2" pipe from the Y back,

Offset Inlet, Center outlet. The stock mufflers are 20" long 5x11s I believe.

I want a performance exhaust, however, not too loud, as it's still a luxo coupe. I was thinking of the Flowmaster 50s.

 

Hey, I was thinking about buying two Flowmaster mufflers and tips myself, for my 97 ETC. I was wondering though, what kind should I buy to keep the stock, low rumble, only make it a wee bit (actually quite a bit ) louder? I don't want my exhaust to sound like a mix between lawnmowers and weedwackers thrown under my car...

 

Over at caddyinfo.com somebody put flowmasters, I believe the 40s, on their north*. From what I understand, the flowmasters are a bit on the louder side. I have the Dynomax Super Turbos with 2.5" in and out. Of course, I recommend those. A nice smooth note under 2000rpm. Above 2000, they come alive. I had ordered mine from Jegs. Three years ago, when I got them, they were the best price I could find.

Her they are on the car:

 

Other than glasspacks, Magnaflows are probably the loudest. Followed by Flowmaster 40s, quietest are probably the super turbos.

There's really no way you can get a V8 to sound like a lawnmower fighting a weed whacker...

 

The Flowmaster Series 50 is the Series 40 in a pillow. The Series 50 offers a soft, throaty idle. When you rev the engine, it remains soft. No cabin noise at cruise. This muffler offers us the best of all worlds.
The Flowmaster Series 40 offers throaty idle quality with a sharp crackle when the engine is revved. Cabin resonance is unacceptable for lengthy journeys. Great sound for the occasional driver.

Based on the quote above, I believe I want the Flowmaster Series 50

The Ravin’ sounds virtually identical to a Flowmaster Series 40 at idle. Where this muffler differs is when you punch the throttle. Punch the throttle and the Ravin’ delivers a crackly roar—a nasty bark that might actually startle the guy next to you at the traffic light. This muffler idles friendly and nicely. Where it does its best work is at part-to-full power. It roars! Not recommended for the open road where hearing is threatened; great for weekenders, though.

We were sure the Magnaflow would be noisy, considering its staright-through design. To our surprise, the Magnaflow delivers a soft burble at idle and a sharp, crackly roar when the throttle is opened; good for weekend cruises, but not so good for the open road.

I like the idea of Magnaflows, but sound volume is important to me. I don't want to be the "look at me" guy in everyday driving.

From what we could tell, there wasn’t much difference between the Walker DynoMax Super Turbo and the Ultra Flo. The Ultra Flo is a pinch louder, which wouldn’t be good for the open road. At idle, the Super Turbo offers a soft, throaty exhaust burble that won’t offend in traffic. Under acceleration, it offers us a throaty roar without the sharpness of a lot of high-performance mufflers.

The struggle to my personal needs is between Dynomax Super Turbo, and Flowmaster 50s. Price may determine the outcome. I do like the fact that the Flowmaster does not use sound deadening material. It relies on physics to bounce the sound and cancel waves.
The "magazine" article is located at http://www.mustangmonthly.com/howto/30940/index.html

Credit to "Mustang Monthly"... no flames please! :tisk:

 

Where would the Borla Turbo Mufflers stand with the Flowmaster 50's and Dynomax Turbos?

 

"At idle, the Super Turbo offers a soft, throaty exhaust burble that won’t offend in traffic. Under acceleration, it offers us a throaty roar without the sharpness of a lot of high-performance mufflers."

This is true on the North* also.


"The Flowmaster Series 40 offers throaty idle quality with a sharp crackle when the engine is revved. Cabin resonance is unacceptable for lengthy journeys. Great sound for the occasional driver."

This is exactly what I read read about over at caddyinfo.

 

I thin the model # was 17733. I cannot remember the length. It was about 3 years ago that I had them installed. I am not at home right now, so I can't get to my car's paperwork. Here is a pic of the back of my car:

http://cadillacforums.com/forums/attachment.php?attachmentid=3771&d=1093703335

Your exhaust looks custom--that's a larger pipe going from the Y down to the mufflers isn't it?

