Dumping the footwell blowers?

ianc · 12-22-2005, 09:18 PM

Hi folks,

My engine room blower fan packed up (of course).

I did the 'Wavey' mod by replacing the factory fan with the Grainger fan. Works great. However, the footwell blowers that were still working with my (barely alive) factory fan quit working since I installed Grainger.

This does not disturb me greatly since the heat with just the engine room fan is enough to cook me, not to mention the fact that the footwell blowers were ridiculously loud in the cabin. No screeches, etc., but just a lot of fan and air noise.

Still, I'm left with the choice of either getting the footwell blowers to work, or *****canning them. Since they seem (by all accounts) to be pieces of crap, I'd rather save some weight and just ditch them.

I've just spent about 2 hours reading over old threads, but every one I can find has to do with how to get them to work after you do a heat backdate, which is not what I'm interested in. I want the opposite: heat a la SC.

What is involved in terms of ditching them? I noticed from a pic someone posted (should have saved it but didn't) that the inlet to these motors is a single pipe, but the outlet is a 'Y' connection. I'm assuming one section leads to the defroster vents, and the other to the footwell area.

Has anyone ditched these blowers? If so, what did you use to connect the single input to the dual output?

Thanks for any help,

ianc

Hugh R · 12-22-2005, 09:24 PM

Not sure, but if you ditch them I don't think you'll have defrost. Kind of dangerous if you ask me.

ianc · 12-22-2005, 09:34 PM

No, the defrost will work just as it does in the SC, provided I can find a means of splitting the single in to the dual out - footwell and defroster.

Believe me, with the amount of rain we get here, I could never do without defrost.

ianc

Gordo2 · Gordo2's Garage

My '83SC is a daily driver. I have removed all of the electric blowers associated with the heat, vent and A/C (my A/C is removed)

-I backdated the heating system with the removal of the blower that was in the engine bay. A huge improvement to engine access and looks. My heater has been sufficient to get me through some cold Northern VA winters. Slow to defrost anything more than a thin layer of frost but warm enough to ride comfortably in 30 deg temps.

-I also got rid of the electric blower motor that works with the fresh air/vent system (fan assembly in the trunk). I don't get as much fresh air flowing with the vent open/on however, my car is a Targa... I have all the fresh air I want.

-Defog works fine using the heater. I now live in Eastern NC where we get our share of spring rain. The defog works without the fans. Could be better, but I could have said the same thing when the fans were installed and working.

Good luck, Gordo

OffCamber00 · OffCamber00's Garage

To you remove the footwell blowers, you will need to replace the hose that goes from the blower itself to the hot air diverter in the front trunk. The footwell blower is directly connected to the heater outlet in the door sill so the hose that goes from the blower to the trunk is not long enough. All you neeed to do is get a longer section of hose that will connect to the door sill up into the front trunk to the diverter. Its very obvious when you look at it. With this setup, you will lose the heat that comes out of the side air vents but you will retain the heat to the footwells and the front defrost vents. This was not a problem for me.

I had some left over hose from when I backdated my engine heat and used that. It was the Aircraft Spruce hose that is popular on this board.

PM me with any questions as I am in the middle of this project right now.

Mysterytrain · 12-23-2005, 06:26 AM

What Matt said!..The typical SC setup was the rear blower and a hose in the footwells going up into the trunk area on each side. Since you have an 87 you have the addition wye connections on the footwell blowers that allow heated air to flow to the side dash vents. I'm guessing in sunny california its not an issue and you don't need the heated air hitting the side windows..here in NJ it was a major upgrade. So basically just run a long hose from the sill opening in the footwells up into the trunk. If you find you want to keep the plumbing intact I'm sure you could fabricate a splitter. Just keep in mind that the heated air is frickin' hot, over 250 degrees F when I measured it. On my car, I was never happy with the volume of air being pushed from the rear blower and I have found that using the footwell blowers with a deleted rear blower the ticket. I did some testing of the blower speeds before I installed them and found that running the blowers wide open generated too much noise. In the end I fabricated my own resistor circuit to slow the blowers down.

k9handler · 12-23-2005, 08:06 AM

I want some footwelll blowers...are they pretty simple to install?

KCPSG · KCPSG's Garage

Why not just leave the footwell blowers in place and disconnect them to only allow the rear blower to run....if noise is all that your worried about?
otherwise I can't imagine it would be too hard to find what you need to go from the bottom of where the footwell blower connects to the splitter, @ your local Home Depot or Lowes

Mysterytrain · 12-23-2005, 08:18 AM

they will melt if you leave them in place which can be an issue. They will also block the airflow. Actually now that you mentioned it what you could do is remove the squirel cage from the blowers and disconnect the motors. Then you could still leave the duct work in place.

