|
|
|
|
| Author |
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Tech Article: Running Footwell Blowers After Removing Engine Blower
A number of us with 3.2 Carreras have eliminated the engine blower for the heat, but want to keep using the footwell blowers. In stock configuration the footwell blowers need the resistance of the engine blower running to get the blower relay to turn the footwell blowers on. Some individuals have wired a switch in to run the footwell blowers, but I wanted them to operate as they do when the engine blower is in place. It has been suggested that a resistor could take the place of an engine blower. A couple of members of this board tried Radio Shack type resistors, but they burned up almost instantly. Then John Walker and Wavey suggested perhaps using a ceramic ballast resistor such as the type used on some older American cars to reduce voltage to the ignition points. Sounded worth a try so I got the parts and went to work. Went to the auto parts store and told them what I needed and they sold me a ceramic ballast resistor for $8.00. It came with a hole through it that I could use to install the resistor where the engine blower used to fit on the intake manifold. You will also need a 6mm bolt a couple of flat washers and a lock washer. Also a couple of wire connectors. Here is a picture of everything needed:
 The small brass screws and nuts came with the resistor. Here is another picture showing the resistor inside the ceramic housing. 
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. Last edited by Rot 911; 10-23-2004 at 05:22 PM.. |
||
10-23-2004, 04:52 PM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Ok, now locate the wire and plug that went to the engine blower:
 As you can see with the power running it draws around 12 volts"  Now cut off the plug and crimp on a couple of connectors:  now connect the wires using the brass screws and nut. Doesn't matter which wire goes to which side. I figured the resistor would get hot so I made sure the connector did not touch the ceramic housing: 
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-23-2004, 05:06 PM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Continued: Thought I would see if it worked before I bolted the resistor down to the manifold. Turned the heater knob all the way on and the blowers fired right up! My suspicions of the resistor getting hot was confirmed. It gets red hot as you can see in this picture. In addition the ceramic housing gets hot enough to burn your fingers! A bit of smoke came of the resistor when it first heated up, but quickly dissipated:
 Here is the final installation. I let the footwell blowers run for about 10 minutes without the engine running. I estimate the ceramic housing gets around 200-300 degrees. The aluminum manifold acts as somewhat of a heat sink, but doesn't even get warm. With the engine running the air being drawn into the engine compartment will also help to cool the resistor. As you can see there is nothing close to the resistor that can be damaged by the heat. The wires to the resistor got warm, but not overly hot. 
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-23-2004, 05:18 PM
|
|
|
Somewhere in the Midwest
Join Date: Oct 2001
Location: In the barn!
Posts: 12,499
|
Nice Kurt, but I thought I was the Gruppe B Director of Thermal Testing and Development
|
||
|
10-23-2004, 05:29 PM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Couple of more pictures showing the final installation:
 
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-23-2004, 05:32 PM
|
|
|
Registered
Join Date: May 2004
Location: washington,DC
Posts: 1,087
|
excellent work Kurt,much appreciated as l`m in the midst of backdating myself.l was planning to use a 3" inline fan to take the place of the engine mounted blower though.Placement of the unit is a work in progress and once l get all my turbo ancilliaries fitted l`ll have a better idea if l can even do it. l really don`t want to lose on HVAC operation and due to my A/C l`ll only be using the driver side air vent from the fan shroud.l think an inline fan should bring operation up to at least as well as stock.l still need the conversion part that goes off the shroud to allow the plumbing to connect to the heat exchangers.l may just give up and buy the factory part from a 930 if l have to..
__________________
my life begins at 150MPH |
||
|
10-23-2004, 05:34 PM
|
|
|
|
Registered
Join Date: Jan 2003
Location: IL
Posts: 1,638
|
Kurt... did you bail on the thought of getting this working by 're-wiring'? I seem to recall a thread recently where it was explained how to do this...
found it... Pulled engine heater blower, now footwell blowers won't work! -bernie
__________________
Database and Website Consulting Services in Chicago Last edited by einreb; 10-23-2004 at 07:02 PM.. |
||
|
10-23-2004, 06:54 PM
|
|
|
Registered
Join Date: Dec 1969
Location: Lac La Biche, Alberta, Canada
Posts: 951
|
Nice work Kurt, but one suggestion.
Does not the load of the blower fan simply key the blower relay which in turn supplies power to the footwell blower relay (pin 4?). Why not simply jump that line instead? Tim
__________________
1986 911 Cab 2008 Audi A6 |
||
|
10-23-2004, 07:18 PM
|
|
|
Registered
Join Date: Jan 2003
Location: Langley,B.C.
