velocity stacks

[njv]

hi
what is a good distance between the top of a velocity stack on a carb and the inside of the top of the air filter.

i only have 45 mm tall air cleaners and have ordered some 25mm tall (short by most peoples standards) velocity stacks .

no room for taller air cleaners in my typ 3 but i know the stacks can do wonders for hp.

but with only 20mm of room above them am i defeating the object?

love to know what you all think.

[Farmer]

20 mm. is just about the min. requirements. But that matter is always the problem in T3 & 4´s

I talked to a German guy in Holland a couple of years back. He had a 1910 back in a 412 Variant, with better cam -carbs etc. He had a lot of trouble getting the consumpsion right. It would always run rich or lean for him. Right up until he went for the CB "update" conversion. Then fuel economy went back to what is was when stock. (Read 30 % better) He did´nt gain any real power by doing it, exept for a more even torque band. For what it is worth, he and others meant that the horizontal discharge tube is working much better under these tight clearances. (Somebody please explain why !)
Worth considering if things really turn to the ugly.

[njv]

hi
all i know about fuel economy at the moment is the local petrol station see a lot more of me lately.

i cant keep my foot out of it at the minute though theres always some wise guy in his new bmw as were leaving a 50 kph zone who thinks oo look at the old sqr back ill just scoot past that .

wrong when there 100 meters behind me and im doing 120kph i slow down again so i can look at there faces in my mirror what a delightfull sport it is 8-)

back to the point i have wondered about the fact that there is only like 20mm between the tops of my jet stacks and the filter top.

some have said they noticed no difference with the update kit mayby my application is where it will come into its own?

i know i have standoff occuring as there is yellow fuel marks on the inside of my filter tops nothing major but its there mayby the small stacks can contain this a bit..

i may get the update kit later.

i really should start keeping a record of fuel consumption i suppose and leave the bimmers to overtake me once in a while!!

[kdanie]

My thought is the horozontal discharge tube on the CB update kit is less touchy about straight/smooth airflow than the stock booster vents to function properly. The update kit would probably be worth the expense with so little air cleaner clearance.
ken

[njv]

hi
yes i can see thinking that the update is probably the way forward in my situation with small air cleaners.

what do you actually get in the kit ?do you have to specifie size required i cant beleive its a one size fits all thing !

many thanks.