|
|
Post by reveeen on May 15, 2011 8:10:15 GMT -5
I *suspect* the overheating would be caused by the reduced chamber outlet diameter on the pipes meant for 50cc (and believe this, along with chamber volume, to be the only major difference between a 70cc pipe and a 50cc pipe). I'd be willing to bet, with an increase in outlet diameter, a 50cc pipe would work just fine (or good enough) on a 70cc+ motor.
I'm *thinking* packing with stainless steel wool (and willing to donate some to you to try). The noise level is higher, but something *must* be going on, because here I had to re-jet (richer) when I swapped stainless steel wool for the traditional Fiberglas wrap (of course, to us "old fellas", stainless steel wool is "the traditional", and Fiberglas wrap is "new-fangled" stuff).
|
|
|
|
Post by 90GTVert on May 15, 2011 12:38:56 GMT -5
The stinger diameter is what's supposed to have a big effect on heat retention in a tuned pipe. I'm just not looking to mod my pipes that worked well on the 70 to make it work for 20-30 miles of test riding.
I might try the steel wool (I have a bag of steel wool here, not stainless though) at some point. Dunno if I'll do it right at this stage or at some other point. Kinda wish the pipe was stock instead of all modded for this test to be honest.
|
|
|
|
Post by 90GTVert on May 15, 2011 22:25:22 GMT -5
Leo Vince ZX [/color] Next up, I installed my Leo Vince ZX exhaust. This pipe was purchased for a 100cc Yamaha Aerox. It is not the more common 50-70cc version. I have removed all restrictions, and then some. Details on the modifications to this pipe can be seen HERE.  This exhaust only needed a few washers stacked up to space it out. Otherwise installation is pretty simple.  Here's a vid with the sound revving and riding. The silencer has been repacked, but it's pretty similar to original in sound right now. The volume level is much louder than stock or the Phongeer, but not obnoxious. It definitely attracts more attention though, which can be good and bad. I increased the main jet to a 92, just one size up from what the Phongeer exhaust liked. Otherwise it was good to go. I kept the 5g sliders in place, knowing this exhaust has a higher powerband. I went for a 50 mile ride to evaluate the change and enjoy a bit of nice weather this afternoon. Acceleration is noticeably slower than with the Phongeer pipe, but still greatly improved over stock. Normally I would try to fix that with lighter rollers or sliders, but read on. Cruising speeds are good, in the upper 40s. Here's the bit that surprised me. Max speed was 53MPH. That's right, exactly the same as with the Phongeer pipe. Unlike the PG pipe, I had to wait a little longer for the last 3MPH. It got to 50MPH easily and would even cruise right around there at times. Max RPM was somewhere around 8,700-8,800. I know that this pipe makes it's max power nearly 1,000RPM higher. The reason that I didn't try to get the revs up is that I just don't think this engine likes to rev that high. The stock port durations are so mild that I don't believe it can make the best use of what the ZX exhaust has to offer at this point. With any exhaust, the power drops off above 8,500-8,600RPM. Unfortunately this mismatch and the higher powerband of the ZX makes it less pleasant to use than the Phongeer pipe which has a much broader range and is better suited to the mild cylinder. I have used this pipe on other motors, so I know it's got potential, but I think we're just seeing the importance of matched components rather than random part swapping for what is the "better" part. Fuel economy on this ride was 41.5MPG. I was quite hard on the throttle and dealing with crosswinds for a bit though.  So, disappointing as it may be, this pipe didn't function as well as the Phongeer. On top of falling short on power, the additional noise seems unnecessary when you don't have the horsepower to back it up. This can be a good pipe, but it's not if the cylinder is as mild as this one. That said, it's still a great improvement over stock. [/center] |
|
|
|
Post by 90GTVert on May 15, 2011 22:31:14 GMT -5
I'm not sure there's much point of testing the 70cc exhausts. I suppose the SP3 might be worth a shot, but the MRP pipe I have is more on par with the ZX or may even like higher revs. Seems like it's not worth the risk of engine damage if it does get hot for that test. If you guys wanna see it, I can do it though.
|
|
|
|
Post by 190mech on May 16, 2011 4:45:13 GMT -5
I think the SP3 may be a good test if the outlet pipe is the same or larger then the stock exhaust..
|
|
|
|
Post by 90GTVert on May 16, 2011 4:51:33 GMT -5
Yeah, I think the SP3 will be fine. Might be interesting to see how it does vs the PG. The MRP has a long, narrow, stinger though. Way smaller than any 90cc stuff.
