Custom Exhaust vs Brand Name

[nkotselas]

Hi all,

I've been very interested in exhaust upgrades lately. I am planning on a euro premuffler and muffler. I was leaning toward M&K because I haven't heard a complaint yet. I just had a couple questions.

1. I haven't seen any reported gains from an M&K muffler, does anyone have any info or numbers?

2. Exhaust shops around town have quoted me between 15 to 20 horsepower with a new muffler, I doubt these numbers, but is it possible that a exhaust shop could get considerably more than a brand name muffler?

3. Anyone have preferences or experiences with custom vs brand name shops working on our cars? I don't like letting inexperienced people touch mine.

Thakns

[DRACO A5OG]

My take, you will gain a little top end HP but will lose low end torque when you open up your exhaust. You may experience some gurgles and back fires but very little, sound is deeper.

In fact was going up an onramp with a bridge overhead, damn she sounded great

I would look into a sport cat with 1 in 2 out, if I had to do it again that is what I would do.

I have my old cat, but like my top end HP.

[Geronimo '74]

1 M&K is good stuff, I'm sure dyno numbers are around. Maybe ask Ben (ben@mkexhaust.com)

2 If your muffler shop could get 20HP gains with just a muffler, They'd be makeing millions by now. They can't. (K&N airfilters don't give 15 HP either )

3 sorry, I'm too far away

[paulgtr]

go for SSI's and an M&K. very nice combination for our cars. you could even talk to Rarlyl8. I think that is his username. He does a set of headers with a larger diameter that may be even better than SSI's for your engine.

[IROC]

In the "dollars per horsepower" ratings, simply changing your exhaust is typically not a great investment. You can change the sound of the engine very easily, but getting much in the way of power gains over what the factory did is difficult. Those guys weren't dummies.

I've had seven different exhaust configurations on my car and none of them have made a noticeable power difference. They sure do sound good, though.

[tobluforu]

You have not searched if you have not read a complaint about M&K, but if that is the muffler you want then check the classifieds because it seems they go on sale every other week.
20hp, good luck with that.

[Geronimo '74]

Originally Posted by tobluforu

You have not searched if you have not read a complaint about M&K, but if that is the muffler you want then check the classifieds because it seems they go on sale every other week.
20hp, good luck with that.

Other than the occasional droning issue with M&K dual in dual out mufflers, you won't find many malcontent customers. (there are of course the wives that complain that some of the mufflers are too loud for them.)
But these two issues are not specific to M&K mufflers at all. Almost all dual in dual out mufflers are prone to droning.
And if there are any issues, you'll find that they have a good customer service. (that you can also read after you search the forums)

20HP is very optimistic for a muffler only, true dat.

[bkreigsr]

M&K knows only one way to make a muffler - loud.
So, be sure you can deal with it before you invest. (- that's the main reason they appear here on the FS forum fairly frequently.)
I have one on my 85,(GT style, 1-in-2-out, center exit) and am very satisfied with it, but after several neighbors complained, I only use it on track days (it's 15 lbs lighter). Changeover takes about 15 minutes.
Bill K

[tobluforu]

Originally Posted by Geronimo '74

Other than the occasional droning issue with M&K dual in dual out mufflers, you won't find many malcontent customers. (there are of course the wives that complain that some of the mufflers are too loud for them.)
But these two issues are not specific to M&K mufflers at all. Almost all dual in dual out mufflers are prone to droning.
And if there are any issues, you'll find that they have a good customer service. (that you can also read after you search the forums)

20HP is very optimistic for a muffler only, true dat.

Agreed to a certain extent and I'm only referring to the dual out muffler which is painfully loud. If you want one of the lightest mufflers, one that looks the best and is loud as hell, then MK is the way to go. But, on my 72 I lost power with this muffler and no amount of tuning helped.
One other thing in regards to custom built mufflers, I built one for less than 200 bucks, is not very pretty, but does not drone and added top end, lost low end. So building your own is cheap and is known to work, just do a search.

[wildcat077]

Nick,

I've had my Fabspeed one in,two out muffler on my 89 for three years and i'm totally satisfied with the build quality and sound of this muffler. NO droning at all and great sound ... Cruising on the highway at 3000 rpm in 5th gear is very pleasant compared to some cars with "other" mufflers !
Although i have the MK Euro "pre muffler" as well which i find is a good complement to the system.

You will get all sorts of opinions but in the end,you get what you paid for ...
There are cheap mufflers that make a lot of noise or there are more expensive well built units that will give you,in the long run way more value for the money !

Cheers !
Phil

[cdrik915]

For a simple muffler , Fabspeed can be ok , but for a complete RSR set , headers + muffler , go away from this brand.

We are two mates , we had bought the same complete set , and we had the same insolvables issues with it.

Nothing was correct with fitting : no correct aligment of the muffler , heaters ways out welded in the wrong way , leaks at the cylinders.........................and an after-sale conform to theirs products : Zero.

2490 euros .


Without any accessories , clamps , ducts for heater ways out.........



We've both gone with Dansk finally.

Just our opinion , with experience.

[89911]

I posted this a few years ago. Still very happy with everything.

Magnaflow Custom muffler made for SSi's and Dual outlets.

[911pcars]

There's an archived thread on the Early 911S Registry forum where an engine dyno test was conducted on a rebuilt engine with 4-6 different mufflers (factory, sport, Dansk, aftermarket, etc.). YMMV as engine configurations will vary.

Look up Ray Crawford (RC70SCoupe). Here it is:
OPEN HOUSE: Engine on a Dyno

Sherwood

[nkotselas]

Thanks for all the advice.
Ideally I would go with SSI but the budget and CA smog laws don't allow that, and it wouldn't be as easy to change every two years like a pre muffler or a bypass.

Sound is not necessarily an issue, I was planning on going one out to be easy on the neighbors, I do see 2 outs for sale in the classifieds quite often so those may be too loud for my anyways.

Would just getting a euro premuffler be the best choice? I already have a SW chip programmed for a euro spec 3.2, which wasn't meant to have a clogged cat as part of the system.

[wildcat077]

I have the Fabspeed dual out muffler with the MK "pre muffler" and the SW chip and i can tell you it makes for an excellent combination ...
If you read through numerous posts you will find that headers on a 3.2 don't give you much of a horsepower gain as compared to headers on a 3.0 Porsche !

Just sayin ...

Cheers !
Phil

[JP911]

Consider a gutted stock muffler. Sounds great.