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Discussion Starter #1
For me this is more of a academic question but anyway.

Lets assume that you have access to dyno with datalogging for a/f ratio, throttle position or manifold pressure, rpm, and exhaust temp.

The things you could play with were :
-basic carb tweak (needle, jets)
-timing (base and advance)
-cam advance
maybe even things like trying a few different exhausts or airbox/filter designs

How would you (or a pro) proceed? I am assuming that there are so many interconnections from one adjustment affecting another that you would need to proceed in sort of circles.

For example after base values
Tweak A until good -> tweak B until good -> tweak C until good -> repeat (as C might have thrown A off)

('until good' meaning you get most satisfactory result)

How do the pros do it? basic fuel ratios 1st and then tweak timing and go back to fuel?

It seems that there might be some kind of routine that would make the whole process less guess work. We all hear from the dyno sessions where huge improvements are done. Where could I learn from what exactly is being done. I am sure experience is king as always but any tips or links to good reading material would be much appreciated.
 

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Depends on what you intend bike to do?
A street bike ridden mainly at half throttle or so for extended periods is going to be a lot different to a drag bike held full throttle for a few seconds or a road racer which needs to accelerate hard then be on the brakes.
 

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Depends on what you intend bike to do?
A street bike ridden mainly at half throttle or so for extended periods is going to be a lot different to a drag bike held full throttle for a few seconds or a road racer which needs to accelerate hard then be on the brakes.
 

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K, my experience is with a few circle track engines and the big-block in my Chevelle.

A good dyno operator/tuner is under appreciated.

The dude that dynoed my 496 would look at the data in totality at first and make multiple changes. We then might tweak them individually, but took big swings at first.

Couple things;

The idea to stick to one thing at a time is nice, but you're paying by the hour. I spent a grand dynoing the Chevelle engine ten years ago on the supposed buddy deal.

Things work together, for instance we always put fuel and timing in together esp initially.
 

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K, my experience is with a few circle track engines and the big-block in my Chevelle.

A good dyno operator/tuner is under appreciated.

The dude that dynoed my 496 would look at the data in totality at first and make multiple changes. We then might tweak them individually, but took big swings at first.

Couple things;

The idea to stick to one thing at a time is nice, but you're paying by the hour. I spent a grand dynoing the Chevelle engine ten years ago on the supposed buddy deal.

Things work together, for instance we always put fuel and timing in together esp initially.
 

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Discussion Starter #6
Cool thanks. For any input. I ordered couple of books and am trying to roam different forums to get a better idea.

these guys had some good info - under tech articles and under procedure. Targeted to customers but still ok stuff.
http://www.bristoldyno.com/info/procedure.htm

Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?

and PJ - I was more curious of the general approach but the scenario I am thinking would be road racing style application where throttle response and partial throttle performance are also important.
 

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Discussion Starter #7
Cool thanks. For any input. I ordered couple of books and am trying to roam different forums to get a better idea.

these guys had some good info - under tech articles and under procedure. Targeted to customers but still ok stuff.
http://www.bristoldyno.com/info/procedure.htm

Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?

and PJ - I was more curious of the general approach but the scenario I am thinking would be road racing style application where throttle response and partial throttle performance are also important.
 

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quote:Originally posted by kerosene



Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?
If you figure the initial cost of the equip, maint, building overhead and operator wages you'll never get it much under $100/hr, esp if dyno time is all you're selling.

Think about sound attenuation, even bikes are loud.

But yes, I was going to dyno my 05 this summer. The shop in Waterloo(40 miles north) I wanted to do it closed. There are three bike dynos in Cedar Rapids(40 miles SE) two at dealerships , one performance shop. I won't take my stuff to any of them.
 

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quote:Originally posted by kerosene



Ken if dyno time was drastically cheaper do you think you would be using it to tweak your bikes too?
If you figure the initial cost of the equip, maint, building overhead and operator wages you'll never get it much under $100/hr, esp if dyno time is all you're selling.