|
|
|
|
Post by 190mech on May 16, 2011 4:53:59 GMT -5
The MRP has a verrrry small stinger! :paranoid:
|
|
|
|
Post by 90GTVert on May 16, 2011 4:57:24 GMT -5
Yeah, I forget now but I wanna say it's something crazy like 1/2" ID. I have used it on a 90cc before, but I also had seizes until I finally got a 90cc pipe.
|
|
|
|
Post by 2strokd on May 16, 2011 7:01:46 GMT -5
It does, the MRP has a small stinger that is. I think Leo ZX,s can be finicky sometimes with the narrow power band and all. Ide be interested in the SP3 test! That stock 90 might really like it? Lets see how it stacks up against the PG? Great work BTW! Thank you!
|
|
|
|
Post by 90GTVert on May 16, 2011 8:46:07 GMT -5
The SP3 went on a 5AM. I really think these are like warning signs of some disease. I'm up till 2AM one night putting one exhaust on, then I get up and put another one on at 5AM another day. Oh no, I've got the scooteritis. :scared: It's OK though, next thing you know it'll go into remission and I won't touch the scoot for a week or two. lol
|
|
|
|
Post by 2strokd on May 16, 2011 8:49:17 GMT -5
:disco: :lol:
|
|
|
|
Post by 90GTVert on May 16, 2011 15:24:36 GMT -5
Leo Vince SP3 [/b] The last exhaust that I have around to try out on Project 90 in this phase is a Leo Vince SP3. It was supposed to fit an Aprilia Scarabeo 50 up to 70cc, so it's not exactly intended for the big 89cc minarelli.  The header and outlets are close in size to the stock 49cc exhaust. The outlet is just slightly larger on the SP3 though. SP3 is on the left in each pic.   The brackets on the pipe were already setup to work on a Chinese minarelli engine, because I've used it before on a 70cc.  This exhaust really hugs the wheel. So much so that I had to use spacers or it would be pressing into the tire.    Here's a sound clip and quick riding shot. Even a little tire spin thanks to some water on the garage floor. lol This pipe is very quiet. Most similar to stock, slightly quieter than the Phongeer. Jetting was moved to a 90 main with the needle set next to the richest position. I used the same 5g sliders just as I have with the other performance pipes. On a 17 mile ride, I saw 46.2MPG. Low and midrange power is quite similar to the Phongeer exhaust. Power at a little higher revs is not bad, but not as good as the PG and ZX pipes. Cruising speeds were in the mid 40s for the most part, while I saw upper 40s with the PG and ZX. Top speed once again fell right in line. 53MPH. That surprised me, seeing how it lacked the power at revs that the other pipes had. It seemed like once I tucked down it did alright though. I think I may have had a little boost from a tailwind, but regardless it was very similar to the pipes intended for a 90cc for max speed. Overall, I'd say it did quite well for a 50-70cc pipe on a 90cc. Well enough to make me wonder what a Leo Vince SP3 that's meant for this displacement would do. That said, I'd still take the Phongeer over every pipe tested at this stage. [/center] |
|
|
|
Post by 190mech on May 16, 2011 19:11:02 GMT -5
Id love to see a side by side pic if the PG and SP3,be cool for a pipe builder to note the difference..Thanks for all the hard work!!!! :nana:
|
|
|
|
Post by 90GTVert on May 16, 2011 21:03:12 GMT -5
As long as I remember I can get you one tomorrow. I can tell you just off the top of my head that the PG has a larger and shorter header.
|
|
|
|
Post by 90GTVert on May 16, 2011 21:25:22 GMT -5
Free Flow Air Filter [/color] With all of the exhausts I have tested, I went back to the stock exhaust and stuck on a free flowing air filter. This is a UNI filter with a pre-filter from a cheap eBay purchased filter. From past experience, it flows the same as a UNI or close enough that I can't tell a difference.  I had to swap all the way up to a 100 main jet. The stock airbox used an 85 main with the snorkel removed and a 78 main with the snorkel in place. That's one heck of a change. I kept the needle in the same position as before (one from the richest), but I think it may have benefited from being set all the way rich. The biggest change is the volume level. Open filters are loud on two-strokes! This open filter is louder than any of the exhausts by quite a bit. I find it to be annoyingly loud. HERE is a video I did in the past showing an airbox vs a free flowing air filter. I went for a 27 mile ride, on which I got 44.4MPG being liberal with the throttle. I expected that number to drop with the addition of the large main jet. Power seemed about the same as stock with perhaps a slight improvement in cruising speeds which were low to mid 40s. I think maybe averaging a MPH or so above the stock airbox with snorkel. Top speed was unimpressive. Back to 51MPH. It almost seemed like the mild setup didn't know what to do with all of the air and fuel it could suck in.  This mod is really not for me.There would have to be a much more of an increase in performance to be worth all of the noise that an open filter makes. [/center] |
|
