Single Port vs. Dual Port

[chased33]

Does anyone have any performance data on whether dual port heads are better than single ports? I'm tired of seeing this:

[wompninja]

http://www.youtube.com/watch?v=z2ID7rwAbXU

[Bruce Amacker]

This is an interesting topic. I think you need more info to give an informed answer, though, like what carb(s), cam, distributor and exhaust you are using, and how you intend to trim the motor out. DPs are undoubtedly going to give more HP on the top end but I do agree that SPs probably make more torque in the low end, like 1000-2000RPM, in a stock configuration.
My 2180 screams in the mid range, but my buddy's stock '66 1300 has more torque than mine in the 1000ish range, my cam has too much overlap to pull down that low.

As a result of this, I will make the comments but refrain from clicking the "vote" button.

Womp: you need to compare apples with apples, I doubt Chased is building a turbo. When it comes to turbo/supercharged engines, port size is not nearly as important as a naturally aspirated car. Turning up the boost will put your VE anywhere you want it.

Good Luck!
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'66 Deluxe Bus
'65 Standard Bus
Build threads:
'66- http://www.leakoil.net/forum/viewtopic.php?f=23&t=2888&sid=54d8dedfb3822f99c7f2ea430cb4e856
'65- http://leakoil.net/forum/viewtopic.php?f=23&t=4263

[chased33]

My purposes will be as a daily driver with mild components and will likely put dual Kads (have found some SP manifolds if I keep it a SP) and will be driving up some gnarly canyon roads.

But, I ask the question in a more general way as in whether anyone has ever built two identical engines except different heads and dyno'ed them.
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Chase

1972 Super Beetle (1641 SP)
2009 Trek 7.1 FX (daily driver)

[Matthew]

Which is better depends on the intended use. If you are going racing and or want maximum horsepower, then DP is better. SP heads have their strengths as well, but which is better for you depends on what you expect from the engine.
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1965 Beetle sedan
Click to view image

[andk5591]

I just did an upgrade to a stock 1600 SP. Was running a 34PICT3 and SVDA. Guessing maybe 40HP at the wheels, but didnt dyno it. It ran fine for a stock 1600.

Installed mildly ported (intake port match) DP heads PLUS dual kads and a TriMill dual tip header. Just under 60HP at the wheels on a chassis dyno. The car is freakin quick and pulls strong up to 5K RPMS, but I lifted at that point.

Not sure if that helps or not - as with anything - you have to look at the engine as a system. If you did what I did on your 1914, I would guess another 15 or more HP at the wheels and it would still be very conservative.

And I have heard the SP having more torque as well, but have not seen any actual test data to verify it..
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D-Dubya Manx clone - 63 Short pan,1914.
Rosie 65 bug - My mostly stock daily driver.
Woodie 69 VW woodie (Hot VWs 7/12).
"John's car" 64 VW woodie - The first ever
Maxine 61 Cal-look bug - Cindy's daily driver.
Max - 73 standard Beetle hearse project - For sale
66 bug project - Real patina & Suby conversion
There's more, but not keeping them...

[wompninja]

I was simply showing that a single port doesn't just have to be a stock engine.

[spyvsspy]

to me this topic is the aircooled vw worlds version of sohc vs dohc. One produces better low end power and the other's benefit come higher up the rev range.
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It is what it is.

[jamestwo]

Never witnessed a 200 + hp HP NA single port......

Single ports produce more torque on stock stroke motors because the rod ratio. You really can't get much air velocity with the short stroke and lazy rod ratio.

A stroker motor with smaller rod ratio will make as much low end torque as you need. It all about air velocity, and the stroker can make it with a larger port.

Since you have stock stroke, it depends on if you want peak power or sub 2500 rpm torque.

BTW, a 1915 with a stock single ports is going to run out of steam pretty quick after the 2500 rpm.
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hEY, lOOK, i'M WRONG HALF THE TIME, AND THE OTHER HALF i'M NOT SURE WHAT THE HECK i'M TALKING ABOUT. MY POST ARE FOR MY OWN ENTERTAINMENT VALUE ONLY.

[jamestwo]

VW did. the 1600cc single port made 53 hp and the DP made 60HP. IIRC

[chased33]

[Bruce Amacker]

[jamestwo]

One thing I've learned is performance is not objective. One mans rocket is another mans sled.

A guy down the street had a rail with a 2007 in it, dual carbs, 4 into one. It made maybe 90 -100 hp. Honestly, it felt slow to me.

To someone who is used to driving a stock VW, it would have felt like a rocket.

So to be a 1915 single port would fell like crap. Just being honest because I'm used to driving a motor that pulled to 7K.

Ultimatly torque is about air flow, dual ports will make more torque and more HP on a bigger motor.

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hEY, lOOK, i'M WRONG HALF THE TIME, AND THE OTHER HALF i'M NOT SURE WHAT THE HECK i'M TALKING ABOUT. MY POST ARE FOR MY OWN ENTERTAINMENT VALUE ONLY.

[fastinradford]

Ok, well most daily driver engines (besides speed freaks) dont go over 3500 or 4000, where smaller ports rule.

Yes, you can have more POTENTIAL power in a dp head, but do you benefit from it in a realistic range.

It is like cold air intakes, you have more potential power, but preheated intakes produce more efficient atomization, therefore more efficiently transferred energy, at the sacrifice of a high top end.
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95 jetta 5spd, (first waterpumper vw)
the nice 74 Ghia, (of course the fiance drives that one).
My mk1 jetta 1.6d

"It'd still be like my grandads old broom though, original, only 3 new heads and two new handles" -Marv [UK]

[chased33]

[Gary]

Just throw a small block Chevy in it and be done.
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West Virginia State Board of Education v. Barnette, 319 U.S. 624 (1943)

[69 Jim]

[Gary]

[martyhibb]

A 2bbl...... Love the singleports and the 2bbls.....

[tuna]