Drilling Transfers To Intake Manifold

[ThirtyTwo]

Why do people drill a hole up from the transfer ports into the intake manifold??? From what i hear it increases horsepower. Does it just make it flow better since its like adding two more little transfer ports?

[flotek]

it isnt like adding 2 transfer ports actually ,but yes it helps ,there a long winded explaination for why boysen(also called turbo,auxialiry ,finger ,etc...) ports help ,but basically it adds lowend torque and smoothes out power delivery on 2stroke motors and increases the overall response,most all modern 2 stroke engines use this design. it has proven itself over the years .although alot of banshee guys who have added or taken away the boysens will tell you they saw no change or seat of the pants power increases with or without them

[ThirtyTwo]

well i noticed on my friends banshee jugs that there was a stock port from the intake manifold up to the same level as the transfer ports but not actually connected with the transfer ports, and then he had those holes drilled from the crankcase side of the transfer ports to the intake manifold. So i thought maybe it was just a way to get more airflow from the crankcase up above the piston.

do you know of any online articles that explain the technicals of what those holes do?

[flotek]

not exactly sure what yo u mean... but yyeah it does aid/route in getting the incoming charge into the transfer jackets and large intakes are genrally a good thing ,you can check out macdizzy.com or search in panetsand.com for more in depth info on them

[Bu Saif]

Originally Posted by ThirtyTwo

Why do people drill a hole up from the transfer ports into the intake manifold??? From what i hear it increases horsepower. Does it just make it flow better since its like adding two more little transfer ports?

Do you mean like doing a porting or polishing?

[fiveOnick]

Originally Posted by eviltwin

not exactly sure what yo u mean... but yyeah it does aid/route in getting the incoming charge into the transfer jackets and large intakes are genrally a good thing ,you can check out macdizzy.com or search in panetsand.com for more in depth info on them

I dont think he is talking about actual boysen ports as you are thinking. Not the ones you and I cut on the bottom of the intake into the tunnels, but instead I think he is talking about a hole into the back of the secondary at the level where its feeding into the cylinder. I think in theory its supposed to feed through some and push the secondary transfer flow toward the exhaust which is better for higher rpm normally. I have seen this done an several honda cylinders and recently saw some banshee cylinders that someone did that to. In the banshee case they were so small that they were pointless to even have in there. In the hondas they were obviously capable of being larger, but to say that its a good idea, well Im not going to. I dont think it is, if it was you would see intake designs in modern cylinders like Cheetas and cubs as you do the sub ports and boysen(boost) ports.

[flotek]

my bad.... i thought we were talking about the boysens lol

[ThirtyTwo]

well here, pictures speak 1000 words

im talking about the holes indicated by the red arrows

the blue arrow is the port that was stock on the banshee jug

[flotek]

hey thats my 87 lt pic lol ,but the red are the boysen ports i described earlier ,and the blue is the upper boost port .

[fiveOnick]

Originally Posted by eviltwin

hey thats my 87 lt pic lol ,but the red are the boysen ports i described earlier ,and the blue is the upper boost port .

Well I gues I was wrong in interperating the thread. You said it was raised to a level even with the transfers so I assumed you actually meant the trans port window and not the bottom which is refered to as the transfer tunnels. In that case I like them, on some setups. Your going to find mixed opinions on them.