Muffler improvement power increase
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Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Fri Jan 01, 2010 9:29 pm quote
I have made an alteration that has solved the suffocation within the exhaust. This change has allowed a significant power increase, unfortunately I am unable to post photos. How do you put a photo into this blog?
Enthusiast
2010 GTS Super 300ie "Nero Bello"
Joined: 06 Aug 2009
Posts: 75
Location: Oklahoma City
Sat Jan 02, 2010 9:46 am quote
Check out: FAQ: How do I upload a photo? (and be sure that the image size conforms.)
Ossessionato
GTS, LX, VSD, VSX, VNX, LD 125, Chucky, LI125
Joined: 21 Oct 2005
Posts: 4183
Location: San Jose CA
Sat Jan 02, 2010 10:01 am quote
Buddy of mine opened up a GTS exhaust and did some 'removing' of constrictions...no sensed increase in power....and it backfires alot now.

Did lighten it up 3 LBS tho.

Some pics of your changes would be of interest...does it backfire?

R

Ossessionato
01 ET2 - 01 ET4 -- 05 GT200L / 05 PX150 / 1986? Honda CH150 Deluxe.
Joined: 27 Nov 2005
Posts: 3000
Location: SoCal OC
Sat Jan 02, 2010 11:56 am quote
If you have just altered the stock exhaust, a power increase would likely be very small. It will just make alot more noise. Did you test it on a Dyno to see the before and after results?
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Mon Jan 04, 2010 7:10 pm quote
Not any increase in backfire, only a bit louder. The trick is to maintain resonance and not just tear out the entire interior. There is a factory designed length of initial muffler pipe and that integrity must be maintained. Still working on pics.
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Tue Jan 05, 2010 2:59 pm quote
ANY PICTURES??? I just ran a big drill bit up the end of my ET pipe,gradually increasing the size of drill until it sounded better!!!, has a nice little burble when I throttle off no backfire. Stock pipe was too quiet
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Tue Jan 05, 2010 6:39 pm quote
a Drill in the tailpipe actually will reduce the length of the internal pipe which in turn is counter productive. You have eliminated the thrust required for proper resonating effect. The internal pipe will wrap within the muffler to produce the factory engineered function. The problem within the factory muffler is considered to be "suffocation" or inability to eliminate gasses within a timely manner. The purpose of suffocation is to assist with cleaner emissions.
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Wed Jan 06, 2010 2:49 am quote
Seems to work for me mate!! has no effect on top speed/ mpg etc JUST sounds better! that works for me! any pics yet????
Ossessionato
Blue GTS300 Super 2015, White GTS300 Super 2018
Joined: 01 Nov 2005
Posts: 2832
Location: Sydney, Australia
Wed Jan 06, 2010 4:24 am quote
Also waiting for details. I must admit I am sceptical. A louder engine can sound as if it is more powerful.

But I would prefer a GRRRRR or VROOM to the present AAAARRGH sound.

Mike
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Thu Jan 07, 2010 7:11 pm quote
This should assist you to understand, when you increase air flow (exhaust) you increase the ability of the mechanism to work more efficiently. With the engine exhaust working properly the output is increased. You are only able to make minor improvements but the compilation of minor increases will compound to what is known as a tuned engine.



Ossessionato
GTS, LX, VSD, VSX, VNX, LD 125, Chucky, LI125
Joined: 21 Oct 2005
Posts: 4183
Location: San Jose CA
Thu Jan 07, 2010 9:32 pm quote
Defendo007 wrote:
This should assist you to understand, when you increase air flow (exhaust) you increase the ability of the mechanism to work more efficiently. With the engine exhaust working properly the output is increased. You are only able to make minor improvements but the compilation of minor increases will compound to what is known as a tuned engine.
Dude...

Now I totally understand.

You rock!

Great pic!

R

Hooked
Joined: 26 Dec 2009
Posts: 314

Fri Jan 08, 2010 8:16 am quote
glasseye wrote:
Defendo007 wrote:
This should assist you to understand, when you increase air flow (exhaust) you increase the ability of the mechanism to work more efficiently. With the engine exhaust working properly the output is increased. You are only able to make minor improvements but the compilation of minor increases will compound to what is known as a tuned engine.
Dude...

