Is it worth it?

[KevinAce]

Right now I have FTRA kit, K&N filter, Whispier Lid, and a Ravin Z55 Muffler (2.75" chambered). I'm looking to pick up a 3" S-pipe and a 3" I-pipe from a junkyard, and throw on a 3" Catco catalytic converter. The questions is...is it worth getting a new muffler that's 3"? If so, chambered, non-chambered, or what? (I already have the tips, and everything else...so I'll just be getting a muffler, not cat back).

Any suggestions would be greatly appreciated!

[nikon]

for a 1/4 in. ?...If im not mistaken for size increases that small they use the same muffler just different leads going into the muffler. And remember if you dont have enough backpressure you will LOSE power, if you just want sound, then sure, I know guys that have done that and it sounds great but they lost a few tenths in their E/T

BTW, sweet ride ;)

[ May 18, 2003: Message edited by: nikon ]</p>

[KevinAce]

Thanks for the compliment!

As far as backpressure goes, I have a thread going on over at camaroz28.com concerning this, and I still do not see how backpressure harms performance AT ALL (aside from possibly throwing off the stock tuning of the headers to create pulses to pull the air out once the valve opens).

I think a full 3" open exhaust would do a ton of good for my car. I think it'd sound better, and the performanc would increase.

I'm just asking if it's worth going from 2.75" to 3" for the muffler? Should I keep the one I have now or upgrade to 3"?

[KevinAce]

Correction on that...I have the RA554259 Z-55 Ravin muffler which is 2.5" in, 2.5" out. I think I'd be worth going with a new muffler with 3" in/out. Any recommendations on company/model?

[Dirty8-un-Dreds]

You see logically you wouldnt think that it would make a difference. But time and time again the guys on the boards that actually dyno test their cars have proven numbers that show lower hp with their cutouts open and larger 3" piping.

Some of the guys that are running power adders have opened up to the 3" or 2.75" and not had a problem. But as far as I know those of us with the 3.8 N/A have issues with open exhausts and larger piping. You can do what you want but it seems like its been done before with very mixed results.

For mufflers I would always go with flowmaster. I have not heard the ravin but I hav heard the borla, american thunder, and dynomax. The flowmaster 80 sounds much much cleaner and deeper IMO than the others. Its all up to you though, as for piping just have the shop fabricate it, no sense in spending 600 + on a set of pipes that the shop coule make for less than half the price.

[ May 18, 2003: Message edited by: Dirty8-un-Dreds ]</p>

[Ted]

Kevin, im in just about the same situation you are, down to the same exact muffler (well kinda, I have a few muffler setups in my garage), here's what I say: I'd save the money you'd spend on a 3in muffler. You already have the z55 already i don't think it's going to be the biggest difference in the world if you go with 3in. You could always put a cutout in, it should be good to drop a nice 2/10s off your ET. And if your really worried about flow you should check into a carsound or random technology cat. For a little more you'll be getting a more durable cat with about 50-75cfms over the catco. You cant' go wrong with spending the money on a set of pacesetter's either.

[toast]

My car gained power going with 3inch i-pipe and a 3inch catco cat. On my stcok cat and stock 2.25inch i-pipe with the cutout open i ran a 15.1 in the 1/4. Now with my new exhaust i ran a 14.8. You might lose alittle low end but you will gain alot in on the top end.

[nikon]

well you see its not just the size of the pipes that determine back pressure....what CFM is your muffler/cat, are they mandrel bent pipes...its hard to find just the right setup...but hey if it works for you go with it....I personally have a 2.5in I pipe which turns into a 3in S bend and 3in muffler with 2 2.2in exits....works alot better than the POS flows I had....EDELBROCK BABY WOOOHOO!!!

[Wicked 3800 V6]

Are you racing? maybe do it
Just street? don't waste your money on anthing else.

[Dirty8-un-Dreds]

<blockquote>quote:</font><hr>Originally posted by toast:
My car gained power going with 3inch i-pipe and a 3inch catco cat. On my stcok cat and stock 2.25inch i-pipe with the cutout open i ran a 15.1 in the 1/4. Now with my new exhaust i ran a 14.8. You might lose alittle low end but you will gain alot in on the top end.<hr></blockquote>

What you need to do is get dyno proven numbers. My best time I ran with my cutout open, but dyno's have proven on at least two occasions that a open cutout loses 5-7 hp for some reason. With your exhausta smallaer size you may have run better, it all has to do with climate and track conditions, thats why et's can be very deceiving.

[Bliggida]

You never lose power with an open exhaust. You simply gain MORE horsepower than you do torque.

