exquivical

All I know is that it is a general concensus among tuners that a well running NA 13B will yield close to a 30% increase in power with a non-restrictive (way too loud) exhaust. Pettit, Mazdatrix, Rotary Performance, etc.

I have no first hand DYNO experience (aside from butt dyno), but I really doubt the major players in Rotary tuning would have all gotten together and threw a number out the air.

Obviously, someone's 13B with over 100k on it that's 11-15 years old isn't going to see a 30% increase in power. If that's your arguement, I agree.

turbotwista

Hey did you actually look at the damn catalog they gained 28% at the wheels which if you look at the dyno sheet stock HP was 98hp so the gained 27hp and I wish my buddy still had his or I would have him go put it on the dyno for you because he had that exhaust and trust me there was a nice seat of the pants diff.

wpgrexx

abecx, we showed you proof, now are you gonna leave, please. everyone here is sick of your ignorance.

Barwick

rotaries love different exhaust. By going with an SCCA ITA legal motor (stock internals, stock porting, stock intake manifolds, rejetted close to stock carb, etc..) with a Heintz Bros. Intake filter setup, balanced, and their exhaust, SDJ Motorsports goes from the 100 stock HP to like 172 on a friggin' mostly stock 12A.

AbecX

wpgrexx, no one has proved anything, and a little uninformed terd ike yourself isnt going to run me out.

Barwick

Oh yeah, and turbos, the lower backpressure after the turbo, the more boost it can make (I guess) that's why it goes up so much higher.

dre_2ooo

HEY!
I HAVE PROOF

CLICK HERE

NOW, shut the **** up forever about how turdy N/A's are.

wpgrexx

one thing i am not is little, call me a terd all u want though, the dyno sheet is right here on the page. can't u read.

bcty

wpgrexx

that is a hilarious attachement. can y email that to him

Turblown

iTrader: (12)

I think he just jealous, Abex, your basing all your information on Piston engines, that info has little/no use in comparison here.

SonicRaT

iTrader: (6)

AbecX, you have no understanding of a rotary engine, so you're not about to be able to comprehend why opening the exhaust is so beneficial. As I stated before, when a piston engine fires, there is no force behind the piston PREVENTING it from moving downwards, on a rotary, there is a force behind the rotor preventing it from rotating freely, which is called exhaust. This is because there's no fancy valve system, and the exhaust port is always open, and it's always putting pressure on the rotor. The less pressure on the rotor, the easier it will spin, which IMPROVES performance. This has been proven in the dyno that you believe is 'fake'. If you had any mechanical ability, you would be able to see that reducing restriction in exhaust allows the rotors to spin a hell of a lot easier, and don't bother telling me about a restriction in a piston engine, because the restriction isn't preventing the crankshaft from spinning freely. This is provable by simply looking at the design of the RX-7. How much of an increase is this? This is stated by mazdatrix, and proven by them as well. If you want to act childish, or defend your manhood by denying something you obviously know nothing about, that is fine, go right ahead, because you've been proven wrong more than once. Look at the way it's designed and if you can't tell why improving exhaust flow is so important to the rotary engine, then you lack the capabilities to argue this at all.

blu_gxl

DANG THIS IS GETTING HEATED! lol

redstreak

Ok you just contradicted yourself which proves you don't really know what you are talking about. Your mustang engine goes boing boing boing with 4 complete strokes. A rotary spins and here is the key, is performing intake, combustion AND exhaust at the SAME time. This means that if you remove the restriction in the exhaust cycle all of a sudden 1 side of the rotor is doing a LOT less work and now it is easier to take air in and keep that rotor moving. At no point does back pressure help the rotor turn (And before the experienced rotorheads jump all over me, Unless you have a S4 car where the 6 ports are actuated by back pressure), removing the back pressure can only help in exponetial ways.

Chris Ng

This is kinda getting silly...
Have you people even concidered this:

A Stock 86 n/a FC is rated at aprox 140 HP at the flywheel..
Taking in account for 15% driveline losses, that puts you at aprox 119 HP at the wheels..

MazdaTrix Dynoed their 86 n/a at 98HP at the wheels.. now add that 15% figure and you come out with 113 HP to the flywheel... a 27HP diffrence from stock figures

Now they install their exhaust system and this time they dynoed 125 to the wheels or roughly 143HP to the flywheel...

wow.. they gained 3 HP to the flywheel over a stock properly running n/a!

Do you people actually belive that they would have seen as great of an increase in power if they had dynoed a car that was running within spec in the first place?? Doubtful.. It's called marketing and many of you are falling for it..

I could dyno my T2 at 100 hp to the flywheel because of a severly clogged airfilter .. then install a diffrent airfilter and then dyno at 160 hp... a 60% increase in HP, with just a cone filter! how laughable would that be??

stinkfist

WHAT!?!? Stan has some ******* explaining to do! We run His motor/intake/exhaust in our IT7 car and we only dynoed about 125hp at the wheels! We are front runners in our region so I guess no one else around here runs his 172 hp motor either. We run against several other people with his motors and most of the also run up front.


