Project: Vespa 300 SUPER (should end up living up that name)

[jrflanne]

You still have my Leo Vince slip-on there? Put that on, although the Akra is much better.

[Micah / AF1 Racing]

I gave away your old LV to the guy who sold me my airplane. I was thinking Akro for the first pipe but now am leaning towards building my own again because I do not like the length of the header pipe on any of the aftermarket systems. Since a scooter only has to "be on the pipe" in a narrow rpm range I am first going to get as much as I can fromit naturally aspirated and with simple tricks like correct header length, resonant intake track length and such. The stock header will be cut up and re welded with gasketed flanges for the turbo if I even get the time. Hell I made all the flanges over a year ago. Right now they just keep my new turbocharger company in SA box beside my bench.

If anyone see a cheap spare 300cc Vespa motor please post it here or a link. I need a spare to minimize build vs downtime and I always like having a motor to compare against as a quick reference. Basic turbo plan is this: Malossi v4 head, stock piston with valve pockets machined. Stock piston and cylinder are boost ready dished low compression items. Where to hide the water/methanol tank and pump...to be decided. It will be a very well intercooled motor when it is is ready to play with the dyno.

This is as pretty as you can make the stock cylinder head with much porting and love added and .35mm removed from the bottom deck of the cylinder head for a little added compression! Notice especially the areas of high air velocity at the points where the head casting blends now into the valve seats! This alone was pretty damn impressive on the dyno, a great mod for someone with tool, aptitude, free time and not enough cash to buy the Malossi head kit!



Here is an unlit version of that same basic pic to show reground valve seat contact areas...




Pic taken down well lit exhaust port...





Now a not so good pic down the ported stock intake port:



In this next two pics set I am using the cam to open valves to full open position so what you are seeing is stock max valve lift on the intake first and exhaust second.



Here is the full open set of exhaust valves with the port internally lit up with LED stick lights inserted into the port itself.

[scooterman]

Micah...don't know if you're still looking for a throttle body for a 500 but there's currently one on Ebay to the tune of $200 in San Jose, CA....

http://www.ebay.com/itm/Piaggio-MP3-...#ht_500wt_1313

[Micah / AF1 Racing]

Actually I am good now on the tb. If I have to I will over pre but only slightly, I think the sticker is plenty big though, especially after porting down screws and shaft a bit.

I am measuring 32-33mm for the throttle plate so it is plenty large given the size of the actual intake port. There might be a very small gain possible from using the Guzzi V7 injection unit with a reflash since it is 38mm but definitely not a major power gain.



From the top to get an overview of the ecu/tb/immobilizes/everything....here is pretty much proof the throttle plate is right at 32mm I think?



From the front:



From the rear, or vacuum side:



Some smart porting of the throttle body might actually be good for power, the shaft is overkill size, the bolt heads and tails fairly restrictive to central flow...hmmmm



Yes, I think some porting of this area, rounding of the blades leading edge to make it more winglike, removal of excess bolt material and smoothing the shafts transition areas might just pay off!

[kenbike]

I opened up my air box on my 300 super and it did not make much of a difference in power. It result in slightly less intake noise a lower speeds. with my frame 6 ft 200 lbs it tops out around 84 on the speedo. I thinking of adding a slip on or installing some Doctor Pullet sliders. Any advice?

[jrflanne]

That is the speed limiter talking. If you want more top speed, you will have to deal with that. There is an aftermarket ECU. Try scooterworks.com

[nimmnenkeks]

hi,

there is a Guy working on a 300° cam with 10mm stroke. His 280° cams were Sold out. But his modified original cams, made to 280° are very good.
Now we build a new piston for a 295 ccm cylinder for the stroke of the 300° cam.
But in Germany is the only Solution to get a New Mapping for the MM MIU ECU by RexXer (www.RexXer.eu) for 500€. Wich aftermaket ECU's for the GTS 300 are available ?