Posts: 12,002
|
Wow, that is great. I am sure glad I did not have to go through any of that when I backdated.
Jeff
__________________
Turn3 Autosport- Full Service and Race Prep www.turn3autosport.com 997 S 4.0, Cayman S 3.8, Cayenne Turbo, Macan Turbo, 69 911, Mini R53 JCW , RADICAL SR3 |
||
|
10-23-2004, 07:52 PM
|
|
|
Registered
|
Will my '77 have the same issue? I'm in the process of getting all the backdate parts for my 3.2. I'm not sure if I even have footwell blowers.
__________________
Rick '76 Carrera 3.0, track '77 3.2 targa, back home '95 993 C4 M030, SOLD PCA San Diego |
||
|
10-24-2004, 05:47 AM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Quote:
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-24-2004, 06:05 PM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Quote:
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-24-2004, 06:07 PM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Quote:
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-24-2004, 06:09 PM
|
|
|
Registered
Join Date: Jan 2003
Location: IL
Posts: 1,638
|
Quote:
 . I just need to pretty up my fiberglassed backdate part a bit.Nice write up! -Bernie
__________________
Database and Website Consulting Services in Chicago |
||
|
10-24-2004, 06:14 PM
|
|
|
Registered
Join Date: Oct 2002
Location: St. Louis region
Posts: 3,147
|
Wow, thanks Kurt, very nice work! I'll bet you got a lot of gold stars when you were in grade school. I'm inspired to try yet another pair of footwell blowers, or better yet find a more durable replacement, and get that blower out of the engine compartment.
__________________
Deceased: Black '88 Carrera Coupe, Steve Wong and Russell Berry chips, Dansk premuffler, custom MK GT3-style muffler, Magnecores. Al Reed 7 & 8 X 16 Fuchs. Full Elephant Racing suspension, 21/28 T-bars, Turbo tierods, bump steer kit, Bilstein Sports, BK strut bar. Ruf bumpers, 935 mirrors, Carrera 3.0 tail, DasSport bar. '11 BMW 328iX, '18 Nissan Frontier 4X4, '92 Acura NSX. |
||
|
10-25-2004, 11:40 AM
|
|
|
Senior Member
Join Date: Jun 2000
Location: N. Phoenix AZ USA
Posts: 28,943
|
Nice project!
Joe
__________________
2013 Jag XF, 2002 Dodge Ram 2500 Cummins (the workhorse), 1992 Jaguar XJ S-3 V-12 VDP (one of only 100 examples made), 1969 Jaguar XJ (been in the family since new), 1985 911 Targa backdated to 1973 RS specs with a 3.6 shoehorned in the back, 1959 Austin Healey Sprite (former SCCA H-Prod), 1995 BMW R1100RSL, 1971 & '72 BMW R75/5 "Toaster," Ural Tourist w/sidecar, 1949 Aeronca Sedan / QB |
||
|
10-25-2004, 11:50 AM
|
|
|
Registered
Join Date: Sep 2001
Location: Kerrville, Texas
Posts: 1,021
|
Thanks Kurt. Wiring has always been close to alchemy or some sort of black magic to me. Now I can focus on building the block off plate.
__________________
1987 911 Guards Red Targa, nearing 200,000 miles, lowered, 7's & 8's, 964 grind cams from John Dougherty, A.P.E. Mass Flow Sensor with chip to match, cat bypass, strut brace, dual out muffler. Will consider newer model in 8 years when I turn 75 and then maybe not. 2012 BMW 528i (wife's) 2007 Toyota FJ (rain and off road days) |
||
|
10-25-2004, 12:30 PM
|
|
|
Registered
|
That really makes the engine compartment look much cleaner.
I am very tempted to follow, and great write-up too. In terms of heating is it about the same? Defrosting or defogging concerns?
__________________
Tim. 1988 911 Carrera. Silver. 1973 914 Metalic Blue. 2012 Cayenne S |
||
|
10-25-2004, 01:51 PM
|
|
|
Friend of Warren
Join Date: Oct 2000
Location: Lincoln, NE
Posts: 16,494
|
Quote:
__________________
Kurt V No more Porsches, but a revolving number of motorcycles. |
||
|
10-26-2004, 05:06 AM
|
|
|
Registered
|
Thanks Kurt for the confirmation on the blowers, get write up and Pics!
__________________
Rick '76 Carrera 3.0, track '77 3.2 targa, back home '95 993 C4 M030, SOLD PCA San Diego |
||
|
10-26-2004, 05:44 AM
|
|
1977 Porsche 911S targa 3.2
Pumpkin
1988 Porsche 911 3.2