Think about sound attenuation, even bikes are loud.

But yes, I was going to dyno my 05 this summer. The shop in Waterloo(40 miles north) I wanted to do it closed. There are three bike dynos in Cedar Rapids(40 miles SE) two at dealerships , one performance shop. I won't take my stuff to any of them.
 

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Discussion Starter #10
just pure scifi speculation - if there was cheap (<1000$) dyno equipment - do you think there would be broad interest or do you think that the Sunday tuner would be too clueless to use the data provided by dyno.
 

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Discussion Starter #11
just pure scifi speculation - if there was cheap (<1000$) dyno equipment - do you think there would be broad interest or do you think that the Sunday tuner would be too clueless to use the data provided by dyno.
 

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I think there is some inexpensive dyno equipment out there.

Keep in mind a dyno's only as good as what it can measure and record.

For instance the engine shop that built most of my circle track engines bought an ancient water brake dyno that what they'd do was go WOT then load the engine to bring it down to desired rpm and record measurements.

That didn't measure the accelerational effects of lighter engine components or transitional things going on in the carb. In restrospect not much more than a run in stand.

Now my 496 was done on a Superflow 901. The brake was electrically released allowing the engine to gain rpm at a predetermined rate while tracking a/f, egt's, everything. Much more useful.

Here's what I'm saying, your brake release needs to mimic the rpm/sec gain rate the engine will see in use.

Like for airboxes and stuff, chassis dyno mounted in a windtunnel. I think these exist at top secret government facilities. Multliple brake release programs to mimic the rpm/sec rate gain in different gears and at different ground speeds.

I've tried to talk to motorcycle dyno guys about this stuff, one of us has plainly not got it in all these conversations. I don't get the big drum bike dynos unless all this is in the brake program to where the operators don't need to understand it.
 

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I think there is some inexpensive dyno equipment out there.

Keep in mind a dyno's only as good as what it can measure and record.

For instance the engine shop that built most of my circle track engines bought an ancient water brake dyno that what they'd do was go WOT then load the engine to bring it down to desired rpm and record measurements.

That didn't measure the accelerational effects of lighter engine components or transitional things going on in the carb. In restrospect not much more than a run in stand.

Now my 496 was done on a Superflow 901. The brake was electrically released allowing the engine to gain rpm at a predetermined rate while tracking a/f, egt's, everything. Much more useful.

Here's what I'm saying, your brake release needs to mimic the rpm/sec gain rate the engine will see in use.

Like for airboxes and stuff, chassis dyno mounted in a windtunnel. I think these exist at top secret government facilities. Multliple brake release programs to mimic the rpm/sec rate gain in different gears and at different ground speeds.

I've tried to talk to motorcycle dyno guys about this stuff, one of us has plainly not got it in all these conversations. I don't get the big drum bike dynos unless all this is in the brake program to where the operators don't need to understand it.
 

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Chassis dyno, (where you connect bike to a big heavy drum)
are real useful as they can be programmed to different scenario's.
They do need careful set up initially though, matched airflow for intakes and exhaust extractors if you have a dyno 'cell'

They are also real useful for acceleration and part throttle cruising if you have the correct sensors and software.
With CV carbs they need to be used at specific engine rpm/load as slides don't lift based on throttle position.
Main problem is, most operators are not trained to use them in 'diagnostic' mode.
The other problem as far as I'm concerned, I don't have a spare $30~50,000 to buy one ;)
 

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Chassis dyno, (where you connect bike to a big heavy drum)
are real useful as they can be programmed to different scenario's.
They do need careful set up initially though, matched airflow for intakes and exhaust extractors if you have a dyno 'cell'

They are also real useful for acceleration and part throttle cruising if you have the correct sensors and software.
With CV carbs they need to be used at specific engine rpm/load as slides don't lift based on throttle position.
Main problem is, most operators are not trained to use them in 'diagnostic' mode.
The other problem as far as I'm concerned, I don't have a spare $30~50,000 to buy one ;)
 
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