Better (Air) Cooling

[FJCamper]

Venturi, Volute, or plain old Funnel?

Porsche made enough running changes to the 356B engine (introduced in 1960) to redesignate it (616/2 to 616/12) and one of those changes was to add a fan shroud intake volute that really improved air flow.

The 356B models, specifically the Super's, were running hotter and needed the cooling help.

VW did not add this feature to the Type 1 until 1975, for the hot-running FI engines. Awesome Powdercoat

http://www.awesomepowdercoat.com/Venturi_Ring.html

... run by the hardworking Clark Callis offers a copy of the factory device which he calls a venturi ring, and

http://www.mamotorworks.com/acvw-air-co ... -8663.html

... Mid America MotorWorks offers one as well.

The photo above shows the device we ordered from Clark. Excellent fit, and easy to pop-rivet in place.

The device really isn't technically a venturi, but fits the volute description better. In the Porsche Technical Manual, Henry Elfrink calls it a plain old funnel. No matter what you call it, Porsche never made such changes for nothing. The device smooths airflow into the fan housing intake, making the fan work more efficiently.

The result is better cooling.

FJC

[sideshow]

I am under the impression that the VW one was in part (or full) for noise reduction. I installed the awesomepowdercoat part on a fresh air puma, but it was during a full tin rework and welded in place so A-B-A testing was not done.

[Glenn]

Before adding the ring, you should make sure you have all the tin in place. Including the little V deflectors in the cylinder tin between the spark plug holes. That you carefully trimmed the cylinder tins to clean the larger dual carb intakes and did not simply hack it larger. That you have the 2 small tins by #2 and #4 that are usually missing. If you're not running heater boxes you have industrial shields that close off the space between the heads and the J tubes. And finally you have both flaps in the shroud. Even without the thermostat they help direct the air over the heads.



After all that you can add the ring if you need it.

[FJCamper]

Hi Glenn,

You are so right. We in fact have Awesome Powdercoat's industrial shields ordered and on the way, and have all the other pieces you mentioned already in place.

Nice photo you posted. Very sanitary work.

Sideshow, the idea of the VW volute serving for noise reduction is interesting. I have no reliable info on that. I do know that for the 1963 356B (616/12 engine series) Supers that in addition to the volute, they added an improved oil cooler. A significant change to the 616/12 was plain cast iron cylinders, a downgrade (in my opinion) from the previous light-alloy cylinders.

Perhaps the improved cooling was necessary for the cylinder material change?

Porsche also changed piston design for the new cylinders, indicating they felt piston mods were necessary with the change.

FJC

[Glenn]

Awesome Powder Painting has done a real service to the VW community by reproducing all those small pieces that really made a difference.

My 2180 never exceeds 205F even on the hottest days and climbing hills.

Dual IDAs, 9.5cr, 30 degrees max advance, 93 octane, all OEM tin, stock Type 1 cooler, 1.5qt sump, remote filter, 10W-30 oil, 26mm pump and NO SECONDARY COOLER.

[vwchuck]

50 bucks. I can buy the whole shroud for that much. That is funny

[63busguy]

You can always make your own industrial tins yourself

http://www.thesamba.com/vw/forum/viewtopic.php?t=401943

[Xyclone]

does anyone have any comparison numbers for this? Its def an interesting theory, but I could really only see a slight velocity increase if it is in fact reducing turbulence.... and thats a big if. I'm hesitant to just bolt on a ring without seeing some numbers behind it, since it would seem more to be just compounding the idea of using ALL the proper tin. Yes porsche may have added it with the 616 series, but with the number of other changes they made, I find it hard to connect the dots that easily.... just my 2C

Perhaps when I get my shop back I will try doing a comparison with it, but thats a few months off :shrugs:

[Piledriver]

Speaking of "all the original tin", Joe Cali (and others) report seeing better cooling with the thermostat flaps installed, even if they are wired wide open. (Runnin w/o a working tstat IMHO a bad idea, but you know the old saw about opinions)

[63busguy]

I installed the ring and flaps (no thermo) and saw a consistant drop in head temps and oil temps. The engine is now VERY sensitive to ambient temps. The engines ability to cool back down after highway speeds was significantly quicker as well.

Id say in my case an average of 30* drop in head temp, 50* in oil temp.

This was using a non fresh air puma shroud.

[Xyclone]

I installed the ring and flaps (no thermo) and saw a consistant drop in head temps and oil temps. The engine is now VERY sensitive to ambient temps. The engines ability to cool back down after highway speeds was significantly quicker as well.

Id say in my case an average of 30* drop in head temp, 50* in oil temp.

This was using a non fresh air puma shroud.

You saw a 50 deg drop in oil temp? what was it running before? where is your sensor located? Also, 30 deg head temp drop vs a 50 deg drop in oil temp seems a little strange, not saying your wrong, just would seem there would be a much higher head temp drop for such a large oil temp drop :shrugs:

I could see a drop in temps just from having wired open thermo flaps, especially since they help direct cooling air at separate areas instead of one large area (possibly causing slight turbulence?). Area 1: the V splitters in the head tin more effectively, feeding the majority of the highest velocity air at the outside of the shroud out to the corners of the heads 2: then the other is partially directed through the center of the heads. Something I've always wanted to test :scratches chin: Thermostats are where its at though.

[bugnut68]

Here's a question: if one has a case with damaged corners (where the sled or industrial tin bolt on to the case) how can this be rectified/fixed? What is the recommended approach?

[63busguy]

Id say in my case an average of 30* drop in head temp, 50* in oil temp.

You saw a 50 deg drop in oil temp? what was it running before? where is your sensor located? Also, 30 deg head temp drop vs a 50 deg drop in oil temp seems a little strange, not saying your wrong, just would seem there would be a much higher head temp drop for such a large oil temp drop :shrugs:

I guess my average depends on season but here were my initial findings.

I went from an empi 36hp DH shroud some fins but not as many as an original, no flaps 3 piece duct and front tin.

1699cc
stock 043 heads hi rev springs
110 cam
9:1 compression
1 3/8 header single muffler
dual ICTs
019/blue coil

Temps:
In town 275 CHT 200 Oil
Freeway with load 300-400 CHT 220-230 Oil

With Puma shroud (with venturi ring and flaps but no thermo) and small lower and industrial tin.
In town 200 CHT 170 Oil
Freeway with load 250-350 210 Oil

[Xyclone]

well if you went from a empi shroud to the puma and the rest of the tin, I would say your temp drop was 90% of that, everything else is just bonus