More precisely Lexan scoop question. I have an issue with my truck, the carb is right up against the current cowl hood, vent tube is maybe 3/8" away. I know it is not ideal, and I know it's costing me MPH if nothing else. Being a stop guy mainly that's what I am after MPH. The thing currently does not really respond to any jet changes and where it currently is its PIG fat, both by plug and data on RP. My current hood also basically sits on the windshield.


So my question is has anyone tried one of those Lexan and what sort of result did you get? Let me also say I loathe the things honestly. But I really do not want to put a large proper scoop on the truck, even though I know it's the right thing to do. Looking for any input here on those particular style scoops.

Never used a lexan scoop, but used to use the old style hilborn scoop on a carb. All air is FORCED into the carb. When i took that scoop off, and put a fiberglass with a scoop tray with foam and my truck lost 2 mph and .05 in et. It took a decent amount of tuning to get the et back, only gained about 1 mph back. With that being said, if your carb is fat, and you put a scoop on it that forces all air to the carb, you will see some dramatic improvements.

Some time ago K&N developed a formula for the size of the scoop opening (but not the shape) based on the engine size and maximum RPM. That article may still be available from K&N.

Several articles have been written about the shape of the scoop and the best method of sealing the scoop so that the air is forced toward the carb opening. K&N might be able to provide some valuable information on the subject.

Bob

quote:

Originally posted by RPROGAS:
Some time ago K&N developed a formula for the size of the scoop opening (but not the shape) based on the engine size and maximum RPM. That article may still be available from K&N.

Several articles have been written about the shape of the scoop and the best method of sealing the scoop so that the air is forced toward the carb opening. K&N might be able to provide some valuable information on the subject.

Bob

Yes they do and if I were after .01 and .1 MPH I would put a real scoop on it..It is an aesthetic thing honestly on the real scoop. Not to mention a bit of vision thing. I know I am being stubborn about it. Not sure I really need to go faster in S/ST but also would like to be able to clean up the tune up some.

Curious…… how tall is the cowl hood? Presently use a carb spacer..if yes how thick?

Its a 4" Cowl, no spacer but does have a 1.75" throttle stop on it.



This picture kinda shows the issue with a 1.75" spacer...Also why I am trying to avoid any scoop as it back on the windshield

You might be able to put a NACA Duct in the cowl hood. It will not raise your hood line at all.
Scoops ram air in...NACA Ducts Create a low pressure zone which sucks air in.
NACA Ducts create a low or no drag condition unlike the drag of a scoop.

Have you considered a linkage stop and drop carb to intake Id hate to cut up hood

quote:

Originally posted by Top355x:
Have you considered a linkage stop and drop carb to intake Id hate to cut up hood

I am not sure I can be consistent with an inline deal, especially for how long I am on the stop..

Any shorter intake manifold options?

quote:

Originally posted by markemark:
Any shorter intake manifold options?

Unfortunately, no for this combo. This is it, Mopar ya know

I went to an APD Max speed to keep our hood clearance. After you figure out what it wants, it works well.

Mark

Max speed by Bogaki

Bogaki on Max Speed

quote:

Originally posted by Mark Yeager:
I went to an APD Max speed to keep our hood clearance. After you figure out what it wants, it works well.

Mark

I have one and it's been a consideration. I have one here but have heard mixed reviews on the larger carbs with consistency.

I know I am picking nits here. The things is fast now. Of course more back half MPH is what I am after, like we all are I think?!?

Al, have you considered milling the top of the intake? You could gain just a bit there and it might be all you are looking for without doing a lot of body work or running one of those ugly scoops.

quote:

Originally posted by Al Alguire:
I know I am picking nits here. The things is fast now. Of course more back half MPH is what I am after, like we all are I think?!?

I'm pretty sure you have your own answer to "picking nits here." The only thing I would be concerned about is your vents being close to the hood, being PIG fat & not responding to jet changes.

As for more back half MPH, is it really an advantage when a good many are doing the same? That's for you to answer!

This is how I look at being a high MPH car in my class, Pro. I probably have 10-15 MPH minimum over 90%+ of the class & equal to the MPH of a few dragsters running in the class. That's a clear advantage to my strengths in bracket racing. It does have its drawbacks when racing the slower end of the class, but I do have a strategy for them races.

IMO, I see a distinct MPH advantage in my situation but see little to no advantage in yours. That's my two cents worth.

2BKING

Never enough MPH for the stop But yes I generally have most everyone covered, I had success before that way but that was a decade ago. Some cars are faster than they were then for sure. I am actually looking for a back half number more than an ultimate MPH number honestly.

As for picking nits yes, it is. But isn't that something many of us do on new combos. Why I am here asking if anyone had real world experience with the fugly lexan boxes. I will likely never put a real scoop on it. Yes she is pig fat but works well. By not following the weather I mean when the air gets real bad everyone else is falling off 7-9 numbers I am dropping 2 at most. When the air is really good conversely I don't pick up as much either. I have found a "happy spot" with the jetting and bleeds where its predictable just doesnt follow the weather in the traditional sense.

As for the intake we cant really do much but loosed at it. There just is not much carb pad to work with MAYBE 3/8" max. That wont leave much if any transition though.

quote:

Originally posted by Al Alguire:Yes she is pig fat but works well

What’s “pig fat” numbers in afr?

quote:

Originally posted by markemark:

What’s “pig fat” numbers in afr?

On a good day low 11's high 10's if the air gets bad, take anymore away from it and it slows WAY down, like mid 11's on the racepak. Plugs look like they came out of grandmas daily 63 Fairlane after a pass. I have found a combo of bleeds and jetting that keep it relatively happy for now in the fall here.

But I want to start racing the thing. Not just paying money at a race to test it. Unfortunately, we don't get to many test days here and the track isn't always great for something that is on the stop for 5 seconds. So far seem no one has an y real on track results with the fugly scoop. I am going to Phoenix to test next month but looks like I will leave things as is for now. Til I convince myself to put a proper scoop on it

This is not a great pic of it but all I have. My hood is also sitting on the windshield, go gap at back. Which I have also been contemplating giving it some room to see. Its a tad deceiving as the brace runs right across the front vent tube, pretty easy with light pressure to hit the vent tubes.



One more pic just to show its not exactly a slug, just trying to maximize what's there, maybe just being greedy

Have you thought about cutting a slight angle on your vent tubes?

2BKING