Notices
928 Forum
Sponsored by:
Sponsored by: 928 Specialists

Ultimate High Output Bosch Alternator fits 1985-1995

 
Old 12-12-2016, 09:42 PM
  #76  
the flyin' scotsman
Addict
Rennlist Member
 
the flyin' scotsman's Avatar
 
Join Date: Oct 2004
Location: Southern Alberta, Canada
Posts: 10,617
Default

Great to talk with Mary today......new power on its way
the flyin' scotsman is offline  
Old 12-12-2016, 11:41 PM
  #77  
Speedtoys
Addict
Rennlist Member
 
Speedtoys's Avatar
 
Join Date: Sep 2010
Location: Boulder Creek, CA
Posts: 9,892
Default

I fell asleep on the couch last night, with a 'working with your DVM and diagnosing voltage drops' video.

Was good to learn how to do it right.
Speedtoys is offline  
Old 12-13-2016, 12:57 PM
  #78  
Speedtoys
Addict
Rennlist Member
 
Speedtoys's Avatar
 
Join Date: Sep 2010
Location: Boulder Creek, CA
Posts: 9,892
Default

Silly question...

Is a voltage drop always the same across a bad connection, regardless of the voltage being fed to it and load behind it?

I want to say "yes".
Speedtoys is offline  
Old 12-13-2016, 01:59 PM
  #79  
ROG100
Addict
Rennlist Member


Rennlist
Site Sponsor

 
ROG100's Avatar
 
Join Date: Jan 2003
Location: Double Oak, TX
Posts: 15,663
Default

Hi Greg,
Does your alternator require a separate ground cable from the alternator to the body like other high output offerings?
Nice as always.
Roger
__________________


Does it have the "Do It Yourself" manual transmission, or the superior "Fully Equipped by Porsche" Automatic Transmission? George Layton March 2014

928 Owners are ".....a secret sect of quietly assured Porsche pragmatists who in near anonymity appreciate the prodigious, easy going prowess of the 928."
ROG100 is offline  
Old 12-13-2016, 03:26 PM
  #80  
Hacker-Pschorr
Super Moderator - Cracklin' Rosie
Lifetime Rennlist
Member
 
Hacker-Pschorr's Avatar
 
Join Date: Aug 2001
Location: Up Nort
Posts: 10,062,700
Default

Originally Posted by ROG100 View Post
Hi Greg,
Does your alternator require a separate ground cable from the alternator to the body like other high output offerings?
Nice as always.
Roger
I thought that additional ground was just to allow a direct grounding port from the alternator to the chassis, not actually required since alternators ground themselves through the block via the installation brackets.
Hacker-Pschorr is offline  
Old 12-13-2016, 03:27 PM
  #81  
SeanR
Running up the Odo'
Rennlist Member
 
SeanR's Avatar
 
Join Date: Apr 2006
Location: DFW Texas
Posts: 34,490
Default

Originally Posted by Hacker-Pschorr View Post
I thought that additional ground was just to allow a direct grounding port from the alternator to the chassis, not actually required since alternators ground themselves through the block via the installation brackets.
Yea, I was sorta chuckling about the idea of a separate ground strap. Very odd set up.
SeanR is offline  
Old 12-13-2016, 03:42 PM
  #82  
GregBBRD

Rennlist
Basic Site Sponsor

Thread Starter
 
GregBBRD's Avatar
 
Join Date: Feb 2005
Location: Anaheim
Posts: 9,695
Default

Originally Posted by ROG100 View Post
Hi Greg,
Does your alternator require a separate ground cable from the alternator to the body like other high output offerings?
Nice as always.
Roger
Truthfully, I don't see any need for that.....just seems like unnecessary stuff. Perhaps it is needed because of the funky adapter brackets that are required on that other offering, which look like they are powder coated black (which is not conductive.) I have no idea.

The bare aluminum body of my alternator bolts solidly to the huge aluminum bracket for the power steering with 10mm bolts, making contact with that bracket in three separate places. (Just like the stock alternator.) That bracket bolts directly to the engine block with two 8mm bolts and one 10mm bolt. Again, with three separate points of contact. (Completely stock.) No cheesy adapters required....this alternator bolts directly to all the original mounting pieces with all the original hardware.(*)

If anyone needs more grounding than that, they have worse problems than needing a high output alternator, right?

Also, there is no separate "lug" on the Bosch alternator for grounding....so they obviously feel it is not necessary, either.

