single port versus dual port

[staggerwing]

Could someone please direct me to the differences between single port and dual port engines?

[David O']

The heads, intake manifold and the size of the carburetor. The carb is smaller on the single port, but the manifold doesn't require boots. Horsepower with the single is about 3 hp less than the dual port! That's it!

[Faron]

OK so what is better? Can I build my Single Port to be a fun & Quick motor? I have talked to a few people and they all tell me to convert the Single over to a Duel Port! I dont know what to do!

[GregR]

generally speaking, a built up single port by it's very nature won't match a built up dual port. SIngle port means that each cylinder head has 1 intake port feeding 2 cylinders a dual port has 2 ports on each cylinder head, 1 feeding each cylinder.
So some basic logic would indicate that you will get greater air/fuel flow into the cylinders with a dual port. More fuel and air to explode generally equals more horsepower.
What do you want your engine to be? If you want a screamer then convert to dual port. If you want a mild increase and more solid reliability, a single or dual port , either will do you well.

[carlos del carpio]

VW introduced the dual port, so just say it's a factory improvement for performance, while keeping the reliability and finer tuning... yay!

[staggerwing]

Good information guys - THANKS! I want this thing to be reliable more than anything else. I guess that what VW did was improve the efficiency of the burn to each cyclinder which was probably done for more power and better economy. A friend is trying to sell me a DP 1600 with a big carb for $1200! He's claiming 85 hp (on a dyno) and 1641 cc. I have an offer from another guy for a fresh SP 1600 build for $950. If I'm gonna push a buggy with a 1600 engine and expect good reliability, sounds like a 1600 SP is a good deal to me.

[GregR]

Don't misunderstand....
A stock or nearly stock dual port is as reliable as a stock single port. The issue comes when you want to "build" the engine, i.e. going to 1776 and bigger. The dual port heads have the capacity to flow enough air/fuel to keep up with the increased dispacement. Single port heads arguably do not.
So it's back to the original issue. What do you you your engine to be?
A built up screamer or a reliable stock? A screamer would do best as a dual port. A rliable stock engine can be single or dual port. Personally, I don't think a 1641 dual port can be called built up. Anyone else?

[David Head]

A single port 1641 for $950 sounds kind of high to me. Greg is right, All things considered. A Daul Port is just as reliable as a single port. I would rather have a DP vs a SP. DP are very common. Most everybody runs daul ports. DAvid

[blackthree4me]

all good info
a good built single port will run any buggy just fine
David f 911 car is a single port and he wins the best engine all the time
if you want a stock look and power do the single
if you want more power go with the dule port
its that simple
I have a 1641 with duel carbs and slightly hoped up and Im ready to go bigger already I just run out of power the way i drive it
blackthree4me

[Faron]

OK This brings up a couple more questions. I have been told that some single port blocks can be converted to a Duel port. They told me that they could tell me by some number on the block. Please Help???

If one of the Blocks can be converted, what all will I need?
On top of that will it end up costing me more then just Starting off with a Duel Port Motor?

So many questions!! I am sorry!!

[carlos del carpio]

I never thought it was the block, I thought the option was due to the HEADS that you use??

[David O']

The only thing that you have to change are the top four inner head studs. I have those in stock and they don't cost hardly anything! Who ever told you that you could tell by the numbers on the block......don't know what they are talking about!

[Faron]

David, I am going to give you a call in the morning! I am so greatfull that you are a part of this group!

[David Head]

AMEN TO THAT!!!!!!!!!!!!!!!!!!!!!!!!!!