Results from my Turbo GS500 (link for pics)

[94gsrider]

Hey guys, now that my project is complete and school is finished I finally got around to letting everyone know how the project turned out.  For those who don't remembered I designed a draw-through turbo kit for the good ole gs500 for my senior design project.

As for results, I dynoed the bike at two boost levels 5psi and 15psi.  My project goal was to exceed 20% in HP, which I did.  At 5psi I netted 49hp and 37lb-ft.  Horsepower gain was 22.5% and torque gain was approximately 42.3%!  The more impressive numbers came from 15psi where I acheived 76hp and 50lb-ft, gains exceeding both 90% horsepower and torque.  

There is still some room for improvement.  Most of my troubles came from attempting to use one of the two original CV carbs from the GS.  Because the carburetor is mounted in front of the turbo, after lefting off the gas (turbocharger is still spinning) the vacuum slide is essentially tricked by the turbo and allows for more fuel to be dumped into the carb.  Following this the carburetor would be loaded up with fuel the next time the throttle was pulled back.  This problem may be fixed simply by using a harder spring for the slide, but I have also considered using a different carburetor all together.

Anyway, here's the link for the kit on the bike, and for the dyno results.  

http://pg.photos.yahoo.com/ph/bobbygianfagna/album?.dir=e702

The difference is power is amazing, especially in second and third gear.  Just this past weekend I was having some fun with a friend on his sv650.  From a second to third gear roll our bikes were in a dead heat (not bad considering sv's run high 11's and gs's run high 13's).  By the way, since I am having to keep the bike in my parents garage I may have to get rid of it, so someone could have the chance to own (as far as I know) 1 of 2 turbocharged gs500's.  

Let me know what you all think and again, thanks for all the help guys!
-Bob

[Jazzzzz]

Why did you wait until I drove to Chicago to pick up a GS to decide to sell yours right here in town

Sounds pretty sweet -- have you changed the slide spring over to a stiffer spring yet, or are you just dealing with it backfiring/etc. when you let off the throttle?

[Roadstergal]

That's nucking futs.

Does it mess with the handling to have that stuff on the right?

[chbix]

ok if you got 49 HP at 5psi what was your baseline?  How high boost do you think you could do max and still be reliable?  What do you think you could do max?

[The Lazy Destroyer]

Nice job!

[raylarrabee]

very cool.  I hope you got an A  

[linuxman2003]

damn! 76hp on a gs? that thing must FLY!!!

[DarkCyDE]

Know what I want for christmas now!

Ill take one!!

[cernunos]

Congratulations. Glad it worked out. Now you are ready to go into the world as one of the all-knowing wizard engineers...where you can drink beer, go to T&A bars, eat much steak, and BS with the best of them!  :lol:
Good luck in the job hunt if you don't already have one. Love the little twin, the mighty GS 500...rip snort, Alabama (even with Joe living there), and this forum.

C........

[94gsrider]

As of yet I have not changed out the spring, just have learned how to ride it to avoid the bogging.  

As far as baseline, I did not dyno it prior to and modding.  However, on this site a gs500 with k&n, jet-kit, and exhaust dynoed at 43hp and I believe 26lb-ft.  

I don't know exactly how much boost the gs could handle, but I believe "Bling" was boosting something crazy...like 30psi on 105 octane.  I'll try to get some video footage so you can hear it run.  If you didn't notice in the picture the exhaust in a 2" pipe coming straight off the turbo so it sounds pretty mean.

[stefman722]

YES!!! i wanna hear and see this thing run. I wanna hear a "whoooosh" sound. Is there a blow off valve on there?

[sprint_9]

What did you ever do for jetting, I know you had a post a while back asking for suggestions.

[94suzuki500]

YES!!! i wanna hear and see this thing run. I wanna hear a "whoooosh" sound. Is there a blow off valve on there?

If you look at the pics you can see the waste gate actuator that opens the wastegate, very similer to a blow off valve, I havent been around many turbo engines so I dont know the sound difference but I would imagine them to be close because its just air escaping, so it probably makes a woosh.  I would also like to know if you installed a bov on the system or are you just using the turbo wastegate.
I would also like to know about jetting, how did you figure it out.  trial and error or did you use a formula of some sort?
great job by the way looks awesome.

[BigRedMonkeyButt]

Freikin Awesome.

[94gsrider]

I don't have a blow off valve on this kit.  I designed it and made it as simple as possible.  Also you can not run a blow off valve on the intake side of this kit.  Remember the carburetor is mounted in front of the turbo, so air and fuel are being sucked through the turbo and intake.  It is possible to intall a blow off valve on the exhaust manifold but I did not bother (even though they sound cool!).

[94gsrider]

Sorry I forgot to tell you about the jetting.  Jetting was done on a trial/error basis.  There's not a whole lot of information out there to figure out exactly what would work best for this application.  Like I said before, I'm using one of the two original carburetors from the GS.  While I was dynoing it we messed around with main jet sizes.  To be quite honest I don't remember if I've got a 150 or 160 main in right now, and I'm running a 40 pilot.  The different in jetting mainly has to account for the fat end since that is when it is truly pulling more fuel.

[VTNewb]

Turbo GS? No problem!

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&rd=1&item=4555708278&category=50028

[94suzuki500]

The different in jetting mainly has to account for the fat end since that is when it is truly pulling more fuel.

Thats what I was thinking for use with the turbo or else it will totally run way lean and seize if it wasnt jetted for boost.   I have seen fuel enricheners on bikes, it pumps alot of fuel in when boost hits and allows for a deacent low range too.  Since your bike doesnt have the enrichener does it bog or does it run well at low rpms?

[70 Cam Guy]

I don't have a blow off valve on this kit.  I designed it and made it as simple as possible.  Also you can not run a blow off valve on the intake side of this kit.  Remember the carburetor is mounted in front of the turbo, so air and fuel are being sucked through the turbo and intake.  It is possible to intall a blow off valve on the exhaust manifold but I did not bother (even though they sound cool!).

Atmospheric wastegate with a smaller twin of the big exhaust would be sick    ....also be loud as ^&%$

have you thought about using an ignition retard on your bike?  I'm not sure how it could be done on our bikes without a custom box like the MSD turbo ignition.  I bet you'd see further gain with the ignition retard at full boost (unless that is for higher boost apps)

btw, looks awesome, I'm glad it works!    

[Ed_in_Az]

94gsrider, I think you did an outstanding job there.

After viewing your creation I thought of what ought to be an interesting and probably somewhat less involved project. Since I'm more of the cruiser persuasion I'd like to see a melding of an SV650 engine into a VLX600 frame, creating Hondazuki speed cruiser. Since what that particular Honda lacks is power, gears, and speed, that would be an interesting ride.