(*) I do include a shorter bolt for the upper pivot. The rear threaded portion of my alternator has a more modern captive nut. This allows the use of a 110mm long bolt, instead of the stock 130mm bolt. While the stock 130 bolt works perfectly, getting a 20mm shorter bolt past the fan housing is a real blessing. (Anyone that has pulled that bolt out and has had to reinstall it knows what I'm talking about.)
__________________
greg brown




714 879 9072
[email protected]

If the kids keep breaking a crowbar in the sandbox, sometimes it is easier to just give them a stronger crowbar, instead of trying to figure out what they are doing in the sandbox.
GregBBRD is offline  
Old 12-13-2016, 04:33 PM
  #83  
John Speake
Addict
Rennlist Member
 
John Speake's Avatar
 
Join Date: Feb 2002
Location: Cambridge England
Posts: 6,879
Default

Another side result of circuit resistance is the heat create by the power loss.

For example if a piece of wire with a resistance of 0.01 ohms will drop 0.25v at a 40A load current, then it gets 10watts of heat dissipated in it.
John Speake is offline  
Old 12-13-2016, 04:34 PM
  #84  
Taguid
Addict
Rennlist Member
 
Taguid's Avatar
 
Join Date: Feb 2016
Location: Gonzales, LA
Posts: 336
Default

Greg,
Put me down for one and I guess I'll need a supplementary wire on my original harness that is on my 91 S4.
Thanks
Taguid is offline  
Old 12-13-2016, 05:57 PM
  #85  
dr bob
Chronic Tool Dropper
Lifetime Rennlist
Member
 
dr bob's Avatar
 
Join Date: Oct 2001
Location: Bend, Oregon
Posts: 17,729
Default

Careful with what you discredit. The accessory ground wire on Carl's alternator is a Good Thing. Every load except the starter, temp sensors, injectors, plus a couple other small things, grounds through the chassis rather than the engine. Any resistance between alternator/engine block and the chassis risks havoc with injectors, temp sensors and the like. A direct ground from alternator to chassis removes alternator electrical noise from those systems.

Look at how later cars have a separate ground braid from coil brackets to the engine at the heads. One might presume that the heads are very securely grounded through the block. But -any- corrosion on the head bolts and mounting surfaces offers chance to leave some ignition voltage in the heads. Can you say "galvanic corrosion" three times fast?

So a direct ground from alternator to the chassis adds protection from injection and sensor errors, avoids possible galvanic corrosion issues across the mostly aluminum ground path to the other side of the block, and also electrical noise issues that might show up in audio components. What's not to like?

Further, the original ground point positioning under the coolant reservoir overflow is less than ideal. I get that the other side is clogged with steering gear and all on LHD cars. Still, from a functionality point of view, having individual connections from starter to frame, alternator to frame, and coils to heads makes much better electrical sense than what they came up with. It was good enough while the copper braid was new, and relatively easy to assemble on the car.

---

If you haven't done so already, REPLACE the copper ground braid between chassis and engine block under the right side of the engine (on LHD cars anyway). It will do charging and engine sensors nothing but good. This piece is one of only several very reasonably priced pieces left on the car. Grab an extra for later, when copper prices approach gold standards.
dr bob is offline  
Old 12-13-2016, 06:52 PM
  #86  
GregBBRD

Rennlist
Basic Site Sponsor

Thread Starter
 
GregBBRD's Avatar
 
Join Date: Feb 2005
Location: Anaheim
Posts: 9,695
Default

Bob:

If you read my original post, you will see that I put emphasis on making sure all the grounds are in perfect condition. I also offer a complete ground kit and an additional power wire between the alternator and the starter, if there is any doubt.

BTW....the starter does ground through the engine and then into the chassis. Goes through the stock ground strap.

Realistically, if the engine ground wire is good enough for the starter to turn the engine over (250 amps minimum load), an alternator that puts out 150 amps (maximum) isn't going to have any issue getting the power back to the battery....through the exact same ground strap.

That being said, when changing the alternator, it is a great time to review and refresh (if needed) any ground connections/cables. I've already emphasized this.

The large majority of my clients are trying to keep these cars as original as possible....or as close to original looking as possible. Hanging an alternator with cobbled up mounts which needs an extra ground cable run which is secured into the chassis by drilling a hole and adding a screw isn't going to fly, with almost all of these people.

Like I've also hinted at, these Bosch people have a pretty good handle on what is needed for electrical pieces.....and I'm using the same alternator to engine block attachments that they do, in the original application of this alternator. And....the engine grounding strap and chassis to battery ground are actually smaller, in the original application.

I didn't have to re-invent the wheel. My alternator mounts from the same locations, ends up with bigger ground straps, has the same size power wire (as in my looms), spins at a lower rpm, now operates in a lower heat environment, virtually jumps into the car with all the original hardware, weighs less, and looks so similar to the original that no concours judge is ever going to know it is there.

It just produces more amperage, which almost all 928s, with just the addition of a modern stereo with an amp and a subwoofer need.

In summary:

No "extra" ground wire hanging under the alternator, randomly drilled into the chassis and secured with a screw required in my application.

Just make sure what is there is good.



