Exhaust Systems: Opinions?

Layton · Post by **Layton** » Feb 20, 2005 1:30 AM

It's about that time . . . . getting ready to replace the die-hard stock exhaust on my 535is! I've looked through pages of posts regarding this subject, and would like some current opinions from those of you that have installed aftermarket cat-back systems.

What I'm looking for.....

Peformance is key. I'm after a system that has a sound level that is close-to-stock at idle and low rpm's, and has a good yessir sound beyond there. I don't want anything that is going to resonate into the cabin of my car. I'm not very interested in building a custom system.

UUC used to make a great system for M5 E28's, but I don't think they're making them anymore. The TCD system looks good, but I haven't heard from anyone using it. I was really interested in the Stebro package, but now I've read that fitment is an issue. It looks like the MM system is way overpriced, and the Billy Boat (B&B) system may be way too loud.

Am I asking for something that's not out there? Post your experiences with what's out there!

Thanks,

- Layton

Guest · Post by **Guest** » Feb 20, 2005 2:10 AM

i got new downpipes from steve haygood to ------> straight pipes in place of CAT to -----> super sprint resonator to --------> supersprint muffler. The sound is pretty nice, its a deep bassy sound with a bit of growl... at idle you can hear it in the car but its not loud, not annoying at all to me Anyway. My only issue with the supersprint parts is that they seem to be a bit low toward the ground... i dont know if they were put on incorrectly or what, but i've had another shop look at it and fix it as much as possible, and the resonator still seems like it sags a bit... not that big of a deal, its not even really noticeable unless you look at it from the right angle.. If you are going to keep your CAT i guess it would sound about near stock, but i am not positve about that.. if you want i could record a clip of audio as to how my car sounds.

fastpat · Post by **fastpat** » Feb 20, 2005 2:26 AM

[QUOTE="Layton"]It's about that time . . . . getting ready to replace the die-hard stock exhaust on my 535is! I've looked through pages of posts regarding this subject, and would like some current opinions from those of you that have installed aftermarket cat-back systems.

What I'm looking for.....

Peformance is key. I'm after a system that has a sound level that is close-to-stock at idle and low rpm's, and has a good yessir sound beyond there. I don't want anything that is going to resonate into the cabin of my car. I'm not very interested in building a custom system.

UUC used to make a great system for M5 E28's, but I don't think they're making them anymore. The TCD system looks good, but I haven't heard from anyone using it. I was really interested in the Stebro package, but now I've read that fitment is an issue. It looks like the MM system is way overpriced, and the Billy Boat (B&B) system may be way too loud.

Am I asking for something that's not out there? Post your experiences with what's out there!

Thanks,

- Layton[/QUOTE]

I have a new front to rear OEM system, and it's nearly perfect. Quiet enough to hear the stereo system while driving, and good enough to be adequate through about 250 horsepower.

Spark, up in Napa, has the Super Sprint system which he likes, it looks good but is too loud for my tastes, but quieter than the Billy Boat Triflo system.

The ne plus ultra of exhaust systems would be the Dinan adaptation of the M5 catalytic converters up front, together with the Rob Levinson M5 exhaust which isn't loud according to those that have heard it, but there's few systems that would flow more than this combination. Should be good for over 400 horsepower.

[Edit by fastpat on [TIME]1108884652[/TIME]]

Guest · Post by **Guest** » Feb 20, 2005 2:45 AM

400 hp huh? :~

fastpat · Post by **fastpat** » Feb 20, 2005 2:51 AM

[QUOTE="88 535is south florida"]400 hp huh? :~ [/QUOTE]

Yep, Levinson ran a turbo on his M5 for the last few years, don't remember what power level he achieved, more than 400 if memory serves. Used the UUC muffler system on it.

[Edit by fastpat on [TIME]1108885952[/TIME]]

Guest · Post by **Guest** » Feb 20, 2005 2:53 AM

so that m5 exhaust can be used on any e28?

[Edit by 88 535is south florida on [TIME]1108886057[/TIME]]

fastpat · Post by **fastpat** » Feb 20, 2005 2:57 AM

He'd have to have a muffler shop make two small adapters to enlarge the exhaust just out of the stock cat from something like 1 7/8ths inch to the 2 1/4 inch UUC muffler system, a low cost task. Other than that, the UUC muffler fits the stock hangers. The UUC muffler isn't cheap at $945.00, but what custom system would be?

