CatBack/ Exhaust size.

[BLLDOGG]

the reason you got a higher trap speeds was because you gained hp.

and you dont lose torque people, it moves.

reprogram you *** gauge next time before you say you lose power.

you now what i think about this moving torque curve. it helps those who cant get traction. there isnt as much push at the beginning which helps alot of people. just a thought

[WickEdSix9838]

your theory about why manufact.s make them with small exhaust pipes is wrong. its to keep them quiet, not to gain HP.

the smaller pipe makes the cars more driveable...a manual car w/a stock motor and a 3" exhaust is a ***** cruising around town cuz the car doesnt have any balls down low...

PS. I need to read all the posts before i post so i dont have to keep editing and adding posts! [img]tongue.gif[/img]

[TheStupidFock]

*Round 2*
So, now I understand that I should go with the 3", but now what brand?
:ding ding::

[tWiStEdBird]

Originally posted by TheStupidFock:
*Round 2*
So, now I understand that I should go with the 3", but now what brand?
:ding ding::

I've only heard Flowmaster in person on a 3.4, and it sounded really good. I've heard clips of the magnaflows and they sound pretty good too. Have yet to hear Borla on a 6 though. I don't know, I'm thinking of going with a 3" flowmaster cat back myself, but I haven't made my mind up yet. Keep going back and forth.

[WickEdSix9838]

When i had the Texas Speed rumbler on my car with the stock manifolds and stock cat it sounded awesome, kinda loud but not so loud you could hear it a block away...it sounded way better than the flowmaster did. But if you start adding headers and high flow cats it can probably get a bit obnoxious.

[asdf1234]

Originally posted by HBHRacing:
am I a genius? hell know.

that one made me lol.

[HBHRacing]

lol. I was going for hell knaw in my best red neck voice but function took over and came out know.


and no.. manufatures do not make smaller exhaust to be quite. and I never said it makes HP. it simply makes the best use of the TQ that they have. if a honda had 3 inch exhaust from the factory it would take it a light year to make it from stop light to stop light. it's not about the power you make, it's where you have it. again. manufactures tune there exhaust to make use of the power that the motor makes in the space that they want it.

It's far easier to learn something new then to relearn something contredicting what you thought to be right.

I'm not here to stir anything up. but expecting that what everyone thinks is right to run will be the best way is not going to totaly help you. The idea of not going overbored with exhaust diamiter is something that is fairly comonly known on the V8 boreds.

I'm not saying that you can make more or less power with any setup. perhaps I was not clear enough with my explainations. but you stand a better chance of making better use of your power if you adapt the exhaust acordingly.

Other things to consider is that exhaust mods should be done in conjunction with air intake mods. This will help prevent the power to shift up the RPM band too far. it all comes back to the most inportant part.

Which is having enough exhust flow to fill the volume of the pipe so that it does't disturb volicity. and as most of you should be aware, you want exhaust to exit the motor as fast as possible (which is the exact reason back pressure doesn't make power) high volicity is what you need. when you do not have enough exhust flow you hurt volocity.


still no one ansered by back pressure question

[HBHRacing]

alright. I ahve come across a little bit of a formula for getting close to colector size based on header diamiter. It's not really going to work well unless your running LT's but still. if I knew the diamiter of the headers some of you are running I could semi take a stab at the formula

[mjparme]

I read a book which I don't have the title of or author of right at the moment (it is downstairs and I am too lazy to go get it). In the book the author says that the idea that decreasing backpressure will decrease power or torque is a myth.

Although, he did also mention that in a PCM controlled fuel-injected car it may take some custom tuning to take advantage of the decreased back pressure. In a non-fuel injected engine (carb.) he says power and torque will always increase if you decrease back pressure.

[KBeezy]

Originally posted by HBHRacing:
lol. I was going for hell knaw in my best red neck voice but function took over and came out know.


and no.. manufatures do not make smaller exhaust to be quite. and I never said it makes HP. it simply makes the best use of the TQ that they have. if a honda had 3 inch exhaust from the factory it would take it a light year to make it from stop light to stop light. it's not about the power you make, it's where you have it. again. manufactures tune there exhaust to make use of the power that the motor makes in the space that they want it.

It's far easier to learn something new then to relearn something contredicting what you thought to be right.

I'm not here to stir anything up. but expecting that what everyone thinks is right to run will be the best way is not going to totaly help you. The idea of not going overbored with exhaust diamiter is something that is fairly comonly known on the V8 boreds.

I'm not saying that you can make more or less power with any setup. perhaps I was not clear enough with my explainations. but you stand a better chance of making better use of your power if you adapt the exhaust acordingly.

Other things to consider is that exhaust mods should be done in conjunction with air intake mods. This will help prevent the power to shift up the RPM band too far. it all comes back to the most inportant part.

Which is having enough exhust flow to fill the volume of the pipe so that it does't disturb volicity. and as most of you should be aware, you want exhaust to exit the motor as fast as possible (which is the exact reason back pressure doesn't make power) high volicity is what you need. when you do not have enough exhust flow you hurt volocity.


still no one ansered by back pressure question

Best use of the torque they have? thats the biggest piece of bull**** I've ever seen ANYONE pull out of their ***. They make smaller exhausts for a few reasons.