Now I totally understand.

You rock!

Great pic!

R

lol.
Ossessionato
GTS 250ie
Joined: 21 Jun 2008
Posts: 2046
Location: Rhode Island
Sat Jan 09, 2010 5:54 am quote
Defendo007 wrote:
This should assist you to understand, when you increase air flow (exhaust) you increase the ability of the mechanism to work more efficiently. With the engine exhaust working properly the output is increased. You are only able to make minor improvements but the compilation of minor increases will compound to what is known as a tuned engine.
Well, yes and no. IF the exhaust is very restrictive, reducing backpressure only moves the bottleneck up the chain to valves, ports, intake.

To actually take advantage of anything a pipe would do, you need to deristrict the intake, rejet a carbed bike, and often adjust ignition timing. Better flow through the head by porting or high flow replacement also reaps gains here.

In addition, there is such a thing as resonance--by opening up the chamber and then forcing the exhaust to exit a through a smallish pipe an exhaust can actually help with scavenging. Sometimes removing baffles actually reduces this effect, diminishing or eliminating any gains from lower restriction.

Backyard "engineers" tend to reduce the reliability of their rides while gaining little in performance. The bike may sound more powerful, but it probably isn't.

I've got plenty of friends who are riders of all stripes. A friend of mine called me after he got his Harley done up--special cam, head, pistons, bored cylinders, carb, straight pipes, fully built up and "tuned". He spent a freakin' fortune and proudly let me ride is bike. He said it was a monster, and real powerful.

OK, off I go. At 2200rpm it started to pull like a train. At 2600rpm it was totally out of steam. Yeah, when you opened the throttle it kicked you in the pants, but the bike was an unrideable piece of shit. He loves it still, because he "knows" it's much "faster" and "better" than a stocker.

Show me on a dyno and I'll believe you, otherwise enjoy your hobby, but don't bother me with your claims.

P.
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Sat Jan 09, 2010 9:05 am quote
Please read what I wrote again. You must have a compilation of factors for any improvement. One variable will affect another. Your knowledge of engine functionality is admirable. Once you begin to change from stock to tuned you are entering an area that is subject to debate and this is what the forum is about.
Ossessionato
Blue GTS300 Super 2015, White GTS300 Super 2018
Joined: 01 Nov 2005
Posts: 2832
Location: Sydney, Australia
Sat Jan 09, 2010 2:22 pm quote
Still no photo or details. Is this topic going anywhere?
Mike
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Sat Jan 09, 2010 2:59 pm quote
PICS ????
Here are some of the inside of a spare ET4 stock exhaust I had and cut open whilst we are waiting for defendo's pics . What parts did you modify?




THIS IS THE PATH THE BIG DRILL BIT I USED TOOK

Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Sat Jan 09, 2010 3:12 pm quote
ps if you set the image quality on your camera to its lowest the pics come out larger
Ossessionato
GTS 250ie
Joined: 21 Jun 2008
Posts: 2046
Location: Rhode Island
Sun Jan 10, 2010 8:30 am quote
Defendo007 wrote:
Please read what I wrote again. You must have a compilation of factors for any improvement. One variable will affect another. Your knowledge of engine functionality is admirable. Once you begin to change from stock to tuned you are entering an area that is subject to debate and this is what the forum is about.
Ok, I get big-headed some times.

Edited to try fix my personality.
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Sun Jan 10, 2010 6:07 pm quote
END OF PAGE, POST NO MORE I will post again in a month or so. With photos and technical data.