Cosmoblau · Post by **Cosmoblau** » Feb 20, 2005 3:08 AM

I have BMP design supersprint resonator and supersprint muffler on my 535i and I love it. The sound is deep and great. I think you would definetly be impressed if you had a chance to hear it.

shifty · Post by **shifty** » Feb 20, 2005 4:12 AM

Layton, don't be a pussy. Just run straight pipes from the cat back! :p

Oh, that brings something to mind, though. You could go with the Euro 535i resonator and muffler. My old euro had Stahl headers and the full Euro 535i system back from there (resonator then center silencer then rear muffler), and it sounded BADASS. Not too loud at idle whatsoever, but it sounded SO SWEET at WOT.

You could near-duplicate that sound by just running the Euro resonator and muffler out back of your cat.

. . . if those pieces are still available. The muffler was $300 back when the original owner bought it in like '97. Can't remember the resonator pricing back then.

Spark · Post by **Spark** » Feb 20, 2005 12:09 PM

One word for ya....

Supersprint

Love mine, not too loud at idle, sounds great when you put your foot into it coupled with the TCD CAIS.

kendogg1 · Post by **kendogg1** » Feb 20, 2005 6:28 PM

I do have a question, though, do both those exhaust lines just merge together inside the cat, or is it like tru duals all the way back to the muffler? Cause, I was thinking about making an X-pipe in my exhaust, but, if it flows together in the cat already, then that defeats the purpose of another x-pipe. And, if it does, then I may simply try running straight pipes all the way back for mine this summer. And if it's too loud, I may simply put some kinda muffler on it. I just want mine insanely loud, lmfao.

fastpat · Post by **fastpat** » Feb 20, 2005 8:07 PM

[QUOTE="kendogg"]I do have a question, though, do both those exhaust lines just merge together inside the cat, or is it like tru duals all the way back to the muffler? Cause, I was thinking about making an X-pipe in my exhaust, but, if it flows together in the cat already, then that defeats the purpose of another x-pipe. And, if it does, then I may simply try running straight pipes all the way back for mine this summer. And if it's too loud, I may simply put some kinda muffler on it. I just want mine insanely loud, lmfao.[/QUOTE]

The stock 535i exhaust is two pipes into one oval cat, and two pipes out, which functionally is an X-pipe. The M5 uses dual single inlet and outlet cats, but I'm not certain if the pipes are connected anywhere along their length or not, Russ C. had a set on his Turbo 535is, he'd know.

kendogg1 · Post by **kendogg1** » Feb 20, 2005 8:39 PM

How's the Bosal Exhaust? My buddy has that on his car, which is the car I'm considering parting out, along with a high flow cat. Both are about a little over a year old, and have only actually been driven with for maybe 6 months.

fastpat · Post by **fastpat** » Feb 21, 2005 12:05 AM

[QUOTE="kendogg"]How's the Bosal Exhaust? My buddy has that on his car, which is the car I'm considering parting out, along with a high flow cat. Both are about a little over a year old, and have only actually been driven with for maybe 6 months.[/QUOTE]

Average life span of a Bosal is 2-3 years according to those hat have had them, not good unless they're free.

Layton · Post by **Layton** » Feb 21, 2005 8:31 AM

[QUOTE="fastpat"]snip . . ."]The ne plus ultra of exhaust systems would be the Dinan adaptation of the M5 catalytic converters up front, together with the Rob Levinson M5 exhaust which isn't loud according to those that have heard it, but there's few systems that would flow more than this combination. Should be good for over 400 horsepower.
. . .snip"][/QUOTE]

Pat -- thanks. I was aware of the Levinson/UUC system. I might take another shot at trying to dig one up. Fortunately, I do have a very good friend who's M5 was the beta car for the system. Maybe they'll produce some more, you never know!

Layton · Post by **Layton** » Feb 21, 2005 8:35 AM

[QUOTE="Shifty"]snip"]Layton, don't be a pussy. Just run straight pipes from the cat back! :p

Oh, that brings something to mind, though. You could go with the Euro 535i resonator and muffler. My old euro had Stahl headers and the full Euro 535i system back from there (resonator then center silencer then rear muffler), and it sounded BADASS. Not too loud at idle whatsoever, but it sounded SO SWEET at WOT.
snip"][/QUOTE]

Shifty -- LOLOL, thanks man! If I could only spend more time at the track, I'd do it The Euro system is an option, though. I'll talk to GregB and the Parts Pimp and find out about more about this route --

Layton · Post by **Layton** » Feb 21, 2005 8:39 AM

Thanks everyone! Any other ideas, let me know! Don't know which route I'll go yet, but I'll keep everyone posted!

