PX 2011 - Exhaust question
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Vespa PX 150 2011 & Vespa GTS 250ie 2005
Joined: 03 Sep 2011
Posts: 19
Location: Australia - Townsville
Sun Feb 18, 2018 12:19 am quote
Hello All,
I own a Vespa PX 2011 150cc that has the emissions exhaust system and in my opinion underpowered although I am 100kg in weight plus whatever I am carrying and I only get a max speed of about 80km per hour. Question, if I was to fit a standard (old school) PX exhaust without emission system would I get near 100 km per hour in speed or close to it?
Thanks in advance, see you on the road (if in Australia),
Bucko
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Joined: 26 Oct 2015
Posts: 2184

Sun Feb 18, 2018 7:43 pm quote
Re: PX 2011 - Exhaust question
Buckomp wrote:
Hello All,
I own a Vespa PX 2011 150cc that has the emissions exhaust system and in my opinion underpowered although I am 100kg in weight plus whatever I am carrying and I only get a max speed of about 80km per hour. Question, if I was to fit a standard (old school) PX exhaust without emission system would I get near 100 km per hour in speed or close to it?
Thanks in advance, see you on the road (if in Australia),
Bucko
Hey Bucko, I have a 2005 PX150. It's pretty much the exact same as a 2011. I weigh 70 kg, and top speed on mine with the factory muffler was about 75kph. I installed a Sito+, and it brought up the top speed to about 85kph...and this was in a speed tuck with no headwind on a flat stretch of road. Then again, one of my friends also has a 2005 PX150 (with a Sito+). He weighed in at around 115kg(?). A while back, we were out on a multi-day tour, and we were going as fast as we could down a steep mountain highway for about 8 kilometers. With him being 115kg, plus another 30kg of camping gear, he got that little 150cc up to 114kph! We both had Garmin GPS's. I pulled up beside him (I was on my P200) while we were going that fast, and looked over at his GPS. His read 114kph, and mine did to.

My point of the short story is, NO, you won't get anywhere close to 80kph on flat level ground with no head wind. If you throw your scoot off the side of a mountain (pretty much what my friend did), then yes, you can reach 80kph.



...and before all of the haters hate, the "real world" top speed on my friend's PX150 (on the flat, with no head wind) during that trip was closer to 72kph.
Ossessionato
2 matching N.Z. '69 VBC Super, 177cc Racer, VespaCross Bodge, Puch SRA150, Piaggio Zip 100! & others
Joined: 26 May 2013
Posts: 3903
Location: That bushfire place
Sun Feb 18, 2018 7:59 pm quote
Borrow a pipe off someone & try it... They can make a huge difference, but often at a certain rev-range ... Ie Sterling & Scoot-rtsht only work @ full noise...I use Boomstick, but had to buy from USA.

Somewhere here some extra did a heap of testing on different pipes, so a search may be helpful.

BTW: AnaKey has stupidly LONG primary, 177 Polini, lots o mods but not often does it "get on th pipe" in 4th... Been there a few times (perfect conditions). TOP SPEED: 140kmh!
Started life as a standard LML NV 150 .

OHH... Speedy got 132kmh (before I lost balls & shut throttle off) on the dyno!
On 8" wheels! Did 117kmhwhile riding on th weekend (then thought it was safer to look at th road!).

There is still hope for you, but it costs $$$$ & reliability
Molto Verboso
Joined: 15 Nov 2008
Posts: 1896
Location: Seattle
Mon Feb 19, 2018 8:38 am quote
Re: PX 2011 - Exhaust question
whodatschrome wrote:
Buckomp wrote:
Hello All,
I own a Vespa PX 2011 150cc that has the emissions exhaust system and in my opinion underpowered although I am 100kg in weight plus whatever I am carrying and I only get a max speed of about 80km per hour. Question, if I was to fit a standard (old school) PX exhaust without emission system would I get near 100 km per hour in speed or close to it?
Thanks in advance, see you on the road (if in Australia),
Bucko
Hey Bucko, I have a 2005 PX150. It's pretty much the exact same as a 2011. I weigh 70 kg, and top speed on mine with the factory muffler was about 75kph. I installed a Sito+, and it brought up the top speed to about 85kph...and this was in a speed tuck with no headwind on a flat stretch of road. Then again, one of my friends also has a 2005 PX150 (with a Sito+). He weighed in at around 115kg(?). A while back, we were out on a multi-day tour, and we were going as fast as we could down a steep mountain highway for about 8 kilometers. With him being 115kg, plus another 30kg of camping gear, he got that little 150cc up to 114kph! We both had Garmin GPS's. I pulled up beside him (I was on my P200) while we were going that fast, and looked over at his GPS. His read 114kph, and mine did to.