Thank you for all your responses and input. Evidently some of the readers over estimated the extent of the modification by removing everything. Please always research before you alter any of the systems of these delicate machines.
Banned
2:6
Joined: 11 Jan 2007
Posts: 7719
Location: San Francisco
Sun Jan 10, 2010 9:38 pm quote
Defendo007 wrote:
EEvidently some of the readers over estimated the extent of the modification by removing everything. Please always research before you alter any of the systems of these delicate machines.
What? No one did any such thing. You were having issues posting pictures so a very clear picture was posted of all the internals to aid in the conversation. All you have to do is speak to what part of the internals of the pipe you modified.
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Mon Jan 11, 2010 4:15 am quote
Defendo007 wrote:
END OF PAGE, POST NO MORE I will post again in a month or so. With photos and technical data.

Thank you for all your responses and input. Evidently some of the readers over estimated the extent of the modification by removing everything. Please always research before you alter any of the systems of these delicate machines.
look forward to it , cheers Bill
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Tue Jan 12, 2010 6:40 pm quote
PHOTO!!!!
OK, here is the photo of the finished muffler. I started with a SITO aftermarket muffler with no converter. Opened it up with a plasma cutter. Did my homework by contacting a person with their degree in Indusirial Arts, Engine design and MIG welded everything up when finished. The tailpipe is now 1.5 inched in diameter.



Petty Tyrant
GTS250 GTS300 MP3 500
Joined: 11 Oct 2005
Posts: 30075
Location: Bay Area, California
Tue Jan 12, 2010 8:36 pm quote
So besides a bigger tip, what else did you change?
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Wed Jan 13, 2010 2:00 am quote
nice ! do you have any pics of what you did to the internals? If not feel free to use my cutaway pics to show the path of gas flow .Do you still have the SAS connected ? see arrow, also is the area outlined in red where you cut open the muffler? very interested in what changes you made internally ans I still have my spare to play with lol Cheers Bill



Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Wed Jan 13, 2010 5:58 pm quote
I should have taken pictures of the inside, I got so wrapped up in this I forgot. With the exhaust permitted to evacuate much faster the result is overall performance increase. I have taken this Vespa LX to 70 but afraid to do it again.
Ossessionato
GTS, LX, VSD, VSX, VNX, LD 125, Chucky, LI125
Joined: 21 Oct 2005
Posts: 4183
Location: San Jose CA
Wed Jan 13, 2010 11:45 pm quote
Okay...you pulled some bits out and increased the diameter of the tailpipe....I am assuming from the front chamber to the rear outlet.

How much weight did you shed?

backfiring?

What is the diameter of the tube you used for the tailpipe section?

Any dyno work-up?

Any better than a sito plus?

Good to see some metal work on the stock pipes...

R

Member
Joined: 25 Dec 2009
Posts: 13

Thu Jan 14, 2010 1:18 am quote
Defendo, if you like the increased noise, good for you. I don't recall even once I wanted a louder bike riding from coast to coast many times and Los Angeles to Portland dozens of times.

It wasn't long ago you could buy regular and unleaded gasoline. Friends and neighbors would buy new cars and punch out the unleaded restrictor so they could buy the cheaper regular gasoline. Oregon had a limited area around Portland for emission testing. With no testing, it only took a few raps of a hammer. Not sure what the laws are today.

Your knowledge of this muffler project is way beyond most. You are happy, and good for you.
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Thu Jan 14, 2010 7:00 pm quote
Muffler improvement.
When my LX gets up to 70 miles per hour and cruises at a much improved rate than stock I would consider that a significant improvement, noise is a byproduct. The pipe of 1.5 in. dia. at exit is sufficient to expel gasses at an accelerated rate. The exhaust improvement is only one concomitant to a tuned engine. To eliminate pipes for noise serves no purpose, to improve air flow serves a purpose.
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Thu Jan 14, 2010 7:09 pm quote
Answering questions
The weigh loss was insignificant , a few lbs.

The Sito muffler was available so I used it, did not consider any others.

The plasma cutting of the casing was easy to do and with a MIG welder easy to repair any slits to the original casing.

A dyno test is an excellent indicator of any before and after change. Since I did not dino prior to work it appears that was my mistake.

The true test is overall performance. The speedometer being at 70 is my indicator for now.