I looked at the prices, and the Dynomax Super Turbos are significantly more attractive (they also have superior flow to the Flowmaster 50).

I'm wondering about what size to get--for noise abatement reasons:


17730 Super Turbo
4.25x9/75 x 14 (18.5 overall length)
*vol=580 ci


17746 Super Turbo
4.25 x 9.75 x 20 (25.5 overall length)
*vol=828.75 ci

Stock
5 x 11 x 20
*vol=1100 ci

if + vol = + sound dampening

then

stock = 100
17746 -> 828 x 100/1100=75 --> 25% less damping material (aka louder)
17730 -> 580 x 100/1100=53 --> 47% less damping material (aka louder)

I certainly don't want to go through the hassle only to be just as loud... so I'm thinking of going with the 14" 17730.

Eldyfig, how much louder than stock would you say you are at:

1)idle,
2)70 mph cruise, and
3)WOT?

Any MPG difference? Do you turn heads at idle?


Thanks!

DISCLAIMER ***vol calculations are inherently innacurate because they don't take into account the elliptical shape of the muffler (due to unknown foci) ... however they suffice for comparison purposes, assuming all factors equal (similar curvature).
​

 

From the Y to the mufflers used to 2". I opened it up to 2.5".

I may have noticed a little increase in MPG. Usually, an exhaust upgrade is a good way to get an increase. I can't say how much of an increase I got because it has been a while since it was stock. As a matter of fact, it was the first thing I did to the car besides an oil change.

At idle, there is a definate difference over stock; deep note but not offensive. My neighbors say they know when I start up the car. Anywhere above 2000 rpm, the note is more aggressive. So at 70, I am usually running just a hair above 2000, I think. When I gun it, people hear it coming. My buddy that works on custom trans says it sounds like a Maseratti. I haven't heard one myself, but I take it as a compliment.

I do remember before I too the stock mufflers off, those stock ones sounded like crap compared to these Dynomax's. Hope this helps.

 

From the Y to the mufflers used to 2". I opened it up to 2.5".

I may have noticed a little increase in MPG. Usually, an exhaust upgrade is a good way to get an increase. I can't say how much of an increase I got because it has been a while since it was stock. As a matter of fact, it was the first thing I did to the car besides an oil change.

At idle, there is a definate difference over stock; deep note but not offensive. My neighbors say they know when I start up the car. Anywhere above 2000 rpm, the note is more aggressive. So at 70, I am usually running just a hair above 2000, I think. When I gun it, people hear it coming. My buddy that works on custom trans says it sounds like a Maseratti. I haven't heard one myself, but I take it as a compliment.

I do remember before I too the stock mufflers off, those stock ones sounded like crap compared to these Dynomax's. Hope this helps.

Sounds good.
You mention you have the 14" Super Turbos (2.5 O/C 17733), for me to install those (well actually the 17730 with 2" O/C) with the existing setup, there's a shortage of stock pipe (about 2" short). With the 20" I have room to cut stock pipe. Meanwhile the 20" model is more expensive... so I wonder if they come out even (After getting pipe, etc)

Is yours the ETC? I think with the more aggressive gearing, the L37 N* ends up with higher RPMs at 75mph (compared to LD8 N*)... if I'm not mistaken. I'm just worried about highway @ 75 MPH during trips that last a few hours. I think I'm convinced though.

Thanks!

 

I replaced all pipe from about a foot behind the cat to the back. There was a bit of finnagling to get it all lined up good. I still think it could have been better.

Mine is a base Eldo. As far as road trips, you don't notice the exhaust much. It certainly isn't louder, to the ears in the car, than a moderately playing radio.

