Go Back   EcoModder Forum > EcoModding > Motorcycles / Scooters
Register Now
 Register Now
 

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 09-17-2016, 12:45 AM   #1 (permalink)
EcoModding Lurker
 
Join Date: Apr 2015
Location: suburbia
Posts: 76
Thanks: 15
Thanked 13 Times in 11 Posts
Replacing R/R for better MPG?

I am looking to replace the OEM Shunt type R/R with series unit, and if my math correct depending on speed this should give me 3-13% MPG improvement?

OEM stator is rated at 35A (420w) and this is constant load due to shunt type R/R. The actual electric load is 190w less, which with series unit should reduce engine drag by 0.26hp.

Per calculator depending on speed (35-65mph) road+aero load is 2-10.3hp, so the 1/4hp drag reduction should give ~3-13% improvements.

Am I missing something?

I suppose at lower speed the stator output will be less than max, so 13% is over-estimate.


Last edited by cyclopathic; 09-17-2016 at 01:30 AM..
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 09-28-2016, 11:08 AM   #2 (permalink)
Master EcoModder
 
Join Date: Feb 2010
Location: Elmira, NY
Posts: 1,276
Thanks: 162
Thanked 206 Times in 179 Posts
If we are talking about a generator system then minimum drag is when there is no current in the field windings or the armature is not moving. The core of the field coils will have some residual magnetism so there will be some slight output with the armature moving. A clutch on the armature shaft could control it such as used on an AC compressor though there would need to be enough current from a battery to engage it.
  Reply With Quote
Old 02-25-2017, 03:13 AM   #3 (permalink)
EcoModding Lurker
 
Join Date: Jun 2012
Location: Florida
Posts: 71
Thanks: 0
Thanked 9 Times in 7 Posts
Just remove the alternator, and install an exhaust driven turbine driving a generator.
Really, you don't need an alternator, are better off with a rotating exhaust turbine.
  Reply With Quote
Old 02-26-2017, 02:17 PM   #4 (permalink)
EcoModding Lurker
 
Join Date: Dec 2011
Location: Michigan
Posts: 74
Thanks: 12
Thanked 22 Times in 15 Posts
Quote:
Originally Posted by ProDigit View Post
Just remove the alternator, and install an exhaust driven turbine driving a generator.
Really, you don't need an alternator, are better off with a rotating exhaust turbine.
That's just gotta be a joke. If such a thing existed and was viable, we'd be using it already I'd think. Back pressure would reduce performance and if it were made so that it wouldn't do that so much then it probably wouldn't be able to keep up with enough charging. A couple little windmill generators at the bar ends charging a pack of Lithium ion batteries on a no alternator/generator engine would probably be just as effective. (or just as ineffective as the case would probably be) If real, then I'd want to see a source.
__________________
_______________________________
Southeast Michigan Dark Side Rider
4 Honda Reflex scooters & a FSC600A Silverwing
Originator of the "Darkside" Honda Reflex.
"Yeah dude, that IS a car tire there on the back of my scooter."
Sometimes I'm so far outside of the box, the Hubble telescope can't find me
  Reply With Quote
Old 02-26-2017, 03:52 PM   #5 (permalink)
EcoModding Lurker
 
Join Date: Jun 2012
Location: Florida
Posts: 71
Thanks: 0
Thanked 9 Times in 7 Posts
Back pressure trades top speed for torque, so your MPG should go up, as well as your acceleration.

As far as an exhaust driven turbine, powering an alternator, no one invented this yet.
But if you want to ride alternator free, the exhaust is a good place to harvest the energy from.
  Reply With Quote
Old 02-26-2017, 04:04 PM   #6 (permalink)
ScanGauge <3
 
Join Date: Dec 2016
Location: CID
Posts: 258

Winter Sacrifice - '96 Subaru Outback
Subaru
90 day: 24.6 mpg (US)
Thanks: 129
Thanked 82 Times in 60 Posts
Quote:
Originally Posted by ProDigit View Post
Back pressure trades top speed for torque, so your MPG should go up, as well as your acceleration.

As far as an exhaust driven turbine, powering an alternator, no one invented this yet.
But if you want to ride alternator free, the exhaust is a good place to harvest the energy from.
A lotta "shoulds" and "ifs" and "no one ___ yet" in there. We like tested and proven stuff on this forum.
__________________



Best tank (so far): 32 MPG
  Reply With Quote
Old 02-26-2017, 06:04 PM   #7 (permalink)
EcoModding Lurker
 
Join Date: Jun 2012
Location: Florida
Posts: 71
Thanks: 0
Thanked 9 Times in 7 Posts
Quote:
Originally Posted by ThermionicScott View Post
A lotta "shoulds" and "ifs" and "no one ___ yet" in there. We like tested and proven stuff on this forum.
Nothing works tested and proven 100%, however, back pressure allows more hot exhaust in the cylinder to warm up the incoming cold air/fuel.
It's a proven fact to increase torque and MPG. That's why many manufacturers do this especially for small bikes, and performance cars as well, using exhaust back pressure valves, or some form of restrictive exhaust can.
  Reply With Quote
Old 02-26-2017, 06:12 PM   #8 (permalink)
ScanGauge <3
 
Join Date: Dec 2016
Location: CID
Posts: 258

Winter Sacrifice - '96 Subaru Outback
Subaru
90 day: 24.6 mpg (US)
Thanks: 129
Thanked 82 Times in 60 Posts
I was talking about the exhaust-powered alternator, obviously.
__________________



Best tank (so far): 32 MPG
  Reply With Quote
Old 02-26-2017, 06:15 PM   #9 (permalink)
EcoModding Lurker
 
Join Date: Jun 2012
Location: Florida
Posts: 71
Thanks: 0
Thanked 9 Times in 7 Posts
I think trying to disconnect an alternator, is just as unproven.
  Reply With Quote
Old 02-26-2017, 06:19 PM   #10 (permalink)
ScanGauge <3
 
Join Date: Dec 2016
Location: CID
Posts: 258

Winter Sacrifice - '96 Subaru Outback
Subaru
90 day: 24.6 mpg (US)
Thanks: 129
Thanked 82 Times in 60 Posts
Quote:
Originally Posted by ProDigit View Post
I think trying to disconnect an alternator, is just as unproven.
Nope! There are folks on here who have run A/B/A tests of alternator deletes, and good discussions of the pros and cons surrounding them.

__________________



Best tank (so far): 32 MPG

Last edited by ThermionicScott; 02-26-2017 at 06:36 PM..
  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2017, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com