Depending on your vehicle application, modification level, driving style, and over all setup this can benefit or harm your ET's.

For example your car may need the extra torque down low to get off the line quickly and get your ET going. Where as another setup might be fine off the line, so with more horsepower than torque it pulls harder down south of the track and posts better ET's.

But, you do not lose power with an open exhaust.
Never.
Its a matter of where you do or don't gain power. But you never lose it.

Suffice it to say if you are stock or nearly stock, there is no reason for you to run an open exhaust. So unless you are doing so just for sound it has no buisness at the track without a motor that actually needs it.

[ May 19, 2003: Message edited by: Bliggida ]</p>

[Dirty8-un-Dreds]

True but with my mods even, wouldnt it be better for me to run closed since I dont have a power adder? I know that in the dyno that james posted he lost hp but gained torque if I remember correctly. I really dont know, maybe ill just runwith my cutout open and try to test it.

[KevinAce]

I don't run at the track or anything. My Ravin Z55 sounds pretty good...but a little ricey at high RPMs. It makes sense to me that going from 2.25" I/S-pipes and the stock converter that picking up a 3" I/S-pipe from a junk yard for $20 and a $60 catco converter...with another $50 labor would be worthwhile. I'm talking under $150 for full 3" exhaust (aside from the muffler which is 2.5).

From what I understand, it won't hurt at all, and should be a nice compliment to my FTRA / Whisiper lid / K&N setup. I'd just like to get a little more top end (the torque right now is impressive, not sure why mine does so well low end). Nothing for track purposes, just a little more getup and go from 40-&gt;80 on highways and stuff.

And just an overall deeper sound.

[Dirty8-un-Dreds]

then that is a great setup. It will probably seem to respond better and it will sound much better. My car feels faster with the cutout open but I think it mightjust beloud hehe. Oh and not much you can do about that ricy high rpm's we are cursed with it. If you ever get the chance ask someone for a flowmaster 80 sound clip and see if you like it better. Good luck.

[Bliggida]

<blockquote>quote:</font><hr>Originally posted by Dirty8-un-Dreds:
True but with my mods even, wouldnt it be better for me to run closed since I dont have a power adder? I know that in the dyno that james posted he lost hp but gained torque if I remember correctly. I really dont know, maybe ill just runwith my cutout open and try to test it.<hr></blockquote>

You don't have to have forced induction to need an open exhaust. Its really a matter of flow. You have a big cam, ram air, ported heads and intake, headers. Then at that point your engine is flowing so much CFM, any full length exhaust will sacrifice the top-end horsepower your engine could be making.

Its strange that James gained torque and lossed horsepower - if that's accurate. Because an open exhaust tends to increase your top-end horsepower.

I need to break for a second and also go over the simple fact that an open exhaust and what most people do as a "cut-out" are two different things. Most I see are placing the cut-out just prior to the muffler, so they are still going through the cat., and piping. My idea of a cut-out is a dump that is just after the headers, before or in place of the cat. Which is an open exhaust - running straight headers at that point.

So with that, for example if James' cut-out is down south of his exhaust, it might play the same role as any high flow muffler like a loudmouth. Going through the exhaust system he'll gain torque.

Usually what happens is this...

I make 200 horsepower and 225 ft-lbs.
After running open headers, I have 225 horsepower and 225 ft-lbs.
See what I'm getting at?
I didn't lose any torque, I just didn't gain any.
But what I did gain was top end horsepower.

Changing the exhaust affects your power-band. Running an open exhaust means that you change your power band for more top-end. So you may notice that you don't pull near as hard down low when you launch, but as you pick RPM down the track the car pulls much harder. Usually seeing a gain in MPH but retaining the same ET.

For most people they do not need that much flow, and on lower horsepower and torque engines like ours (compared to LS1 and LT1 cars) we need all the torque we can get to pull hard out of the hole, and get us going. Where as with say an LS1 they have an abundance to torque to launch with, which allows them to pursue more top-end horsepower making the car faster as it moves down the track.

So unless its for sound - which isn't a bad thing. A cut-out or rather an open exhaust is not something you should go out and do to expect a performance gain. That is a modification that should be reserved until after other modifications are made.

Another way to look at it, is exhaust is fine detail work - its tuning. Compared to Ram-air adds power. A cam will add power. An open exhaust just compliments those things, to make the engine run more efficiently.

I'm adding a cut-out myself rigging it to run open headers. And at this point in my engine build-up its just for sound. But after I start diving into the engine and really bumping the horsepower up into the 250 horsepower area. You will see a much bigger difference between running my exhaust closed, and running it open. Where as if I were to do the same now, I'd see little to no gain.