Inliners International Forums General Discussion Engines throttle body, velocity stack..seeking fresh ideas

Seems folks on here like to think outside the box, so thought Id pose a question.

I have a ford 300 with stock efi, Ive been bouncing a few ideas around to put a touch on the engine that makes it "mine".

Recently I reshaped the throttle bores, then began having visions of little velocity stacks.

As it sits, there is an inch lip that sticks out past the main body of the throttle body. Easiest solution I could come up with, was to take two 3" long pieces of aluminum pipe, with a same inside diameter as my TB lips outside diameter, braze the pipe to the TB and shape by hand. I could throw money at it and get what I want and probably come close to bolting it on but Im looking for cost effective means to achieve the same goal, I have more time to spare than disposable income.

I found velocity stacks that would work, they are however extremely long and $25 each before shipping.

The intent is not performance gain, just to obtain a "look", if the stack should assist throttle response and overall driveability for some strange reason, well thats just icing on the cake.

This is a photo of the stock TB after my minor port work, the photo makes the lip of the TB appear extremely short but in reality, it protrudes out about an inche, the diameter is roughly 1.5"/42-45mm:



This is the final look I want to achieve, this is a motorcycle carb with velocity stack:




Maybe someone has some scrap aluminum pipe they could let go for little $$$

What is ther nominal wall thickness you need before machining?

I believe .25", is there thicker?

I kinda envision the following (see attached photo), red represents the current TB bore shape, grey represents two pieces of pipe roughly an inch long stacked and offset. Blue represents the material the "cut line" to give it that funnel shape.

This would take a chit load of time to shape by hand, all I know is if I had access to actual machines Id be dangerous and this would amount to a lathe and shaping the pipe outward vs me trying to carve it.



If anyone has a better idea or cheaper source for preshaped velocity stacks, Im all ears. Can be used pieces, Id rather spend the time bringing an oxidized piece back to life than trying to create this. Just needs to be aluminum, as Im gonna probably braze it to the existing aluminum TB and make it appear as if the factory did it.

Velocity stack are "tuned" via length to the frequency of the engine. Using the wrong length stacks will not only not help performance, they may hurt performance.

Do a baseline with no stacks, then run tests after installing the stacks to see if they helped, hurt, or no change.

Jon.

even a short one would negatively affect it? Im just doing this for looks, if its gonna hurt it, well, I can live without it. I only consider this after reading a few articles that said it would have little to no affect on the engine, but I coulda read alotta BS too.

also as a side note to you inline300 you can not braze alum.

It is not going to hurt it w/a short one,,it will only improve the airflow.

Having no smooth entry for the air to go into your TB, will hurt airflow.



MBHD

Well its not technically braze...more like solder...Id be using the alumaloy rods, the TB is thin so it should take. Im gonna test that product on some scrap, if I cant get it to do right, Ill just use epoxy.


Thats what I thought MBHD but wasnt sure.


Still open to fresh ideas and thoughts as to achieve this, maybe there is an easier way and I havent thought of it. Thanks

I don't know what you think of EBay, but if you type in "Velocity Stacks" in the intro page seach box, a couple of hundred pop up.Maybe it's worth a look.

Yeah, got my eye on ebay.

Ive contacted a couple sellers with what appear to be homemade product.

Problem is my outside diameter is an odd size I suppose roughly 1.875" finding an inside diameter a hair smaller or spot on is tough so far. The wall thickness of the TB lip is only 1/8", so not alotta room to play with. That and I dont really have a means to trim the lip down consistantly all the way around. But Ill see, maybe on of them will make one a little smaller for me and keep their nice low pricing.

If you find one a little too small, try using a tailpipe expander to enlarge the one end.

If you find one that's a little too big, get some shim stock and wrap that around the inside. Solder or epoxy into the stack. http://www.mcmaster.com has some interesting materials...