3" piping from the exhaust manifold. Empty catalytic converter. High flow V-Force© muffler. 3" piping to a 3" Y-pipe, into 3" tails and 2 stainless tips....any downfalls of big exhaust? I LOVE THE SOUND!!!

nice congrats man

The only downfall of big exhaust is if you have an NA. You need a certain amount of backpressure in order to maintain the optimal exhaust flow. The turbos already have that pressure thanks to the... well the turbo. But we NA fellas need the backpressure. I had the physics explained to me once, something about pulsation waves and how they cause turbulance and the smaller exhaust keeps the gasses on a strait path outside... or something like that. On turbos I dont think there is such a thing.

Thats gotta be a t2. Its just too damn loud if thats an n/a.

you dont want any back pressure, in fact if you can set it up right, you want vacuum on the exhaust ports

Thats the biggest crock of **** I have ever heard.



Exhaust backpressure is never a good thing from a performance standpoint. People often confuse the high velocity of small pipes with backpressure. Exhaust gas velocity is what makes torque(and ultimately hp). Smaller pipes will have a higher velocity at a given rpm than larger pipes, but become more restrictive as the flow increases

Hm.... interesting. So under the entire rev range will the NA engine perform better with a 3 inch exhaust than say a 2 1/2? Is the reason why people use smaller exhausts for NAs is because they are quieter?



The guy that told me that also mentioned how its like putting your finger on the end of a hose and how the water leaves quicker from the hose even though its a smaller opening. Thanks for clearing that up for me.



BTW: Sorry for contributing to the mis-information of the internet.

https://www.nopistons.com/forums/pub...DIR#>/wink.png Um, a header to large…or piping to large in diameter is only going to make more power at high RPMs, and most of the time actually gives the motor a much smaller and narrower power band. In turn totally throwing off the cars balance. Its all about the velocity of the exhaust pulses. Bigger isn’t always better, unless this FC has some kind of crazy 1000hp 6 rotor sick ass motor!

HUH. https://www.nopistons.com/forums/pub...1047683561.gif

Exactly. Like everything else int he world, its all about compromised. When you do anything, youre not necessarily making it better overall, you are shifting the compromised to better suit your wants and needs.



A smaller exhaust pipe will have a lower torque peak than a larger pipe. If you go too small, you make the powerband overly narrow because it becomes condensed. A small change in flow will have a greater effect on the smaller pipe because that same increase in flow encompasses a larger portion of the flow range of the smaller pipe. As the size increases, the torque peak becomes broader, and occurs at a higher rpm, but the peak torque will be lower.



All this is somewhat of an aside here though, because the headers are what really matter. Everything after the collector has a minimal effect on the powerband, provided the section after the collector can flow more than the section before the collector. There are other factors here, but theyre very complex, and have a smaller effect.



As a general rule of thumb, you want about .025"^2 of exhaust pipe area per hp. The RB headers have the primaries sized to right at 190 hp, which is about what a good full exhaust will put an otherwise stock car n/a.

Wow, very educational. Thanks guys.

TICKETS................could tell you all about it lol https://www.nopistons.com/forums/pub...IR#>/blink.png

Sweet looking setup!!!



If your car is an n/a then my only question is...did you have your 5th and 6th intake ports blocked off/air pump actuated/or perm open?



I know I'm new and all...but all over this forum I have read that you need exhaust back pressure to trigger the actuators for your 5th and 6th intake ports. Without these ports you will lose alot of your top end power. The car will try to run more fuel, but will not have the correct amount of air flowing in...therefore run rich. Along those lines, if the 5th/6th ports are perm open, then you will lose a lot of low end power by running too much air and not enough fuel. Rotaries + Lean mixture = bad.



Again this is only what I have read on this forum. Or I might be crazy and missed the part where you dealt with this problem. In either case, write a post and let me know how the car feels. Again sweet looking system.

nice pics, congrats,.

when you say "air pump acuated" what did you mean?

i never thought of that but now that you say that i have noticed that i am running a little bit richer. is there some way that i can correct this problem? if you or anybody knows please let me know....thanks Jack

will disconecting the air pump have anything to do with the 5th and 6th ports? i am running the stock catalytic converter (or whats left of it https://www.nopistons.com/forums/pub...DIR...) so i still have that little pipe coming out of it hooked up. is that the thing that opens my 5&6 ports? what can i do to ensure that i am getting optimal performance out of this mod?

oh my god that looks so sweet

AH!!!

ive been looking for exhaust for my FC but they all look like crap except for this trillion dollar one. but that one looks sooooooo good

give me details please

like how much it is and where i can order it

I would love to hear that in action at WOT ... damn ...

mazdaspeed, it looks like this one is your baby,,,ha sorry dude.

oh and is it louder then the stock exhaust?

