Want More Torque

[oskala]

I just bought a new '09 Busa. I'd like to add a little more Torque down low where I'll need it for a HOT street Busa. My HP #'s are fine and I don't even mind losing a few HP to gain some TQ. I'll be doing my build in stages so it's important to get the right parts the first time that will work with any future mods.

I'll be starting next Spring with a full exhaust system, EFI remapping, and possibly adj. cam sprockets so I can retard my cams a hair for more TQ down low.

Then I'll be looking for some TQ producing head work or a new head, cams that make good TQ down low, along with fixing my Squish to .030".

If I still need more TQ I'll add a stroker crank instead of a big bore kit, or instead I might just add a Nitrous system so I can have some instant power when I need it.

And thoughts on how I should go about acheiving my goals?

I'll be doing all my own work as I'm quite anal about things being as close to perfect as possible. Not to mention the money I'll save.

 

[Commuta_Busa]

remember this isn't a car but a motorcycle engine.

you could save yourself a ton of money and time just by swapping some sprockets around so that your in the power band when you need/want it.

 

[oskala]

remember this isn't a car but a motorcycle engine.

you could save yourself a ton of money and time just by swapping some sprockets around so that your in the power band when you need/want it.

I only have 150 miles on my '09 Busa and so far I really like the gearing. I'll need to put on some more miles before I decide if I'll change my gearing to a 44 rear sprocket when my stock sprocket wears out. But changing my gearing will not give me between 110-120 ft. lbs. of TQ at the rear wheel.

 

[oskala]

I should add that I'll also be installing a manual cam chain adj., P.A.I.R. block off plate, UNI air filter, and possibly a Scotts or K&P cleanable oil filter next Spring.

Have I missed anything else?

Also in the future I'd like to reduce my Busa's unsprung weight with new rims and Galfer wave rotors. With a 4-2-1 full exhaust and rims I should be able to get my Busa's weight down under 550 lbs..

 

[oskala]

Are there any oiling system mods I should also look into?

 

[Mr Bogus]

I think I would ride it a bit more, think about the gearing change that "think" over the mod list for a bit.. I see some issues that will just start a long debate... Commuta hit it pretty spot on, it is not a car engine.. (FWIW.. you would go "down" on the rear tooth count if you are trying to maximize the torque of the bike and let the engine work harder instead of faster)

 

[Commuta_Busa]

you have drive wheel torque at the rear wheel. Calculate the engine torque x gearing X drive line loss to find out what you're laying down at the rear wheel.

But changing my gearing will not give me between 110-120 ft. lbs. of TQ at the rear wheel.

 

[oskala]

I think I would ride it a bit more, think about the gearing change that "think" over the mod list for a bit.. I see some issues that will just start a long debate... Commuta hit it pretty spot on, it is not a car engine.. (FWIW.. you would go "down" on the rear tooth count if you are trying to maximize the torque of the bike and let the engine work harder instead of faster)

Thanks for your thoughts.

It's still a water cooled, 4 cycle, internal combustion engine. It's not really that complicated. It's just an air pump and IMHO the key is getting great VE.

Changing gearing will just move my rpm's up or down compared to mph. I may want more rpm at lower mph so a larger rear sprocket would be in order. I'll lose a little on the top end which I don't mind.

Exhaust, EFI remapping, cam timing, head work, cams, and fixing squish are all very basic performance mods no matter what kind of engine we're talking about. A stroker crank will produce more TQ, just look at the undersquare HD's that put out gobs of TQ.

 

[dadofthree]

I thought the Gen II came with a stroker crank, anyway I would suggest changing sprockets for a little better low end performance. Much cheaper and way easier to maintain. I'm thinking you're close to the torque you want out of the crate. These things shred rear tires from the factory. Light weight rear wheel, etc. full exhaust, bazzaz controller or flashing the E C U are great ideas.

 

[oskala]

I thought the Gen II came with a stroker crank, anyway I would suggest changing sprockets for a little better low end performance. Much cheaper and way easier to maintain. I'm thinking you're close to the torque you want out of the crate. These things shred rear tires from the factory. Light weight rear wheel, etc. full exhaust, bazzaz controller or flashing the E C U are great ideas.

Thanks Dadofthree for taking the time to post a reply.

The Gen II's do have a 2mm longer crank. See, even Suzuki thinks like me. I doubt I'll need to go with a stroker crank as I think I can get to 120 ft. lbs. Tq. without it. But I'll leave that option open for when I rebuild my bottom end someday. My bike is in storage for the Winter but when I get her out in March I'll put some miles on and see how I like the stock gearing. So far the gearing is spot on so I may just leave it where it's at. My '08 FJR had a 5-speed and I hated the gearing. Right now if I remember correctly I'm turning around 3K at 35 mph which is very close to what I'm looking for. If anything I'd only need to add one tooth to the rear sprocket to get a little more rpm at all speeds. When I'm in touring mode I can run at 3k and get decent gas milage and I won't be lugging my engine when I'm just cruising around doing the speed limit. In sport mode I usually turn around 4K so I'm in my Tq. band and ready for anything that comes along. I'd like to get around 120 ft. lbs. Tq. out of my Busa and I don't think a full exhaust and EFI remapping will get me there. But with a full exhaust, EFI remapping, cams, and a good porting I'll be real close to 120 ft. lbs. tq..

