exhaust

[nixon]

Im planning on chopping off the resonator but got a question or 2. First I have a Ractive straight through muffler on right now, with the res off I wont loose to much back pressure would i? or is that a dumb question?

As well will it make it retardedly loud with a straight through muffler?

[dhurst765]

ive got all stock piping on mine to a 2.5 in inlet to a 4 in outlet straight thru muffler and its not to loud

[[ion] C2]

Yes it will sound pretty gay with a fart can and no resonator. Why do you want to do that anyway?

[dhurst765]

gee thanks that is what i got but i also have the eco

[Caboose73]

gee thanks that is what i got but i also have the eco


well you still have a resonator so your fart can doesnt sound as bad as his will

[dhurst765]

now what about if i hae a custom catback ade would it sound different

[Misuseofyou]

Ecotec with a fart can, wow. That would blow any honda out of the water as far as sounding like shit goes.

Heres an ecotec sound clip http://www.youtube.com/watch?v=b6kPRp6xZak

[nixon]

haha come on now, my car doesnt sound THAT bad...so it's just going to sound worse then without the res on it?

[Spilner521]

with the res off I wont loose to much back pressure would i? or is that a dumb question?
I'll be honest with you...

Yes, that's a dumb question. The stock resonator is pretty restrictive, so yes, if you remove it, you will lose backpressure. But that's a good thing. You don't want any backpressure in an exhaust system.

It will be pretty loud with all stock piping, no resonator, and a straight through muffler. If you don't want to do the whole exhaust, I would maybe get a 2" straight through resonator to put in place of the stock one you remove. That would somewhat keep the noise down a little.

[nixon]

hmm good to know but correct me if im wrong...and to this may be totally different when dealing witha v8 but i know in my dodge dakota R/T that if too much back pressure is released then you loose a lot of the low end torque. would this not apply to my car as well??


oh and im getting rid of the muffler i got pulled over on thursday for a "illegal" muffler and 110 dollar fine haha so thats going and im trying to find a nice magnaflow but all of them are straight throughs

[[ion] C2]

LOL the typical backpressure myth...

Sure, if you cut off the entire exhaust it's going to run like crap and have little torque, and it will have zero "back pressure" but that's not why it's bad. It's all about exhaust VELOCITY. The velocity of the moving air aids in pulling the combustion gases out of the cylinder head.

[nixon]

ah so its not really true that it affects the torque then eh? and what muffler would anyone recommend with the resonator removed, if i got pulled over as is definitely not sticking with straight through or at least a ractive straight through

[Caboose73]

get a dynomax super turbo i know it sounds good on the LD9 so it should be fine on the eco

[nixon]

well thats good cause I have the LD9 haha. does the super turbo have baffles in it? because i thought if it had baffles on a 4 cyc it would make it sound...hows a way to explain it...like a tiny can or something...

[Caboose73]

o haha no clue about the baffles but i know it sounds good on me and Ions cars and ive never herd anyone say they sounded bad

[nixon]

hmm alright well i'll give that one a shot, guess i might as well just run all new piping from the cat all the way back too haha

[heineck]

a Dynomax on an eco sounds fine, nice tone, not too deep but not ricey at all and definentily do it up with a catback. 2.5 worked fine for me

[AbHeLlRaZoR]

just get a 2.25" custom cat back with a Magnaflow muffler it doesn't get any better than that for a start on a exhaust system... well in my mind.

[PappaSmurf]

Nixon,
If you want a bad-as% sounding exhaust system, that you can build upon (once piece at a time) like me than I suggest getting yourself a Magnaflow 14816 StreetSeries Muffler to start out with. This is what I did (bought it from alerosaint here on the forums) and I LOVE the sound! Not to loud and obnoxiuos like most hondas with fart cans, but definitely an attention getter. I have had the muffler on for a week and a half and my wife has had to remind me to back me down from a couple of challenges, mostly because my son was in the back seat. NOT street racing, we have open races here at BAMA Dragway (local drag strip) on Saturdays, where it is LEGAL to "see what ya got". I plan to get the highflow catalytic converter from Magnaflow and put it where the stock resonator is, then 2.5" piping to the muffler. I think that you will be amazed at the sound it gives you. NICE deep tone on the lower RPMs yet it's quiet once you hit the higher RPMs, unlike the "bumble bees in a coffee can."
-Smurf-

P.S. Call me sometime and I would be more than happy to let you hear it. PM me for my number.

[Alerosaint]

well thats good cause I have the LD9 haha. does the super turbo have baffles in it? because i thought if it had baffles on a 4 cyc it would make it sound...hows a way to explain it...like a tiny can or something...

