I completed my GY6 swap about a year ago and aside from my first salvage motor randomly failing catastrophcly, piston broke and cracked the cylinder sleeve, all while idling at a stop light
the second motor has been very trouble free. While I should be perfectly happy with a scooter that runs 55mph up hill and tops out around 65 the mod bug has slowly been nagging at me to start a new project on the ruck. In the past I turbo'd a 280z and last october I finished up a twin turbo kit on my 05 cadillac CTS-V that I still drive very often, I'm obviously a big fan of turbochargers so naturally I want to turbo the ruckus.
My Ruck is an 03 that had about 6000 miles on the stock motor, on the GET it would top out at about 35 and just seemed tired. I did the gy6 swap with Pray for Mojo weld on mounts, modified the stock harness with some help from the battle scooter write up, welded a caliper mount on the stock forks and drilled out the axle holes to mount the gy6 front disc rim. I did install a functional Nitrous kit, but I never sprayed it. Here are some pictures just after finishing the swap.
I purchased the turbo and the Fuel Injection kit from MBE motorsports, the turbo is a VZ21 or a RHB31 as far as I can tell they are the same turbo just different names and possibly different manufactures. I cant find any kind of compressor map for the turbo, but through google it seems they are rated for 200-600cc motors. Obviously the 150cc gy6 is small for this turbo, but I'm hoping with the variable transmission keeping the rpm's up the turbo will spool. a 180cc big bore kit is in the near future which will also help get the turbo moving some air. The FI kit seems to be based off of a MicroSquirt kit, or at least the tuning software seems similar. This is a bonus to me because on my 280z mentioned earlier I built and installed a MegaSquirt kit, so Im familiar with how the system works.
Enough rambling, on to the build.
First thing is mounting the turbo. For the header flange I cut the flange of the stock exhaust and used that for a starting point. From there I used 304 SS weld elbows that you can order from McMaster Carr, I ordered the 1.5" schedule 10 elbows and 2' of shecule 10 straight pipe. Everything is tig welded and packpurged. I chose the shedule 10 pipe over regular thin wall exhuast pipe to help keep heat in the exhaust as another measure to help spool the turbo. The Turbo flange I orderd from ebay, there is a guy selling a complete kit for around $40.
Turbo mounted, I will fiberglass header wrap the pipe soon. In these pictures the pipe is tack welded, I have since finished out all the welds.
I also welded a support that attaches the turbo to the swing arm, I'll try and get a picture of the support later.
For the oiling I drilled and tapped the case with a 1/8 NPT thread. The oiling port is easy to find, it is the brass plug on the front of the case, near the cylinder. But be CAREFUL drilling it out!!! I mangled my first case trying to drill it out. Here is a tip, drill the brass plug with a small bit, then take a machine screw and thread it into the plug so you can pull the plug out.
Brass plug, I'm showing this for a "before" picture, this plug is actually the drain plug on the bottom of the case, but they are both plugged with the same style brass plug. Do not drill out the plug on the bottom of your motor, it is not pressurized oil, drill out the plug on the front of the motor near the cylinder.
Drill it out then thread a machine screw into the hole and yank that sucker out.
Tap the hole and thread your fitting, I used a 1/8 npt to -3an 90 degree fitting.
from the fitting pictured above I'm using a pre made piece of -3an line that is 3' long. It is important to know that the RHB31 turbo has a non standard oil feed thread. I think it is m8x1.25, very odd ball as far as turbo's go. MBE sells a bushing adapter that will allow you to use the standard 1/8npt threads, I'll try to get a picture of this bushing. On the oil feed side of the turbo I'm using the bushing adapter and another 1/8npt to -3an adapter.
Next is the old return. I REALLY didn't want to mess with a scavenge pump to return the oil so I made sure the turbo was well above the oil pan. Scavenge pump technology has improved and they can be reliable, hell, I'm currently running one on my twin turbo CTS-V, but my main concern is the extra load on the GY6's already questionable charging system.
The flange kit came with a oil return flange, to which I welded this -6 an steel weld on fitting.
From the flange pictured above I will build my own 8" piece of -6 return line, and it will dump into the bottom of the case through an Aluminum -6 an weld on fitting.
I have read through various forums that previous attempts at turboing a scooter failed because holding the throttle wide open for more than a few seconds will put a hole in the cylinder. If this is true its caused by high intake air temps, too much timing, and probably running lean. The Fuel Injection kit will solve the timing problem, it will be set to pull timing as intake temps increase and fueling should not be an issue. If it is I will install a bigger fuel pump and injector. But to cool off the Intake temps I wanted to install an Intercooler. The problem is finding one small enough....gotta love cheap ebay intercoolers
I should have taken a picture before hand, but you get the idea. I chopped off the bottom 1/3 of the intercooler and welded on new end tanks. Important!!! intercoolers can only be cut the directon WITH the bar and plates like how I cut in the picture below. The core ends are sealed and if you cut against the bar and plates it is impossible to weld a new end tank.
I'll post more updates as I make progress, currently I'm waiting for my engine gasket kit to come in so I can reassemble the motor, mount it to my frame and then run the charge piping.