Turbo'd GS850G

[silent_soul]

Hi,

For starters I did search and tried various ways of finding a topic about this. However If I still missed a thread explaining my question Im sorry.

Anyways What Im looking to do is run 4 small turbos on my gs850g, that or atleast 2. This is more or less for the fun of it and obviously for some increased performance.

Anyways I was curious if this has been done or if anyone would know where to start.

Thanks
-Alex

[Nessism]

Hi,

For starters I did search and tried various ways of finding a topic about this. However If I still missed a thread explaining my question Im sorry.

Anyways What Im looking to do is run 4 small turbos on my gs850g, that or atleast 2. This is more or less for the fun of it and obviously for some increased performance.

Anyways I was curious if this has been done or if anyone would know where to start.

Thanks
-Alex

Nice first post Alex. Four turbos on an 850? Hummm, that would be a first. Go for it and post lots of photos.

[tkent02]

Two turbos would make sense, one on each side. Probably almost the performance of a nice tight 1100, and only seventeen times as much effort.
I like it. Like Ed says, post up some pics!

Welcome to the forum, you're going to love it!

[Steve]

Your first task will be to find turbos that are sized for 212 cc @ 9000 rpm.
(It's hard enough to find one that is sized for 850 cc.)

Next, you will need to do some VERY creative plumbing to get the exhaust into and out of the turbines.

You going to have "suck-through" or "blow-through" carbs?
Or are you going to feed them from a plenum fed by ONE carb?
Or are you going with fuel injection?
Oh, the joys of synchronizing four carbs on turbos.

Don't forget to order the special "almost zero oil pressure necessary" bearings for the turbos, as the 850 only runs with 3-5 psi.

You know? I agree with the other guys.



.

[SqDancerLynn1]

Yep the 850 is not a good candidate for a turbo. Suzuki did make a turbo bike in 83 I believe. You would need all kinds of special one off parts and lots of money to do it !!!!

[BassCliff]

Greetings and Salutations!!

Hi Mr. silent soul,

Let me share the love.

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Here is your very own magical, mystical, mythical, mind-expanding "mega-welcome". Please take notice of the "Top 10 Common Issues", the Carb Rebuild Series, and the Stator Papers. Now let me roll out the welcome mat for you...

Please click here for your mega-welcome, chock full of tips, suggestions, links to vendors, and other information. Then feel free to visit my little BikeCliff website where I've been collecting the wisdom of this generous community. Don't forget, we like pictures! Not you, your bike!

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BassCliff

[silent_soul]

Wow, I must admit this thread got alot more response then I expected. Nice to find a place with alot of guys who ride gs's and love to chat it up.

Alot of questions were asked:

For starters Ive yet to start any work, hoping someone had done this previously

As for being insanely out there this is kinda the point, my bikes a shafty so huge power gains and what not arent really what im looking for just something super unique and fun.

I havent quite figured the best carbs for this yet, and did plan on staying carb'd(gotta love the tune, retune, retune, maybe got it...nope, and retune some more)

As far as the placement if I go with for a figured a staggered 1 up 1 down(well lower) 1 up and 1 down...maybe outsides down or up and insides down or up depending on fitment issues. Ive done plenty of welding so making the plumbing isnt an issue unless its complete impossible to fit from the get go( I dont want to chop the frame tooo much preferably not at all)

Lastly for now I realized there is a performance section if this thread belongs there by all means feel free to move it. Ill do some digging and see what I can find for turbo's. Ive got all winter and figured something like this should keep me busy through it(hopefully)

[gearhead13]

Hi Mr. silent soul,

Let me share the love.

<< Click for a bigger picture.

IIRC those XN85's were 650's ? Why? Why so small an engine when you could just buy an 1100 or 1150 and have all the power and more without the turbo lag

[silent_soul]

Your first task will be to find turbos that are sized for 212 cc @ 9000 rpm.
(It's hard enough to find one that is sized for 850 cc.)

Next, you will need to do some VERY creative plumbing to get the exhaust into and out of the turbines.

You going to have "suck-through" or "blow-through" carbs?
Or are you going to feed them from a plenum fed by ONE carb?
Or are you going with fuel injection?
Oh, the joys of synchronizing four carbs on turbos.

Don't forget to order the special "almost zero oil pressure necessary" bearings for the turbos, as the 850 only runs with 3-5 psi.

You know? I agree with the other guys.



.

Well I was wondering if you knew where to find turbo's that size? Ive been looking over google and cant seem to find anything. Its really driving me nuts maybe im looking the wrong way but any help would be great. Part of the problem is im not finding turbos with a cc rating.

EDIT:
seems quad turbo isnt feesible as the smallest turbo Im finding is a tad big for a 400-440cc bike so Id maybe be able to run a twin turbo set up.

[Dave8338]

You have my attention!