Go to dynomax website, the have information about their technology and diagrams of inside the muffler

[Spilner521]

just get a 2.25" custom cat back with a Magnaflow muffler it doesn't get any better than that for a start on a exhaust system... well in my mind.
2.5" would be better :thumb:

[Ghadsphi]

I have an eco, and this isn't my place to make a comment but I'm gunna get a flowmaster 50 delta. I don't know of anyone having one or mentioning the sound. Cat back is going to have to wait 2-3 months cuz of ASS09.

[nixon]

i thought most flowermasters didnt sound to good on 4 cyc?

[dhurst765]

i had a flowmaster it sounded like sh*t so i took it off

[AbHeLlRaZoR]

2.5" would be better :thumb:

he can get it for his. I spent the money on mine I'm not turning back now

[bryan213]

You don't want any backpressure in an exhaust system.!!!!!!!!!!!! haha lie!!! u need back pressure unless ur wanting to buy a new motor dont even touch ur resnatior u have a 4 cylinder point less!

[Cliff8928]

You don't want any backpressure in an exhaust system.!!!!!!!!!!!! haha lie!!! u need back pressure unless ur wanting to buy a new motor dont even touch ur resnatior u have a 4 cylinder point less!

This deserves one or more of those face palm pics...

That whole back pressure myth was only slightly true with old cars with primitive (badly adjusted?) fuel systems.

[AbHeLlRaZoR]

The whole back pressure thing is debatable people will tell you need some others will tell you that you don't need any me I personally don't care it's not that big of an issue to me.

[AlbinoMonkeyRat]

my personal experience: you need at least a little back pressure (not a lot though) for NA/SC, and more for Turbo (just to get spooled)

[Spilner521]

You don't want any backpressure in an exhaust system.!!!!!!!!!!!! haha lie!!! u need back pressure unless ur wanting to buy a new motor dont even touch ur resnatior
my personal experience: you need at least a little back pressure (not a lot though) for NA/SC, and more for Turbo (just to get spooled)
http://img151.imageshack.us/img151/4027/picard.jpg

Sorry, you don't want any backpressure at all in your exhaust system. Backpressure = a restriction somewhere. Think about it.....backpressure is exhaust trying to push back to where it came from. That is bad. You want the exhaust to get out of the engine and out of the exhaust pipes as quick as possible.

On a naturally aspirated engine you want to choose the right pipe size to maintain fast exhaust velocity to help with scavenging. With a header and the right sized exhaust, the velocity helps pull the exhaust out of the cylinder, and during valve overlap, actually helps pull the intake air into the cylinder. You also want to get rid of the retrictions with free flowing, straight through mufflers.

On a supercharged or turbo engine, the air is being forced in, and there isn't much of the scavenging effect that there is on the NA engine. With boost, there's also a bigger volume of exhaust gas to get out of the engine, so you can go with larger piping than NA.

If you have backpressure on a turbo engine, the pressure pushes back on the turbine wheel. That slows down spool, it doesn't help it. The turbo is the restriction, and you want to get all the restriction off the turbo, so the larger the piping the better. The lower the backpressure in the exhaust system, the faster the turbo can spool, and the more power it can make.

u have a 4 cylinder point less!
Your whole post was pretty well thought out and informative. And I agree, 4 cylinders are pointless, and can't possibly be very powerful...

/sarcasm

This deserves another
http://img151.imageshack.us/img151/4027/picard.jpg

[nixon]

that was a lovely explanation, thanks.

I agree 4 cyc = waste of time/money no power at all...ha

[Fast Eddie]

Actually, you do want some back pressure. Since there is typically overlap between the time the exhaust valves close fully and the intake valves opening, if the flow out the exhaust is too fast you will pull the intake air and fuel out the exhaust side. That hurts performance, since the whole goal is to have as much stuff blow up in the cylinder as possible.

On turbos the turbine provides the back pressure so everything after that can be as free as a bird, without hurting performance. You also want to have it flowing as fast as possible from there to keep the temp down.

I've got charts somewhere at home (from when I cared) showing the difference from stock to header->larger piping->high-flow cat->performance muff. And there is a reduction in TQ.

[KenshinZero]

o haha no clue about the baffles but i know it sounds good on me and Ions cars and ive never herd anyone say they sounded bad

I second the DynoMax, I have a video of how it sounds with stock piping, if it’ll help, its the MySpace link, lol. But I love that muffler, it is baffled and has a little bit of fiberglass, its pretty quiet @ idol and sounds pretty sweet @ high RPMs ^_^

[Spilner521]

Actually, you do want some back pressure. Since there is typically overlap between the time the exhaust valves close fully and the intake valves opening, if the flow out the exhaust is too fast you will pull the intake air and fuel out the exhaust side. That hurts performance, since the whole goal is to have as much stuff blow up in the cylinder as possible.

