The New Thread (928 community chat)
06-29-2008, 08:03 PM
#151
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
Sorry Jason, I have to rub salt in your wound. Here's this morning, started out at 5:30am to meet up with a 997 Turbo, a 996 Turbo, 3 996's and two M3's. We ran up Palomar Mtn, and back down past Lake Henshaw, up thru Mesa Grande to have breakfast in Julian. About 120 miles for me. All I will say is there are 7 other drivers that have a new found respect for air-cooled 3.2 Carreras. Or, at least one '84. 
We had some 110+ straights thru the valleys, where I may have been slightly underpowered, but on the twisties, Ruby had no superiors.
We had some 110+ straights thru the valleys, where I may have been slightly underpowered, but on the twisties, Ruby had no superiors.
Ed great pics keep em coming no matter what pain it may cause me
06-29-2008, 08:09 PM
#152
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
06-30-2008, 08:09 PM
#153
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Jason-
Try to remember that the battery is there to make starting current, and to carry the car at idle when the alternator doesn't make enough to carry the static car loads.
Consider that a 10% smaller pulley will get you the same charging at 850 that you get now at 950. It will also spin the whole mess 10% faster at hihgger RPM's, so you're spinning it the same as 5500 engine RPM's when you are only spinning the engine at 5000. Point is that you really want to b sure that the altaernator you use is capable of extended operation at the higher RPM's without damage. On the last car that had the low-speed charge problem, I ended up switching off the booster amps for extended slow-speed situations.
Try to remember that the battery is there to make starting current, and to carry the car at idle when the alternator doesn't make enough to carry the static car loads.
Consider that a 10% smaller pulley will get you the same charging at 850 that you get now at 950. It will also spin the whole mess 10% faster at hihgger RPM's, so you're spinning it the same as 5500 engine RPM's when you are only spinning the engine at 5000. Point is that you really want to b sure that the altaernator you use is capable of extended operation at the higher RPM's without damage. On the last car that had the low-speed charge problem, I ended up switching off the booster amps for extended slow-speed situations.
06-30-2008, 09:04 PM
#154
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
Thanks Bob. I really don't think we need to worry about the rpms here in the states. When was the last time you did a 100+ MPH run for hours at a time. The speeds here are nothing compaired to Germany but that's just my 2 cents. I think finding maybe a pully 1/2 size of the original pully would solve my charging problem. Anyone heard of or found such a thing? Jason
06-30-2008, 11:11 PM
#155
Chronic Tool Dropper
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Jason--
Do a few calcs and figure out ho wfast the alternator is turning vs engine speed. I'm not next to the car so I don't have a good reference. Point is, you have an idea what the alternator RPM's are compared wth original. Might be worth a question to one of the rebuilders, to see if the armature can stand twice the speed it sees now without significant winding shift, separation, or plain old centrifugal explosion. The alternator is a three-phase device, with each armature pole passing through three stator coils per revolution. So on each revolution, each armature winding pushes then relaxes, pushes then relaxes, pushes then relaxes. The armatures coils are wound on laminated forms. Eachs push/relax cycle causes the coils to move slightly, or at least stress in one direction then relax. Heat causes the copper windings to expand off of the forms, and heat also weakens the varnish that holds the coils intact on the forms. Now add more centrifugal force thanks to the speed doubling. How long will the coils remain intact? If they grow much they start to risk comtact with the stator coils, and that's instant and violent destruction.
So you perhaps can appreciate my concern...
Do a few calcs and figure out ho wfast the alternator is turning vs engine speed. I'm not next to the car so I don't have a good reference. Point is, you have an idea what the alternator RPM's are compared wth original. Might be worth a question to one of the rebuilders, to see if the armature can stand twice the speed it sees now without significant winding shift, separation, or plain old centrifugal explosion. The alternator is a three-phase device, with each armature pole passing through three stator coils per revolution. So on each revolution, each armature winding pushes then relaxes, pushes then relaxes, pushes then relaxes. The armatures coils are wound on laminated forms. Eachs push/relax cycle causes the coils to move slightly, or at least stress in one direction then relax. Heat causes the copper windings to expand off of the forms, and heat also weakens the varnish that holds the coils intact on the forms. Now add more centrifugal force thanks to the speed doubling. How long will the coils remain intact? If they grow much they start to risk comtact with the stator coils, and that's instant and violent destruction.
So you perhaps can appreciate my concern...
