My New Exhaust
11-12-2008 | 01:35 PM
#1
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Joined: Apr 2001
Posts: 2,898
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From: Fort Worth
My New Exhaust
OK... so when I bought my car it had some Spugen single-outlet exhaust with a stainless muffler. The Magnaflow resonator had cracked at one of the seams, the muffler had cracked around the weld to the exhaust (as well as internally rattled), and was WAAAAYYYYY too loud for my tastes.
The exhaust is all mandrel and flanged for easy removal so I figured I would use it as a starting point and just modify it with a new muffler, and try and reduce the sound level some.
Enter the Dynomax Ultraflo SS:
http://www.dynomax.com/products/ultrafloss.html
I've been a fan of these for years. Typically they flow awesome (Dynomax is one of the few muffler mfrs to publish flow data) and sound deep and relatively quiet. So... without knowing how it would work out, I bought at 17283 2.5" center-to-side Ultraflo SS for ~$90 shipped from rockauto.com.
The size worked out to roughly the same length as the muffler Spugen used, and the center-to-side arrangement looked like it would work OK. When it arrived it went in fairly easy. Cut off the old muffler, test fit the Dynomax, tacked it in place, then made sure it would fit OK before welding permanently & welding on hangers. I cut off the Spugen muffler hangers and reused those. Oh, and I also welded up the broken seam on the Magnaflow resonator.
Some pics of the finished product:
I used an OEM exhaust tip for a stock, conservative look:
I tried to tuck the muffler up as much as I could:
A few shots from the back:
The re-welded Dynomax resonator (pardon the hurried welding job):
Muffler and hangers:
The Spugen pipe hangs down more than I would like, but at least the muffler isn't any lower than it:
Here's one of the crack on the Spugen muffler... despite being loud and straight-through, you could still hear the leak at part throttle!
The sound: I absolutely love it. Where the Spugen was just offensively, oppressively loud, this is just as quiet. Under about 3000 RPM, especially with more throttle input, it's downright burbly. It isn't loud at those RPMs until you go more than maybe 30% throttle. Above that, with higher RPMs the sound become stock, and after VTEC, the exhaust note is lost in the normal symphony of VTEC just like stock. It's wonderful. I'm looking forward to regaining the use of a cell when driving and not having my ears ring after driving on the highway for an hour.
One important note, I do have a stock cat installed (no test pipe), though I can say from other vehicles I've had a Dynomax Ultraflo on with test pipes... it raises the general sound level but it's still acceptably loud. Put it this way, I've not heard anything as loud as the Spugen aside from an Invidia or an open header... even vehicles with no cat and a Dynomax Ultraflo.
A few side notes, the Spugen setup I have is 2.5", this engine definitely needs something larger, on the order of 2.75" or more. I doubt it would result in much of an improvement of "feel" but everything I know about exhaust systems points to 240HP requiring more.
Looking at the stock exhaust setup, you could probably do this muffler swap just as easy on a stock exhaust system by cutting the exhaust off at the split just before the axle, and using some straight pipe to extend back to the passenger's muffler area, then attach the muffler there. It would be one-piece but should work just fine.
If you haven't read it yet, there's an article by David Vizard that's great over at http://www.ntpog.org/articles/index.shtml called "No Loss Exhaust." Great reading on exhaust systems and even some formulae and rules of thumb for sizing exhaust systems. It also explains what the funny standpipe is that sticks off of the stock exhaust.
Speaking of stock exhausts, if someone has one they want to give away I'd be interested in picking one up.
If you have any interest in doing something like this to your car, feel free to PM me, I am willing to reproduce something like this for a small fee. Any exhaust shop can do this as well, though.
The exhaust is all mandrel and flanged for easy removal so I figured I would use it as a starting point and just modify it with a new muffler, and try and reduce the sound level some.
