Oi Mate, what's the best exhaust?
We get asked this everyday, so this afternoon we ran up some different scooter exhausts to compare.
The bike used was a completely standard 50cc Yamaha Aerox. It's important to note that these results are only relevant to standard 50cc. If the bike was further modified e.g. different cylinder kit etc. pipes that appear poor in this test could come into their own and vice versa.
We'll repeat the test at some point with different cylinder kits fitted.
Feel free to skip down to the results if you're not interested in the technicals !
The pipes chosen for the test are popular budget pipes, more expensive exhaust pipes are designed to work with more highly tuned bikes and tend to work poorly with standard 50cc kits. For example the PM Tuning 360 and Yasuni R exhaust pipes don't perform brilliantly in this test because they're designed to work with higher revving cylinder kits.
The first graph contains all the pipes tested for direct comparison. For the tests we've removed the variator and used fixed gearing to get a proper power curve for each exhaust so you can see exactly what power the pipe makes at different rpms.
The pipe which made the most peak power was the Leo Vince ZX and (suprisingly) the Leo Vince TT with the Stage 6 Pro Rep very close behind.
(click on picture to expand)
Of course things are never this simple and the pipe that develops the highest peak power isn't necessarily the pipe which makes the fastest bike.
Take the Leo Vince TT for example. You can see from the graph that it makes a very respectable 7.5hp at 8,800rpm. This means that if you play with the roller weights until the bike runs at 8,800rpm (a good variator will hold it there steadily) you'll have 7.5hp available whenever you mash the throttle and at whatever speed you're going. None of the other pipes can better this...
However once you reach a certain speed (approx 30mph on a standard bike) the variator has moved all the way out and will no longer be able to hold the revs at 8,800. This means that the only way the bike can now go faster is for the revs to increase.
You'll notice on the budget pipes (e.g. the TT and the Endy pipe that the power they produce drops off very quickly at higher revs.
If we look for example at 9500rpms we can see that the power for the TT and Endy pipe has dropped off to around 6hp already whilst the Leo Vince ZX and Stage 6 Pro Rep are producing over 7hp at this rpm. Because this rpm would represent a road speed of approx 35-38mph this extra 1hp can make the bike substantially quicker. 1hp might not make a huge difference when accelerating from 10mph to 15mph but accelerating from 35 to 40mph this difference is definitely noticeable and because of this the higher revving pipes are significantly quicker in the real world when fitted to an otherwise standard engine. These also tend to be the pipes that work well if you later upgrade to a 70cc kit which is normally designed to run at slightly higher revs than standard.
It's worth noting though that the lower revving pipes can be easier to setup. Take the Yasuni Z for example, it makes more than 5hp all the way from 7000rpm to almost 10,200rpm, a range of over 3000rpm. The Leo Vince makes over 5hp only over a range of 2000rpm. This means that the Yasuni Z, although being a lower performing pipe will be very tolerant and easy to set it up.
Even if you get the rollers wrong and the variator is worn (can't hold the revs constant) it will still perform well as it's powerband is so wide
(click on picture to expand)
and so the conclusion...
To be fair, for the money this is a cracking exhaust. At £49.95 this performs far better than we thought it would and better than all other aftermarket 'standard look' exhausts we've tried. The power output is a substantial improvement over standard Yamaha making peak power of 6.4hp at just 7,700rpm meaning high engine reliability. Predictably though it does tail off at higher revs and therefore can't compete with the other pipes on top speed.
PM Tuning 360 pipe
Probably not a good choice for a 50cc standard moped especially give the price of £136 for the laquered or £159 for the chromed version unless you're planning on tuning further at a later date. It has a surprisingly broad powerband though, this pipe might be more interesting when we test it later on some 70cc kits but the peak power is made a too low revs for it to compete on top speed against the ZX or Stage6 Pro Rep pipes.
At just £75 this is an impressive exhaust. It's power curve is almost identical to that of it's ZX big brother except it occurs approx 800rpm lower meaning that it looses out to the ZX in top speed but should match it and any of the other pipes neck and neck up to around 30mph. This is definitely a best buy at the price. The Endy pipe isn't far behind and is cheaper at £70 but the TT comes complete with light roller set and clutch springs which the Endy doesn't. Both Endy and TT pipes are probably best avoided if you intend to upgrade the bike to 70cc as they perform best with standard 50cc
This is a classic exhaust but it really does deserve it's popularity. Together with the Stage6 Pro Rep pipe these two pipes stand out as producing the most useable power both peak power and the power developed at higher revs meaning both the best acceleration and best top speed. Currently £99 for the laquered version and £119 for the chromed version this is more expensive than the Stage 6 pipe. There is now a ZX-R version of the Leo Vince out, but first impressions are that this is no better than the original ZX. Whereas the ZX was mostly hand welded, much more of the ZX-r process now seems to be machine automated and first impressions are that it's a cost cutting exercise rather an a genuine new pipe. We'll run one up shortly though for comparison before committing to this !
This pipe has a very broad powerband, making it very tolerant of poorly setup bike, basically it will run well anywhere between 7,500pms and 10,000rpms and will therefore work happily with worn or simply badly setup transmissions, no other pipe in the tests worked so well across such a wide range, it would work well pretty much even with the standard variator rollers left in there meaning the engine can spend most of it's life at much lower rpm than it could with some of the other pipes which substantially increased engine life span and reliability. The price of this is a slight loss of peak power against the peakier higher revving pipes. The Yasuni R was more interesting and curiously was able to develop more hp than any other bikes at 11,000rpm but even so for such an expensive pipe it is outperformed by the ZX and Stage6 pipes in raw power terms. In fairness we know this pipe works extremely well on higher power cylinders right up to MHR rep/ Corsa/ Stage 6 70cc Race which are too highly tuned for pipes like the Leo Vince ZX to work well on. Because of this it's still one to definitely consider if you're going to be doing some significant tuning !
It shouldn't be overlooked that Yasuni is classed as a premium build quality exhaust compared to others in this test due to it's very high design and quality control. They have many premium features not seen on cheaper exhausts. Even the silencers casings are precisely sealed with O-rings!
This Stage6 exhaust really has to be the outright winner. It's very similar to the Leo Vince ZX pipe but the Stage 6 pipe has a wider powerband at an expensive of just 0.2hp loss of peak power over the ZX. However the broader powerband importantly comes into play at higher rpm and develops more horsepower than the ZX pipe as soon as the variator has finished changing out making it marginally slower than the ZX up to approx 28mph but from then on it develops up to 1hp more than the ZX from there onwards. This alone would make it the winner in our eyes but it is also significantly cheaper than the ZX. £99 gets you just the lacquered version of the ZX pipe whereas £99 would also buy you the chromed version of the Stage 6 exhaust. The chrome version of the ZX pipe is an extra £20 and is in the process of being discontinued presumably to save costs (currently Leo Vince have their exhausts sent out to be chromed by a 3rd party). It's worth noting though that the ZX pipe comes complete with rollers whereas the Stage6 exhaust doesn't (budget extra £6!)
For such a high performing exhaust at such a good price you really can't go wrong