vent tubes

rustman

rustman

Active member
I've heard it mentioned that some people run their vent tubes to "atmosphere". It sounds like a pretty cheap mod. Just wondering what is involved in this and what the benefits are. From what I can gather there is a pressure difference between inside the cab and outside the cab. Any input would be appreciated or a nudge in the right direction. ie. previous post or what not.

-Rustman
 

From what I remember, they just make the vent lines long enough to get outside the hood. I believe that DynoTech said to run them up by the gas tank or anywhere they are exposed to the open air. It prevents long WOT lean downs. I am not sure if that was needed for all years or not. I may have to look it up...
 
I thought it was the other way around? I though it leaned out the WOT runs?

did`nt the preasure under the hood, supposedly, increase the float bowl preasure, effectively forcing slightly more fuel through the carbs?

could be wrong..been a while since the subject was kicked around..

AL P
 
Vent Tubes

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ok.. SO if I am correct, by running my vent tubes to open air I will increase my hp and lower the chance of lean down. If I have deciphered this right then all I need to do is connect the vent tubes by t'ing them and extending them out. Should I keep jetting the same?

-Rustman
 
unless I`m reading this wrong..it`s the other way around..at WOT, it would run LEANER with the vent tubes routed to the outside..
Lean is mean.....but...too lean is not good either..lol
what their saying, is at WOT the mix gets richer (with the stock vent tube routing)...which cost a bit of horse power...but...the stock vent tube position is much safer..as far as burning down due to a lean condition..


AL P
 
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Thanks Al,

I thought it would make more sense that if you applied pressure to the float bowls it would force more fuel and rich it up. I guess then for my intent and purpose, I want a trail reliable machine, I'll just leave it alone. I guess sometimes logic can win out over too much tech info. Thanks for all the help so fast.

-Rustman
 
Or you could reroute the tubes and jet for it, then if it got really cold you could unplug the re route so it would richen it up. That is if I have grasped the information properly.
 
My buddy got his 92 and the vent tubes had been inserted into the air box via drilled holes under the "foam filter " at top of the boxes ( no pressure very little vacum if any )
 
I increased my main jets by 5 and routed my lines out to the vents at the back of my hood 4 on each side using chrome plug wire holders from Eldenbrock. It clears up the lauch and mid range tremendously. I don`t really know how it would handle long top end runs. I run 640 feet and a 1000 feet then its shut down for me!
 
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