I had it custom made at a muffler shop in St. Clair, Missouri. Three inches for 3 bills!!! I got a HELL of a deal.

CUSTOM!!!!!

NNNOOOOOOOOOO!!!!!!!!!!!!!!!!!!!!!!!!!!



guess i have to keep hunting for exhaust

OH YEAH! it sounds like a real freakin race car. constantly turning heads...(most don't like it but they all like Hondas!) it sounds real good. deffinatly accomplished LOUD!!!!

Hey FlamingGuts, custom would probably be the cheapest rout. Just find a local shop.

86-88 cars used 2lbs of back pressure sourced at the main cat to open the actuators



89-92 used the emmisions air pump to create the pressure to open those same actuators

I've got 3" down-pipe, followed by a 3" high-flow catatlyc convertor, Y-piped into the Racing Beat mufflers that cut it down to about 2.5"...I think this is the best setup.



I'll tell you something. My brother on his SR'd 240, used to have no muffler, just a 3" down-pipe followed by a crush-bent 3" pipe. His vacuum read extremely high, 20 or so I believe. When he got a 90mm muffler added on, the vacuum dropped to 18, and this actually resulted in a quicker spooling of the turbo.



I believe that overall, back-pressure on a turbo is bad, yes, but, as long as that backpressure isn't too close to the turbo, you aren't causing any problems, and by creating a lower vacuum, I think it makes sense that it takes less "boost" to actually spool a turbo, thus explaining why my brother's car spooled faster.



My car, the vacuum is about 18 as well, but lately it's been way fucked up, cause of some vacuum leaks under the hood, but hopefully that'll be fixed in the next few days...

Back pressure on any engine is bad. On turbos, its worse. There is no exhaust tuning with a turbo after the turbo itself. You want it as free-flowing as possible. There are diminishing returns as the size goes up(you wouldnt see much, if any, gain from a 6" pipe over a 4" unless you were making 1000+ hp), buy generally bigger is better.

so because i have an 88, i can take my air pump off without loosing performance?

as long as i make the block off plate..

loud? i have a straight pipe single setup only 2.25" and its ridiculously loud. i cant even imagine how much louder it would be with a 3".

Such eloquence. I love it!

Ha ha.



So how's that beast of an S5 NA doing lately? Are you still going to get an S2000?

I have about 20in of vaccume at idle and my turbo spools up immediately. I still have stock Y pipe and mufflers, but RB 2.5 downpipe and cat replacement- no emmissions. When i get upgrade injectors Ill be able to deal with the creep of 3" catback

how can i put sound clips on this forum.. if you can tell me how i will do it...or better yet a video clip!!!

I dont know about the S2000. Its still an incredible car, and there are very very few within the same price range Id rather own, but one in particular is calling me. Im not going into details until its done though. Hell, you probably wouldnt believe me if I told you...



On the GTU, its coming along rather nicely. I got the Megasquirt in and running. Im going through the long process of tuning it to have drivability that matches anything on the showroom floor right now. Its time for some bigger injectors as well. I havent even taken the AFM off yet, and I and hitting over 80% duty cycle on both the primaries and secondaries close to 9k. Its a hell of a lot of fun, thats for sure. Especially that flat torque curve from 4500-8500 rpm.



When are you going to get AIM? Ive got lots more stories...

Sounds great. I'd love to get a standalone for mine and mess around with it, along with some other intake manifold experiments.



I've seen a couple S2000s on the track and they look great.



I'll try to find some aim software. https://www.nopistons.com/forums/pub...IR#>/smile.png

Hit me up if you want AIM. I have the next to last release of AIM and DeadAIM, which fixes the bullshit associated with AIM. The latest version of DeadAIM you have to pay for I believe.

Heres a teaser pic of my exhaust...

damn mazdaspeed that looks real sharp!

Ill post full pics tonight. As of today, there are more mufflers than wheels...