streetknight2

iTrader: (10)

I've been to the track twice now with the Super Victor. I made a couple passes and then had a hood hinge break. We ended up pulling the hood off the car and put an air cleaner on it. The car picked up almost a tenth.

Now I'm wondering it the carb being too close to the hood is causing air flow issues. The vent tubes are only 1/4" away from the hood. Was gonna trim them, but someone said it really wasn't the vents as much as the whole carb being too close.

I think I'm going to experiment this weekend and make a couple hits with and without the hood again and see if it makes a difference

fast89stang

iTrader: (2)

Wow. Tenth without hood. Might have to try that. My vent tube touched till I trimmed it.

streetknight2

iTrader: (10)

I went a 6.40 off the trailer. Needed to slow it down to run 6.50 index.
I pulled timing and lowered shift rpm and went a 6.48. Then I pulled the hood off and put and air cleaner on it. That was only change and it went a 6.39.

I had to pull 5 degrees timing and move shift from 7400 to 6000 to get it to run 6.50's

Last pass was ***** out so I moved everything back and it went 6.30

tim burks

we have a local racer that runs a mustang, sbf and im sure its 400+ c.i using rons flying toilet, with a 4 inch cowl hood. with the hood off it would pick up a tenth also. went from 5.98 to 5.87. now he added a scoop and went 5.803 last weekend.

dogsballs

When i tested putting filter on during tuning, it leaned out, producing more torque. Thats my guess thats happening to yours.

Scoop is different, at decent mph it rams air down carb

TXsilverado

iTrader: (18)

a few things could factor in.

1) lost weight with no hood.
2) cooler air to carb without a heat soaked engine compartment.
3) changed AFR by putting the air cleaner on.

fast89stang

iTrader: (2)

These mustangs are pretty tight on hood clearance. Mine has a 2 inch spacer, and I had to trim from tube 1/4 inch just to clear about a 1/8 inch. My hood is only about 1 inch above front of carb

The stunningman

iTrader: (47)

Not a vent thing its a carb thing. What your basically asking is. Does a flat pan a inch away from the carb top hinder flow. Yes. Pulling the hood allowed it to breathe. Put a newspaper box on it with the stock hood and see what happens.

fast89stang

iTrader: (2)

Yeah, that's kinda what I was indicating. I bet the entrance to my carb is less than a inch from hood disrupting the air flow. May try to test it this weekend if I have time

streetknight2

iTrader: (10)

I would love to put a forward facing scoop on the car, but not allowed in my class. I'm gonna test with and without the hood this weekend. If it runs better without, I'm gonna cut a whole in a stock hood and let breather stick thru lol

Whatever works

WE TODD DID

iTrader: (2)

Carb is way too close to the hood. Vent tubes need to be as far away from the hood as possible.

crossbreed383

iTrader: (1)

My vent tubes are tied together to prevent fuel slosh at launch.
Plug boot over front vent tube is touching hood.
Car runs an air pan as well, and is FASTER with hood on car.
My point is,blanket statements like yours are just that
You must test,test and test some more to see what your CAR LIKES

Also those folks who cut vent tubes shorter to clear hood,have they given any thought as to what that does to fuels ability to "pull over" vent tube now that its shorter?Fuel curve?

WE TODD DID

iTrader: (2)

A carburetor is a carburetor. They all work the same. You have an air pan, therefore your carb isn't being smothered. It shouldn't run faster with the hood off, and if it does, that means that you have a problem.

crossbreed383

iTrader: (1)

The air pan sits level with the top of the venturi/main body.Therfore it has NO bearing on vent stand height in relation to bottom of the hood. Your'e talking about 2 different things here

WE TODD DID

iTrader: (2)

It has everything to do with it when you're going down the track.

crossbreed383

iTrader: (1)

The bottom line is as long as the air coming across the venturis/bleeds doesnt negatively affect the fuel curve the engine is eeing,it doesnt matter if the bottom of the hood/air cleaner lid is 1 inch or 1 foot aways from the carb . The proximity of those things(hood or lid bottom) to the air bleeds or vent tube either hinder it or they dont.
You wont see any benefit of moving things farther sway than what they NEED TO BE FOR THAT CERTAIN APPLICATION>PERIOD!

Like a said earlier,ive tried it many different ways on my car and it works with limited clearance just fine.Some apps may benefit from more room for any number of reasons,but to say ALL cars need this X amount of room is just not true.ALL carbs do work of the same basic priciples,but theres many variables to what application they are run on, and how they were assembled by the builder
But hey ,to each there own!

WE TODD DID

iTrader: (2)

A carb up against the hood will never work as good as a carb with room to breath, period. So in what application would a carb run better up against the hood, versus away from the hood? I'm curious because I have never seen one run better smothered. And to be honest, I'm not so sure that it would run as good up against the hood with an air pan either.

SuperSport01

You could mill the carb flange on the manifold down, say a 1/2", to get the carb away from the hood. You would lose minimal plenum volume and would drastically improve airflow into the carb.

crossbreed383

iTrader: (1)

I can take my hood off ,essentially having the carb see all it can,with a very tall air filter and it runs X et.
Then,i can take air filter off,run just a hood,,which sits closer than filter lid, and a filter base and it runs quicker/faster
Then I can RE-install air pan and it runs quicker and faster yet again.
Opinions without data are just that, opinions!
Like I have said over and over, EVERY CAR IS DIFFERENT ,AND THEY ALL RESPOND DIFFERENTLY
Until you try something you never know do you?

Also some time when you at the track,look at how many cars have right angle plugs boots and a hose between their vent tubes to help anti sloshing of fuel.
How close to the vent is that plug boot when its pushed on?
Hmmmmmmm

The stunningman

iTrader: (47)

I would bet that ANY car running a carb so close to their hood that they had to consider vent mods is compromising their set-up.

All engines are air pumps the more air that can get in and out, the more power it will make. Just as sure as there is a calculation for figuring the area of filter required to flow XXXX CFM. There is a space requirement to flow XXXX amount of cfm.

If your working within the confines of rules, then do whatever you have to do to stay within that. If you are looking for a personal best or trying to get every hp out of it, why would you not try to open as clear a path as possible for airflow?