1. Cost effective. Less raw materials in the pipes.
2. MOST customers DONT want a loud exhaust. MOST people dont want to hear their engine.
3. Government regulations in specific areas for NOISE violations as well as EMISSIONS. Yes, a larger exhaust DOES release more gasses in to the air faster.

I could keep going but you seem to think you're Mr. Wizard when it comes to this topic so I'll let you figure the rest of them out. "Most efficient use of their torque" -- HA. Is that why just about everyone who asks "What should my first mod be?" gets the same answer? EXHAUST. It SURELY isn't for the "cool exhaust note" .... It's for the damn power!

Look at ANY race car and tell me that they are using small pipes with back pressure. If you want low end torque you're OBVIOUSLY not doing it for performance. Last time I checked most dragsters ran either open headers or an open downpipe.. Hell, Nascars just run headers and a straight pipe back infront of the wheels. CART cars all do about the same thing. Craftsman Truck Series? Refer you to Nascars.

You talk about people who run true duals and say "I lost power" -- well for one thing a dual 2.5" exhaust is a lot larger single 3" exhaust like we run. So is a true dual 2" exhaust.

Diesel trucks compared to Hondas? dude, apples to oranges...apples to oranges.. You also forget that Diesel motors anymore come with big *** turbos which are in a slightly different category than what we are dealing with here. My old 89 Probe GT Turbo was a SOHC 2.2 Mazda 4 cylinder with an IHI intercooled turbocharger system and a 5spd. I had a hole that started to form after the cat converter so I decided to just unbolt my exhaust from the downpipe until I got it fixed. Sure enough, my down low power wasn't as good as it used to be. But who the hell cared? I didn't. The amount of power it adjusted or gained in the top end was WAY more beneficial than what I had before with a stock exhaust when it was functioning 100%. In races like I said before, if all your power is adjusted for down low you'll take off like hell but your top end is going to suck more than the next porno dedicated to oral sex.

Quit arguing with this man - you are a V8 guy. You're trying to debate with guys who have done this and actually experienced the gains of a 3" exhaust on a V6 car. How about you stop whining here about what knowledge you think you gained by reading a book and go outside and do some actual work. Try a few different setups and go out to the track to see which ones do what for you before you come in here and try to act like you're running game. [img]graemlins/slap.gif[/img] I've forgotten more about **** like this than you know. And its all from experience.

[KBeezy]

I also would like to add that the SLP Loudmouth is a badass choice for a catback. [img]smile.gif[/img] Flowmaster is if you are on a budget. BUT if you have the cash tho, why not go for the stainless steel system (SLP) instead of the aluminum system(Flowmaster) tho?

[HBHRacing]

ok. so if your right and it;s all about noise then why is Z28 exhaust 2.75? why isn't it 2 inch with an even more restritcive muffler.


and you stil never answered my backpressure question. you would rather argue then use facts.


EDIT: BTW Loudmouth is only 300 bucks depending on where you get it and is stainless

[KBeezy]

Originally posted by HBHRacing:
ok. so if your right and it;s all about noise then why is Z28 exhaust 2.75? why isn't it 2 inch with an even more restritcive muffler.


and you stil never answered my backpressure question. you would rather argue then use facts.


EDIT: BTW Loudmouth is only 300 bucks depending on where you get it and is stainless

Uhm. I think I just said that its stainless. You can get a flowmaster kit for about 220.

Edit: And I didn't see your question. My eyes were filled with tears of laughter from a lot of the points in your posts.

Edit (Part II): And I never said "All about noise" -- I said its ONE of the reasons. Maybe you missed the other parts....

[HBHRacing]

stop avoiding.


so if your right and it;s all about noise then why is Z28 exhaust 2.75? why isn't it 2 inch with an even more restritcive muffler.

EDIT. lol. your fighting an arbitriary (sp) point. you say your reason is one thats right but mine can not be a correct reason?

[HBHRacing]

so what are all the other reasons that manufactures seem to size exhaust pipes with motor output? why don't you tell me all of your right reasons instead of my wrong one?

EDIT: also show me links of a 4 inch LT1 LS1 set up. the largest I have ever seen is 3.5 from stainless works. again. anyone running more then 3 inch NA and stock displacment is foolish

So I guess that I should not ahve talked the ricer that came into work out of running 3 inch exhaust pipe to duel mufflers then?


My useage of the terminology might be flawed, as you can tell I am no english major. But my use of exhust theory is not. I never said you would lose horsepower.. I said you would lose low end. It diapears up the RPM band untill the motor can put out enough air.

Why would magnaflow make a 2.5 catback for the V6's if bigger is always better?

HP is NOT everything. so what if you gain 3, 5, 10 hp etc for going big. if your TQ moves up the RPM range sevearly you will not always go faster. Unless you want to argue that TQ doesn't actualy matter in the 1/4 mile as well [img]graemlins/stickpoke.gif[/img]

[ September 30, 2004, 02:30 AM: Message edited by: HBHRacing ]