Originally Posted by dr bob View Post
Careful with what you discredit. The accessory ground wire on Carl's alternator is a Good Thing. Every load except the starter, temp sensors, injectors, plus a couple other small things, grounds through the chassis rather than the engine. Any resistance between alternator/engine block and the chassis risks havoc with injectors, temp sensors and the like. A direct ground from alternator to chassis removes alternator electrical noise from those systems.

Look at how later cars have a separate ground braid from coil brackets to the engine at the heads. One might presume that the heads are very securely grounded through the block. But -any- corrosion on the head bolts and mounting surfaces offers chance to leave some ignition voltage in the heads. Can you say "galvanic corrosion" three times fast?

So a direct ground from alternator to the chassis adds protection from injection and sensor errors, avoids possible galvanic corrosion issues across the mostly aluminum ground path to the other side of the block, and also electrical noise issues that might show up in audio components. What's not to like?

Further, the original ground point positioning under the coolant reservoir overflow is less than ideal. I get that the other side is clogged with steering gear and all on LHD cars. Still, from a functionality point of view, having individual connections from starter to frame, alternator to frame, and coils to heads makes much better electrical sense than what they came up with. It was good enough while the copper braid was new, and relatively easy to assemble on the car.

---

If you haven't done so already, REPLACE the copper ground braid between chassis and engine block under the right side of the engine (on LHD cars anyway). It will do charging and engine sensors nothing but good. This piece is one of only several very reasonably priced pieces left on the car. Grab an extra for later, when copper prices approach gold standards.
__________________
greg brown




714 879 9072
[email protected]

If the kids keep breaking a crowbar in the sandbox, sometimes it is easier to just give them a stronger crowbar, instead of trying to figure out what they are doing in the sandbox.
GregBBRD is offline  
Old 12-13-2016, 07:07 PM
  #87  
GregBBRD

Rennlist
Basic Site Sponsor

Thread Starter
 
GregBBRD's Avatar
 
Join Date: Feb 2005
Location: Anaheim
Posts: 9,695
Default

Originally Posted by Taguid View Post
Greg,
Put me down for one and I guess I'll need a supplementary wire on my original harness that is on my 91 S4.
Thanks
Thank you for your order. While I appreciate it, Mary really appreciates it....she had to write the check for this crazy project!

How are your engine and battery grounds? I'm asking every single person who is buying one of my alternators this question.

I made a complete "kit", with the original engine block to chassis ground strap, a significantly better battery ground strap, and the supplemental wire that goes from the alternator to the chassis for an additional $75, when purchased with the alternator upgrade.

Please call Mary at 714 879 9072, so she get this order going. Don't forget to tell her your tee shirt size, so we can send you a complementary shirt.
__________________
greg brown




714 879 9072
[email protected]

If the kids keep breaking a crowbar in the sandbox, sometimes it is easier to just give them a stronger crowbar, instead of trying to figure out what they are doing in the sandbox.
GregBBRD is offline  
Old 12-13-2016, 08:14 PM
  #88  
supercedar
Addict
Rennlist Member
 
supercedar's Avatar
 
Join Date: Jul 2010
Location: Mukilteo, Wa.
Posts: 939
Default

XXL
supercedar is offline  
Old 12-13-2016, 08:16 PM
  #89  
MainePorsche
Addict
Rennlist Member
 
MainePorsche's Avatar
 
Join Date: Jul 2011
Location: North Country
Posts: 5,660
Default

XL
MainePorsche is offline  
Old 12-13-2016, 08:36 PM
  #90  
Speedtoys
Addict
Rennlist Member
 
Speedtoys's Avatar
 
Join Date: Sep 2010
Location: Boulder Creek, CA
Posts: 9,892
Default

Originally Posted by GregBBRD View Post
Thank you for your order. While I appreciate it, Mary really appreciates it....she had to write the check for this crazy project!

How are your engine and battery grounds? I'm asking every single person who is buying one of my alternators this question.

I made a complete "kit", with the original engine block to chassis ground strap, a significantly better battery ground strap, and the supplemental wire that goes from the alternator to the chassis for an additional $75, when purchased with the alternator upgrade.

Please call Mary at 714 879 9072, so she get this order going. Don't forget to tell her your tee shirt size, so we can send you a complementary shirt.
Ill take that kit as well.

Any chance to visit and knock out some of our issues over holiday??
Speedtoys is offline  

Thread Tools
Search this Thread
Quick Reply: Ultimate High Output Bosch Alternator fits 1985-1995


Contact Us - About Us - Advertising - Cookie Policy - Privacy Statement - Terms of Service

© 2019 MH Sub I, LLC dba Internet Brands

We are a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for us to earn fees by linking to Amazon.com and affiliated sites.
 
  • Ask a Question
    Get answers from community experts
Question Title:
Description:
Your question will be posted in: