Speed Twin Twin Turbo
Discussion
Hi everyone, forgive the random nature of this topic, its more of a brain dump than anything else.
I've had this little devil on my shoulder for a few months now saying "you need a project bike!"...mainly due to my project car nearing the end of its journey in terms of it's build, now it just needs to be enjoyed. Something which I'm already doing.
Link to that project here (370bhp Saxo VTS Turbo) -
https://www.pistonheads.com/gassing/topic.asp?h=0&...
So...my thoughts have been based around my 2020 Speed Twin 1200. I adore this bike and it's one of the best bike purchases I've ever made.
The little devil is saying, add more power to it. Does it need more power? NO! Do I want it to have more power, YES!
Now, before any of you comment...."just buy another bike with more power, don't ruin the speed twin" etc etc....yep I agree 10000%. That's the simple option and probably the right thing to do if the aim is just a faster bike. However, I find the journey more interesting than the destination with respect to projects and that rules out just adding another bike to the stable. I have a S1000XR anyway so this is more about a technical journey.
The project bike urge needs to be itched! Thinking about my skill set, fabrication and welding ability, adding a turbo's to something doesn't come across as difficult. I've done it on the car, why not the bike. I can tig weld, have fabrication access and time....Do I need more reasons?
My plan would be a pair of small capacity turbo's like a Garrett GBC17-200.
https://turbozentrum.co.uk/Garrett-GBC14-200-Turbo...
These are made for small capacity engines. They're oil cooled so would need to figure out a oil feed and return plus cooling. That's probably the 2nd biggest challenge.
Why a pair? I actually think it'll be easier to have two than one believe it or not. The speed twin engine configuration and layout means adding a turbo each side would be a doddle with respect to pipe runs, exhaust, intakes etc. I've even got a plan to intercool it if required. I'd aim at low boost and hopefully not need an IC but I'll cross that bridge later. They'd sit no wider than GS boxer motor and I can place them where I want.
Lastly, To avoid chopping up a rather lovely speed twin I'm looking at a crash damaged bike to use as purely a development rig and then when it's all working and running I'd transfer it over. For example, there is a 2022 speed twin on CoPart right now that would be ideal.
I'm very aware of the supercharger route from TTS but that's just a bolt on kit, not really a project as such. Those sorts of power gains is where I'd be aiming. ~140-150bhp plus whatever torque benefit comes with it.
My other thoughts would be lower compression, do the TTS kits do that? I don't think they do so the standard engine is good for it, that's more of an open question! Injector upgrade, there's only two if that's the case. Fit a wideband, simple enough. Would need a map sensor upgrade no doubt. Beyond that it's an ECU change for something that can take boost or power commander route.
Plenty still to think about before I spend any real money but open to thoughts, opinions, has anyone done it? Things to avoid. Things to get right etc?!
Any feedback welcome.
I've had this little devil on my shoulder for a few months now saying "you need a project bike!"...mainly due to my project car nearing the end of its journey in terms of it's build, now it just needs to be enjoyed. Something which I'm already doing.
Link to that project here (370bhp Saxo VTS Turbo) -
https://www.pistonheads.com/gassing/topic.asp?h=0&...
So...my thoughts have been based around my 2020 Speed Twin 1200. I adore this bike and it's one of the best bike purchases I've ever made.
The little devil is saying, add more power to it. Does it need more power? NO! Do I want it to have more power, YES!
Now, before any of you comment...."just buy another bike with more power, don't ruin the speed twin" etc etc....yep I agree 10000%. That's the simple option and probably the right thing to do if the aim is just a faster bike. However, I find the journey more interesting than the destination with respect to projects and that rules out just adding another bike to the stable. I have a S1000XR anyway so this is more about a technical journey.
The project bike urge needs to be itched! Thinking about my skill set, fabrication and welding ability, adding a turbo's to something doesn't come across as difficult. I've done it on the car, why not the bike. I can tig weld, have fabrication access and time....Do I need more reasons?
My plan would be a pair of small capacity turbo's like a Garrett GBC17-200.
https://turbozentrum.co.uk/Garrett-GBC14-200-Turbo...
These are made for small capacity engines. They're oil cooled so would need to figure out a oil feed and return plus cooling. That's probably the 2nd biggest challenge.
Why a pair? I actually think it'll be easier to have two than one believe it or not. The speed twin engine configuration and layout means adding a turbo each side would be a doddle with respect to pipe runs, exhaust, intakes etc. I've even got a plan to intercool it if required. I'd aim at low boost and hopefully not need an IC but I'll cross that bridge later. They'd sit no wider than GS boxer motor and I can place them where I want.
Lastly, To avoid chopping up a rather lovely speed twin I'm looking at a crash damaged bike to use as purely a development rig and then when it's all working and running I'd transfer it over. For example, there is a 2022 speed twin on CoPart right now that would be ideal.
I'm very aware of the supercharger route from TTS but that's just a bolt on kit, not really a project as such. Those sorts of power gains is where I'd be aiming. ~140-150bhp plus whatever torque benefit comes with it.
