Heater ”backdate” – the $ 15 alternative

[Ove]

This is a way to get rid of the heavy engine compartment blower without having to buy new block off plates.

First, - here’s a picture of the stock air system on a car similar to mine:



I had deleted the engine compartment blower and all the ducting in the engine compartment.
The blower and it’s attachment bracket were removed for weight reasons, the ducting for the looks.

I used an empty tuna can to block off the air on the left hand side. On the right side I have a fiber glass block off plate that I made when I made the fiber glass fan shroud. This weighed less than the stock set up and looked clean, but – obviously - no heat.



Getting the heat I need for winter driving (defrost) basically requires two new “block off” plates with air outlets. Not very expensive, but not exactly cheap either. Since I had the stock air outlet on the left side I figured I could replace the tuna can with something more useful.



This Y shaped piece was found in my local boat supply store for less than $ 15. The inlet is 75mm while the two outlets are 60mm.



75mm makes it a perfect fit inside the stock outlet. All that is needed to hold it in place is a hose clamp.



60mm is the size of the hoses from the stock blower. I purchased new ones, but the stock ducting can be cut to the right length and reused (actually one of my new hoses is 65mm, but that was no problem).



Later I will make an outlet in the right side block off plate to do a proper heater backdate. Now it’s too cold to do any fiber glass work in my unheated garage.



I know it doesn’t look very clean as I still have a hose running on top of the engine fan, but it is a cheap and easy way to loose the heavy stock blower while still getting heat. The air inlet is a bit restricted 60mm vs stock 75mm, but I don’t think that will make much difference.




I am going to add a pair of footwell blowers to help air getting through the system. The blowers may be removed after the winter for weight reasons. The next project is to delete the front ventilation air box and run hoses directly from the footwell blowers to the defrost outlets. I’m also thinking of splitting up the air at the front to get some hot air down at my feet (using vents that can be closed to get max defrost).

[Oh Haha]

I did something similar to mine. I think the bits cost me about 10$ at Lowe's. I had already purchased new hoses so I guess really it costs a bit more than that.

[Ove]

Wayne,

Yes, that's just like I did

[ninesixfour]

Originally Posted by Oh Haha

I did something similar to mine. I think the bits cost me about 10$ at Lowe's. I had already purchased new hoses so I guess really it costs a bit more than

Now if I can just find that piece at Lowe's. Home Depot did not have anything like that in the plumbing section.

[rothaus]

Originally Posted by ninesixfour

Now if I can just find that piece at Lowe's. Home Depot did not have anything like that in the plumbing section.

It looks like a ABS 2 1/2" T and one of the rubber pipe connectors. Right ?

This should work for my '78, because when I got the car, that complete system was and still is missing.

Thanks for sharing !

Happy New Year !

[Porsche-O-Phile]

Nice write-up - thanks for that guys.

[ninesixfour]

Originally Posted by rothaus

It looks like a ABS 2 1/2" T and one of the rubber pipe connectors. Right ?

This should work for my '78, because when I got the car, that complete system was and still is missing.

Thanks for sharing !

Happy New Year !

So that piece is 2 1/2 on all three ends but has that rubber piece added to seal up the larger side?

[ianc]

So with all due respect, how does this work or look better than original?

ianc

[Deschodt]

Originally Posted by ianc

So with all due respect, how does this work or look better than original?

ianc

You crack me up Ian, but you're not wrong... I think if you're gonna bother, you might as well leave the tuna can to the cat and the home depot stuff for you plumber, and spring the $150 or so for 2 used block off pieces...



I know, my engine is hardly "clean" but that's even less hoses now ! That blue "tuna can" is now gone and replaced with a proper backdate plate.. I'll try to dig up a picture !

Edit:

Just taken in the parking lot with an iphone - some coworkers must think I'm strange - a lot cleaner than the tuna can... A/C and cruise module also gone !



Then I extended the backdate to the entire car ;-)

[Ove]

Originally Posted by ianc

So with all due respect, how does this work or look better than original?

ianc

It does not.

It's all about function and weight. It's much lighter (than my stock heater system), but not better.

Here's the front part of my vent system for those interested:

Vent System and Heater - Deleting What I Don't Need, Keeping the Defrost

Home made lightweight vent.air intake

It works in these conditions

[ianc]

It's all about function and weight. It's much lighter (than my stock heater system), but not better.

I would even go so far as to say 'not as good'. Without the engine room fan blowing air through the heater boxes at low RPM, you can't defrost sufficiently in traffic. Sure it's lighter without the fan, but when\if you add the footwell blowers, you're right back where you started, except you had to do a bunch of work and spend some $$$...

I admit those hoses are kinda ugly in SC's, but they don't really get in the way of normal maintenance like adjusting valves, changing spark plugs, etc.

On Carreras it makes even less sense, since those hoses don't run through the engine compartment any more and it takes all of 1 min to remove the plastic accordion hose leading from the fan.

Ove, I like your work up front, but am restricting my comments to the engine room.