Sorry for my bad english

Regards Keks

[Micah / AF1 Racing]

Since the 300cc and 250cc motors are almost completely closed loop a slightly larger injector or bump in fuel pressure should allow all to work fine, especially with www.fatduc.com style lambda signal modifier, about all I am planning on for mods as the power goes up. Raising stock fuel pressure is VERY easy with a ball peen hammer, patience and a little disassembly. Stock pressure at the injector is not that high so that is the first mod I would try. Once I add boost an adjustable fuel pressure regulator with vacuum/boost reference hose added is roughly all I will feel required to add since keeping boost fairly low 7-10psig can be pretty easily managed with only larger injector. If you do find anyone who has an aftermarket "open" ecu please let me know, I would like to avoid adding PCV if possible.

[Micah / AF1 Racing]

I got a new part for my eventual attempt at boost....finally found a stainless exhaust "tank" with o2 sensor location correctly placed for my turbo application...time to start cutting and welding after the weather cools off and the number of bikes through service drops off a bit. Pulling an HD off the dyno, putting a CBR1000rr onto the dyno and prepping for a s1000rr next...long week of extreme heat and more extreme water consumption by me. I realized on these days I drink ten percent of my total body weight in water on a daily basis...seems like a lot of water to me.

I am shooting for some thing closer to constant pressure turbocharging that pulse type turbine pressurization for smoother boost with less surge since exducer and compressor wheels are on the slightly large side for a single cylinder 300cc application. Hopefully the CVT will be my savior as well as the new dual TB system I am designing for anti-lag, a variation of what was used in the 1.5 liter F1 turbo days. Search "per turbo throttle body" in google to get an idea of what I am shooting for. I need about 4 times cylinder volume on the intake side and at least three time cylinder displacement on the hot side for it to work right from6-10k rpm according to my calculations.

[nimmnenkeks]

Found this one in Germany, they offer an open ECU and the Software for their products are free!

SILENT HEKTIK
Automotive Hard- & Software
Hansastr. 72b
59425 Unna
European Union - Germany
order @ silent - hektik . com

[Micah / AF1 Racing]

Interesting....will be doing some reading. Thanks!

[Mike Holland]

Micah, as the instigator of the airfilter box mod on ModernVespa, I am interested in your version of this mod. Have you published it anywhere yet? My mod was tested by PM Tuning some time back, and they reported about 1/3 hp gain right across the speed range.
I have a GTS250 with Malossi cylinder, piston and head, Polini variator, Malossi clutch springs, contra spring and torque converter and Malossi TC Lambda Emulator. My front wheel lifts whenever I take off, and I now maintain 115-120kph up my test hill where my speed used to drop to 95 kph.
Regards, Mike.

[Micah / AF1 Racing]

I have not posted it yet I don't think because each variation has been a bit different. Next time I do one on the dyno from dead stock up to modded I will do an airbox mods test with a logical sequence as well to see which does what ad why. It's funny that the airbox mods make any difference at all because with the radically undersized valves one would not imagine such a small change in airbox pressure would be beneficial at all. I have a host of mods coming to test over the winter so it might get slightly interesting.

[Mike Holland]

Yes, it was a surprising result for a simply pocket-knife mod. Just be warned. When I tried chopping the length of pipe that extends into the airbox, the results were disastrous. That must be a carefully tuned length of pipe from throttle to airbox.
Mike

[Micah / AF1 Racing]

I have actually read your postings on that subject and there is something not quite logical going on there with intake tube length. The resonant frequency of the intake pipe is the distance from the intake valves to the bellmouth of the throttle body...the tube should not make as big a difference as it does. There may be a dual resonance occurring, or even triple counting the hemlotz stuff going on with the airbox. I was planning to test and play with that on the dyno and see if I could find anything definitive to answer that because it has bothered me at some level for a long time. Once I am turbocharged my intake tract length will be radically different so getting a few answers before boosting seems prudent.


In the end I gained 2 bhp in the last 2k rpm with the airbox removed and the filter clamped directly onto the throttle body, I really needed a shorter inlet tract length for correct high rpm resonance, after dialing in fuel this did cost me roughly 1 bhp below 7,300 rpm.