FWIW I'm a mechanic. Unlike 90% of the people that posted in this thread, I actually DO know how a rotary engine works. There is no way in hell that any stock N/A rotary engine will see 28% increase in ANY exhaust mod. You people can flame me all you want but you only make yourself look stupid to those who know what they are talking about.


Good ITS(2nd genN?/A) cars make around 175hp. These are race cars with full free flowing RACE exhaust and mods to the stock intake.

Good IT7(ITA) cars (1st gen 12A) Make around 125hp with full RACE exhaust and mods to the stock carb.

Now by RACE exhaust I don't mean these quiet little presilencer, true dual, muffled exhaust you get from RB or Mazdatrix. I'm talking about 3 inch pipes dumping out a straight threw muffler or no muffler at all.


You guys are funny,
Mike

rxseven

C'mon guys you know Chris is right on this one. marketing ploy! If this were true, putting this exhaust on will get you more power than a stock turbo of the same year, atleast as much. All you guys wanting the N/A to t2 conversion, forget it, swap the exhaust and be done with it!

rxseven

thank you stinkfist. Now if you can just convince the folks on this forum that they won't see a 15HP gain by putting a cone filter, more so without a cold air box, I would appreciate it very much!

stinkfist

What!?! Your crazy! I got 17 HP from my type R K&N cone filter. It's true I've got dyno sheets to prove it......They are here somewhere........Umm, well I can't find them right now but I do have them.

Mike

rxseven

Hey, don't joke like that. Some people probably ordered theirs from ebay after they read your post! Just the other day somebody on the forum explained that using the stock air filter was like sucking through a straw and using the cone was like drinking it straight from the bottle.....something like that. He stopped calling me stupid after i told him I actually do airflow calculations for a living

kristopher_d

There are so many math tricks and **** ups by so many people on this thread, I'm going to go puke. Exhaust will have a noticeable impact. If it doesn't it wouldn't sell because nearly everyone who buys exhaust asks others for their experience first. If the Exhaust didn't perform up to expectations, word of mouth advertising would be negative, and product wouldn't sell. I have no experience with this, so I must take the experience of others, apply my capacity for RATIONAL thought, and come to my own conclusions. It appears that with some people, logic is futile. So...

to the Nay sayers unwilling to believe (within rational tolerances) the proof offered:
Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up! Shut the F up!

Mr rx-7 tt

iTrader: (5)

Stinkfist, You don't know what you are talking about. Quote :"FWIW I'm a mechanic. Unlike 90% of the people that posted in this thread, I actually DO know how a rotary engine works. There is no way in hell that any stock N/A rotary engine will see 28% increase in ANY exhaust mod. You people can flame me all you want but you only make yourself look stupid to those who know what they are talking about.
***** I have seen on a first gen 101 hp to 129 hp with a full exhaust. Mazdatrix (Dave Lemon) just forwarded the stats as it's a racing beat exhaust. Joe @ Rotary Engineering actually saw a 33% gain with their system and with twin webbers the hp went up to 154 hp. These numbers are at the crank. I have been building, porting (street, bridge, pp) turbos, Nos and supercharged rotaries for over 20 years.

Maxthe7man

Just to give you guys some ideas on n/a hp, I have been tracking my efforts on my n/a with a G-tech and some other n/a's as well..
Now get this, most bone stock FC's will show no more than about 50 hp on a g-tech, I kid you not..
With cat back exhaust, I personally went from 50 to about 70 hp on the g tech, with pre-silencer and midipe I put down about 85, with a header, k&n, fixing the sixth ports nailed me up 93, then with the throttle body mod, some tuning via ignition timing, and port opening rpm, I nailed 107 hp on the g -tech, so with my mods I saw over a 100 % increase in power.. And as it has been saying a 100% increase of what, if you took mazda's number and added a 100%, well thats about 300 hp then..NOT.. The n/a advertised at 146 hp, was nowhere near that,, mine was in decent tune for a stocker and made 50.. So yeah its marketing...
Mazda has always been a little out to lunch on there Hp numbers, most recently they got on the miata.. Seems to me they may be taking to many lessons from Ford..
So how fast is an n/a with full custom exhaust.. well not really that fast at all, noisy then all hell, but its like watching syrup pour sometimes..Max

Mr rx-7 tt

iTrader: (5)

Do you really believe a stock n/a Rx-7 with a 13b makes 50 hp..? If so please refrain from posting anymore as you have the Iq of a worm. BTW: 50 hp in a 2900 lb car will give you a 22.5 second 1/4 mile time.

Node

iTrader: (1)

G Techs a piece of crap for measuring hp...