2 1/4" or 2 1/2"

[Tortured Soul]

I'm replacing my stock mufflers with Edelbrock's new SDT mufflers. What size do I need?

My car is not here so I can't measure it for myself.

Thanks!

[Letitroll98]

Stock is 2" or less at the mufflers. (There is some disagreement around here about the actual stock size) But most agree that 2 1/4" where the exhaust is dual is the best for torque, with 2 1/2" for anything before the split. So somewhere along the line your installer will be welding in a reducer.

[SupaStealth]

my stock exhaust after the cat was 2.25" O.D. (outside diameter)

[MadMatt]

My 1998 is 1 7/8" in and 2" out at the mufflers. I just got a set of Vortex mufflers in that are 2 1/4" in and out. Hopefully I'll have them installed by the end of next week.

[Letitroll98]

Yeah, 2 1/4" in the single and 1 7/8" in the duals is what I measured by eye (lining up a tape measure). But others said I was wrong, and it was only a quick look see for S&G's, so I couldn't be sure. 2 1/4" is what the muffler sites say is optimal aftermarket size for the muffler piping with our engine size and hp rating, so you're right there maddmatt. Only if you are going catback do they recommend 2 1/2" before the piping splits.

[Marc]

Whenever I want to measure the OD of an exhaust pipe,
I always use a micrometer, seen below. This one is open to 2 1/4'', and can go to 5"

[Tortured Soul]

Thanks for all the feedback. I thought I had a C clamp that I could use for a micrometer, but I can't find it. I have a feeling that the exhaust pipe after the split is 2 1/4". I'll have to find out for sure before I order the mufflers.

Is it worth replacing the split with a new y-pipe? Then I would probably need all new pipe from the split back...?

I've looked at those Vortex mufflers, they look pretty cool! I think you'll be happy with them.

Here's a pic of the SDT's I'm getting...

[Letitroll98]

I don't know this brand, but the design looks a lot like the Dynomax Super Turbo or the Flowmaster Std 40 series. Both of these have a deep, rumbly tone, with the Flowmasters being the louder, more aggressively toned muffler. Don't know how the Vortex would compare. The best for performance I've seen in tests in similar engines (Ford 4.6L) is the Magnaflow and Borla XL mufflers. Aurora40's Corsa system is really great, but it's a custom cat back installation derived from a Cadillac application. What kind of price are they asking for these?

[Tortured Soul]

The muffler in the pic I posted is a new Edelbrock SDT. They are about $90 each. They are replacing Edelbrock's old RPM mufflers.

www.edelbrock.com/automotive_new/mc/exhaust/sdt_mufflers.shtml


Here is a pic of a Vortex V-Baffle muffler... www.supremeperformance.com

[Tortured Soul]

I'm pretty sure I'm going to go with 2 1/4"

What has everyone else used?

Anyone???

[colinbanfield]

Are there any performance mufflers out there (Corsa, Magnaflow, whatever) that are not much noisier than stock. Would like the added performance of a high-flow straight-through design, but not at the cost of a lot more noise.

[Letitroll98]

colinbanfield said:

Are there any performance mufflers out there (Corsa, Magnaflow, whatever) that are not much noisier than stock. Would like the added performance of a high-flow straight-through design, but not at the cost of a lot more noise.

No.

Is there another question?

[Aurora40]

colinbanfield said:

Are there any performance mufflers out there (Corsa, Magnaflow, whatever) that are not much noisier than stock. Would like the added performance of a high-flow straight-through design, but not at the cost of a lot more noise.

Well, it's just my opinion, but on the last part, that's exactly what a Corsa is. Straight-through but not that loud. At least, not loud in cruising and low-throttle driving. It's pretty loud when you get on it, as I realized this summer when I had a chance to be behind it at WOT (which I hinted at before, but I can't believe no one picked up on).

However, nothing will be as quiet as stock and flow better. You will invariably get more noise with more flow.

What car do you have, though? From what it seems to me, the 2nd gen is quieter with aftermarket exhaust than the classic. Steven's car sounded like it had Flowmasters on it, but they were just regular Dynomax mufflers. It wasn't loud when cruising, though. A friend of mine with a 1998 Aurora with Corsa's went for a ride in mine and was surprised by how much quieter mine was. He always talked about how quiet his car was with them, and I just assumed it sounded like mine does. He was sort of blown away by my car in general. So if you have a 2nd gen, you might be able to get away with upgrading the exhaust without really having that much more noise to show for it.

"not much more noise than stock" is really subjective, though. We all have a different idea of what is too loud.

[Marc]

We all have a different idea of what is too loud.

My ideas here:

1. If the noise interferes with conversation, then it's too
loud.

2. If you have to turn up the stereo, then the exhaust is
too loud.

[Tortured Soul]

I got my mufflers installed and I'm pretty impressed. They have a very nice tone and not too loud at all. I've tried Flowmaster before and the Delta Flow technology doesn't keep it quiet inside the car like they say. Edelbrock says the SDT's are quiet inside the care and they were definately telling the truth.

colinbanfield... I would give these SDT's a try

[colinbanfield]

Thanks to all for the advice. It occured to me...I'd like a complete cat back system with bigger pipes (perhaps 2.5"). However, except for modifying a Corsa Seville system, there doesn't appear to be any off the shelf system for the Aurora (I own a '97). So my question is, if I decide on Edelbrock, Magnaflow, Borla or whatever mufflers, would I need a shop to build a new Y pipe from scratch (with the larger diameter). What about the resonator after the cat? Who makes a low noise, high flow resonator to replace the stock resonator?

[MadMatt]

letitroll98 said:

colinbanfield said:

Are there any performance mufflers out there (Corsa, Magnaflow, whatever) that are not much noisier than stock. Would like the added performance of a high-flow straight-through design, but not at the cost of a lot more noise.

No.

Is there another question?

Gonna have to disagree with you on that answer, letitroll. Just had my Vortex mufflers installed and although they have a V-Baffle system they are considered a straight-through design.
I was hoping for a bit of rumble but even my wife feels that they are, basically, no louder than the stock mufflers. When I flatten the pedal I hear a bit of difference but it's negligible.
The apparent difference is in the acceleration, especially at 55 mph. Hit the gas at that speed and there is an obvious difference in take-off.
The other thing I noticed is that according to the DIC my fuel mileage looks like it will increase by about 2 mpg (if I can drive with a bit of restraint ). I'll give you additional feedback after I've hit the highway a few times.

[oldsauroraman1]

Any results yet? This looks like a fairly easy do-it- yourself system to upgrade to 2 1/2"