I recently went to Orlando from Jacksonville, and the wife didn't complain any. She did get on me once though. There was another couple in their car behind me, friends of ours. They were following me. Well, I go to change lanes and have no problem. Well someone gets behind me too close for my buddy to get in. My buddy, he is to my back driver's side, running next to the car behind me. Check it out...I am going to make a hole for my buddy to get in. He knows it too. My wife didn't know. I plant my foot into the accelerator just long enough to make a hole. My buddy gets in and my wife calling out my name. She wasn't ready for that. Needless to say, she is never in the car when I do a WOT. That exhaust scared her.

 

As far as road trips, you don't notice the exhaust much. It certainly isn't louder, to the ears in the car, than a moderately playing radio.

You're right... when the speeds climb past 60 the Eldo is overcome by wind noise... hearing the exhaust over the wind noise is probably not that big of a deal.

Regarding your road trip, that's nice to be able to hear (ear candy) the car during a maneuver--it's the constant sound that I would dread. My Eldo does have a resonator, so I suspect that would mean I'm slightly less loud.

I believe the exhaust was revised due to older folks complaining it was too loud (stock) in the early Northstars.

At 75-80, my RPMs are @ 2500.

I still have some time to think about either 14" or 20."

I appreciate your input! :worship:

Thanks.

 

How much would the flowmasters run me? 40 series delta flow

 

Being that I live in South Florida no emissions Thank God!!! If I replace my cat with a glasspack what will the sound difference be?? Any body have an idea?? :highfive:

 

Why not just run straight pipe to the mufflers if you want to get rid of the cat. Glasspacks don't last long before getting burned out.

 

Thanks or the reply edlyfig. I am just concerned it may be too loud and a glasspack b4 the muffs might be more sound restrictive.:shhh: I like too use my Nstar throttle adjuster. Let me know your opinion Thanks again:highfive:

 

May I suggest the Spintek muffler? A friend of mine has a North* from a `97 Seville STS in his Fiero, with Spintek mufflers. You wanna talk about a noticable difference than my stock North*. They are nice and throaty, a bit quieter than the flowmaster at idle, but louder and throatier under WOT conditions! I'm getting ready to install them on my `97 S-STS

Just FYI!

 

I have a 93 STS that has Flowmaster 40 Series DF's. When I put them on there was a piece of straight pipe where the cat was. It sounded like a bunch of ball bearings rattling in a can due to the electronic ignition. I put a glasspack on and it smoothed it out and quieted it just a bit. By the way, the 40's on a Northstar sound great, but they are rather loud. I wish I had gone with the 50's most of the time. Though starting the car in the parking lot and setting off car alarms is kinda fun. Good Luck!

 

In 1995 the exhaust system was modified in the Eldo and Seville, to include a resonator, behind the cat. It resembles a glasspack, at least in shape and dimensions.

So, 1995 and up are quieter cars. Apparently a lot of folks (older) had complained it was too loud. Cadillac's response was a resonator. Here's a sample of one of those complaints... this one, submitted to Car Talk:

Dear Tom and Ray:

I am retired, age 75, and I finally splurged on a new car that I have only dreamed about up until now. I figure I only have so many years left, and since you can't take it with you...I bought a new Cadillac Eldorado with the new Northstar engine. It's a beauty, and it lives up to all the hype. I haven't as yet tried out everything they advertise about it, like the 0-60 in seven and a half seconds and the 150 mph top speed (and I probably never will), but it's a terrific car. The only think I don't like is the exhaust sound. If I were in college like my grandsons, I would think it's really cool. It sounds like the muffled hot rods that we used to drive 50 years ago that had special exhaust pipes, except it's not as loud. I notice it mainly when driving at highway speed and then especially when I accelerate at that speed. Now, don't tell me I shouldn't be driving that fast, because if I go any slower almost everyone passes me. The dealer's service department has examined the exhaust system and says there are no leaks--period. At my age, I don't need to listen to that muffled hot rod sound. Is this normal? What would cause it? And can I do anything to eliminate this bothersome sound in an otherwise wonderful car? Joe

Tom: Gee, Joe. I'm afraid it's your own fault. Cadillac makes three similar cars off of this same basic "platform" or "chassis." There's the Eldorado, the Seville STS, and the Seville SLS. And of the three, the Eldorado is the sportiest. It's marketed to swingers....people in their 50s and 60s. Not old geezers like you, Joe.