Enter the Dynomax Ultraflo SS:
http://www.dynomax.com/products/ultrafloss.html
I've been a fan of these for years. Typically they flow awesome (Dynomax is one of the few muffler mfrs to publish flow data) and sound deep and relatively quiet. So... without knowing how it would work out, I bought at 17283 2.5" center-to-side Ultraflo SS for ~$90 shipped from rockauto.com.
The size worked out to roughly the same length as the muffler Spugen used, and the center-to-side arrangement looked like it would work OK. When it arrived it went in fairly easy. Cut off the old muffler, test fit the Dynomax, tacked it in place, then made sure it would fit OK before welding permanently & welding on hangers. I cut off the Spugen muffler hangers and reused those. Oh, and I also welded up the broken seam on the Magnaflow resonator.
Some pics of the finished product:
I used an OEM exhaust tip for a stock, conservative look:
I tried to tuck the muffler up as much as I could:
A few shots from the back:
The re-welded Dynomax resonator (pardon the hurried welding job):
Muffler and hangers:
The Spugen pipe hangs down more than I would like, but at least the muffler isn't any lower than it:
Here's one of the crack on the Spugen muffler... despite being loud and straight-through, you could still hear the leak at part throttle!
The sound: I absolutely love it. Where the Spugen was just offensively, oppressively loud, this is just as quiet. Under about 3000 RPM, especially with more throttle input, it's downright burbly. It isn't loud at those RPMs until you go more than maybe 30% throttle. Above that, with higher RPMs the sound become stock, and after VTEC, the exhaust note is lost in the normal symphony of VTEC just like stock. It's wonderful. I'm looking forward to regaining the use of a cell when driving and not having my ears ring after driving on the highway for an hour.
One important note, I do have a stock cat installed (no test pipe), though I can say from other vehicles I've had a Dynomax Ultraflo on with test pipes... it raises the general sound level but it's still acceptably loud. Put it this way, I've not heard anything as loud as the Spugen aside from an Invidia or an open header... even vehicles with no cat and a Dynomax Ultraflo.
A few side notes, the Spugen setup I have is 2.5", this engine definitely needs something larger, on the order of 2.75" or more. I doubt it would result in much of an improvement of "feel" but everything I know about exhaust systems points to 240HP requiring more.
Looking at the stock exhaust setup, you could probably do this muffler swap just as easy on a stock exhaust system by cutting the exhaust off at the split just before the axle, and using some straight pipe to extend back to the passenger's muffler area, then attach the muffler there. It would be one-piece but should work just fine.
If you haven't read it yet, there's an article by David Vizard that's great over at http://www.ntpog.org/articles/index.shtml called "No Loss Exhaust." Great reading on exhaust systems and even some formulae and rules of thumb for sizing exhaust systems. It also explains what the funny standpipe is that sticks off of the stock exhaust.
Speaking of stock exhausts, if someone has one they want to give away I'd be interested in picking one up.
If you have any interest in doing something like this to your car, feel free to PM me, I am willing to reproduce something like this for a small fee. Any exhaust shop can do this as well, though.
11-12-2008 | 07:57 PM
#7
Thread Starter
Registered User
Joined: Apr 2001
Posts: 2,898
Likes: 1
From: Fort Worth
I didn't want an angle but the size of the can and the config of the spugen piping didn't let me change that really. I did minimize it, though.
The Magnaflow can is about 10lbs, the Spugen as near as my bathroom scale and my fat ass could discern was about 7lbs. I didn't weigh the rest of the exhaust.
The only other mod planned at this time is wheels/tires. That's if I can find someone to buy my AP1s and the Rotas I had on the Prelude. No dice so far.
The Magnaflow can is about 10lbs, the Spugen as near as my bathroom scale and my fat ass could discern was about 7lbs. I didn't weigh the rest of the exhaust.
The only other mod planned at this time is wheels/tires. That's if I can find someone to buy my AP1s and the Rotas I had on the Prelude. No dice so far.
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