So I purchased a muffler form summit to install in my e250. It is this unit:

http://www.summitracing.com/parts/jex-f726-6d/overview/

It is a louvered straight through design I am unclear on which way I should install it. The inside walls of the straight through tube has a bunch of little scoops on it that are all facing the same way. Should I install so the exhaust gas flows with the scoops (over the back side of them for smoother flow) as seen in the pic


or against the scoops in this pic


I want to quite down the exhaust without sacrificing performance/efficiency. Thanks

 

it should be marked on the case inlet/outlet.

 

This is pulling from waaay back, but I think I remember an article in Diesel Power Magazine where they installed one of these mufflers on a truck. IIRC they said exhaust entering the little ports (i.e., open side front) was the quieter of the two options, but that it could be mounted either way.

Your method and results may vary.

Edit: tack it in place and try it, then turn it around and try it. Post results.

 

On my silver line muffler it's made the same. If you are trying to quiet the truck down you need to have the open side of the louvers towards the engine, to catch the exhaust passing thru. Now if you are trying to put a little rumble under it have it on the other way open side facing rear of the truck.

It does make a difference! I used clamps and a electrical wire as a hanger to hold it up until I decide which sound I like best.



But again mine is not a DD

 

Thanks guys. That was the info I was looking for. It doesn't have inlet and outlet marked on it since it is not directional. I had read about it being quieter one way than the other, but I couldn't find where is said which was which. I got clamps so I can test it, but I think I am going to go the quieter route (I must be getting old.....). My van is my DD, family vacation cruiser and tow vehicle. It is currently straight piped since something came loose in the original muffler and would rattle terribly. The drone at 60-65mph on flat ground isn't terrible, but if I go any faster, get into hills or hook up a trailer it gets real loud real quick. Sounds good/mean, but gets old on road trips.

Trying to make it a nice highway cruiser for long family trips. My house to family in Texas is a good 24hr cruise.

 

it happens to us all.you'll know when your over the hill when you like it loud again cus you lost your hearing.

 

Old is good.
Quiet is good.

 

Louvered core mufflers are generally reversible. Louvers facing upstream=quieter, louvers facing downstream=louder.


Problem though is that when installed with the louvers facing upstream I've heard the flow is terrible.

 

I didn't want to reduce my flow/performance so I went ahead and clamped it in with the louvers facing downstream. The difference in drone/volume was incredible. I can still hear the exhaust if I roll down the windows and hammer it, but inside the cab the WOT noise level is what the cruising at 65mph noise level was before the muffler. I will give it a couple of weeks to insure that I like it and then weld it in.

 

Hmmm not sure how that could be... I mean there's still a full 3.5" or whatever of straight through area? Is it just because of increased turbulence? If so, why would putting it the other way make that much difference?

 

I saw a flow test somewhere but yes...they said the louvers cause a lot of extra turbulence in both directions, but especially so with the louvers facing upstream.

 

Interesting that there's NO information about those louvers, or about which way to orient the muffler, or even about the effects of the orientation of the muffler either way, on their web site.

 

Restrictions. Stick your hand out the windows @ 70mph. That's the effect all those louvers have on your exhaust.