MazdaRx7Racer4Life

Is 350rwhp possibe on an na? I know it sounds like a newbie question, but I was wondering, maximum outputs of the na, notstock, far from stock. I am thinking of prting my engine once I go for a rebuild, what is the largest port on an na engine that will last me more than 90k miles on my engine. What is the potential with a carbeurated setup rather than efi? What are the possibilities of nitrous on a carbeurated, big azz ported, na engine, and with all these things what is the true rwhp potenial of an na? The reason I would choose nitrous over turbo is I want power when I need it, I don't want to be forcing the engine ALL the time, only with important races. This is all considering the basic mods of emissions removals, a/c, p/s, just pure na power with a little juice. Give me some numbers, rotary gurus

Roy James

I would say with a partial BP with a carb or haltech, and a good 200shot you could get WELL over 350RWHP. Hell, with a great SP and good engine management you might get over 200 to the wheels with a SERIOUS port. S5 rotors, you should be able to do it.

scathcart

For the motor, go with a bridgeported 4 port NA. You're lookingat around 300 hp there... add 250 nitrous and you're at 475 to the tires.

Phu5ion

well big azz ports will cut the engine life in half if not worse. from what i've heard you won't get much more than 30k miles out BP motor. You might be able to get 90k out of a BIG street ported motor then add your 200-250 shot of nitrous and you should be able to put 350 hp to the street.

nonameo

for all the time and money

you could just do a turbo.

TriTurboGen3 RX-7

All you damn turbo freaks bealive that there is only one way to make HP. Do you guys sleep with one under your pillow every night or something ?

Makenzie71

Not that there is only one way to make power. Of course there' more than one way. But unless you want to rebuild your engine every 10K miles and want to dump *** loads of money into it turboing is just a better option. There's no arguing it.

200-250 is all you'll ever see when it comes to reliable NA horsepower on a 13B. People turbo their cars for a reason...they didn't just pull these gadgets out of their asses one night and decide it's good.

Why spend serious money on unreliable horsepower...if you're going to do that just buy a lot of NAWS and start dumping...save you time and money.

Fast, reliable, cheap....you can only pick two.

scathcart

Nitrous is not unreliable power, so turbo is not your only option.

But you do need a form of forced induction.

Turblown

iTrader: (12)

310rwhp PP standalone etc, w/o nitrous

Makenzie71

310!!! Damn...and it's still a daily driver?

How long have you been putting numbers like that down...have you crapped out any engines doing it? Is that pic in your avatar your engine?

slidingsky

YEah 310 hp and absoulty no torque. Anyone ever figure out that the NAs only pull hard above 4.5 k rpm. My na pulls as hard as a stock TII. All that time and I can hang with a stock TII. Plus its dead until 4k. My TII on the other hand pulls hard, very hard at 4k. Even though it dosnt make gobs of HP it has a much better powerband than the NA. The NA is just street ported too. Imagine a BP. Wow useless under 5k. Even at that getting over 225 hp though the NA driveline? The only NA rotary that makes decient power would be a 20b. Oh and no I dont sleep with my turbo under my pillow. It does alot more under the hood. Either displacement or forced induction.
NOS should not be a real option for a rotary when they come with turbos as an option. Oh no did I start a TII vs NA battle? Sorry Im just trying to save my NA brothers the time I wasted on my NA.
sky

TriTurboGen3 RX-7

I do have to agree very good points made there. Just trying to have a little N/A faith since i'm to poor for a T2.

Ohh....the turbo under the pillow thing was a joke......

slidingsky

Sorry I though you were serious. Sometimes people say some odd stuff on the forum. I really do love my NA but no matter how much I try to concince myself the TII is just more fun. I do like the sound of the NA better though.

SureShot

1) Fast
2) Cheap
3) Reliable

Pick any TWO....

Bridgeported

That's because it is the only way to make SERIOUS power. You can make lots of power with an NA rotary, or lots of power with a supercharged rotary, or add nitrous, but when it comes down to hanging with the big boys... you gotta be turbocharged.

Nitrous doesn't count as NA in my opinion.
350 rwhp on an NA 13B can be done - but you won't have a streetable engine. We are talking about an full race peripheral port and upgrades necessary to allow the engine to spin to 12,000 rpm. Zero low end torque - good power STARTING at 5,000 rpm.

So basically you can't have a 350 rwhp NA 13B in a streetcar. If you want to defy the norm, and not go turbo or supercharged, then do a nitrous engine. You can make 350 rwhp on a Nitrous fed 13B with the proper mods and tuning. Be sure to do lots of research though before doing this. Nitrous is not as unreliable and deadly to your engine as everyone thinks. Another forum member put it best when he stated that using Nitrous is a lot like owning a rotary engine; if you don't know what you are doing you will mess it up.

NA Bridgeports can easily go over 30k miles. It all depends on how radical you make the bridge, and how much boost you push into it (unless it's NA). If I had a street driven bridgeported NA 13B I would be kicking myself if it didnt' last 30k. The longevity will depend on proper tuning mainly, but also on the fact of how big you make the new ports (aka how skinny the bridge is). Reliability and power is all about proper tuning... that's the secret to everything.
For instance, I plan on my 22 psi boosted Bridgeported 20B engine to last over 30k miles. It will be done!

