Question for the Big-Brain engine guys




fallenarch

THE SLOW RIDER
Registered
My bike was dyno tuned almost 8 years ago. The dyno tune was amazing and the bike has the best response of anything I've ever ridden. Throttle is extremely precise and predictable, smooth bottom end and it screams all the way past 11K - and still does. My question is does a tune need to be refreshed periodically? Engines change as they wear, so is it a good idea to re-tune it every so many miles?

Just curious

PS: This is a N/A Gen 2 engine, mostly stock except Yoshi full exhaust and K&N.
 
My bike was dyno tuned almost 8 years ago. The dyno tune was amazing and the bike has the best response of anything I've ever ridden. Throttle is extremely precise and predictable, smooth bottom end and it screams all the way past 11K - and still does. My question is does a tune need to be refreshed periodically? Engines change as they wear, so is it a good idea to re-tune it every so many miles?

Just curious

PS: This is a N/A Gen 2 engine, mostly stock except Yoshi full exhaust and K&N.
Hi. I would say your tune is still close. At the race track they adjust the tune all day because of tepm and humidity. was it tuned for max HP or driveabilty like for low speed or mid range HP? fuel makes a difference too summer blend winter blend brand octane too. does Shell 93 make the same HP as SUNOCO?
 

Yellow09

Registered
My bike was dyno'd and tuned a few years ago (previous owner). I have a Bazzaz tuner on it and can plug in the lap top to check AF readings after a ride if I wish.

Last time I checked it the AF was 12.8 which I'm told is pretty good. and that was before a fresh set of plugs and air filter clean so it could be even better now.
 

busakiller

Registered
If this is a street bike your tune should be good for like ever. Lol. Only time you want to change the tune is if you do any more mods. Or if your a racer and you have changed different altitudes and trying to squeeze everything out of the bike. But if it’s a street bike just ride it. You don’t need to change the tune if you put miles on the bike.
 

Yellow09

Registered
I recently watched a good video on dyno runs...it was very interesting to see what changes the outcome of dyno figures.

-Tires (the guy said standard tires were the best for gaining hp-he didn't mention a brand name though)
-Rims (lighter the better) and bearings
-clean and adjusted chain
-fresh spark plugs
-oil viscosity
-brake drag
-ambient temperature

All the things @c10 mentioned before

I got to thinking....these are very clinical numbers which are not necessarily transferred to the street. Add in friction from pavement, slight inclines, wind, resistance of body, mirrors, etc...and these dyno numbers would drop substantially...

Even the AF factors can change due to atmospheric conditions and elevations.

This whole tuning thing is really more complicated than I ever thought. Most people turn on the key, stab the starter button and off they go oblivious to all this that's going on...

Of course I'm not saying anything new or hasn't been thoroughly discussed before-it is just interesting is all.
 

Mr Brown

Registered
I recently watched a good video on dyno runs...it was very interesting to see what changes the outcome of dyno figures.

-Tires (the guy said standard tires were the best for gaining hp-he didn't mention a brand name though)
-Rims (lighter the better) and bearings
-clean and adjusted chain
-fresh spark plugs
-oil viscosity
-brake drag
-ambient temperature

All the things @c10 mentioned before

I got to thinking....these are very clinical numbers which are not necessarily transferred to the street. Add in friction from pavement, slight inclines, wind, resistance of body, mirrors, etc...and these dyno numbers would drop substantially...

Even the AF factors can change due to atmospheric conditions and elevations.

This whole tuning thing is really more complicated than I ever thought. Most people turn on the key, stab the starter button and off they go oblivious to all this that's going on...

Of course I'm not saying anything new or hasn't been thoroughly discussed before-it is just interesting is all.
What's interesting is how people think dyno numbers are a legit means of comparison. As you point out there are so many variables, it's impossible to compare across time and place. All they can tell you is what that bike (or car) did on that dyno on that pull. Interesting, but not comparable.
 

Yellow09

Registered
What's interesting is how people think dyno numbers are a legit means of comparison. As you point out there are so many variables, it's impossible to compare across time and place. All they can tell you is what that bike (or car) did on that dyno on that pull. Interesting, but not comparable.
It's infinite at how many variables there are-I forgot to mention helmet shape even adds to the resistance...

I suppose that could explain how bikes with more hp/tq on the dyno can be out-performed in real life riding due to all these variables..

Pretty interesting stuff...
 

Tached1300

Registered
It's infinite at how many variables there are-I forgot to mention helmet shape even adds to the resistance...

I suppose that could explain how bikes with more hp/tq on the dyno can be out-performed in real life riding due to all these variables..

Pretty interesting stuff...
It’s because we don’t race dynos in the real world, dynos are great for serving as a baseline prior to changes, A-B or A-B-A testing, they are great for tuning, looking at torque and hp curves, area under the curve, air fuel ratio, bsfc etc but performance in the real world always comes down to the entire package for sure along with the variables mentioned. All of that helps to select gearing or in a car with an auto the ideal converter stall etc...

Make no other changes but ride it to another dyno and make a pull and you’d get a different number might not be much diff or it may be, but in particular with drag racing if you pick up ET or mph then what the dyno says is irrelevant in terms of rwhp. (Accounting for weight, 60 ft, weather conditions and elevation etc of course)
 

Yellow09

Registered
It’s because we don’t race dynos in the real world, dynos are great for serving as a baseline prior to changes, A-B or A-B-A testing, they are great for tuning, looking at torque and hp curves, area under the curve, air fuel ratio, bsfc etc but performance in the real world always comes down to the entire package for sure along with the variables mentioned. All of that helps to select gearing or in a car with an auto the ideal converter stall etc...

Make no other changes but ride it to another dyno and make a pull and you’d get a different number might not be much diff or it may be, but in particular with drag racing if you pick up ET or mph then what the dyno says is irrelevant in terms of rwhp. (Accounting for weight, 60 ft, weather conditions and elevation etc of course)
So it's basically a tool for tuning...many manufacturers sure set a lot of store on those figures.
 

Tached1300

Registered
So it's basically a tool for tuning...many manufacturers sure set a lot of store on those figures.
Because it sells... everyone likes to talk about peak numbers but it’s about getting a fat area under the curve, unless it’s a single purpose type deal that will only spend its time in a narrow rpm range and has been geared and optimized for that

It is great for tuning you can learn a lot of information to help drive other choices that would take much longer to sort out at the track for instance
 



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