Mr Paddle.Shift
08-25-2006, 03:23 AM
http://www.vsengineeringtrack.com/track_reports/LFA_Aug_2006/andy_me.jpg
It's been a while since I posted about my track reports. The 37th event at Buttonwillow seems like a perfect time to post.
So how did it go? Those who read my blog already knew what I went through. For those who didn't, let's just say that for the first time I joined the "BW-2-LA" Tow Club. But wait...the SC didn't blow up. It's still as reliable as day one. Sorry to disappoint some of you out there.
But something did die. My second alternator. This is the alternator I replaced alternator back in 2003. 30k miles later it died. But of course, alternators do fail after some time still I am not convinced that it died this early. Has my track driving got to do with it? Maybe to a certain extent but a little search on this forum and other forums reveals that those who didn't track their cars still have alternator failures.
Now what has this alternator got to do with a topic under Forced Induction. For those who didn't quite install your own SC kit, you will most likely didn't know that you have a Bosch or Valeo alternator with the air duct shaved off. The reason is to accomodate SC pipings. Here's a picture of the Bosch unit when new:
http://www.vsengineeringtrack.com/track_reports/LFA_Aug_2006/bosch_cooling.jpg
Bet you didn't know that BMW actually routed the air from the brake duct. I didn't know and I am extremely ashamed of that. And did you know that all BMW models with V8 engines come with water-cooled alternators? Really they do.
So just how important is alternator cooling? Well, Bosch and BMW engineers apparently think it's crucial, otherwise why bother installing one with a duct. If you do a google search, you will find a couple of good links. But nothing to quantify the relationship between the life of an alternator and cooling.
Bosch patent: http://www.wipo.int/pctdb/en/wo.jsp?KEY=98/21059.981015
On alternator heating and cooling: http://www.madelectrical.com/electricaltech/delcoremy.shtml
On testing the regulator on the alternator: http://www.amplepower.com/ps_reports/v2-2/index.html
After talking to some folks who had alternator failures, I decided to make something work. I found a clear path from the front of the bumper to the shaved off duct area and routed a neoprene 2" duct hose. I installed a temperature sensor and reprogrammed my MDACs (http://www.vsengineeringtrack.com/MDACs.htm) to perform the necessary datalogging. I can't wait for the next track event hence I decided to do a couple of short runs on the street and on the highway at night.
The test is simple: log the temperature with and without the cooling duct. Also the ambient temp and all other engine parameters (EGT, RPM etc) are all logged.
Assuming you trust my expertise as an engineer to run a simple test like this with both circumstances conducted under similar driving conditions, and you trust that all my sensors and equipment are calibrated, here's the finding:
http://www.vsengineeringtrack.com/track_reports/LFA_Aug_2006/alternator_cooling_test.jpg
The old saying still hold "Heat Kills". Two simple words yet so powerful. I won't attempt to analyze the data because it's that simple to read. For a more detailed report, visit my blog and click under the Aug 18 2006 event. Note that the alternator temperature data is NOT from a track event.
Now is there a direct relation between not cooling and causing the alternator to fail early? Yes I am sure there is but I don't think I can narrow down the range of the correlation coefficients. You see, failure of a part is an intricate process to analyze. The alternator can fail due to an overworked rectifier, a bad quality controlled solenoid, contaminated bearings from dust and power steering fluid etc. One thing leads to another.
But one thing I know for sure, I will have the cooling duct for the alternator from now on.
Thanks for reading.
Til then...drive safe.
It's been a while since I posted about my track reports. The 37th event at Buttonwillow seems like a perfect time to post.
So how did it go? Those who read my blog already knew what I went through. For those who didn't, let's just say that for the first time I joined the "BW-2-LA" Tow Club. But wait...the SC didn't blow up. It's still as reliable as day one. Sorry to disappoint some of you out there.
But something did die. My second alternator. This is the alternator I replaced alternator back in 2003. 30k miles later it died. But of course, alternators do fail after some time still I am not convinced that it died this early. Has my track driving got to do with it? Maybe to a certain extent but a little search on this forum and other forums reveals that those who didn't track their cars still have alternator failures.
Now what has this alternator got to do with a topic under Forced Induction. For those who didn't quite install your own SC kit, you will most likely didn't know that you have a Bosch or Valeo alternator with the air duct shaved off. The reason is to accomodate SC pipings. Here's a picture of the Bosch unit when new:
http://www.vsengineeringtrack.com/track_reports/LFA_Aug_2006/bosch_cooling.jpg
Bet you didn't know that BMW actually routed the air from the brake duct. I didn't know and I am extremely ashamed of that. And did you know that all BMW models with V8 engines come with water-cooled alternators? Really they do.
So just how important is alternator cooling? Well, Bosch and BMW engineers apparently think it's crucial, otherwise why bother installing one with a duct. If you do a google search, you will find a couple of good links. But nothing to quantify the relationship between the life of an alternator and cooling.
Bosch patent: http://www.wipo.int/pctdb/en/wo.jsp?KEY=98/21059.981015
On alternator heating and cooling: http://www.madelectrical.com/electricaltech/delcoremy.shtml
On testing the regulator on the alternator: http://www.amplepower.com/ps_reports/v2-2/index.html
After talking to some folks who had alternator failures, I decided to make something work. I found a clear path from the front of the bumper to the shaved off duct area and routed a neoprene 2" duct hose. I installed a temperature sensor and reprogrammed my MDACs (http://www.vsengineeringtrack.com/MDACs.htm) to perform the necessary datalogging. I can't wait for the next track event hence I decided to do a couple of short runs on the street and on the highway at night.
The test is simple: log the temperature with and without the cooling duct. Also the ambient temp and all other engine parameters (EGT, RPM etc) are all logged.
Assuming you trust my expertise as an engineer to run a simple test like this with both circumstances conducted under similar driving conditions, and you trust that all my sensors and equipment are calibrated, here's the finding:
http://www.vsengineeringtrack.com/track_reports/LFA_Aug_2006/alternator_cooling_test.jpg
The old saying still hold "Heat Kills". Two simple words yet so powerful. I won't attempt to analyze the data because it's that simple to read. For a more detailed report, visit my blog and click under the Aug 18 2006 event. Note that the alternator temperature data is NOT from a track event.
Now is there a direct relation between not cooling and causing the alternator to fail early? Yes I am sure there is but I don't think I can narrow down the range of the correlation coefficients. You see, failure of a part is an intricate process to analyze. The alternator can fail due to an overworked rectifier, a bad quality controlled solenoid, contaminated bearings from dust and power steering fluid etc. One thing leads to another.
But one thing I know for sure, I will have the cooling duct for the alternator from now on.
Thanks for reading.
Til then...drive safe.
