omg pipes, pipes, pipes, im so confussed...

[Dr Todd]

<blockquote>quote:</font><hr>thank you, thats all i have to say on the matter <hr></blockquote>

ok

[strobhen]

Engines don't need backpressure

You do need to keep the velocity in the pipes up, however.

That means not going too big on the pipes, and doing your best to keep as much heat as possible in the pipes.

Is 3" too big? I don't know. I know 3.5 or 4" would be too big. And I know that the velocity issue is much more important where headers, heads, and intake manifolds are concerned.

Look, backpressure is a myth. Velocity is not. Backpressure is just an easier thing to understand, so it has been used instead.

Best kind of exhaust system is one with a properly sized pipes with no cat or muffler.

All this information coming from real professionals that make headers for a living.

[99Camaro99]

ok great, you may have a higher horsepower/torque rating at the peak, but how's the "area under the curve" on your dyno sheet as compared to before. I'm telling you guys to do what you want but IMO 3" is too much for our motors unless you're going N2O, S/C, or Turbo. Oh and nice sarcasm there with us so-called "experts." If you're such an expert why are you wasting countless dollars into a motor that runs MAYBE a tad faster than mine. :rolleyes: Look I have no grudges with you and I'm all for an intelligent debate but please don't mess with me by calling me a so-called expert. There are certain areas where I know a lot and other areas I know a little. I'm not like many others on this board (not naming names) who just opens their mouth and just says something because they heard it elsewhere...I'm sure you know what I mean.

[F1GT]

<blockquote>quote:</font><hr>Originally posted by WickEdSix9838:

you can go too big! engines do have to have some backpressure, if you dont believe me, go ahead and put u a 3.5" I pipe, u'll slow down...also just because ur peak dyno number is higher doesnt mean you will run faster,to a point,w/a smaller exhaust the motor will accelerate faster in the lower RPM's making it run better times, it may not dyno as high of peak HP but it will be faster because the average HP is higher...<hr></blockquote>

Agreed.

Look at the rest of your power curve, not just your peak. For my exhaust, even though it's just a measly 2.5", I still lost some low end. I know I lost some because on this freeway, where I used to go 65mph in 5th up a slight grade I can't do that anymore. I have to down it to 4th. But anything above 2k, I gained.

[SlimJim1284]

Maybe its just me but so far every time I look at somones time on this board, the guys with the larger pipes have better times, with the full 3" going the fastest at around 15.0. So i guess our 3.8's can handle the 3" well after all. Anybody make one for our cars besides borla?

[Camarorulz]

<blockquote>quote:</font><hr>Originally posted by SlimJim1284:
Maybe its just me but so far every time I look at somones time on this board, the guys with the larger pipes have better times, with the full 3" going the fastest at around 15.0. So i guess our 3.8's can handle the 3" well after all. Anybody make one for our cars besides borla?<hr></blockquote>

Maybe you're right, but pipes are not necessarily the only variable. Plenty of variables determine quarter mile times. The ultimate way to test how a modification improves a car's et is to run it before, make the mod, then run it again in almost identical conditions. I believe that 3" is too much, thats why I went with 2.5"

[99Camaro99]

<blockquote>quote:</font><hr>Originally posted by Camarorulz:


Maybe you're right, but pipes are not necessarily the only variable. Plenty of variables determine quarter mile times. The ultimate way to test how a modification improves a car's et is to run it before, make the mod, then run it again in almost identical conditions. I believe that 3" is too much, thats why I went with 2.5"<hr></blockquote>

yes exactly. My 1/4mi may not be the greatest due to the fact that I live in a humid climate coupled with a crappy track. However I do have before/after comparisions with the catback. Over 4 runs I had an average imporvement of 0.1sec on the ET and an increase of 1.5MPH. Hope that helps. That's with 2.75" piping BTW (on my old Dynomax muffler and stock cat).

