Single port versus Dual Port 1600cc

[Nid]

Other than the obvious single/dual port differences, are there any differences between these engines? I mean performance wise, econononmy wise, whatever, why did VW go from single to dual ports in their 1600cc type 1 engine?
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My, you've been naughty. How.....Delicious.
You're such an inspiration for the ways that I'll never ever choose to be
Oh so many ways for me to show you how your savior has abandoned you
Fuck your God, Your Lord and your Christ, he did this
Took all you had and left you this way
A Perfect Circle - Judith

[VW Addict]

The 1600cc dual port has a larger carb and it works less, improving gas milage. It is also more sufficient and has a horsepower gain.

[Nid]

Thats odd. The 1600 dual port in my parent's '72 Super gets roughly 24 mpg, but can indeed go well over 70mph if it needs to (not for very long though), and the 1600 single port in my '67 seems to be getting around 35 mpg, but tops out around 70 max. I drive it around 60-65 normally.

Does the single port have slightly more torque? It seems to accelerate a little harder than the dual port in the super. Or is this different gearing?
_________________
My, you've been naughty. How.....Delicious.
You're such an inspiration for the ways that I'll never ever choose to be
Oh so many ways for me to show you how your savior has abandoned you
Fuck your God, Your Lord and your Christ, he did this
Took all you had and left you this way
A Perfect Circle - Judith

[SLawson]

Single port has more torque. Thats why I am able to snatch 2nd with mines but a friend of mines had a dp. She couldn't snatch for sh*t. My other friend that used to have a bug also could snatch 2nd with his 1600 single.
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$heldon

[VW Addict]

[vwracerdave]

The difference in performance between the 72 super and 67 is in the tranny gearing, not the engine. total weight is why the 72 super gets less milage because it is heaver then the 67.

[danimal]

the single port is very flow-restricted, it's the last thing you want to use for performance... the case metallurgy is vastly inferior, as are the 10mm head studs, the narrow cooling fan, tiny oil galleys, etc... it's a tinker toy motor, lol... but many people think that the 30pict carb works better than the dual port 34pict3.

you can put single port heads on a dual port motor, and fix most of those shortcomings, fwiw... but in the long run, the dual port configuration is the way to go, because that's where all the parts are... i don't think that single port heads have been in production for quite awhile.
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[JamesT]

Cal Imports sell all new single port heads. I don't know how good they are, but they are still produced. The biggest problem with the dual port heads is not in the head itself, but in the intake manifold. The design is flawed, since you have a single 34mm hole, that splits into two pipes the same size, which again split into two more slightly smaller holes on each side, so by the time the intake gets into the heads, it's only moving at a quarter the speed it is just over a quarter of what it was going through the carbs. This isn't a problem on larger displacement engines with dual carbsor at higher engine speeds, and will actually gove more power, but robs power from the lower RPM range, which is where you want it for good drivability. Why do you think all type III dual port engines had either dual carbs or fuel injection? The single port system had less of this problem because after the carb stem, the rest of the intake manifold was smaller piping.
Despite the inferior metallurgy, you will find a lot less cracked single port heads than dual ports.
They're good heads, just don't use them on any high reving or large displacement engines.
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-James T

1968 Kombi
1995 Eurovan Camper
2006 Garbage Jetta TDI

[danimal]

if somebody was casting brand new single port heads, there would be brand new single port heads all thruout the vw retail stores, not just cal imports... go read their internet ad, and look at what they claim to have done to those heads you are referring to... basically a bunch of stuff that you shouldn't need to do to brand new heads.

and i specifically stated case metallurgy, not head metallurgy.

the dual port manifold moves the choke point up a few inches... but it still decreases the reversion pulses between the ports significantly... the single port head basically creates a bunch of mud going into each combustion chamber... it's a tuning disaster.
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[Nid]

Forgot about this thread....

I discovered 35 mpg was due to....a disconnected fuel gauge. Ran out one morning
_________________
My, you've been naughty. How.....Delicious.
You're such an inspiration for the ways that I'll never ever choose to be
Oh so many ways for me to show you how your savior has abandoned you
Fuck your God, Your Lord and your Christ, he did this
Took all you had and left you this way
A Perfect Circle - Judith

[2Lo4FatHo's]

I like the low end torque from the sp especially with dual 34's, sweet...
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63 Beetle