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Just for future reference, here are the two plugs that I used. By the way, I first used the "holed" plugs because that was all that I had available at the time, so I thought it would be okay to test, since it created a bleed similar to the stock heater boxes. I had just installed a header and had a chance to attend a cruise and car show, so went ahead and tried them. Ended up leaving them in for several weeks. Then did the swap to the full plug. In looking at my notes, the guage temperatures went down around ~8 degrees after installing the full plugs, so that's what I've stuck with. Please note that this was from city and highway driving (ie. road tested), not bench tested. I prefer road testing, as you deal with air flow and other real life factors:

Piledriver wrote:Probably not a matter of theories working or not...

There's just no point trying to sell $10-15K T1 motors.
The market is too small to consider.

I think you've identified the key point: trying to build a bullet-proof hi-po engine can cost big bucks...especially when you're trying to take a 57 HP 1600 cc Beetle engine and make 200+ HP. What happens is that some builders try to make the engine "be all things" and then when they have problems they blame the Type 1 engine...instead of their combo.

There was a post from one of those Type 4 shops (on another forum) saying that they've quit building Type 1's and have now switched to Subaru engines...

It's funny how every time this topic comes up its always the half regurgitated incorrect internet parroting info that comes out.

The 181 Thing shrouds with no heater outlets have different deflector lay out inside to compensate for the lack of heater outlets.

When Jake did the testing on the type 1 doghouse shroud with all his fancy gear what the big deal was when there's no heaterboxes and hoses connected that the outlets plugged off completely caused slight turbulence inside the shroud which caused the 2 sides to run at different temps.

Not enough that you notice with normal driving and would be undetecable without a head temp on each plug but it would have a long term impact on the engines life span.
Most people don't drive there VWs enough anymore for that matter though.

Having the appropriate sized hole in the plug created the same back pressure that stock heaterboxes provide.

Buggin_74 wrote:the outlets plugged off completely caused slight turbulence inside the shroud which caused the 2 sides to run at different temps.

No to belabour the point, but this defies the laws of physics...it can't happen.

I understand the sentiment, but the cylinder to cylinder delta measurements I got off my T4 (4 TCs on a switch, not as nice as Jakes setup obviously) pretty much jibed with Jakes reported results.

If it was actually easy to get perfect Volkswagen would have saved millions and ~50 years of development.

neil68 wrote:

Buggin_74 wrote:the outlets plugged off completely caused slight turbulence inside the shroud which caused the 2 sides to run at different temps.

No to belabour the point, but this defies the laws of physics...it can't happen.

Just another example of what should happen in theory being different to what does happen in reality.

Not physics. Fluid dynamics.

Thanks for the great responses on here. I've had several people point me to this research over the last week or so and everything I find keeps going back to these tests. Not being familiar with the cooling differences between the engine types I couldn't really develop an opinion on it. This really helps.

Intelligent discussions; I'm in awe. But I still don't understand what's better, plugging the holes completely or partially. 1.5 years ago I built an type-1 1680cc engine from a converted type-3 block with a mild cam, dual port and stock carb. During the January thaw we had a week of temps in the 40s and I took it on a long drive. And ended up stranded in Manila, Utah, 90 miles from home. Eventually found the problem to be vapor lock. I thought I solved the problem by adding louvers to the '67 engine lid. I took it for a drive Sunday. At the end of the drive I checked the oil. The engine was hot enough that the dipstick left a blister. So covering the outlets seems like the next thing to try, at least for the summer. Also I plan to reset the thermostat bracket for summer and replace the stock muffler with an old low restriction muffler.

kevin

Can you feed a secondary oil cooler with the air from the unused heater outlets?

I do not see any reason why not. Just ensure that the air after the oil cooler exhausts outside of the engine compartment. Otherwise it will raise inlet air temps.

Buggin_74 wrote:

neil68 wrote:

Buggin_74 wrote:the outlets plugged off completely caused slight turbulence inside the shroud which caused the 2 sides to run at different temps.

No to belabour the point, but this defies the laws of physics...it can't happen.

Just another example of what should happen in theory being different to what does happen in reality.

In my understanding, plugged outlets can't cause turbulence...while unplugged outlets certainly can.

Without beating this topic to death, the "reality" is my engine temps are ~8 degrees lower with the fully plugged outlets than with the dime-sized holes...so I'll stick with reality, thanks.

Also, bench tested data doesn't always match road-tested data...look at all the botched Porsche fan shroud info?

By the way, can anyone actually produce this "dime-sized hole plug" versus "plugged" data...how it was measured, what the results were...a photo of how the so-called turbulence was detected? Skeptical...

It was detected with 4 calibrated K-type thermocouples under the plugs, temp compensated NIST traceable meter.
Motor was a bone stock 914 1.7l (with CIS on it at the time)

The delta is what you are looking for, if you only have one TC on #3 it may very well run 8F cooler, while #2 runs 50F hotter...
You will never know with only one TC.
I don't have a T1 motor at the moment, if you want data, look at Jakes data or do your own proper testing.

I did it for my own benefit, I don't sell anything, so believe whatever you want to believe.

More than 10 years ago I had a stock 1970 1.7L D-jetronic 914. Vapor lock was a constant problem. I found a remedy but don't recall what the remedy was. Point is even 914s had cooling problems.

kevin

crvc wrote:More than 10 years ago I had a stock 1970 1.7L D-jetronic 914. Vapor lock was a constant problem. I found a remedy but don't recall what the remedy was. Point is even 914s had cooling problems.

kevin

That wasn't a "cooling problem" per se, they changed the design ~1973, but even that setup still had some issues with the pump next to the engine, on the hot side. I used a 20+ year old Carter clacker as a feeder for the sump, mounted up front.

I put my fuel pump etc on TOP, in the engine compartment, along with a ~1.5L sump. No issues in Dallas summers for many years. (I replaced the ~40 year old brittle vinyl fuel line in the tunnel with brake line as well, even though I had ~no pressure on it with my setup, this is a VERY Good Idea)