Blow thru boxes?

Sidewalk · Post by **Sidewalk** » Thu Feb 07, 2002 1:59 am

How much was the machining?

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'59 bug-unstockStella
'88 Bronco II-unstock Sonja
"Yes, I am a smart ass."
"I'm a DUMBASS too"

But are you gutless?

vert78 · Post by **vert78** » Fri Feb 22, 2002 10:51 am

If I build air tight boxes around my IDF webers can I blow thru them?. Since the pressure will be the same around the entire carb fuel won't spill out. I know this is an old idea but I was just wondering if it works.

Searoy · Post by **Searoy** » Fri Feb 22, 2002 12:33 pm

Yes, but it's not that simple.

I know there are problems, and fixes to the problems, but I'm not schooled on them enough to know for sure. I'll tell you what I think instead, take it or leave it.

If the box is around your carb, and piped to the turbo side of the boost, what heppens when you shift gears? The throttle is closed, but the boost is still high, so all that pressure feeds lots of fuel into your air, making you VERY rich.

If the box is around your carb, but is piped with manifold pressure it might work, but then again the air pressure might back-feed through the jets making you go lean.

I know there is a way to do what you want, but I don't know all the details. I'm sure it has check valves and pressure release valves and such in it. Complicated.

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*** Teach a Man to Fish ***
Searoy

"I tend to lean toward a tighter gap and a
looser skirt....a little slap never hurt." -- Joe of the West

bl67vw · Post by **bl67vw** » Fri Feb 22, 2002 6:28 pm

here is a link to carb mods that should work with turbo use, I havent tried the mods myself but im sure someone here must have at some time tried it, any pros and cons of doing these mods?
bill

[url=http://www.vs57.com/[url]http://www.vs57.com/[url

bl67vw · Post by **bl67vw** » Fri Feb 22, 2002 6:30 pm

http://www.vs57.com/

69bug4me · Post by **69bug4me** » Fri Feb 22, 2002 11:30 pm

From what i've read it will work,they used to do it with old studebakers and a centrifical supercharger.Your throttle cable might need to be sealed,but since it will just leak some air, may not be needed if it is not a huge amount.You will need a fuel pressure regulater with a vacuum/boost port so that your fuel pressure will always be above boost pressure.Floats might have to be changed out for some designed for blow thru i have read they could collapse under pressure.As far as jetting differenes i have no idea.I have a turbo off an Audi turbo diesel that i got for 5 bucks but will only work blow thru,i considered the method you thought of but haven't started yet.Oh the problem with the pressure back up when you shift is fixed with a blow-off valve same as used with f/i turbo it has a line that i beleive senses a high vacumm like the closing of the throttle and vents the pressure into the atmo so the turbo will stay spooled up better. try going to dunebuggy.com they have a decent turbo section.

speedwheel · Post by **speedwheel** » Wed Feb 27, 2002 7:02 pm

read the link above, and you will find out that it is very easy to modify a carb for blow thru....that's what I did....

mcruickshank · Post by **mcruickshank** » Wed Feb 27, 2002 7:27 pm

speedwheel,

I read the link I posted above. I would still like more info. Can you post exactly what you did? Did you machine your own parts? I have done searches on this forum and on the web and noticed a lot of posts about blowing through Weber IDFs. The only solution I found was the one from CB Performance. So I am sure others are interested in what you did.

Thanks,
Mark

speedwheel · Post by **speedwheel** » Wed Feb 27, 2002 7:53 pm

exactly, i had it machined....
and its the other link ....not the CB

[This message has been edited by speedwheel (edited 02-27-2002).]

mcruickshank · Post by **mcruickshank** » Wed Feb 27, 2002 11:41 pm

check out this web site for more info on blowing through Weber IDFs http://www.cbperformance.com/Feb2001.asp

-Mark