GS1150E TURBOS

[Anonymous]

Turbo housing

A turbo can work just as well when mounted a good distance from the head. The turbine housing needs to be sized appropriately to make proper use of the kinetic energy of the exhaust gasses. If a turbo which is sized to harness the energy of the exhaust gasses as they expand is used too far from the head then the result will not be good.

Do a little google search and you will find companies mounting turbos under the boot floor of sedans and trucks. Doing this eliminates the need for an intercooler as well. The results are very impressive. Just like playing naturally aspirated, the combination (i.e. turbine housing) needs to be matched.

[lecroy]

Re: Turbo housing

My bike does not have a boot floor, but maybe next time I can find a way to add one.

[melray]

interesting discussion, missed point-

Marco your project is just brilliant, well done sir! Any clues on a starting point for jetting?

Gentlemen! Yes, heat is pressure, however you could put a torch on the turbine blades until they melted and no boost would occur. Or do as the previous owner of my donor turbo did, burn the car down around the turbo... still no boost.

No question that maintaining the temp of the exhaust gasses will maintain the pressure level, also that cooling those gases reduces the pressure, however it is the flow of those gases pushing the turbine blades that spins the air compressor, producing the intake pressure we seek.

Marco's (wow! ) installation demonstrates that enough flow can be had to be effective, even with the cooling of a full size 4-1 exhaust upstream of the turbo. How much power can a skinny rear tire use, anyway?

[marcovandevelde]

Melray, thanks for your enthousiasm.

My bike indeed has a longer-than-usual-exhaust path to the turbo, but works great nevertheless. The benefit is that I have created a smooth, even flow with these equal length downtubes. The downside is a bit more lag, but as I use a VNT turbo, this lag has become neglectable.

Starting point on jetting?
I currently have DJ126 mains in there (orig. 34mm mikunis), and lifted the jetneedles one clip-position higher. Don't remember the airscrew-setting.
This way it runs a bit rich (with dynamic boostcompensation on the floatbowls!), I still need to put it on the dyno to check fuelling throughout the range. I can only do that in a couple of weeks as my clutch is fried now. Will fit a lockup clutch to prevent re-frying too.

I have chosen a 160/60-18 rear tyre, as I rather want the tyre to spin than the std. trans to break. For a wider tyre I'd need an offset sprocket anyway, not a good idea with this kinda power.

Greetz, Marco.

[lecroy]

Hello all you one time posters

[marcovandevelde]

One time poster? Could be right.
Maybe it's because we ride our bikes instead of discussing heat in relation to pressure. Zzzzzzzzzz....

Marco.

[Anonymous]

Hello to you too lecroy!

As this is my second post, does this mean that I am now a two timing forum poster?

As an engineer who loves his motorsport I know exactly why turbos are mounted close to the head. One reason is as you described very well in laymens terms, the other is because it is always done that way.

Remember, if you always do what you have always done, expect to get what you have always got.

[melray]

more turbo yak

I agree that in theory putting the turbo right on the exhaust ports is the best thing. I do not agree that adding another serious heat radiator right in the cooling airstream of an already thermally marginal engine with the intention of causing that engine to make even more heat is a good idea. It seems a bad enough idea to preheat the cooling air with an oil cooler- oops sorry, I am sure the correct term would be 'air-oil heat exchanger'.

If I were working on turboing a watercooled engine I would try to find a way to mount the turbo right up close to the head. My best prior scheme for GS involves putting the assembly up in the fairing forward of the steering head. This would probably cook me every ride, but the exhaust would be short! and the cooling air flow relatively unimpeded both to intercooler and engine. I shudder to consider sitting somewhere in traffic.

Getting rid of heat is the main problem, in my opinion, even normally aspirated. I have been scratching my head for some time over this particular issue, sketching ducts and heat barriers, and lots of weird stuff. Marco just skipped the fooling around and went out and built the solution. Gee, things are so much easier when someone shows the way...

Obviously he is giving up some energy in the longer than optimum exhaust. Good thing he has made enough power that this particular energy loss is not significant. Good show! Cool stuff, very inspiring.

now how do I not melt the seat? hmmmm

[marcovandevelde]

Although I'm pleased you like my design, Melray, It's not the most ideal but born out of the wish to be stealthy and not being able to weld complicated headers.
How will you fit the intercooler in this design? There's hardly space for the turbo itself. Anyway, I think intercoolers are a waste of time on a roadbike. But then we have 97 ron fuel here.
If you insist on maintaining the GSX's orig CR, I'd use waterinjection. You will still have problems with things like the head-gasket. I'd go the whole deal and fit a home-made jig-sawed thin alu spacer between two base-gaskets, get a copper head-gasket and slot my camsprockets for accurate timing. Less fussy than an intercooler and built to last.

The base of the seat is steel, so you won't melt it. To be able to get rid of the heat of the turbo, I removed the rear inner mudguard and replaced it under the seat by sheet aluminum. This provides a heat shield and something to mount you electrics on. The battery had to be placed sideways and further back to give room for the turbo. So the cooling air can flow freely along the turbo to the back wheel without your bottom roasting. For the turbo itself it doesn't matter anyway. In cars they are stowed away between the engine and the bulkhead, and don't have watercooling.