On turbos the turbine provides the back pressure so everything after that can be as free as a bird, without hurting performance. You also want to have it flowing as fast as possible from there to keep the temp down.

I've got charts somewhere at home (from when I cared) showing the difference from stock to header->larger piping->high-flow cat->performance muff. And there is a reduction in TQ.
Sorry Eddie, that's incorrect.

With backpressure in the exhaust, the piston has to work harder to push the exhaust out of the cylinder. The harder the piston has to work, the less efficient it is and the less power the engine makes. With no backpressure, the exhaust is easy to push out of the cylinder.

High exhaust velocity helps the scavenging effect, and any amount of backpressure slows down the exhaust. The exhaust exiting the cylinder at a high velocity helps pull all the exhaust out of the cylinder, and when the valves overlap, helps pull fresh air into the cylinder, letting the piston work less and therefore more efficiently to draw in fresh air.

You say air can escape through the exhaust if the velocity is "too fast". There's not a set amount of air that's going to enter the cylinder. Even if air escapes into the exhaust stream during overlap, there's still air being drawn in by the piston after the exhaust valve closes.

Even on a turbo car you want to reduce backpressure before the turbo, since the turbine itself is a big restriction. You'll want a free flowing manifold and turbine housing with a low backpressure wheel, as well as large, free flowing piping after the turbo. High velocity and equal pulses before the turbo, and low restriction after the turbo help it spool faster and make more power.

[PappaSmurf]

Hey guys,
What if I was to replace the stock catalytic converter with a magnaflow HI-FLOW cat. and leave the stock resonator would this kind of be redundant? I am also thinking of replacing the cat and deleting the stock resonator and running 2.5 pipes to the muffler. I DO understand that the car would be louder by doing this, however my question is would it sound like a honda with a fart can?
Thank you to the guys that have already tried answering this for me...Alerosaint, Heineck, Sburke.

I am interested in getting in contact with Chris (C2) to find out what his car sounds like with the muffler in place of the resonator.
Any info would be appreciated.
Thanks,
-Smurf-

[KenshinZero]

Hey guys,
What if I was to replace the stock catalytic converter with a magnaflow HI-FLOW cat. and leave the stock resonator would this kind of be redundant? I am also thinking of replacing the cat and deleting the stock resonator and running 2.5 pipes to the muffler. I DO understand that the car would be louder by doing this, however my question is would it sound like a honda with a fart can?
Thank you to the guys that have already tried answering this for me...Alerosaint, Heineck, Sburke.

I am interested in getting in contact with Chris (C2) to find out what his car sounds like with the muffler in place of the resonator.
Any info would be appreciated.
Thanks,
-Smurf-

When I bought ion's old rims and tires, I got to hear his exhaust in person, along with the S/C whine ^_^ It sounds realy good, a little louder than I thought, but still sounds great. I think he has a magna flow "race" muffler as a resonator, high flow cat and DynoMax muffler W/ dual exits.

Im gonna geuss that deleting the resonator wouldnt make it sound terrable, or too much louder with a DynoMax, but then ageain i dont know for sure, I have stock pipeing, lol

[Fast Eddie]

Sorry Eddie, that's incorrect.

With backpressure in the exhaust, the piston has to work harder to push the exhaust out of the cylinder. The harder the piston has to work, the less efficient it is and the less power the engine makes. With no backpressure, the exhaust is easy to push out of the cylinder.

High exhaust velocity helps the scavenging effect, and any amount of backpressure slows down the exhaust. The exhaust exiting the cylinder at a high velocity helps pull all the exhaust out of the cylinder, and when the valves overlap, helps pull fresh air into the cylinder, letting the piston work less and therefore more efficiently to draw in fresh air.

You say air can escape through the exhaust if the velocity is "too fast". There's not a set amount of air that's going to enter the cylinder. Even if air escapes into the exhaust stream during overlap, there's still air being drawn in by the piston after the exhaust valve closes.

Even on a turbo car you want to reduce backpressure before the turbo, since the turbine itself is a big restriction. You'll want a free flowing manifold and turbine housing with a low backpressure wheel, as well as large, free flowing piping after the turbo. High velocity and equal pulses before the turbo, and low restriction after the turbo help it spool faster and make more power.

Like I said, I've got dyno pulls that show a reduction in low end torque with a higher flowing exhaust, but, your still right :banghead:

[Spilner521]

Like I said, I've got dyno pulls that show a reduction in low end torque with a higher flowing exhaust, but, your still right :banghead:
Sounds great. Post 'em up, along with the specs on the engine and exhaust.

I know I'm right :dance1:

[Oldsman]

Sounds great. Post 'em up, along with the specs on the engine and exhaust.

I know I'm right :dance1:

I know your theory does not apply to all motors and every setup out there.

So unless you have built every motor known to man and every setup possible and dyno tested all of them, your cockyness is only that.

[spyhunter]

I'm siding w/ spilner on this one.

[spyhunter]

Like I said, I've got dyno pulls that show a reduction in low end torque with a higher flowing exhaust, but, your still right :banghead:


You don't race at 2000-3000rpm do you?

[Oldsman]

You don't race at 2000-3000rpm do you?

however if you hit max torque in this range and normally your going to launch in this range.....well as any drag racer knows torque wins races.

So if he is launching a 455 the above applies and if on the dyno he produces more torque with closed high flow exhaust rather than open headers or straight pipes this would lead that person to believe that a little bit of back pressure is better than none because it works best for his setup.

This is where the confusion and back and forth comes from.

Because my buddy with his GN has a 3.5" downpipe to a muffler right under the passanger seat so it is basically no back pressure and he produces more power than a closed high flow exhaust system so in this case it is the opposite.

It all depends on your setup, power band, fuel curve, etc.

Another example...........3" exhaust straight pipes on a N/A alero isn't going to produce more power or better ET than that same alero with a SLP exhaust system.

[spyhunter]

Another example...........3" exhaust straight pipes on a N/A alero isn't going to produce more power or better ET than that same alero with a SLP exhaust system.

I believe this was already discussed in the thread, when talking about velocity.


I launch almost at 4750-5000rpm, I have different ideas of launching. :-D

[Spilner521]

I know your theory does not apply to all motors and every setup out there.

So unless you have built every motor known to man and every setup possible and dyno tested all of them, your chickenyness is only that.
Regardless of which engine we're talking about, and my apparent "chickenyness", you still want the least amount of backpressure possible.
however if you hit max torque in this range and normally your going to launch in this range.....well as any drag racer knows torque wins races.

So if he is launching a 455 the above applies and if on the dyno he produces more torque with closed high flow exhaust rather than open headers or straight pipes this would lead that person to believe that a little bit of back pressure is better than none because it works best for his setup.

This is where the confusion and back and forth comes from.
It may lead someone to believe that backpressure is making more torque, but in reality the setup that makes less torque doesn't maintain high velocity to maximize the scavenging effect.
Because my buddy with his GN has a 3.5" downpipe to a muffler right under the passanger seat so it is basically no back pressure and he produces more power than a closed high flow exhaust system so in this case it is the opposite.
Throwing a turbo in the exhaust stream is a different story. You want large piping to get all the restriction and backpresure off the turbine wheel so it'll spool faster and make more power by staying spooled longer. The largest, straightest, shortest exhaust pipe is the best for a turbo.
Another example...........3" exhaust straight pipes on a N/A alero isn't going to produce more power or better ET than that same alero with a SLP exhaust system.
Again, this goes back to velocity. The 3" system will make more power, but it'll peak higher up in the rpm band. With smaller piping, yet still free flowing mufflers, the exhaust will have higher velocity and therefore make more low end torque, with the possibility of slightly lower peak, high rpm horsepower.

[Bad99Olds]

ah the good old backpressure debate.

[Oldsman]

Again, this goes back to velocity. The 3" system will make more power, but it'll peak higher up in the rpm band. With smaller piping, yet still free flowing mufflers, the exhaust will have higher velocity and therefore make more low end torque, with the possibility of slightly lower peak, high rpm horsepower.

this was my point. And depending on your power band of your setup it determines which exhaust setup is best for your car.

[Fast Eddie]

Sounds great. Post 'em up, along with the specs on the engine and exhaust.

I know I'm right :dance1:

They are at home. I'm not sure where they went (over 5 years old) and not interested in looking for them. Like I said, I really don't care that much about the performance of the 'ho any more. I'm also not interested in arguing over the Internet, so if it makes you feel better you can be right:rolleyes2:

Have a nice day!

[Spilner521]

this was my point. And depending on your power band of your setup it determines which exhaust setup is best for your car.
Exactly, that's kind of what I was getting at in the first place. How the car is going to be used determines the exhaust setup that will work best to maximize torque and horsepower. And regardless of how the car is being used, backpressure is still your worst enemy in an exhaust system.
They are at home. I'm not sure where they went (over 5 years old) and not interested in looking for them. Like I said, I really don't care that much about the performance of the 'ho any more. I'm also not interested in arguing over the Internet, so if it makes you feel better you can be right:rolleyes2:

Have a nice day!
That's ok Eddie, I figured they'd be lost :p I'm not trying to start a fight, I could care less about arguing over the internet, I was just correcting some false information so other people that don't know can get the right information.