By design I have eliminated a common problem, backfiring is minimal and not noticeable.
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Fri Jan 15, 2010 3:23 am quote
Re: PICS ????
xmanhoe wrote:
Here are some of the inside of a spare ET4 stock exhaust I had and cut open whilst we are waiting for defendo's pics . What parts did you modify?
thanks, pity you never took pics of inside! I know what you mean about getting carried away lol, can you indicate on my cut away pic where or what you removed??? as i would like to do this to the spare muffler I split and try it on my ET4 125 as I have access to a Dyno and can test before and after thanks ,really looking forward to trying this one thanks again Bill
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Fri Jan 15, 2010 7:14 pm quote
Here is what you change
The original exhaust pipe must not be altered, this is the one that "loops 180 degrees and is a direct pipe from the exhaust gasses. You must patch up the drill hole as indicated in your photo, big mistake to alter this section. The final chamber the gasses enter (upper most and smallest) is where you increase the expelled gasses with a larger diameter section, 1.5 inches no larger than 1.625. continue with the enlarged diameter one chamber at a time with this size pipe, thinwall no seam mild steel. Direct the flow of gasses outward at original exit. I used a lathe to machine the final exhaust that is visible in the photograph. Mig weld everything up but do not braze ( the heat will affect the braze -resulting in brittleness and fatigue stress cracks).

Good luck
Ossessionato
GTS 250ie
Joined: 21 Jun 2008
Posts: 2046
Location: Rhode Island
Tue Jan 19, 2010 4:47 am quote
While generally skeptical about home tuners, what you described is quite sound, thoughtful and should actually help with power.

Great job!

P.
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Tue Jan 19, 2010 9:13 am quote
Hi Defendo, is this the section of pipe you replaced with the 1.5 pipe ??(marked section 1 and 2) and then where it enters the rear section of muffler as shown with arrow in my other picture??? would really like to try this as I have one cut open and ready lol ps only found ot after i cut the shite out of it that I could have gotten 50 for it on ebay !!! lol look forward to your reply BIll





Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Mon Feb 01, 2010 1:51 am quote
bump ! any thoughts on this yet Defendo????
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Mon Feb 01, 2010 6:03 pm quote
Correct
Bill, you are 100% correct. That is my formula, I had outstanding results doing this. Next I go to 190 Malossi Top end and Experiment with variator.
Good luck
Molto Verboso
Belvoir Wine Team RC (Buckfast Commando) ,Rusty Sheriff's Badge MCC, 07 ET4 ,07 Piaggio X8
Joined: 19 May 2007
Posts: 1499
Location: Belfast N.Ireland
Tue Feb 02, 2010 1:31 am quote
Cheers thanks bill
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Tue Feb 02, 2010 12:02 pm quote
Be patient !
To do this I used a plasma cutter , drills, rotating hand held small grinder. It takes time to get it perfect but if I did it you can easily do the alterations.I know your results will match mine and the results are obvious and noticeable with not much noise change.
Molto Verboso
Joined: 10 Feb 2008
Posts: 1104
Location: Midwest
Wed Feb 03, 2010 11:25 am quote
Defendo007,

You now are seeing 70 on your speedometer.Just curious what number was you seeing before the mod? Curious about the change. Thanks.
Hooked
LX 150
Joined: 02 Aug 2009
Posts: 194
Location: Camarillo CA
Sat Feb 06, 2010 3:28 pm quote
Speed
Before the modifications I was seeing on the speedometer 80.


Just kidding it was reading 62. I realize that the stock speedometer is approximate but one thing I am certain of is that no one was passing me at the 80 mph speedometer reading!!!
Lurker
Joined: 08 Jun 2010
Posts: 1

Tue Jun 08, 2010 10:32 pm quote
Re: PICS ????
xmanhoe wrote:
Here are some of the inside of a spare ET4 stock exhaust I had and cut open whilst we are waiting for defendo's pics . What parts did you modify?
I would cut or drill holes in the final pipe between the smallest baffle and medium baffle. If the exhaust is properly tuned from the factory then you want to maintain the tune but reduce the back pressure. Modifying this section of pipe will maintain the tune and eliminate some back pressure.
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