hp than me. Trash the RB exhaust and I'm willing to bet the car does 215 to the wheels...

I should've just pulled a Honda-tech and said, "NO PIX, NO PROOF, NEWBZZ!!!"

 

Wow, seems like alot of trouble for 10 horsepower. One time I dynoed my car with both electric and belt fans, and found an 8 hp difference. That and a cold morning with low humidity should easily get you over 200.