Give these guys a good look. Loads of people there tha can and have turbo'd nearly everything...

http://www.turboneticsinc.com/

[chiphead]

There's a member here that builds turbos for a living. I've bought parts from him. I can't for the life of me think of his name. He may be up in Canada? I know - I'm a lot of help. Maybe use the search for "turbo".

[Steve]

Well I was wondering if you knew where to find turbo's that size? Ive been looking over google and cant seem to find anything. Its really driving me nuts maybe im looking the wrong way but any help would be great. Part of the problem is im not finding turbos with a cc rating.

I think you missed the point. I said "YOUR first task ..."

I don't know of any engine that small that would have a turbo. For the cost and effort involved in adding a turbo to that size engine, you could substitute a larger engine that would be easier and cheaper.

If you have never been involved in turbocharging an engine, sit down and realize what you are up against. There are kits to put a turbo on a motorcycle, so obviously, it's possible. I don't think I have ever seen a bike with twin turbos, let alone multiples. Even though you claim to have "a lot of welding" experience, just locating the turbos will be hard. By "locating", I don't mean finding them, I mean putting them on the bike. Where were you thinking of putting them?

There are two locations I have seen for the single-turbo setup. On a more-or-less stock bike, they will remove the carbs and airbox and mount the turbo in that area under the tank. The exhaust will either snake around the side of the engine, back to the turbo, or it will go under, and come up between the engine and the swingarm. (On the 850, that exhaust setup won't work.) The single exhaust from the turbo will usually exit out the left side, drop down along the frame rail, then go toward the back. On the intake side, there is a single carb that is mounted to the intake of the turbo, so at least the intake side is somewhat easy.

I know this is not on a GS, but it shows a turbo installed and the single exhaust going down and back.
This bike has the exhaust pipes under the engine, coming up to the turbo behind the engine, so you can't see them.


Now try to duplicate that with two or four turbos.

The other installation method I have seen is usually on drag bikes. That is because the turbo is mounted low, in front of the engine. The front end might have to be raked out a bit to make room for it, but this picture shows the location:



Now to get down to "why".
Other than just having 'fun' or doing an engineering exercise, the main reason for using multiple turbos instead of a single one is to reduce the "lag", which is the time it take for the turbo to start making boost. A smaller turbo has less mass and will spool up quicker, giving boost quicker. A turbo small enough for the 850 will probably spool up quickly enough, I don't think the split-second difference between the single- and double-turbos would really be noticeable.

More things to consider:
Converting an engine to pressurized intake has other considerations. The compression ratio of the engine in the bike is already reasonably high for performance. By simply hanging a turbo on there, you will not be able to use much boost, meaning you won't see much of an increase in power. That's a LOT of work for not much reward. By lowering the compression ratio, you will lose a bit of power when not using boost (which will be most of the time), but will be able to use more boost, which will really wake up the engine. The cams that are in the engine are ground to maximize efficiency at the upper end of the band, while still being docile enough to give respectable performance at idle and low speeds. The very characteristics that give the cam high-end performance work against it for turbo use, so you might have to look for a milder cam, and that would have to be custom-ground.

We have several racing guys on the forum, but I have not seen any of them respond to this thread yet. Probably because virtually all of the performance-related improvements are directed at the 16-valve engines.

I agree that the concept of a turbo (or two, or four) on an 850 is interesting, but if you simply want a bit more power, pull the 850 engine out and substitute a 1000 or 1100 engine. They pretty much bolt right it, but you have to move the driveshaft over along with the engine.

Not trying to discourage you, just giving you food for thought.

.

[silent_soul]

this forums threads are really odd, and will take some getting used too, however I actually found a website talking about the great work of a guy who builds turbos and he apparently lives in canada. It was on a kz forum that i belong for my 440s ive redone. ill take a look at that site though.

[Dogma]

There is probably some turbo out there that can be made to work with the 850, but it will probably be a bit oversize. I think the brick wall you will hit will be finding pistons for an 850 capable of dealing with turbocharged compression ratios. The bottom line is that not enough performance parts were marketed for the 850. You'll have to come up with your own stuff. Which would be a fascinating project covering several years.

If you mount a 1000G motor in your frame, that will open up some options. Gobs more usable power right off the bat. The chain drive 1000 was raced, and a lot of the performance parts will fit, yielding even more oomph. There may even be some precedent for adding a turbo. Plan on repairing and reinforcing the output flange and drive shaft. The bevel gears should wear faster with high-torque play, but they will survive. But the bottom line is that performance parts will be available to go with your turbocharging ideas. Even easier if you start with a 16V 1100. Or rather, much less difficult.

[Steve]

Even easier if you start with a 16V 1100. Or rather, much less difficult.

Until you take into account that whole chain / shaft drive thing.

As far as I know, there were no 16-valve shafties (except for the GSX1100G, made from '91 to '94) and all 850s were shaft-driven.

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