Powerband of Yamaha R6 motor

[TheForce]

Hey guys. Does anyone know what the approximate powerband of the Yamaha R6 motor is on a fsae car? Usually the max power occurs at 14500rpm and the max torque at about 11000, but it should be lower on a car as opposed to a bike shouldn't it.

Cheers,

Luke

[Mikey Antonakakis]

Originally posted by TheForce:
Hey guys. Does anyone know what the approximate powerband of the Yamaha R6 motor is on a fsae car? Usually the max power occurs at 14500rpm and the max torque at about 11000, but it should be lower on a car as opposed to a bike shouldn't it.

Cheers,

Luke
Yes, it will probably be lower, but it's location is up to you, or at least your engine system head.

[Lutter]

What year is your R6 motor? We have a 05, 06, and a 07. The 06 and 07 have a different design then the 05, they have a higher redline. Not sure on the torque/power curves, but test driving last year it seemed as though there was a lot of power up around the 14-15K range.

[Jordan Yeomans]

Hi Guys,

Im working on this aspect of the car with Luke this year.

We are using the 03-05 R6 engine. As luke said we are looking for information regarding the power curve given the 20mm intake restrictor.

Cheers
Jordan

[Mikey Antonakakis]

Okay, so, depending on how you design your intake and exhaust, the power curve could have any one of a number of shapes... but I can say with pretty good certainty that you probably won't have much torque below 4000rpm, regardless of your intake design. If you can think of better questions though there are plenty of people on here that would probably be happy to help steer you in the right direction. My buddy would probably tell me to just say "the answer to your question is no."

[Jordan Yeomans]

Ok,

Thanks for you reply and time. I understand its a very general question with a number of very broad answers.

I'll let you know how it progresses and if we come up with any specific questions.

Cheers,
Jordan

[Mikey Antonakakis]

Try googling "resonance tuning" and in general just try to find any info you can on intake and exhaust design. There's plenty out there but it's hard to get started on the right track.

[Jordan Yeomans]

Yeah, I understand the very basics of exhaust design. I researched it briefly earlier this year for a bit of introduction to engine tuning.

I understand varying diameters and lengths of header pipes allows the power curve shape to be changed around. I will have a deeper look into this though, and air intake. Thanks for the tips.

Just for clarification, after talking to one of the older members of our team. I realised my previous question was more directed at how the power curve moves with the restrictor as opposed to how the shape changes. What I should have said was, with the 20mm restrictor above a certain RPM does the engine start to choke.

Regards,
Jordan

[Mikey Antonakakis]

Originally posted by Jordan Yeomans:
Yeah, I understand the very basics of exhaust design. I researched it briefly earlier this year for a bit of introduction to engine tuning.

I understand varying diameters and lengths of header pipes allows the power curve shape to be changed around. I will have a deeper look into this though, and air intake. Thanks for the tips.

Just for clarification, after talking to one of the older members of our team. I realised my previous question was more directed at how the power curve moves with the restrictor as opposed to how the shape changes. What I should have said was, with the 20mm restrictor above a certain RPM does the engine start to choke.

Regards,
Jordan

The answer to your question is yes. With an R6 your restrictor will choke. It will have a large impact at high rpm. Search for how to calculate choked flow through a venturi, and you'll at least get in the ballpark of the max flow rate through the restrictor. You'll see that a stock r6 will flow more air than this at high RPM. And here's another hint, intake geometry is probably more significant than exhaust geometry when you have an intake restrictor. If you design your intake well, you can get power to basically plateau above the choke RPM, which depends on your setup. That's the main difference... the restrictor has an effect at all engine speeds, but more so at high speed. I suggest you read all you can on intake design. There are several SAE papers out there dealing with FSAE intakes in particular.

Re-reading your question, I wouldn't say the power curve "moves" as much as the top end kind of gets lopped off. Once you approach the choked flow, you won't be making anymore power... what you decide to do with that is up to you. Some teams try to make all the top end they can, some try to make lots of torque down low. Some try to strike a balance. But on a 600cc sportbike, if you can generalize the effect at all, it's that at a certain point your power will plateau because you have choked flow through the restrictor.

EDIT: I'm sorry if this post has excessive rambling, been up all night.