CatBack/ Exhaust size.

[Rob@USC]

Question for Adrenaline_Z:

How much would a shop charge to do a tuned exhaust setup and what kind of shop would I have to go to for this? I wouldn't do this for a while since I already got a cat-back like 2 years ago, but I'd like to get something that I know helps.

And to be honest, mine's a 3" exhaust and my car felt slower after I put it on. Until I did induction work, I felt like I did the wrong thing with the exhaust.

I'm not a 'real' engineer yet, but I'm studying Mechanical Engineering - a lot of this makes sense from taking thermo. I don't know any formula's since I haven't taken a fluids type class yet, but it makes sense what you're saying.

-Rob

[tdaddyz]

yeah , harlan and tino (hbh and adrenaline) know their stuff. when people try agree with them i feel stupid afterwards, cuz they always shut down the idiots with scientific FACTS. not just duh, well my sotp dyno says i gained 50rwhp and a whole second in the quarter

[KBeezy]

*looks around* who said SOTP Dyno? *looks around* from what I'VE seen posted on here NUMEROUS times is that a 3" exhaust IMPROVES performance vs stock. and thats ALL i keep telling you stupid ****ers. And comparing a 3" vs a 2.5" catback -- both stock, the 3" will do more. BUT i am NOT arguing the fact that there are better setups out there.. WE JUST HAVEN'T FOUND THEM YET! DUUUUUUUUUUUUHHHHHHHH!

How many ****in times do I have to say this!?

[HBHRacing]

KBezzy. you have a tech admin and a "Old School Veteran" agreeing with us. Would you PLEASE stop talking and try and save yourself from further embarasment. I an SICK of your doubts, arguments, avoidence and shear topic changes instead of actualy confronting our statments directly. You should look into politics. you would be a natural


I can see that the roots of doubt run very deep here. But it would be worth it for all the nah sayers to really take some time to re read this thread, do some thinking and try to see where we are coming from.

If you listen to all of the doubts that is all you will see. If you look at the facts then that is what you will notice.


if Kbeezy would actualy read the posts he would have realized at page one that we never said that 3 inch will not increese perforamnce. Cause it will. if all you are after is peak HP changes. but modifications are always goinng to work better when you look at the big picture. If you just look at peak HP all you see is the narrow view of failure. Look at the big picture and work it ot for yourself.

""BUT i am NOT arguing the fact that there are better setups out there.. WE JUST HAVEN'T FOUND THEM YET! DUUUUUUUUUUUUHHHHHHHH!""

anyone who actualy listend to what we said CAN find them. It's actualy REALLY simple. unles your just again being lazy and will wait for the perfectly tuned exhaust from headers to tips to be sold then you will never have your better set up because you refuse to take part in what is needed to do so.

[Adrenaline_Z]

Rob,

The shop I work for doesn't have a dyno.

We build motors, and set them up, but any dyno
tuning is done off site.

The rates for our local dyno's are $140 /hour
unlimited access.

Bring your own materials and parts for testing,
or go to a dyno shop that supplies parts for testing
(such as Forrest&Forrest Racing).

We tried exhaust parts, flow plates, timing curves
and wide band fuel ratio adjustments with my own
cars. That cost me $140.00 and taxes.

For customer cars, it's normally not as intense
unless they are hardcore racers. Some clients
reserve the dyno for the entire day. They spend
up to $800.00 for tuning! Well worth it for the
gains.

Call the dyno operator and find out what is included. If they are also a specialty shop, they
will carry common parts for customers to test
(usually without a fee).

If you want the technician to tune your motor,
they charge an additional rate ($80/hour).

[ October 05, 2004, 09:05 PM: Message edited by: Adrenaline_Z ]

[tdaddyz]

Originally posted by KBeezy:
*looks around* who said SOTP Dyno? *looks around* from what I'VE seen posted on here NUMEROUS times is that a 3" exhaust IMPROVES performance vs stock.\

i never said any names, i just know their are some idiots out there that believe what they "feel" is an improvement when it may not be. if you want to be that idiot it's fine by me [img]smile.gif[/img]
oh, and i never 3" wouldn't improve over Stock, the question is, is it an improvement over 2 1/2 on a car with minimal mods?

[HBHRacing]

When people do a 3 inch catback and feel more power it;s because of 2 things. the better flow from getting rid of restictions. the retrictions come from the stock mufflers and in most cases the bad stock bends. thats why you see power from a larger cat back.

[TheStupidFock]

Sorry again for not coming back. After reading more, I've noticed that I should get the 2.5" instead since I do shift a lot at or around 2000rpms to save on gas.
Thanks again for everyone's help.

BTW, this thread should become a sticky, or at least some information in it created into a sticky/added into the modification part of teh site.

[shortdog273]

^No need for a sticky. This 3" exhaust debate has been going on for years. It needs to be locked.

[TheStupidFock]

Sorry, I'm obviously new to this board and havn't seen any of that in page 2 of the forum.

[KBeezy]

Originally posted by TheStupidFock:
Sorry, I'm obviously new to this board and havn't seen any of that in page 2 of the forum.

Search [img]smile.gif[/img] Its ALWAYS going on.

[HBHRacing]

if he had searched then he would probably gone with 3 inh instead of making his own choice. Free will is a great thing instead of playing follow the leader. We are ALSO not saying that 2.5 will work best. It can still be done wrong. Just remember the key points. Free up restrictions and keep diamiter close and you will be fine.

[FirebirdGT]

OK, let's add fuel to the fire.

What about headers? Both Pacesetter and CIA have 3" Y-pipe collectors.

Carsound does not have flowrates for their cats, but provide a engine size. I am assuming that the larger the engine rating the higher the flowrate - safe bet? And that the inlet size is not relevant.

[HBHRacing]

finaly some muffler companys are staring to give us CFM rates. I asume that cats will not be far behind. What are the primery diamiters for the headers? and yes inlet and outlet does matter. I ahve to head to work. maybe Tino will be able to answer sooner then when I get home.

[Adrenaline_Z]

"I am assuming that the larger the engine rating the higher the flowrate - safe bet?"

Here's a link to Pacesetter. I'm waiting for their
tech support to mail me the flow rates. Notice
the engine displacement vs. inlet/outlet size:

http://www.pacesetterexhaust.com/perf_exhaust.htm

"And that the inlet size is not relevant"

I'm thinking you're correct. From a marketing
standpoint, we can't be sure. From a design
standpoint, the inlet size will have no effect
because the catalytic internals will dictate the
rate of flow.

IE: A tighter 'honeycomb' will be more restrictive.

It's up to the mfg. how well they want it to flow
based on materials used, and emissions standards
they need to meet.