Hood scoop cause a lean air/fuel condition?

[jmlcolorado]

Hey guys.
I was playing around in the garage tonight and something came to mind.
Will a large air cleaner scoop cause a lean condition at high speeds?

I've got a big giant cleaner cover that'll act like a scoop and I don't want the truck to lean out at highway speeds.
Just thinking out loud.

Here's the suspect:

 

[offroadrolls]

I wouldn't think it would. Denser perhaps.

 

[zzrodder]

I think you'd need to be going over 100 mph before any scoop really starts to create any ram air effect, doubtful if it would cause a lean condition..........

 

[Sam_Fear]

Keep it under 120mph and you should be fine. I'm gonna guess it is a non-issue, especially since you have a filter in there.

 

[jmlcolorado]

I'll take 3 no answers as the correct answer
Thanks guys.

I'm going to run a wide band a/f gauge anyways so that should tell me how the truck reacts to different setups.

I'm new to the carb tuning world (have only tuned, balanced and sync'ed a 4 carb setup on a 4 cylinder bike before) so 4 barrels are new to me.

 

[Old Iron]

Dang, I wanted to put my 2 cents in.
No it won't

 

[jmlcolorado]

Dang, I wanted to put my 2 cents in.
No it won't

Do it! I wouldnt be posting if I wasn't looking for feedback, both positive or negative

 

[ronnysplymouth]

With that tiny air filter I highly doubt a lean condition will ever be an issue

 

[Dr Crankenstein]

A scoop can't increase the density or reduce the temperature of the atmosphere. It only provides the best air available.

Since you have an a/f meter, try it with the scoop on backwards. I know it defies logic, but try it and compare to scoop forward. You might be surprised at the results.

 

[old man dave]

The good Dr. might be on to something as a rear facing scoop would still allow a large supply of fresh air it would also have less turbulence. When I was drag racing some cars found that they ran better with a large air filter for the same reason. Mildly modified small block Chevrolets perform better with a little exhaust back pressure, as opposed to open headers, due to better scavenging of exhaust gases. The hand crafted scoop JML built looks amazing and should not cause any problems.

 

[jmlcolorado]

A scoop can't increase the density or reduce the temperature of the atmosphere. It only provides the best air available.

Since you have an a/f meter, try it with the scoop on backwards. I know it defies logic, but try it and compare to scoop forward. You might be surprised at the results.

I don't have an a/f gauge yet, and actually don't have the truck on the road yet, butim intrigued with your comment. What affect would having the scoop on backwards produce?
Sounds like logic doesn't play a big role in this so I'm interested in the facts.

The good Dr. might be on to something as a rear facing scoop would still allow a large supply of fresh air it would also have less turbulence. When I was drag racing some cars found that they ran better with a large air filter for the same reason. Mildly modified small block Chevrolets perform better with a little exhaust back pressure, as opposed to open headers, due to better scavenging of exhaust gases. The hand crafted scoop JML built looks amazing and should not cause any problems.

I didn't really think of turbulence. This thing will certinly cause plenty of that! I was actually thinking of cutting a hole in the very back near the bottom to give an exit for the air. Plus my cowl vent is right there and I think that would help shuffle more air into the cab after the scoop catches it.

I worked on the air cleaner a bit this weekend. It took some time to get warmed up to it since I first thought it was a little too over the top for this truck. But now it's starting to fit the truck better.
Still gotta add the last two bars, but I think it looks pretty cool.

 

[old man dave]

Turbulence probably would not even be noticed on a street car but on race cars everything is tested to gain every available horse power advantage. The addition of the bars looks killer.

 

[Sam_Fear]

Yeah, the hood scoop is a little 'over the top' since the rest of the truck is so plain.

/SARC

 

[Dr Crankenstein]

Caveman tech. Some years ago I bought a jet boat. I noticed many similar machines with the scoop mounted backwards. [S I started asking questions. The explanation?

- To avoid sucking in water and hyrolocking the engine. (That makes sense).

- No noticeable difference in performance. I didn't believe that nonsense. So I tried mine backwards and I couldn't tell any difference either. I did not have a/f readings to compare, strictly a seat-of-the-pants experiment to satisfy my curiosity. I would expect the backwards scoop to cause a rich condition and sluggish performance, but that was not evident in my experiment.

Logic. The engine got the air it needed either way. Like I said previously, a scoop doesn't change the properties of the available atmosphere, it only makes it immediately available. I do believe facing forward guarantees that and I continued to run mine that way. Better pushed than pulled.

I read someplace that the ram air effect occurs at well over 200 mph. Only then do you actually begin to compress the air and elevate the atmospheric pressure. Then you have force-fed air and definitely a lean condition just like a turbo or blower does. That's what I think I understand from it all, anyhow.

So, I'm as curious as you are. Please share those a/f readings when you have them. Again with the logic, I expect a difference, but I don't think it will be as dramatic as we would like to believe.

 

[jmlcolorado]

Yeah, the hood scoop is a little 'over the top' since the rest of the truck is so plain.

/SARC

I'm confused
You agree that the truck is plain? Cause that's kinda what I think. I don't see it as being Extream compared to some of the builds I see.

 

[Yodaforce]

C10 frame?

 

[Yodaforce]

I briefly read through the other comments.

You really would have to be going WAY faster than most stretches of pavement would ever allow (physically or legally. Lol) in order to actually start boosting.
I believe the whole "ram air" concept is purely to make things a bit more efficient. The easier it is for the engine to feed on air that is.

That is a wicked machine you got going there. [ddd

 

[jmlcolorado]

C10 frame?

Indeed!

I briefly read through the other comments.

You really would have to be going WAY faster than most stretches of pavement would ever allow (physically or legally. Lol) in order to actually start boosting.
I believe the whole "ram air" concept is purely to make things a bit more efficient. The easier it is for the engine to feed on air that is.

That is a wicked machine you got going there. [ddd

I wasn't really concerned with boost as much as leaning out the a/f mixture causing a lean condition and premature wear/failure on the pistons.

Though if boost were that easy to obtain, you can bet I'd build the scoop even bigger!

 

[Sam_Fear]

Yes, I was being sarcastic. Even without the air cleaner, your truck is definitely one of a kind.

 

[bob w]

On a car with a hood, where under hood temperature is significantly higher than outside air a scoop will deliver the cooler air to the carb. But since an engine will run in temperatures from below zero to over a hundred degrees without rejetting, even that effect is minimal.