Turbo SV650s better mileage and power

[naturalextraction]

I waited awhile before posting here as I now have just about 10k miles on it. I've worked out all the bugs for some time now and have done some decent mileage runs.
I built this system for a few reasons:
1. No one in America, but one person in Germany, has turbo charged an SV650 Mostly due to the much propagated scenario of the cranks breaking. I want to prove that a good build with fail safes installed and limitations will provide a fun, powerful, economical bike.
2. To incorporate some aspects from another build in relation to fuel consumption which has increased in the area of 12-15% maintaining my horrible driving habits.
3. That the results are accomplished through sound engineering and not incorporating any pseudoscience falsehoods often touted on forums.

Yes there is always a limit to any mechanical function by avoiding over stressing of rotational parts, limiting mass, not exceeding rotational speed, limiting pressure and the list goes on. But quantifying limiting factors and building within those specs will and does work. To date I have not modified anything to the motor on any level. I did go colder plugs was all. I will after my 10K install a lightened stator. I may incorporate some other electrical regeneration thoughts to try...or not. This is my daily driver and use it literally 6 or 7 days a week. Hence the miles.
Mileage varies of course due to ambient temperatures, wind, hills of course and where I get the fuel. Many stations have different blends that can vary the consumption for the vehicle.

That's pretty much it. Turbo's can be installed to make just power and consume gobs of fuel or installed to increase adiabatic efficiencies, Volumetric efficiencies with less fuel consumption than stock if done correctly.

It's been fun to change power levels on command, have Liter bike performance (dead on to TLS1000, Aprila Falco). Ultimately my average consumption is lower than ever before. My best run is 61mpg with quite a few times in 4lbs of boost. I max at 7lbs if I adjust for such. The down side is this is carbureted. The only blow through I've ever done. I've always used EFI which would be much better for programming a much better consumption. My other bike does considerably better. But it's a different animal all together. Btw, I installed this back in December as the bike was at 70K+ miles.

[gil]

Thanks for sharing, I have always wanted to turbo my bike for more power and better fuel economy. NIce to see some positive results of of something that is hardly ever attempted. EFI would of definitely helped you out for better results. In the other hand you definitely have some engineering skills to pull off a blow throw turbo system.
Do you have anymore pictures? What kind of turbo dd you use, it looks familier, IHI turbo?


Gil

[naturalextraction]

Yes it is an IHI, good eye. I can post a video I did on it back in December and I am almost done with another that shows comparison runs. Trying to get it on the dyno soon. At the time I tried running a closed loop oiling system for the turbo but found the electric motor to be unreliable. You'll see in the video where I had to rebuild it. I made some bushings from C93800 Bronze which have worked out well and modified to accept heavier oil. The turbo and pump have been fine now but it's only job is to scavenge and return. 9k miles without a hiccup now. Oh, my apologies for bad selection of music, it's a bit much. My new film will be out soon.

http://www.youtube.com/watch?v=VYu1pXI4gvU

[gil]

Great video, A lot to take in. Great clips of you doing the work, not seen much on forums. Now how much oil pressure are you running to the turbo? Are you using a restrictor in the oil line to the turbo? The dyno numbers are going to be interesting that's for sure.


Gil

[naturalextraction]

Yes I do have a restrictor that I made to adjust. Pressure varies of course with system RPM however max doesn't see more than ~14.

[gil]

Really 14 psi max oil pressure, thats much lower than I expected. I understood that only ball bearing turbos needed low oil pressure. What is the lowest oil pressure the turbo sees?

At one point I was planing on turbo charging my Honda Helix scooter, but the oil pressure was ZERO when warm and at 6k rpm. I think it didn't require high oil pressure because of the Ball bearing crank and ball bearing cam. On my current bike, Yamaha XV-250, I expect to see 40psi max on one of the lines going to the camshaft that i can tap.


Thanks for the insight.
GIl

[mechman600]

Wow. I wish I had a quarter of the tooling and talent that you do! Very very impressive.

[naturalextraction]

Thank you Mechman600 for the compliment. May I add, I enjoyed reading through your blog on your Mazda conversion. It's been a long and getting longer goal to fulfill in an EV build. I've been slowly working on my ACVC Turbine electric hybrid, but that's moved slowly in comparison. It also takes way more deblumes than some of my other projects. Plus real work can get in the way of course.
Gil, I went back to some notes and have a correction on the oil pressure to the turbo: at idle it's like just 4.5 lbs but at 5kRPM I show 31lbs. Looks like that's where I left it at, last entry anyway. Just wanted to make sure I conveyed the right information there! I may recheck it here at my 10K inspection just to make sure nothings changed and if so why.
Going to the drag strip tonight although we may get rained out. I've been trying for like two months now and there has always been something to sidetrack or like last time total brown out. (where the wind wips up the sand out on the mesa so bad you cant even see the mountains or much distance)

[metromizer]

Are you trying to keep the turbo supply side oil pressure low as to not over come the seal, or some other reason? I am not turbo tuner, but most of the guys I know who build their own turbo systems just tap into an oil galley or tee off the high pressure side of the oil pump and use unrestricted oil pressure through a small diameter line, -3 or -4. At least that's what I thought they did...

[naturalextraction]

Yes. On most smaller turbos or just iron ring type sealing rings, anything much over 30psi can pass through. Also depending on the type of oil, it's densities at low and high temperatures effects the spool up speed. It's a fine balance to get the right flow of oil to reduce drag rate or reduce parasitic loss on the shaft while maintaining the lubrication qualities necessary to avoid catastrophic failure. That's why I machined my own bearings with the orifice size I wanted for the type of oil I like to run and at a given flow rate. Using an adjustable means to control pressure and flow rate allow for those operational characteristics. In the next video I'll be posting, you can hear how freely the impellers rotate and for how long upon shut off from idle. I use a different Bronze material than what is typically used for bushing type turbos.

As of recent, it has done well for over 10K miles!