My point of the short story is, NO, you won't get anywhere close to 80kph on flat level ground with no head wind. If you throw your scoot off the side of a mountain (pretty much what my friend did), then yes, you can reach 80kph.



...and before all of the haters hate, the "real world" top speed on my friend's PX150 (on the flat, with no head wind) during that trip was closer to 72kph.
your experience may not translate to his later 2011 PX. it is not' pretty much the exact same' as a 2011.

the 2011 models had extra, other restrictions such as a redsigned ignition that incorporated a Rev limiter as well as a casting change in the inlet port to limit inlet timing.

this rev limiter cuts the engine at 7000 rpm. this limit, with standard gearing is rigt about the 100 kmph mark in 4th, and more importantly, limits your over rev to about 75 kmph in 3rd, requiring you to shift into 4th earlier, lower down in the power band.

getting the necessary 6800 or so rpm out of a stock 2011 px150 in 4th with a stock exhaust is... iffy.

but, you may get near it with an SIP road. and a CDI swap to one without the rev limiter. the inlet restriction will be the one gotcha that might prevent you from doing as well as you'd hope.
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Joined: 26 Oct 2015
Posts: 2184

Mon Feb 19, 2018 10:46 am quote
I didnít know about the casting change. Thanks for setting me straight Rob.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 7388
Location: Victoria, Australia
Wed Feb 21, 2018 12:28 am quote
I thought I remembered someone here measuring the intake on a late PX150 and it was clearly larger than the earlier type, potentially allowing better performance?

Here's the CDI you want. It's available from a few places but these guys are the manufacturers.

http://www.ekmpowershop2.com/ekmps/shops/readspeed/readspeed-zeus-vespa-px125150-cdi-6216-p.asp
Ossessionato
Joined: 26 Oct 2015
Posts: 2184

Wed Feb 21, 2018 12:47 am quote
Re: PX 2011 - Exhaust question
whodatschrome wrote:
Buckomp wrote:
Hello All,
I own a Vespa PX 2011 150cc that has the emissions exhaust system and in my opinion underpowered although I am 100kg in weight plus whatever I am carrying and I only get a max speed of about 80km per hour. Question, if I was to fit a standard (old school) PX exhaust without emission system would I get near 100 km per hour in speed or close to it?
Thanks in advance, see you on the road (if in Australia),
Bucko
My point of the short story is, NO, you won't get anywhere close to 80kph on flat level ground with no head wind. If you throw your scoot off the side of a mountain (pretty much what my friend did), then yes, you can reach 80kph.
I just reread what I had posted a few days ago. I meant to type 100kph on flat ground, NOT 80kph (especially since your PX already goes 80kph)! Sorry for that confusion. But I guess it doesn't matter anyhow since mine's an older 2005 model.
Molto Verboso
One or two fun scoots....nothing too precious
Joined: 17 Jul 2013
Posts: 1278
Location: UK (South East)
Fri Feb 23, 2018 4:27 am quote
Ginch, I didn't measure the inlet length on my 2012 PX150, but I did note that it was shorter and narrower than my 1976 VBC, which has never been modified. Having said that, the available rotary pad is much longer on the late PX engine, meaning that you can grind out a lot of material, particularly at the back end, which gives you your earlier inlet opening. I took mine back to give ~115 degrees BTDC opening, and the Jasil cut crank gives me a close of about 60 degrees ATDC = 175 inlet duration. It's my BGM 177 commuter build, so I didn't go nuts!!

Edit: just checked my old post again. I actually determined that the 2011+ PX inlet is of similar length to the old VBC, but the VBC is wider, thus providing a greater surface area for mixture induction. The Jasil crank closes off the inlet at 65 degrees ATDC (not 60), so total inlet duration of 180 was achieved.
Veni, Vidi, Posti
74 Super, 75 Super, PX project, LML off-roader and new to 2018, '66 Blue Badge Smallframe
Joined: 30 Nov 2011
Posts: 7388
Location: Victoria, Australia
Sun Feb 25, 2018 3:53 am quote
Maybe it wasn't you? I can't remember. So you're saying it's smaller in area than a VBC?
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