My other thoughts would be lower compression, do the TTS kits do that? I don't think they do so the standard engine is good for it, that's more of an open question! Injector upgrade, there's only two if that's the case. Fit a wideband, simple enough. Would need a map sensor upgrade no doubt. Beyond that it's an ECU change for something that can take boost or power commander route.
Plenty still to think about before I spend any real money but open to thoughts, opinions, has anyone done it? Things to avoid. Things to get right etc?!
Any feedback welcome.
I love modifying and almost every car and bike I own is modified
However, I can't see the point of twin turboing a motorcycle - particularly that one - unless you're going for a particular high speed record, they're just better normally aspirated
That said if you're the type who just wants to do it because you can, fair play to you but I struggle to believe there aren't better project options
However, I can't see the point of twin turboing a motorcycle - particularly that one - unless you're going for a particular high speed record, they're just better normally aspirated
That said if you're the type who just wants to do it because you can, fair play to you but I struggle to believe there aren't better project options
Stupid idea - I love it!!!
Although he specialises more in inline 4s (particularly gixer/bandit oil boilers), Dave Dunlop might be a good person to bounce some of your ideas off as turboing bikes is what he does for a living, kits and custom. He's certainly done a couple of twin turbo 4s and his trike, captain sensible, has a compound charged oil boiler.
Although he specialises more in inline 4s (particularly gixer/bandit oil boilers), Dave Dunlop might be a good person to bounce some of your ideas off as turboing bikes is what he does for a living, kits and custom. He's certainly done a couple of twin turbo 4s and his trike, captain sensible, has a compound charged oil boiler.
A turbo on a single cylinder will always struggle as the lack of exhaust energy won't spin it up well.
As said previously, a single turbo fed from both cylinders will be better although the cylinder pulse character may prove a challenge to building any boost without a loooong rpm run up.
Next up you'll likely have to reduce the CR or run low boost as well as manage the additional fueling, ignition timing and elevated temperatures not to mention fabricate a sealed intake plenum and throttle plate as it's unlikely the OEM throttle bodies can withstand any positive pressure.
You might also find the internals of the bike in no way able to handle additional cylinder pressures as wellas the 270 degree crank angle leading to a huge increase in crank rocking which isn't a good thing...
If you're serious (and I'm serious here) go fit a turbo to a single cylinder lawn mower and see what works vs what doesn't before trying it on a bike.
As said previously, a single turbo fed from both cylinders will be better although the cylinder pulse character may prove a challenge to building any boost without a loooong rpm run up.
Next up you'll likely have to reduce the CR or run low boost as well as manage the additional fueling, ignition timing and elevated temperatures not to mention fabricate a sealed intake plenum and throttle plate as it's unlikely the OEM throttle bodies can withstand any positive pressure.
You might also find the internals of the bike in no way able to handle additional cylinder pressures as wellas the 270 degree crank angle leading to a huge increase in crank rocking which isn't a good thing...
If you're serious (and I'm serious here) go fit a turbo to a single cylinder lawn mower and see what works vs what doesn't before trying it on a bike.
Edited by Steve Bass on Tuesday 3rd June 21:07
Steve Bass said:
A turbo on a single cylinder will always struggle as the lack of exhaust energy won't spin it up well.
As said previously, a single turbo fed from both cylinders will be better although the cylinder pulse character may prove a challenge to building any boost without a loooong rpm run up.
Next up you'll likely have to reduce the CR or run low boost as well as manage the additional fueling, ignition timing and elevated temperatures not to mention fabricate a sealed intake plenum and throttle plate as it's unlikely the OEM throttle bodies can withstand any positive pressure.
You might also find the internals of the bike in no way able to handle additional cylinder pressures as wellas the 270 degree crank angle leading to a huge increase in crank rocking which isn't a good thing...
If you're serious (and I'm serious here) go fit a turbo to a single cylinder lawn mower and see what works vs what doesn't before trying it on a bike.
Ha ha! https://youtu.be/zjKzF5iQQn0?si=f0mtN2iAL5U7cVgx&a...As said previously, a single turbo fed from both cylinders will be better although the cylinder pulse character may prove a challenge to building any boost without a loooong rpm run up.
Next up you'll likely have to reduce the CR or run low boost as well as manage the additional fueling, ignition timing and elevated temperatures not to mention fabricate a sealed intake plenum and throttle plate as it's unlikely the OEM throttle bodies can withstand any positive pressure.
You might also find the internals of the bike in no way able to handle additional cylinder pressures as wellas the 270 degree crank angle leading to a huge increase in crank rocking which isn't a good thing...
If you're serious (and I'm serious here) go fit a turbo to a single cylinder lawn mower and see what works vs what doesn't before trying it on a bike.
Edited by Steve Bass on Tuesday 3rd June 21:07
Indeed, the exhaust pulses are potentially an issue and spooling etc. But plenty have run small turbos on single cylinders before. Its not new news. I will say though, each pulse is from a 600cc combustion. It's a 1200cc remember, what a 600cc 4 pot delivers in 4 combustion events is done by 1 in this case. Is that a good thing? maybe, is it a bad thing..maybe?!
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