Ray: And because they're trying to sell it to younger folks, they make the ride a little stiffer, the acceleration a little faster, and the exhaust noise a little louder. They went to great pains and expense to purposely create this throaty exhaust noise because they assume anybody who wants a sporty car would want to hear the engine roar--at least to a point.

Tom: You probably should have gone for the Seville SLS (the "sport-luxury-sedan"), which is a little softer and a little quieter (by the way, STS stands for "sport touring sedan"). The SLS has the same engine as the Eldorado, similar performance, and even a set of back doors. And it's very nice car.

Ray: The only mechanical solution I can think of (other than just turning down your "Miracle Ear"), would be to see if your dealer would be willing to order an SLS exhaust system and try to install it on your Eldorado. It's risky, because taking everything apart and "customizing" it may make the noise worse, and could effect your emissions as well. On the other hand, you WILL have the only 1995 Eldorado RGE on the road (that's the Rube Goldberg Edition).

Tom: Here's my advice. Next time you buy a new car (you sound like you're gonna be around for a long time, Joe), buy an SLS. And don't worry about your losing that sporty image. You'll still be able to pick up plenty of babes in the SLS (you probably called them "chicks" in your day, Joe. But FYI, "babes" is now the politically correct term).

 

What exactly does the Resonator do? And what would happen if you remove it all together? I hear it would free up some HP, or atleast some airflow. But how would it affect the sound exactly?

 

The resonator is used to somewhat quiet the exhaust sound (resonate). My 72 Olds 98 had them after the mufflers. Now on that big boat with the 455, resonators helped quell the beast within. But ofcourse I went and changed the exhaust, dropped the resonators, and had a big 455 barking out the pipes.

 

What exactly does the Resonator do? And what would happen if you remove it all together? I hear it would free up some HP, or atleast some airflow. But how would it affect the sound exactly?

I think the resonator is a straight pipe with holes and insulating material around it (or sound cancelling chambers, depending on the design). I doubt it restricts much flow if at all.

The Corsa system for later Sevilles and 00+ DeVilles has the resonator as well as the two straight-pipe mufflers.

Eldyfig is correct in that it muffles out unwanted sound (well sometimes unwanted). I have read on this forum or on Caddyinfo, that without the resonator, some aftermarket mufflers are too loud or raspy--those are all opinions and observations. Individual results vary with personal taste.

 

In 1995 the exhaust system was modified in the Eldo and Seville, to include a resonator, behind the cat. It resembles a glasspack, at least in shape and dimensions.

So, 1995 and up are quieter cars. Apparently a lot of folks (older) had complained it was too loud. Cadillac's response was a resonator. Here's a sample of one of those complaints... this one, submitted to Car Talk:

I have a 98 ETC now, but had a 94 base coupe before that... The first thing I noticed going from the 94 ot the 98 was that I couldn't hear the 98...

I also have a 96 Corvette for reference and my 94 at idle was actually louder than the Corvette with stock exhaust system at idle... The 98 ETC is quieter than the Corvette...

Sometimes I think about getting the mufflers from a 94 model again and transplanting them on my 98...

 

I have a 98 ETC now, but had a 94 base coupe before that... The first thing I noticed going from the 94 ot the 98 was that I couldn't hear the 98...

I also have a 96 Corvette for reference and my 94 at idle was actually louder than the Corvette with stock exhaust system at idle... The 98 ETC is quieter than the Corvette...

Sometimes I think about getting the mufflers from a 94 model again and transplanting them on my 98...

It's not the mufflers, it's the resonator. The 94 does not have a resonator behind the cat.

 

It's not the mufflers, it's the resonator. The 94 does not have a resonator behind the cat.

Hmmm, I don't remember seeing a resonator on my 98... I'll have to look again when I get home next month...