[WickEdSix9838]

<blockquote>quote:</font><hr> Maybe its just me but so far every time I look at somones time on this board, the guys with the larger pipes have better times, with the full 3" going the fastest at around 15.0. So i guess our 3.8's can handle the 3" well after all. Anybody make one for our cars besides borla? <hr></blockquote>
i only have a 2.5" NON-mandrel bent cat back, i ran my 14.86 at Temple Academy, and if you know about this track its definately not the best! if i went down to houston i believe i could run a 14.5-14.6 on a good winter day, but i cant afford it so im not...BTW i havent even spent over $1000 on mods so im really impressed w/what i ran...and if you do plan on running a power adder i would go w/3" exhaust, otherwise not bigger than 2.75", but its your choice....

<blockquote>quote:</font><hr> Engines don't need backpressure
You do need to keep the velocity in the pipes up, however.

That means not going too big on the pipes, and doing your best to keep as much heat as possible in the pipes.

Is 3" too big? I don't know. I know 3.5 or 4" would be too big. And I know that the velocity issue is much more important where headers, heads, and intake manifolds are concerned.

<hr></blockquote>
a higher velocity will create more "backpressure", the slower the velocity, the less "backpressure", so ie. the bigger the pipes you have, the less backpressure, do this, blow out of your mouth with it wide open and with it closed some, which to you have to use more pressure to push the air out???? Velocity is a key factor in intakes, cylinder head porting as well as headers/exhaust, there is a line somewhere that is the sweet spot for a motor but no one can tell you whats better cuz noone on here has had acutally dyno time, back to back runs w/2.5", 2.75", or 3" exhaust, id say believe what u wanna believe cuz this thread is just wasted space of peoples opinions and not facts

[ April 11, 2003: Message edited by: WickEdSix9838 ]</p>

[SlimJim1284]

wicked six what were your other mods on that run?

[TheBlackSwordsMan]

If your going for performance get 2.5 or 2.75 if you want deeper sound and you know you are going to upgrade your car later on go 3". When I went from 2.5" to 3" i didn't notice much difference.

[jhkcam]

Something that should be noted in this thread because not everyone is going to agree on this subject. Your performance will increase overall, whether you go with 2.5, 2.75, or 3" over the stock setup. I debated this myself forever before i finally bought a cat-back. There are a ton of opinions on which is the absolute best, but bottom line is, the most important thing is just getting rid of the highly restrictive stock setup and replacing it with aftermarket mandrel bent pipes IMO. [img]smile.gif[/img]

-Justin

[ April 11, 2003: Message edited by: jhkcam ]</p>

[WickEdSix9838]

lid, 180* thermostat, home made CAI, 3.73's/LSD, 2.5" catback w/3" cutout before muffler

[imported_admin]

&lt;-- 3" all the way

If you think 3" is too much for a V6 you're a fool... those myths have been proven wrong by dynos and track times of the fastest F-Bodies time and time again over the years.

Way back in the day several years ago when the first V6 F-Body message boards started, people laughed at me for going with a full 3" setup. They said I would lose torque, yada yada, blah blah blah... yet my setup has received more props than any other I know of. I had so many e-mail requests for info I had to make a page, www.projectvirus.com/ultimateexhaust to describe it. To reiterate what was said earlier, look at the fastest V6 F-Bodies, they all have 3" setups. 3.5" or 4" is overkill, yes, but 3" works just fine. 2.5" you're just selling yourself short.

Russ--your cutout results do conflict with those of James. He lost something obscene like 10+ ft-lbs with his cutout open. Dunno if that had anything to do with the NAWZ or not though, might want to consult him about that. The gain/loss of both of your cars head to head with the cutouts open/closed would make a nice feature for debate around here. [img]smile.gif[/img]

[SlimJim1284]

Stefan, how hard is it to get that LS1 3" flowmaster catback on our car?

[99Camaro99]

Stefan yes they all have 3" but yes they are ALL doing forced induction or spray. I said before and I'll say again 3" is only necessary IMO if you're using one of the two. For NA applications, 3" is too much for the 3.8