- Layton

Steve Haygood · Post by **Steve Haygood** » Feb 21, 2005 8:45 AM

Ran a full oem euro system on an 83 533 for years, was a great setup, only worries..the hangers are not the same in the rear,let me know if I can help

Layton · Post by **Layton** » Feb 21, 2005 9:49 AM

[QUOTE="Steve Haygood"]Ran a full oem euro system on an 83 533 for years, was a great setup, only worries..the hangers are not the same in the rear,let me know if I can help[/QUOTE]

Thanks, Steve! YGM!

Dinan e28 · Post by **Dinan e28** » Feb 21, 2005 3:56 PM

I love my Dinan Stainles system it is made like an M5 exhaust, But it is over priced like most Dinan things

doug · Post by **doug** » Feb 21, 2005 4:34 PM

has anybody tried making their own custom exhaust system, with, say, parts from magnaflow, flowmaster, or whatever? Do they make a muffler that will fit in the tunnel?

Post by **Shawn D.** » Feb 21, 2005 4:53 PM

[QUOTE="dotrp"]has anybody tried making their own custom exhaust system, with, say, parts from magnaflow, flowmaster, or whatever? Do they make a muffler that will fit in the tunnel?[/QUOTE]

As usual, the archives come through:

http://forums.mye28.com/e28/messages/62755.html

http://forums.mye28.com/e28/messages/3538.html

Just a couple of the many in there...

doug · Post by **doug** » Feb 21, 2005 5:17 PM

Thanks (hanging my head in shame ...)

RetiredDoc · Post by **RetiredDoc** » Feb 21, 2005 6:29 PM

When my original muffler failed in 1988, I went to Midas. I have had 17 years of free replacements,with no problems. By the way, that's only 3 mufflers and assorted plumbing and hangers.

When I owned a MGB, the 3 muffler replacement cycle , running Stebro exhausts, took only 4 years.

But, the e28 was just a commuter car until I retired. Now it's what gets me to the barn, where I mount my one horsepower performance machine..

Thirty-plus mph cross country on a thousand pound thoroughbred. Life doesn't get much more fun!

smackmybutter535i · Post by **smackmybutter535i** » Feb 21, 2005 10:24 PM

So... what would it be OK for me to run straight pipes all the way back? besides it being incredibly loud and illeagle, I am just worried about it screwing anything up. if I just ran a pipe from hedders to the back, would I get a significant horsepower increase? or not?

fastpat · Post by **fastpat** » Feb 22, 2005 1:38 AM

You would not get a significant increase in horsepower by running only pipes to the rear of the car. It would not be worth your time, money, or the hatred of everyone with one mile of where you live.

Not to mention the fact that it would sound like crap. It would be cheaper to buy a beater for $100.00. and every time you get the urge to hear unmuffled exhaust just fire that up and drive it around for 10 minutes. Then return to normal and enjoy your good car. :p

Guest · Post by **Guest** » Feb 22, 2005 2:31 AM

on the other hand i like how my car sounds without a cat.. but i have a resonator.. its not too loud.... i dont know what supersprint exhaust sounds like WITH a cat....

shifty · Post by **shifty** » Feb 22, 2005 2:58 AM

[QUOTE="88 535is south florida"]on the other hand i like how my car sounds without a cat.. but i have a resonator.. its not too loud.... i dont know what supersprint exhaust sounds like WITH a cat....[/QUOTE]

I like the sound of a 535i without a cat, too. Sounds suh-weet!

I'm thinking about doing the same with my eta. It's time for a new cat-back, and I'm thinking about going a little farther upstream and just having the cat gutted. . . or removed altogether, a pipe welded in its place, and the proper flange welded on the end.

BMWJustin · Post by **BMWJustin** » Feb 22, 2005 1:05 PM

Hartge headers, straight pipes to the muffler, and no cat. Its fairly loud but I love it, at idle its not too bad but when you hit the gas it roars. If you dont want to do something that extreme the B&B exhaust is a great system with a cat. If you can, and you probably already have, try to get a ride with someone with one or more of these combo's.
Good Luck
Justin

Guest · Post by **Guest** » Feb 22, 2005 1:26 PM

My deceased 533i had Euro manifolds and downpipes with a crossover for the O2 sensor bung, dual 2-1/4" cats then pipes to a Euro M5 rear muffler. IMO, this system was perfect, not too loud, no weird cabin resonance at 2-3k rpm and sounded GREAT at RPM. The downside is cost of the components and the fabrication work.

