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Any turbo guys out there?

  • Thread starter Thread starter H.M.S.
  • Start date Start date
H

H.M.S.

Guest
I am working on a '83 gs750e. I fabricated a custom turbo set up using a garrett turbocharger. I worked out most of the bugs exept the carburetors. It will idle and run good up until about 4000 rpm(right when it starts building boost),then it seems like it runs out of fuel. Now before you jump to conclusions, I am using a pitot tube to pressurize the fuel bowls, I installed a fuel pump and regulator, so fuel delivery should not be a problem. I also tried using very large main jets and it doesn't seem to be cleaning up. Should I go for a dynojet stage 3 kit for a starting point or try something else? And where is a good place to buy jets and anything else I may need?

IMG00137.jpg

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not really an answer to your question... and probably a stupid question from myself, but arent you worried about the heat from the turbo damaging your front tire?? You dont seem to have a whole lot of clearance there and I know how hot a turbo can get.. lol
 
I have nothing constructive to add. Never messed with turbos on carbs, and never on bikes at all.

But it is very cool. I hope you get it working. My 2cents is buy more life insurance before you get it running right. :D
 
:eek: :twistedevil: :D I like it! A tracker? If not watch the speed bumps! :lol:

As for what you are describing and keep in mind that the only turbo I own is in a T-Bird...it does sound as though a fuel shortage is the problem. As far as kits are concerned a Stage 3 may do it but I'de calculate your CCM/CFM first and see to it that the carbs themselves are up to the task.

If so...play on. Also I don't know if the stock ignition is up to the task, that may need to be looked into if not already done.
 
Got an old school Blake kit on a 1980 GS11. Haven't rode it for about 3 years. Put it away after a mishap and haven't missed it. Way more power than the chassis and brakes can handle
 
How much fuel pressure? What do you have the regulator set at? Also, if you are using stock needles, that needs to be changed first. The fact that it runs ok at lower rpm tells me you don't have too MUCH fuel pressure but it could also not be enough. Do you have a Pingel petcock on it yet or just the stock one? If STOCK, you WILL need a Pingel. I would start with the needles & try Dragbike.com also. I am suzukiray on that site. Ray.
 
rapidray said:
How much fuel pressure? What do you have the regulator set at? Also, if you are using stock needles, that needs to be changed first. The fact that it runs ok at lower rpm tells me you don't have too MUCH fuel pressure but it could also not be enough. Do you have a Pingel petcock on it yet or just the stock one? If STOCK, you WILL need a Pingel. I would start with the needles & try Dragbike.com also. I am suzukiray on that site. Ray.
Click to expand...

I am using a mallory bypass style regulator with a boost signal port. Pressure is set at 3psi at idle and it is about 6psi at 0" vacuum. the fuel petcock is stock but I took out the diaphram. Any idea where I can the needles?
 
I'm a turbo guy, but not on motorcycles. I work with turbos daily. Disgusting, nasty, technical stuff that makes people fall asleep.

What are you doing to the timing when boost builds? You need to retard it, almost the opposite of how you advance timing as a NA engine builds speed. I don't think this is the entire problem you are desribing, but it was worth asking.

I too am curious if you are starving the fuel pump when the fuel pressure ramps up.

~Adam
 
CV carbs

CV carbs

OK, correct me if i'm wrong. Looks to me like you are pressurizing the side of the carbs that originally connected to the air filter. CV carbs are opened up by the pressure being lower, (more vacuum), on the head side of the carbs, which raises the slides. Now if you generate anything higher than atmospheric pressure, or vacuum on the air filter side, won't this just slam the sliders shut. Most turbo setups I've seen run either fuel injection, or 1 carb on the inlet side of the turbo. Ive seen several running an S&S Super G, or a smoothbore carb attached directly to the inlet side of the turbo. Go to http://www.mrturbo.com/ , the customer gallery might give you some ideas.
 
KY, this is a "Blow Through" system & the CVs work fine this way. These systems have been done this way for a long time. I really think it is a fuel delivery issue, as in it isn't getting ENOUGH! You can either get a Dynojet jet kit or, if it were me, a FactoryPro kit. FactoryPro's # is 415-491-5920 Ray.
 
Are you running low compression pistons and as mentioned the timing needs to retard. The first time you do hit boost you may go boom.
I've only seen Dyna 4000 ignitions used with turbos to retard the timing.
I love the fact you're going for it!
 
Sorry

Sorry

rapidray said:
KY, this is a "Blow Through" system & the CVs work fine this way. These systems have been done this way for a long time. I really think it is a fuel delivery issue, as in it isn't getting ENOUGH! You can either get a Dynojet jet kit or, if it were me, a FactoryPro kit. FactoryPro's # is 415-491-5920 Ray.
Click to expand...

:o Sorry, I've only seen the draw through systems. Shutting up now, hopefully to learn some new tricks.
 
rapidray said:
KY, this is a "Blow Through" system & the CVs work fine this way. These systems have been done this way for a long time. I really think it is a fuel delivery issue, as in it isn't getting ENOUGH! You can either get a Dynojet jet kit or, if it were me, a FactoryPro kit. FactoryPro's # is 415-491-5920 Ray.
Click to expand...

Ok thanks, I'll try to get some needles and retard the timing a little. I had a xtra set of stock main jets so I drilled them out with a .072" drill bit, which I thought was huge compared to stock and the plugs are still bone white. Its probably the needles.
 
I have been doing allot of research on turbos lately because I want to do a turbo on my 81 750 next year.

Not trying to sell anyone short here but I have found a ton of info on this site
http://forum.oldskoolsuzuki.info/cgi-bin/Yabb/YaBB.pl
If you go to the forced induction section there are several people on there that currently have GS750 turbo set ups I have posted over there a few times and they are very helpfull.

I would think between here and there you should be able to get that thing spooling up real nice.

By the way I really like your bike I hope you keep posting your results and I have one question for you have you done anything with your clutch everything I have read the 750 will hold up nicely to around 140ish HP but they seem to have clutch slippage issues.
 
Take the regulator off and run it straight for now. I run 7 psi on mine. What type carb and how big???? You will need a two stage retard for the ignition and a pressure switch in the intake manifold so that you can control it. Hopefully you are running 7.8:1 comression or you will never get above 10 psi of boost without hand grenading your engine. Give me a call and I will fill you in 661-203-7177 Kris
 
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