Form follows function...

ianc

[Mothy]

Ove

How much weight was saved in the engine compartment? I'm thinking of doing the same thing and have been keeping track of all the weight saving projects I have done so far - it all adds up.

Tim

[rothaus]

Originally Posted by Deschodt

You crack me up Ian, but you're not wrong... I think if you're gonna bother, you might as well leave the tuna can to the cat and the home depot stuff for you plumber, and spring the $150 or so for 2 used block off pieces...

This is what I need, since I don't have all the parts including blower. Are these poarts from an early 911 like '71 or so?

It looks really nice, the car also. Are those 6 and 7 x 15 wheels?

Thanks
Engelbert

[Deschodt]

Originally Posted by rothaus

This is what I need, since I don't have all the parts including blower. Are these poarts from an early 911 like '71 or so?

It looks really nice, the car also. Are those 6 and 7 x 15 wheels?

Thanks
Engelbert

Yes, the parts are from early cars. The only clearance issue is on the left side, where the distributor goes, as the SC distributor is way bigger than a classic car's. So a little shaping with a hammer followed by touch up paint, and voila ! No tuna smell in the car, no flushing noise from plumbing PVC ;-) I kid, people, I did the tuna can thing too at first ! Sorta... Salvage yards such as EASY or parts heaven can probably set you up, though you'll do better at swap meets.

No, those are 7 and 8 x *16* superlites (minilite knockoffs). I'd recommend 15s, they are probably easier to fit in the limited space of the front fender. Same weight as similarly sized fuchs, but muuuuuch cheaper.

Ian doesn't like'em, so I figured between the wheels and tuna can discussions, he'd have a ball ;-)

[ianc]

Ian doesn't like'em, so I figured between the wheels and tuna can discussions, he'd have a ball ;-)

It's a curmudgeon's wet dream!

ianc

[Ove]

Originally Posted by ianc

I would even go so far as to say 'not as good'. Without the engine room fan blowing air through the heater boxes at low RPM, you can't defrost sufficiently in traffic. Sure it's lighter without the fan, but when\if you add the footwell blowers, you're right back where you started, except you had to do a bunch of work and spend some $$$...

I admit those hoses are kinda ugly in SC's, but they don't really get in the way of normal maintenance like adjusting valves, changing spark plugs, etc.

On Carreras it makes even less sense, since those hoses don't run through the engine compartment any more and it takes all of 1 min to remove the plastic accordion hose leading from the fan.

Ove, I like your work up front, but am restricting my comments to the engine room.

Form follows function...

ianc

Ian,

Please read my first post again. This is a cheap way to "backdate" the heating system. Not claimed to be more than just that. You get heat, but you are left with one hose running on top of the engine fan. This is the early style vent system (the early cars did not have an engine compartment blower), but without the clean look. You get what you pay for. You loose many of the SC hoses, but not all. Spend another $ 100 and do a "proper" backdate if looks are important.

The vent system will be less efficient after removing the blower. That's obvious. Pointing it out here is kind of finding a thread about sound deadening removal and saying that road noise will increase...

The defrost on my car works in the winter, although it takes a while to heat things up. No engine compartment blower and no front fan. I only have the engine fan to push the warm air through the system. When driving it's like having a ventilation fan in position one all the time. I will install a footwell blower later (one will probably be enough).

Tim,
I'm sorry, I don't know the weight of the engine compartment blower or the other parts. If I find the blower in my garage I will post the weight here. There is also a metal bracket holding the blower that adds some weight.

[Ole Petter]

The weight of the fan and hoses is some 1,5 kg or 3,3 ibs. I think the fan was a little more than 1 kg.
I have removed everything and run headers on my car. No heat at all. And a simplified fresh-air blower in the front compartement.

Then my car is a nice weather/sunny-season car, a 10/74 S. Very lightweight and with a tuned 2.7 engine. Great

I did buy a small ceramic heater for the event of a cold night or early morning drive in spring/autumn. I must say the little heater impresses with its output - and its weight is under 0,3 kg.

[rothaus]

Originally Posted by Ole Petter

The weight of the fan and hoses is some 1,5 kg or 3,3 ibs. I think the fan was a little more than 1 kg.
I have removed everything and run headers on my car. No heat at all. And a simplified fresh-air blower in the front compartement.

Then my car is a nice weather/sunny-season car, a 10/74 S. Very lightweight and with a tuned 2.7 engine. Great

I did buy a small ceramic heater for the event of a cold night or early morning drive in spring/autumn. I must say the little heater impresses with its output - and its weight is under 0,3 kg.

Can you post more info about the ceramic heater ?

Thanks

[Rot 911]

Greg, that is a beautiful car. Is the color Platinum Metallic?

[Deschodt]

Yup, platinum, but sorry, didn't mean to hijack the thread... just meant it as a joke, I started backdating the heater and look where it got me !!

If you want to see more of that car, you can go there:

Ready for my 911SC project - long