I'm getting my engine ready for install and since I won't have heat, headers and no tubes in longs, what should I shouldn't I leave or bock off on the engine? Do I remove the flaps on the fan cowl? Bolch the holes at the bottom of the fan cowl? Remove the controller that moves the flaps?
This is a 2056 with Carbs..

Thanks,

Brad

Just cap off the long tubes in the engine compartment. I used hose clamps and thick plastic like a tarp. I would not recommend removing anything in the front, unless it’s a race car, then you could also remove the ventilation assembly’s. For the street cold air does a good job of preventing the windshield from fogging up.

The plastic caps from spray paint cans also fit perfectly as caps for the longs. You can then strip out any heater components in the rear you like: flappers and associated pipes, rear heater blower, cables and lever if you want to tidy things up. If you remove the J-pipes that run through the engine tin, I would figure out an alternative way to block those holes to keep the cooling system working properly and prevent crap from getting into your engine compartment. If you pull the heater cables, I'd also plug the tubes that run through the firewall.

The only non-racing advantage I can think for messing with the front would be to remove the paper tubes behind the speaker housings to allow more speaker options. If you do that, you'll need to plug the inlets on the diverter boxes under the cowl. I'd probably plug the fronts of the longs too just for good measure. I agree that for a street car you want to keep the fresh air system (everything under the cowl) in working order.

Try not to confuse engine cooling with car heating ,the engine stays as is DON'T remove any of that,the operation of the air flaps via the thermostat are very important parts that need to work properly.
Yes by all means block the heater flaps closed,if you don't you loose 10% of your cooling fan air,these motors need all they can get.
I have a six with headers and have blocked off the heater tubes @ each end,hell I have even deleted my heater control,as Steve points out cool air will offer some form of defrost...works in my case.
Good luck .

Thanks @steve @bbrock and @porschetub

So to make sure I'm clear.....

Block this.

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Leave these alone.

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My thought was if I deleted all of that, the engine would actually run cooler and take longer to heat up. I live in Miami Fl so don't think I need to worry about warm up time. Is that not the case? Wouldn't the engine tin keep all of the circulation contained? These items seem to be blocking the airflow at times.

School me please.

If you remove the flaps, the engine will run hotter. When the flaps are open, they divert air through the oil cooler. When they are closed, the cooling air bypasses the cooler to allow the engine to warm faster. If you remove them, you also mostly bypass the oil cooler. If you delete just the thermostat but leave the flaps, it will operate like you describe (maximum cooling all the time but take longer to warm up). The only reason to do that is if you want your engine to wear out faster. So yes, leave all the engine cooling stuff alone. Good call @porschetub !

I'm actually not sure if blocking the outlets in the first pic is good or bad. The heater flapper boxes allow air to flow through those outlets regardless of whether they are open or closed. Not sure if that flow is important for cooling air flow or not. My hunch is that blocking would be better but I don't like to second guess the engineers.

The cooling flaps warm up the engine in a controlled manner it has little to do with the climate in your area,make sure it all works correctly,none of these parts removed will improve cooling.
Porsche never installed spare parts on motors that were not needed regardless of model.
Try to find the little alloy flaps and pivot pins to block off the heater ducts,on my last build I just installed some small alloy tabs to hold them closed.

BTW, I notice you are missing the linkage that pulls the flap over the oil cooler up. You'll want to make sure that is installed.

Thanks @porschetub

I think I got it now. I'll get the flaps installed. Appreciate all the info!

Thanks @bbrock

Yep didn't install the linkage for the photo op. I'll get it installed and follow what you and @porschetub said.

Really appreciate you guys thanks a lot!!!

Remove the flaps between the fan shroud and the heater pieces. Leave them open, as the system was designed to have them. I remember reading something Jake wrote about how blocking them actually causes the fan to loose efficiency.

I've read this here before, and I'd like to see that info from the horse's mouth because it truly doesn't compute. Seems like an oft-repeated Old Wive's Tale to me.

How would blocking off airflow/pressure loss cause the engine to run hotter? Doing so would actually increase the delta-P across the engine, resulting in more airflow, thus a cooler engine.

I blocked off those ports on my racer's engine. Makes absolutely no common sense to leave those open to pressure loss. I also seem to recall that there was one version of the Bus that didn't have those ports at all, due to having a gas heater.

As a related aside, Chris Foley completely removes the warm-up flapper system with his remote oil cooler kit (http://www.tangerineracing.com/remotecooler.htm). Seems to me the factory bellows/flapper design is more there for faster oil warm-up than for the engine cylinders or heads (those get warmed up fast enough by the combustion process).

http://www.volksbolts.com/faq/cooling.htm

I don't know much about fluid dynamics but I'm not sure cooling efficiency is determined solely by volume of air. IIRC, a laminar flow of air across a hot surface will transfer heat more efficiently than turbulent air. If that's correct, I could see where bleeding off a bit of air to reduce pressure flowing across heads might be a benefit.

I'm not arguing for or against blocking the outlets because I'm not qualified. I'm just suggesting there might be more to the equation than air volume. It does make me wonder why the heater flapper valves were designed to dump air through those outlets regardless of whether you were calling for heat inside the car. Seems like it would have been cheaper to design those flappers to just block air flow when heat was not needed in the cabin.

It would be interesting to see a comparison of head and oil temps with those outlets blocked vs. open. That would be more definitive than any theoretical benefits of one configuration or the other.

These work great also. Available in the plumbing supply section of your hardware store...


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I disagree with the premise of the fan graphic referened previously that states where the airflow is going and in what proportion. This is graphic is based on an over simplification.

"As Blown Air Is Delivered Circumferentially From A Centrifugal Fan We Can Simply Draw Lines From The Origin Of The Fan Circle To Cover The Outlet Zones Of The Blown Air Outlets. We Can Then Take Measurements And Use Some Trigonometry Calculations To Work Out The Percentages In The Below Graphic."

Air flow is like water, it prefers to take the past of least resistance but at the very same time requires a pressure delta to drive the airflow. You cannot simply say that because a particular outlet occupies 10% of the area that it will get 10% of the airflow.

Without knowing the exact fan curve for the Type4 cooling fan and what the relative delta pressure is between the fan housing and the respective outlets (Cyl. 1/2, Cyl 3/4, alternator, heater outlets) you cannot say for sure where the air is going to flow and in what proportion.

However, I can say with certainty on my 1st 914, I stripped off the heat exhangers and blocked the fan housing heater outlets with absolutely no cooling issues in Michigan's environmental conditions that include 98-100F temps (summer) +80-90% relative humidity. OP is from Miami and like MI it is flat with few grades. I don't think OP will have any issues whatsoever blocking the heater outlets.

As a reiteration of previous posts. DO NOT remove the thermostat and/or cooling flaps. This will lead to extended warm up times and overheating. Whoever started that rumor that removing cooling flaps helps improve engine cooling clearly had no idea what they were talking about. My 2nd car is rumored to have been a Florida car. It had the thermostat and the cooling flaps removed.

There was a massive amount of rust in the sump and in the oil breather housing. I completely believe that this rust likely came about from excessive case water condensation due to extended warm up times and/or short driving cycles that never got the oil hot enough to drive the condensation out of the system. See my build thread in my signature if you want pictures of that rust in the sump and the oil breather (pages 5 & 6).

Interesting stuff to say the least!!! I’m leaving the flaps and will also leave the lower ports open. It will take a few months but I’ll record temps and then block them off and record again. I’ll let you all know what I find out.

Thanks everyone!!!!