KCPSG · KCPSG's Garage

I can't see how they would melt since they were deseigned for heating the car, however they may block a little of the air flow. I had left my footwell blowers that were not working in there for over a year and just let my rear (engine) blower do the work...that heated the car very nicely and took care of my defrost issues as well.
This year I decided to get some new footwell blowers and use them as well, mine don't make any noise except when on the highest setting.

ianc · 12-23-2005, 09:01 AM

Yes, I think leaving them in place dead would be a problem. With the factory setup, they are never completely off.

Mysterytrain, you have a good suggestion with just taking the squirrel cages off, but I was thinking of selling them after (got one PM already just from this post and haven't listed them yet), and I'm sure whoever they went to would need the ductwork. Can you provide more details of your resistor setup to slow the blowers down and produce less noise?

I hadn't really noticed that my side windows have any defrost. Did all 87's have that? I'll have to investigate that a little more thoroughly. That would be a nice feature with all the rain we've had here recently.

I may just go to OSH or something and see what they've got; just wondered if anyone had any bright ideas. Thanks for the responses,

ianc

JohnJL · 12-30-2005, 11:11 PM

Hi HD.
I have a complete heating system for sale, including footwell blowers, all nutsnbolts, brackets, clamps, hoses, electrical connectors, and pics of the dis-assembly.

Also have same for the entire AC system...

EDITED FOR MORE COWBELL

Mysterytrain · 12-31-2005, 06:43 AM

Phil...Maybe melting was too harsh a word. The housings won't turn into a blob of plastic but the squirrel cage is known to fuse itself to the housing. I think the factory's work around for this was to have the motor spinning at a slow speed even when the speed swtich was in the off position and to prevent an electrical fire they also added inline fuses. I once measured the heated air temperature at the dash and was amazed to find it over 250 degrees!
My heating system works better then ever with the footwells and minus the rear blower. I can really push hot air up thru the defrost vents and thru the side vents. You might not need heat in San Rafael but you might be sorry not to be able to defrost/defog.

rob justice · rob justice's Garage

Quote:

Originally posted by Mysterytrain
Phil...Maybe melting was too harsh a word. The housings won't turn into a blob of plastic but the squirrel cage is known to fuse itself to the housing.

After stripping down one of the blowers - this is exactly what went - causing the car to fill with smoke and the blind panic that goes with it.
Not the best of designs from what I can tell.

Wil Ferch · 12-31-2005, 05:57 PM

Just asking....are you sure the fans keep running at slow speed when "off" ... ?

????

- wil

efhughes3 · efhughes3's Garage

Shoot, I'm trying to figure out how to get mine to work after removal of the engine compartment blower. The one thread I found talked about a resistor across the now useless plug that went to the vanshed blower. Didn't work for me. IT seems I really need the footwell units to get any decent heat with the top off on cold days.

ianc · 01-01-2006, 01:58 PM

Quote:

Just asking....are you sure the fans keep running at slow speed when "off" ... ?

Wil, from what I can understand, the early Carreras didn't do this, but then they changed later to also run slowly at '0'. Not sure if this is correct (although I've read quite a few people saying this is so), or what year this change was made.

ianc

ianc · 01-01-2006, 02:00 PM

Quote:

I'm trying to figure out how to get mine to work after removal of the engine compartment blower.

Ed, don't know if this will work or not (just a theory), but try applying voltage to pin 4 of the controller in the engine compartment. I think that is how the controller knows the main fan is running. If it works, you could wire something to a switch.

ianc

efhughes3 · efhughes3's Garage

Quote:

Originally posted by ianc
Ed, don't know if this will work or not (just a theory), but try applying voltage to pin 4 of the controller in the engine compartment. I think that is how the controller knows the main fan is running. If it works, you could wire something to a switch.

ianc

Thanks, back in the small fuse box for the blower?

dfink · 01-01-2006, 03:54 PM

Just spent a couple of hours trying to figure out that rear controller. I have an old one where the rear blower still works but the foot wells don't. I don't see why this can't be simplified dramatically. I am not an electrical engineer but in in essence it appeats the controller is just two relays. One to run the rear blower and one to run the front blowers. In my case relay 1 is working but relay 2 doen't not engage. If I manually engage relay 2 the footwell blowers will function. For some reason however Porsche has decided to complicate things with a control circuit "logic circuit" of some sort. Maybe the same controller is used for the auto heat. There appears to be a heat circuit breaker of some sort and a potentiometer that controls who know what. Anyhow it look like for us manual heat people a simple two relay replacement could be made to make all these little and expensive problems go away. Some of the diagrams show one of the pins going to the speedometer for some reason. Unplugged my controller and the speed-o still works.