Marco.

[melray]

more turbo talking

Hey thanks for contributing more time to this. The one thing we cannot buy is time, I always appeciate it.

On the compression issue, I think stock 1100 works out to around 8.7 -1 and if I melt the pistons, oh well. Our old Triumph engines would melt the domes off the pisons until they self-adjusted to a compression ratio they could live wth...

I am looking to keep a good quench band, raising the cylinder kills that. If I have to go down on compression then it will be dished pistons. Easier to make across the board power with decent compression and less boost. well, until they melt..

Also I will probably use a spare 1100 chassis instead of the 1150 that was allocated to this project, your observation regarding space is spot on. I would need to build a custom swing arm to have enough room in there for the exhaust lead in pipe. You ran right up thru the swing arm, in the tire zone?

A point which didn't really come up in the previous heat/pressure discussion is; the turbo compresses the intake charge, thus heating it. Not good. Also I have observed turbos in operation and there is a fair amount of heat transfer from the exhaust scroll to the turbine intake body (and everything else within a couple feet) , again not good. Both combustion and engine temps suffer from preheating the charge.

I have an extra set of ES body work, and intend to mount the intercooler in the place of one lower panel on the fairing, with a bit of aluminum paneling inside to direct airflow into it, and also guide airflow from the head away from it. That would be a nearly useless arrangement without ducting air to the intercooler and actually forcing it thru. This way there is room. without significantly incrasing frontal area. There is just not enough real estate up in front, and of course front mounting raises the previously mentioned inter-heating issues.

With luck the intercooler will not be an intake heater... Piston aircraft engines duct air to both the engine fins and oil cooler and have worked well for years. Of course aircraft tend to be up in nice cool air and rarely sit still in traffic. It remains to be seen how much forward velocity will be needed to keep some cooling flow going. I spend very little time in traffic and will surely avoid it even more with all this extra heat.

DJ126 mains? is that equivalent to the Mikuni numbers? I have 132 mains in my sea level GS1150, it is jetted pretty near perfect. So are you getting lots more total fuel due to juggling pressure in the float chambers?


yak yak yak, time to get busy. Now to get the actual turbo so we can start cutting and welding. Sheesh I met a lunatic seller on ebay, think I will keep looking. Not too confidence inspiriing when the guy starts yelling about being insulted right away. Gee if I wanted to get yelled at I could just stay home...

thanks for a lively and helpful discussion-

[marcovandevelde]

Intake heating: Yes. This will create some losses. But making the intake tract longer and make it run through a intercooler will give losses too. And lag.

The turbine charge pipe goes through the swingarm where in its previous FZR life the shock lived.

DJ 126s are DynoJet items. I've so many of these left from other bikes that I can create a vast range. The dynamic boost compensation makes the carbs go rich on boost, exactly what you want. A fellow-rider here in Holland who rides a blow-thru GSXR1100 turbo can use his std. mains!

Yelling? I'm also having trouble getting a lockup clutch here because of a same type of guy. All rights and no duties. He will never make ''salesman of the month''.

Now 'nuff said, start building and keep us posted!

Marco.

[lecroy]

One time poster? Could be right.
Maybe it's because we ride our bikes instead of discussing heat in relation to pressure. Zzzzzzzzzz....

Marco.

I thought we were talking about compressing bricks.

[lecroy]

As an engineer who loves his motorsport I know exactly why turbos are mounted close to the head. One reason is as you described very well in laymens terms, the other is because it is always done that way.

Remember, if you always do what you have always done, expect to get what you have always got.

Good to have a real engineer on-board to keep us in check. Stick around.
You can help us disprove the compressable brick idea.

In the first few posts you see the one of the old kits that was sold by Mr. Turbo and the turbo was mounted in the rear. Many of the old bikes were setup like this before moving them to the front. My old bike is setup like this as well. Still see them at the tracks from time to time.

A turbo can work just as well when mounted a good distance from the head.

I don't think having the turbin mounted a mile from the exhaust is going to work very well no matter how you size it, but give it a shot and show me your results.

I agree 100%, marco has one cool setup. I like home built stuff like this.

[Anonymous]

Money where mouth is.

Check out

https://www.ststurbo.com

Apart from a ratty old gs1100 which I intend to turbo charge eventually, I have a twin turbo, methanol injected 350 chev which makes around 1400hp to the strip at 30psi. Guess where the turbos are mounted? Under the bonnet next to the heads of course. I wouldn't have it any other way. I love the look. Nough waffle from me, not saying there's a right or wrong way, just that there is more way than one to skin a cat.

[lecroy]

Interesting site, thanks for posting it. I notice its all low pressure. They make a comment "The basic systems provide ~5 psi of boost, but with additional tuning and turbo upgrades the systems can produce near 20 psi of boost.".