 

[trekfuel]

Try three up on the back...may get the results you are looking for....

Like mine that way. Cheap fix....

 

[Mr Bogus]

Thanks for your thoughts.

It's still a water cooled, 4 cycle, internal combustion engine. It's not really that complicated. It's just an air pump and IMHO the key is getting great VE.

Changing gearing will just move my rpm's up or down compared to mph. I may want more rpm at lower mph so a larger rear sprocket would be in order. I'll lose a little on the top end which I don't mind.

Exhaust, EFI remapping, cam timing, head work, cams, and fixing squish are all very basic performance mods no matter what kind of engine we're talking about. A stroker crank will produce more TQ, just look at the undersquare HD's that put out gobs of TQ.

If you look at the HD drive train they build the transmission and gearing to use that torque..

lower gearing, wider gear ratios and a lot less RPM for MPH.. you are going in opposite directions if you 1. make the motor do more work at lower rpms and then 2 raise the operating RPM's at a given speed..

Hi torque engine builds require longer legs in the gearing dept.. is why big CID motors have taller gearing smaller high hp motors

but ET's at the race track will show you this when the time comes..

 

[BA BUSA]

I just bought a new '09 Busa. I'd like to add a little more Torque down low where I'll need it for a HOT street Busa. My HP #'s are fine and I don't even mind losing a few HP to gain some TQ. I'll be doing my build in stages so it's important to get the right parts the first time that will work with any future mods.

I'll be starting next Spring with a full exhaust system, EFI remapping, and possibly adj. cam sprockets so I can retard my cams a hair for more TQ down low.

Then I'll be looking for some TQ producing head work or a new head, cams that make good TQ down low, along with fixing my Squish to .030".

If I still need more TQ I'll add a stroker crank instead of a big bore kit, or instead I might just add a Nitrous system so I can have some instant power when I need it.

And thoughts on how I should go about acheiving my goals?

I'll be doing all my own work as I'm quite anal about things being as close to perfect as possible. Not to mention the money I'll save.

Spend $80 and buy a 46 tooth rear sprocket and go ride your bike...you can waste your $$$ later if you think you need to

 

[dadofthree]

Thanks Dadofthree for taking the time to post a reply.

The Gen II's do have a 2mm longer crank. See, even Suzuki thinks like me. I doubt I'll need to go with a stroker crank as I think I can get to 120 ft. lbs. Tq. without it. But I'll leave that option open for when I rebuild my bottom end someday. My bike is in storage for the Winter but when I get her out in March I'll put some miles on and see how I like the stock gearing. So far the gearing is spot on so I may just leave it where it's at. My '08 FJR had a 5-speed and I hated the gearing. Right now if I remember correctly I'm turning around 3K at 35 mph which is very close to what I'm looking for. If anything I'd only need to add one tooth to the rear sprocket to get a little more rpm at all speeds. When I'm in touring mode I can run at 3k and get decent gas milage and I won't be lugging my engine when I'm just cruising around doing the speed limit. In sport mode I usually turn around 4K so I'm in my Tq. band and ready for anything that comes along. I'd like to get around 120 ft. lbs. Tq. out of my Busa and I don't think a full exhaust and EFI remapping will get me there. But with a full exhaust, EFI remapping, cams, and a good porting I'll be real close to 120 ft. lbs. tq..

On the Gen I 4K was the sweet spot for gas mileage, which put you cruising around 70 MPH. Can't tell you on the Gen II. I'll do some research but I'm thinking 110 ft/lbs out the crate brother.

 

[BA BUSA]

On the Gen I 4K was the sweet spot for gas mileage, which put you cruising around 70 MPH. Can't tell you on the Gen II. I'll do some research but I'm thinking 110 ft/lbs out the crate brother.

103 +- a couple of lbs

 

[dadofthree]

103 +- a couple of lbs

Correct, wiki was a little shy on the RWHP value from what's been posted here.

 

[Spkrdctr]

I would also agree with the others here. Buy a new rear sprocket with 5 more teeth than stock. That will wake the beast up a lot. Plus get a speedohealer. Then if your unhappy you can start in on the engine and spending big bucks!! Most likely with the gearing change you will want a longer swingarm and a soft compund tire for hooking up. The guys here that drag race all the time, can give you great rear tire recommendations. I think Mr. Bogus is one of the drag racers on board. He is a guy who has really done it and been there! Good Luck on your bike!

 

[dadofthree]

Just remember this. The Busa gets real light , real quick out of the crate, and by lowering the gearing it could be devastating if you don't use caution. 5 teeth, wow.

 

[djsin]

keep the stock rear sprocket...go down one on the front...that will put you with 17/43 since gen 2 has 18/43 stock
gen 1 has 17/40 stock
myself mr bogus and trekfuel all run 17/43

 

[BA BUSA]

keep the stock rear sprocket...go down one on the front...that will put you with 17/43 since gen 2 has 18/43 stock
gen 1 has 17/40 stock
myself mr bogus and trekfuel all run 17/43

They went to a 18 front, because of the increased power output of the Gen2.

It is better to go +3 (46)on the rear...easier on the chain and close to going -1 on the front.

Final drive ratio...
17/43 = 2.529
18/46 = 2.555

stock Gen2
18/43 = 2.388
Gen1
17/40 = 2.352