06-30-2008, 11:22 PM
#156
Race Car
Join Date: Sep 2007
Location: No where Oklahoma AKA "The Dust Bowl" In The Arm pit Of Hell
Posts: 3,663
Likes: 0
Received 0 Likes
on
0 Posts
Jason--
Do a few calcs and figure out ho wfast the alternator is turning vs engine speed. I'm not next to the car so I don't have a good reference. Point is, you have an idea what the alternator RPM's are compared wth original. Might be worth a question to one of the rebuilders, to see if the armature can stand twice the speed it sees now without significant winding shift, separation, or plain old centrifugal explosion. The alternator is a three-phase device, with each armature pole passing through three stator coils per revolution. So on each revolution, each armature winding pushes then relaxes, pushes then relaxes, pushes then relaxes. The armatures coils are wound on laminated forms. Eachs push/relax cycle causes the coils to move slightly, or at least stress in one direction then relax. Heat causes the copper windings to expand off of the forms, and heat also weakens the varnish that holds the coils intact on the forms. Now add more centrifugal force thanks to the speed doubling. How long will the coils remain intact? If they grow much they start to risk comtact with the stator coils, and that's instant and violent destruction.
So you perhaps can appreciate my concern...
Do a few calcs and figure out ho wfast the alternator is turning vs engine speed. I'm not next to the car so I don't have a good reference. Point is, you have an idea what the alternator RPM's are compared wth original. Might be worth a question to one of the rebuilders, to see if the armature can stand twice the speed it sees now without significant winding shift, separation, or plain old centrifugal explosion. The alternator is a three-phase device, with each armature pole passing through three stator coils per revolution. So on each revolution, each armature winding pushes then relaxes, pushes then relaxes, pushes then relaxes. The armatures coils are wound on laminated forms. Eachs push/relax cycle causes the coils to move slightly, or at least stress in one direction then relax. Heat causes the copper windings to expand off of the forms, and heat also weakens the varnish that holds the coils intact on the forms. Now add more centrifugal force thanks to the speed doubling. How long will the coils remain intact? If they grow much they start to risk comtact with the stator coils, and that's instant and violent destruction.
So you perhaps can appreciate my concern...
06-30-2008, 11:35 PM
#157
Owns the Streets
Needs Camber
Lifetime Rennlist
Member
Needs Camber
Lifetime Rennlist
Member
Have you tried different voltage regulators?
I've got an American unit in mine.
It gave a bit more juice at idle than the Bosch regulator.
It held with all lights and AC on at idle.
Dropped below 12V when I torture tested it with rear defrost on top of the other loads at idle.
So driving in stop and go snowy traffic at night is out for me.
07-01-2008, 02:03 AM
#158
Rennlist Member
07-09-2008, 11:29 PM
#159
Rennlist Member
Thread Starter
It's not Friday and I don't care........
Just wanted to share some updates from this past weekend, and the only 928 content in it will be the fact I didn't get to drive the 928's at all. But had a great time in Marble Falls, which happens to be the same place we have our 3rd Coast even this year.
**Chuck will spill the details for this coming November event for us southern guys. We've set a date and the info will be coming soon.
Ang and the family got to hang out at her parents place on LBJ lake and had a great time. Some pics to follow. It was greatly relaxing and helped gear me up for the 2 weeks that Roger is in England running 928'srus from there.
Hi Rog, how ya doing? I think Laura and I have things well in hand at the Tyson Ranch so far.
This week for me is completing a head gasket job on an '86 at the shop and then Friday figuring out why I've had "Belt Tension" warnings on my '88. In the last couple of months I'd get a warning if the engine was cold and I got on it. It's happened 2x in the last 6 months and didn't give it much of a thought (after a cursory check) but when I was hopping on it yesterday, after driving 30 minutes, it happened at high RPM and it scared the **** out of me. SOOO I'm going to do a tension check. Wish me luck.
Hope all is well with everyone and hope they had a great past weekend.
Here's some shots of this weekend.
Just wanted to share some updates from this past weekend, and the only 928 content in it will be the fact I didn't get to drive the 928's at all. But had a great time in Marble Falls, which happens to be the same place we have our 3rd Coast even this year.
**Chuck will spill the details for this coming November event for us southern guys. We've set a date and the info will be coming soon.
Ang and the family got to hang out at her parents place on LBJ lake and had a great time. Some pics to follow. It was greatly relaxing and helped gear me up for the 2 weeks that Roger is in England running 928'srus from there.
Hi Rog, how ya doing? I think Laura and I have things well in hand at the Tyson Ranch so far.
This week for me is completing a head gasket job on an '86 at the shop and then Friday figuring out why I've had "Belt Tension" warnings on my '88. In the last couple of months I'd get a warning if the engine was cold and I got on it. It's happened 2x in the last 6 months and didn't give it much of a thought (after a cursory check) but when I was hopping on it yesterday, after driving 30 minutes, it happened at high RPM and it scared the **** out of me. SOOO I'm going to do a tension check. Wish me luck.
Hope all is well with everyone and hope they had a great past weekend.
Here's some shots of this weekend.
07-09-2008, 11:40 PM
#160
Nordschleife Master
Nice place there guys! I have done a little slalom skiing on that lake with my late Grandfather-in-law. He had a place in Granite Shoals...good times... That was YEARS before I broke my back!
07-11-2008, 08:34 PM
#165
Rennlist Member
Thread Starter
