HarleyTechTalk

Technical Forums => Milwaukee-Eight => Topic started by: BVHOG on February 25, 2019, 12:39:09 PM

Title: M8 cam comparator
Post by: BVHOG on February 25, 2019, 12:39:09 PM
anyone know of an M8 cam comparator sheet like bigboyz have for the twincam?  Maybe we all need to ask them to do one for the M8  stuff
Title: Re: M8 cam comparator
Post by: Durwood on February 25, 2019, 12:52:35 PM
That would be a great tool to have.
Title: Re: M8 cam comparator
Post by: turboprop on February 25, 2019, 01:07:33 PM
Probably stand a better chance of getting BigBouyz cooperation if the request included a spreadsheet of the various M8 cams and their specs.
Title: Re: M8 cam comparator
Post by: donk_316 on March 05, 2019, 12:28:30 PM
Someone needs to build an app that is basically the BB calculator but with Evo, TC and M8 selectable and ofcourse the cam DB too.

OR someone post the calculations for ccp AND dynamic compression. Ive built a spread sheet for this but cant find these two calcs which ofcourse are the important ones.
Title: Re: M8 cam comparator
Post by: Admiral Akbar on March 05, 2019, 02:05:32 PM
Quote from: donk_316 on March 05, 2019, 12:28:30 PM
Someone needs to build an app that is basically the BB calculator but with Evo, TC and M8 selectable and ofcourse the cam DB too.

OR someone post the calculations for ccp AND dynamic compression. Ive built a spread sheet for this but cant find these two calcs which ofcourse are the important ones.

You cannot calculate dynamic compression in a spreadsheet. You need to know what the volumetric efficiency is.
Title: Re: M8 cam comparator
Post by: donk_316 on March 05, 2019, 07:10:01 PM
Well I found the calculations and I guess I have divided by zero and now the universe will end as I have calculated CCP and dynamic compression ratio which closely mirror the results from the BigBoyz calculator.

Oddly enough... The only VE number that will mirror the BigBoyz calculator is a VE of 142.5% !! Woah shes a breather! haha!

I used variations on the BB page and on my spreadsheet and they are + / - 5psi depending on what altitude im calculating at.


Close enough for the 100s of visits to the BB Calc website. It would be crazy easy to input M8 variables.
Title: Re: M8 cam comparator
Post by: Admiral Akbar on March 06, 2019, 08:55:50 AM
Garbage in, Garbage out.  Where does BB calculate Dynamic Compression?
Title: Re: M8 cam comparator
Post by: turboprop on March 06, 2019, 10:14:02 AM
Quote from: Admiral Akbar on March 06, 2019, 08:55:50 AM
Garbage in, Garbage out.  Where does BB calculate Dynamic Compression?

It doesn't.
Title: Re: M8 cam comparator
Post by: donk_316 on March 06, 2019, 12:46:48 PM
Maybe I'm not understand what you guys are saying?
Maybe it's a terminology issue and we are using different words for the same thing?

Here's a screenshot where the BB calculator is showing static and corrected compression with ccp.

Are you saying these numbers are highly innacurate and mislabeled?

My calcs are based off of equations I found that gave me similar numbers to the screenshot.
Title: Re: M8 cam comparator
Post by: turboprop on March 06, 2019, 01:05:48 PM
Quote from: donk_316 on March 06, 2019, 12:46:48 PM
Maybe I'm not understand what you guys are saying?
Maybe it's a terminology issue and we are using different words for the same thing?

Here's a screenshot where the BB calculator is showing static and corrected compression with ccp.

Are you saying these numbers are highly innacurate and mislabeled?

My calcs are based off of equations I found that gave me similar numbers to the screenshot.

Dynamic compression is just that, it varies with the RPM of the engine. The BB calculator proves a mathematical correction to the static compression based solely on the closing point of the intake. Not dynamic, more like corrected.

Do a google search of corrected vs static compression. Lots of credible information available on this subject.
Title: Re: M8 cam comparator
Post by: donk_316 on March 08, 2019, 03:52:47 PM
Hey thanks for that. I was mixing up terminology then.
Title: Re: M8 cam comparator
Post by: Hillside Motorcycle on March 13, 2019, 02:36:39 AM
Craig Walters Accelerator Program(s) allows the manual input of any cam config.