This system went into the Euro M5 with a custom X-pipe at the output of the headers. It was OK but not exactly what I wanted. So the next iteration of the exhaust for the rebuilt engine will be Euro downpipes from the headers to an X-pipe with O2 sensor bung in front of a dual in/out metallic substrate catalytic convertor, then dual pipes into the Euro M5 rear muffler.

Rich

shifty · Post by **shifty** » Feb 23, 2005 2:02 AM

[QUOTE="BMWJustin"]Hartge headers, straight pipes to the muffler, and no cat. Its fairly loud but I love it, at idle its not too bad but when you hit the gas it roars. If you dont want to do something that extreme the B&B exhaust is a great system with a cat. If you can, and you probably already have, try to get a ride with someone with one or more of these combo's.
Good Luck
Justin[/QUOTE]

Justin, I bet that thing sounds awesome! What muffler is it? Stock Euro 535i?

The B&B sounds pretty good except for the BOOMINESS in the trunk at idle. Peter C, an Aussie living in Dallas, had the B&B on his 535iS last time I was there, and it was loud even with dynamat in his trunk. I think I remember him taking the thing off and selling it because of that.

I wonder if extending the pipes farther out the back would decrease some of that boominess, though. . .

shifty · Post by **shifty** » Feb 23, 2005 2:03 AM

[QUOTE="Rich Euro M5"]My deceased 533i had Euro manifolds and downpipes with a crossover for the O2 sensor bung, dual 2-1/4" cats then pipes to a Euro M5 rear muffler. IMO, this system was perfect, not too loud, no weird cabin resonance at 2-3k rpm and sounded GREAT at RPM.[/QUOTE]

Rich, I'll never forget the sound of that exhaust when you revved it up that time at Dave's! That must've been back in 2001, geez. . .

Walt · Post by **Walt** » Feb 23, 2005 2:31 AM

Stebro fittment isn't all that bad.

I had them make mine with an extra resomator, instead of the cat and include flanges to mate with the headers.

Great sound (quieter than supersprint), good performance and nice looking.

They are, however, dicks to deal with and slower than you can imagine.

Walt

Al Canuck · Post by **Al Canuck** » Feb 23, 2005 2:47 AM

Friend of mine had a Stebro system on his 87 535i. It was WAY too loud for his taste, so he took it off, and went back to stock. He then sold it to another friend, who put it on his 533i. That car was so bloody loud that he managed to get a provincial vehicle safety inspection issued by the RCMP. I could hear his 533 coming from a mile away. It would vibrate the door at my shop, and you could barely talk in the car. Sounded great, but louder than hell.

My 535i has a PO installed, $150 muffler shop system. It hangs too low, is 1 piece from manifolds to muffler, and consists of a single 2" pipe, but besides all the crappy stuff, the cheapass muffler has a great note.

Al

Nick C. · Post by **Nick C.** » Feb 23, 2005 9:55 PM

Ok i want to hear someone with a Stebro. I don't believe that its so loud

. Ok B&B with a stock everything else is not loud at all. Its really personal preference. I could try to make a clip/moovie if you like to show you. I got my B&B because it was SUPPOSED to be %) the loudest for the E28's. Well i was kinda disappointed when i started the car for the first time. Didn't hit me like i expected. BUT, the build quality is GREAT. Everything is SS. Looks good and it should be the last system you ever have to buy. The sound is ok, the droning is the best part ,lol. SuperSprint looks real good but im not sure how long it lasts. I got an almost new bosal sitting in my basement and while it doesn't look appealing to the eye it did have a little sound for a stock exhaust.

BTW BMWJustin i am dying to hear a clip of your car. If you have anything please post it.

stuartinmn · Post by **stuartinmn** » Feb 23, 2005 10:58 PM

My M535 has a home brew system that was installed by the previous owner. It has the euro exhaust manifold and downpipes plumbed into a factory cat and front muffler, followed by dual pipes to the rear with two Cherry Bomb glasspacks side by side at the very end. It isn't as goofy as you'd think.

I've always like the sound - it has a real deep tone with no resonance inside the car. Here's a link to a short sound clip I made last summer (it's kind of muffled, I did it with my digital camera sitting on the passenger seat.) http://home.mn.rr.com/stuartstephens/Audio.wma

[Edit by stuart in mn on [TIME]1109217637[/TIME]]

fastpat · Post by **fastpat** » Feb 23, 2005 11:07 PM

[QUOTE="88 535is south florida"]on the other hand i like how my car sounds without a cat.. but i have a resonator.. its not too loud.... i dont know what supersprint exhaust sounds like WITH a cat....[/QUOTE]

[QUOTE="Shifty"]I like the sound of a 535i without a cat, too. Sounds suh-weet!

