Author Topic: Exhaust Gurgle New EFI Muffler  (Read 3564 times)

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TCP

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on: November 17, 2011, 02:59:18 pm
I'm getting a bit of backfiring from the new EFI exhaust.

I know that the engine controller is supposed to self adjust to the new back pressure.

I wrote off the issue to adjustment duration.

I have about 50 miles on the new exhaust.  Various driving conditions.

Happens when rolling off the throttle.

Any thoughts???

How long should it take for the controller to adjust to the new exhaust system pressures.

Comments appreciated.


Caseman

How long should it take
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The Garbone

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Reply #1 on: November 17, 2011, 03:29:35 pm
My Harley does the roll off gurgle a little, my 07 Enfield does it a lot.  Its a feature..
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TCP

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Reply #2 on: November 17, 2011, 04:11:18 pm
I would occasionally get that with my Triumph as well.  I wrote it off to old Amals.

If it's a feature, I will learn to appreciate it.

Caseman
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Kevin Mahoney

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Reply #3 on: November 17, 2011, 04:16:37 pm
The computer adjusts instantly. The O2 sensor in the exhaust pipe senses the change in air fuel ratio and tells the computer to adjust the mixture. There is no learning curve. Because the silencer is not so silent anymore you are hearing what has always been there.
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Maturin

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Reply #4 on: November 17, 2011, 04:23:57 pm
The more octane I use the less afterfiring I get. It's reduced even more when temperatures are going up.
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TCP

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Reply #5 on: November 17, 2011, 04:30:36 pm
Kevin,

Thanks for weighing in on this one.

I am only using premium in the tank thus far.

The exhaust is tight, but the fit where the header meets the head is a bit dicey.

I lined it up the best I could with all the exhaust components loose, and then tightened it down a bit at a time on each bolt, but I still get a bit (tiny bit) of leakage at the connection point.

Caseman
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2bikebill

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Reply #6 on: November 17, 2011, 04:32:51 pm
I've tried three different aftermarket pipes on my G5, they all backfire. The short Indian one is the worst, the EFI specific ones are better, but they still give out an almighty bang from time to time. That said, the bike is noticeably nippier without the stock monster torpedo tube holding in back (and down!) so it's worth the risk to the horses and the occasional freaked-out pedestrian..... ;)
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TWinOKC

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Reply #7 on: November 17, 2011, 05:37:15 pm
The backfiring only occurs when my C5 is cool and just a few times, after the engine warms up the backfiring almost completely goes away.  It seems to happen only when the outside temperature is in the 50's or lower.  I use regular grade regular fuel (alcohol free) most of the time.  I like the backfiring wouldn't mind if it did it more.   
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TCP

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Reply #8 on: November 17, 2011, 06:00:21 pm
Part of the allure I guess.

No question there is an improvement in performance with the EFI. 

The Caseman

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will keep me from riding unless I can't make bail"

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barenekd

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Reply #9 on: November 17, 2011, 06:02:55 pm
Mine pops whenever it wants to. No conditions are necessary. I did a 240 mile ride yesterday from sea level to 8000 feet and it popped 3 or 4 times over the course. I remember one at about 5000. It was cold up there.
I run just regular old pump gas with ethanol. The bike runs great in all conditions. It doesn't care. The power does sometimes get a bit weak, as would be expected, at those altitudes. but it keeps on truckin'
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Reply #10 on: November 17, 2011, 07:46:09 pm
I was up around 5000 feet a while ago.  There was an incline and the bike was working hard, it wouldn't break 50mph with the throttle wide open.  I'm sure they run well at the 18,000 feet they were tested at in development but I don't think they go very fast ;)

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GlennF

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Reply #11 on: November 17, 2011, 09:25:16 pm
My upswept will backfire with quite loud a bang when you back off the throttle after riding hard.

I am tempted to poke of those 3" long Harley style mini baffles they stuff up the end of open headers in the end of my upswept to see if it makes a difference. If I ever get around to trying it I will post the results up here.


Ducati Scotty

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Reply #12 on: November 17, 2011, 09:44:32 pm
I think those would help a lot of overly free flowing mufflers.  As some people here have noted a very open exhaust is great for top end power but stifles low and mid range torque.  Those little baffles close the exhaust opening a bit.  That makes them a bit quieter but would also add a little back pressure which so many modern engines seem to like.

Scott


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Reply #13 on: November 18, 2011, 04:53:12 am
My short bottle muffler had no backfiring at the original higher rpm set at the factory. I adjusted the idle gown to a nice thump, thump, thump and it started backfiring occasionally during rapid deceleration from high rpms. The computer does seem to have a tiny lag. I turned the rpm up by 1/8th turn of the screw and things are happy again. Just a bit of a gurgle but no big bangs!
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iowarider

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Reply #14 on: November 19, 2011, 03:54:00 am
I think those would help a lot of overly free flowing mufflers.  As some people here have noted a very open exhaust is great for top end power but stifles low and mid range torque.  Those little baffles close the exhaust opening a bit.  That makes them a bit quieter but would also add a little back pressure which so many modern engines seem to like.

Scott
This is one of those I forget what motor mag it was in, but, they put an eye bolt, smaller diameter than the pip, put it in with the bolt toward the wheel, sprayed it black to hide it best they could. Made a good torque increase at the low end. Even had a dyno sheet to prove it. Yep its was that little bit of back pressure, and it was on an open header pipe no muffler at all. If I can find it I'll post the link.
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iowarider

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Reply #15 on: November 19, 2011, 04:14:33 am
Ok, google motorcycle lollipop mod. Several results pop. Most are Harley forum with drag pipes no baffles. All report deceleration popping goes away, brings back the low and mid range torque the lost with the drag pipe. I don't see why it wouldn't help our bikes. only cost a few bucks an maybe an hour to install. Anyway, bit more than I know for sure. Just thought it was interesting.
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iowarider

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Reply #17 on: November 20, 2011, 03:40:18 am
That's the longest URL I have ever seen. The amazing thing is it works perfectly!!
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iowarider

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Reply #18 on: November 20, 2011, 03:48:05 am
http://www.nightrider.com/biketech/exhaust.htm#dyno_results.  This one does a good job of showing why it works as well as how. Dyno sheet to back it up.
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