Alfa (Merc, Lada, WV...) driving dynamics DIY? - Alfa Romeo Forum
You are currently unregistered, register for more features.    
Thread Tools Search this Thread
(Post Link) post #1 of 5 Old 22-09-08 Thread Starter
Status: -
AO Member
Join Date: Feb 2008
Posts: 16

Member car:

156 2.0 TS

Alfa (Merc, Lada, WV...) driving dynamics DIY?

some BMWs have their alternators disabled/suspended during acceleration and that helps both the go and the consumption. AFAIK, the alternators have two sets of windings - one on the rotor and one on the stator. One of these (I guess the one on the rotor) must receive a bias (magnetic filed generating) current that is varied so that the alternator output voltage is around 14 V regardless of RPM. There is also a relay (I assume) than only connects the alternator to the electric network of the car and the battery when that voltage is OK. So, how about making an electromechanical device to cut off the bias current of the alternator during acceleration? I am imagining a small pipe, curved up - the back end points somewhat upwards, with 2 holes on the sides (in the horizontal bottom part) for a LED and a photo transistor, and a steel ball traveling in the pipe. The current through the photo-transistor (when the car accelerates) will open a normally-closed relay to cut the bias current. Such a simple setup would produce abrupt cut-offs and restarts of the bias current. Would that work? Anyone with knowledge of alternators?
EDIT: A switch like the one on the handbrake, hooked up on the throttle, would be simpler. The question still is: would I burn components with the abrupt changes in the bias current?

Last edited by Borislav; 22-09-08 at 07:14.
Borislav is offline  
Sponsored Links
Status: -
AO Silver Member
rancido64's Avatar
Join Date: Apr 2007
Location: Ireland
County: Dublin
Posts: 2,987
Re: Alfa (Merc, Lada, WV...) driving dynamics DIY?


getting stuck straight in there with your first post, eh?

welcome along
rancido64 is offline  
Status: One foot in, one foot out!
AO Platinum Member
zulu ferret's Avatar
Join Date: Oct 2006
Location: wgc
County: herts
Posts: 42,255
Images: 2
Re: Alfa (Merc, Lada, WV...) driving dynamics DIY?

Good electronic science there... Nev? Too expensive to fit on moderately priced machines though? And I guess summat' else to go wrong? Highly technical, Borislav, but interesting nevertheless. Hi! and welcome.:
zulu ferret is offline  
Status: Married
Regional Representative
For East Midlands - AOEM
braddersR's Avatar
Join Date: Jul 2008
Location: United Kingdom
County: Leicestershire
Posts: 42,019
Images: 13
Re: Alfa (Merc, Lada, WV...) driving dynamics DIY?

hello and welcome to AO.....
braddersR is offline  
Status: -
AO Silver Member
ally's Avatar
Join Date: Nov 2003
Location: United Kingdom
County: Perth and Kinross
Posts: 1,738
Images: 2
Re: Alfa (Merc, Lada, WV...) driving dynamics DIY?

Once the engine exceeds 3000rpm or so, a traditional alternator's field windings self-excite and it will charge. You will not be able to engineer in a switch for a traditional alternator, and only a newer switchable type, which is bespoke to the engine will work and fit. Perhaps even a regulator with programmable or variable voltage may work. I don't know if such a thing exists, but it may be possible under the desired conditions to use a different regulator set to a lower charge voltage. You then still need some type of a switch. A switch on the throttle should be the easiest soution, unless the ECU has an extra output controlled by sensing WOT (wide open throttle).

A lot of effort for minimal gains. A remap would be a better solution.
I applaud your thinking though.

[SIGPIC][/SIGPIC]Drive sideways- life's too short not to

Slip-sliding my way through winter. On four wheels and two.
ally is offline  

Go Back   Alfa Romeo Forum > Supported Alfa Romeo Models > Technical & Vehicle Assistance > Alfa 147, 156 & GT

alfa , diy , driving , dynamics , lada , merc

Thread Tools Search this Thread
Show Printable Version Show Printable Version
Email this Page Email this Page
Search this Thread:

Advanced Search

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off

For the best viewing experience please update your browser to Google Chrome