Spraintz

iTrader: (1)

It seems that so many people get hung on a certain HP # and lose sight of other issues. Yes, it would be neat to say you have______HP at the wheels but it stinks having to rev to 4000+rpm before you get any of it.

i personally would opt. for a reliably built, not too big ported turbo engine that could be adjusted and tuned for all situations and still have a hope of being safe, reliable, streetable and raceable.

Now, if it was a car designed to be trailered to the dragstrip and bust out mad 1/4 mile runs then thats a whole nuther talk show.

Thank you for your time, have a nice day

Rotary Racer

This is a very interesting subject to me because I am trying to figure out what way to go on my motor. I spent lots of time researching components that need to match with the style of induction/port. I talked with Jim from Racing Beat on the phone about these exact thoughts. Came to the conclusion that there is only so much you can do with a 6 port style motor. He sent me a copy of Import Drag Magazine. In that Mag there was an article that Racing Beat helped to write about 6 port street ported motors running carbs. The test motor was a S4. I don’t have the article in front of me because I am at work but if I remember correctly the max flywheel HP they were able to get was 230ish. Now for your average street N/A that is some good usable HP. Not to mention that you could get just a smidge more if you were running the S5 rotors (possibly 5-10 more). I am not going to talk about the Judge Ito supa dupa 6 port job because no #’s have been produced.

The only way you are going to make strong N/A HP is a 4 port motor. But there is a trade off of, the more hp you want the more intake and exhaust you are going to need (all motors are just huge air pumps). So you have your choice of N/A induction; Standard Street port, Big Street Port, Standard or small bridge port, Big or J-Port bridge port, and lastly PP.

Now with all these different ports I could make a line graph of port style to reliability/streetablility. The larger the port the more top end HP you will have but unfortunately you will have to rev it higher to see that HP. With that being the case different components have to be chosen to allow the motor to be usable @ that RPM. For example your standard steel 3 piece apex seal will not hold compression at 12 so you will have to use a 1 piece carbon or equivalent apex seal so that it can hold compression. Trade off it two fold, one you don’t make good compression down low (0-5k or so RPM is un-usable, both because of the seal and the port). Second these seals will take the longevity of your motor and flush it down the toilet.

When it come to performance there is always a trade off. Unfortunately there is only way to make larger amounts of HP and be some what reliable (and I use that term loosely). This is to do some type of forced induction. This you get the best of both worlds, more air more gas can be pushed into the motor with out a huge port. The motor will not have to rev as high to make use of that HP. And the motor will till retain a decent idle. The N/A rotary’s are great sports cars. Sports cars were not meant to have huge Mustang, Camaro, Vette HP. They are meant to be quick, light, and great handling.

Oh enough with my rant, answer to you question is yes it is totally possible but there is a trade off. These #’s are just what I have seen and talked with people (like Jim @ Racing Beat) about.

6 port, Street Port W/ Carbs (stock style internals, reliable longer life, nice iddle): 220-240 (approx)
4 port, Big Street Port W/ Carbs (stock style internals, reliable longer life, nice iddle): 235-255 (approx)
4 port, Small Bridge Port W/ Carbs ($modified internals$, shorter life, lumpy idle): 250-300 (approx)
4 port, J-Port W/ Carbs ($modified internals$, way shorter life, supa lumpy idle, minimal compression down low): 275-350ish (approx)
P Port (way to much $ to talk about, race engine life, idle? What is that?, bad compression down low): 290-380ish (approx)

InfiniIIIREX

The best I've seen is Anniversary Racing, who pulled 350rwhp on there naturally aspirated P-port 13B, with twin throttles and HKS F-Con V Pro. Here's the video:
http://a-ds.serveftp.net/a-rf/video/021.wmv

j200pruf

iTrader: (4)

Would there be any benifits of using a 4 port block with the 6 port side housings, or would this just hurt flow?

Rotary Racer

Yes. If you use the TII rotor housings you get a better exhaust port and no diffuser. If you use the TII intermediate housing you get a bigger intake port with more metal "meat" on it for porting purposes.

j200pruf

iTrader: (4)

Yes it would be a benifit, and wouldn't hurt flow?

Rotary Racer

Nope this would increase flow, but not increase it so much that there is any trade off's. You can go all the way to a medium/large street port and still be streetable. It is just when you get larger ports things start to get crazy.

Rotary Racer

There are two #'s on the comp screen when they pan in
302.2 PS = 298.06 HP
352.1 PS = 347.28 HP

I am assuming those are two seperate dyno runs.

Turblown

iTrader: (12)

I'm not making that power, well not n/a I was just stating the most I have heard of n/a. I on the other hand DO sleep with my turbo under my pillow

rx7_ragtop

Well, you could always do a bridge-ported (small bridge) 20B. That would probably get you close to 350.

Brad