I'm thinking about doing the same with my eta. It's time for a new cat-back, and I'm thinking about going a little farther upstream and just having the cat gutted. . . or removed altogether, a pipe welded in its place, and the proper flange welded on the end.[/QUOTE]

You're just trying to goad me, I know it.
(@) The only people that gut catalytic converters on an e28 are the un- or under educated in how a cat works, and why there's nothing to be gained by removing the inards of a BMW cat.

I suppose these notions gained popularity during the production of General Motors cats that were loaded with beads/ the exhaust came in below the beads and was passed over the beads and out of the top of the bead stack. The actual flow was randon and quite poor, and worsened during the life of the cat.

I don't know of a cat built like that now, and BMW cats are among the best, essentially restricting nothing if used with the engine displacement for which they're designed. :@

Gutting a catalytic converter is the functional equivalent of running 13 x 10 inch wheels on your e28 that have been rattle can sprayed green and gold with 225/50-13 tires mounted on them. ~0

Do I really need say more?

[Edit by fastpat on [TIME]1109218245[/TIME]]

shifty · Post by **shifty** » Feb 24, 2005 1:49 AM

[QUOTE="Nick C."]Ok i want to hear someone with a Stebro. I don't believe that its so loud

. Ok B&B with a stock everything else is not loud at all. Its really personal preference. I could try to make a clip/moovie if you like to show you. I got my B&B because it was SUPPOSED to be %) the loudest for the E28's. Well i was kinda disappointed when i started the car for the first time. Didn't hit me like i expected. BUT, the build quality is GREAT. Everything is SS. Looks good and it should be the last system you ever have to buy. The sound is ok, the droning is the best part ,lol. SuperSprint looks real good but im not sure how long it lasts. I got an almost new bosal sitting in my basement and while it doesn't look appealing to the eye it did have a little sound for a stock exhaust.

BTW BMWJustin i am dying to hear a clip of your car. If you have anything please post it. [/QUOTE]

You think the droning is the BEST part? Holy crap! Everyone says that's the worst.

Maybe you need to talk to Raj about the system he had on his 5er a couple of years back. That's probably what you're looking for.

shifty · Post by **shifty** » Feb 24, 2005 1:54 AM

fastpat wrote:You're just trying to goad me, I know it.
(@) The only people that gut catalytic converters on an e28 are the un- or under educated in how a cat works, and why there's nothing to be gained by removing the inards of a BMW cat.

I'm not looking for an increase in performance on my eta by doing away with the cat. The engine is completely stock, so there's no reason to try to increase the flow of the exhaust even if the cat WAS the bottleneck in the current system.

All I want is a better sound, and, if the 535i's without a cat that I've heard are any indication, I know it'll sound better without a cat.

Gutting a catalytic converter is the functional equivalent of running 13 x 10 inch wheels on your e28 that have been rattle can sprayed green and gold with 225/50-13 tires mounted on them. ~0

What the hell's wrong with that? I LOVE 13" wheels sprayed green and gold!

But seriously, Pat, I appreciate the information. It sounds to me like the misconception with catalytic converters is similar to that with reducing the backpressure in the exhaust system. The problems that arise from reducing the backpressure in the exhaust system only existed in carbureted cars. Nowadays, the only negativity that you get from reducing backpressure is increased airflow which, in turn, leans out the mixture. This can, of course, be solved by enriching the mixture which, of course, increases power (more air/fuel flow at the right mixture = more power).

doug · Post by **doug** » Feb 24, 2005 10:33 AM

[QUOTE="Shifty"]The problems that arise from reducing the backpressure in the exhaust system only existed in carbureted cars. Nowadays, the only negativity that you get from reducing backpressure is increased airflow which, in turn, leans out the mixture. This can, of course, be solved by enriching the mixture which, of course, increases power (more air/fuel flow at the right mixture = more power).[/QUOTE]

So is that the current concensus? I've been passively involved in some spirited debates about backpressure, and in the end I tend to agree with Shifty's viewpoint: less is better. But how, if at all, is that related to the issue of pipe size? It's tempting to think 'less backpressure is better' equates to 'bigger piping is better.' But doesn't exhaust size affect the shape of the power band? Is there a body of wisdom associated with exhaust sizing for the m30 and/or m20?

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Exhaust Systems: Opinions?