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Just a FYI I just bought a new Edelbrock vrs carb and standard drop base air cleaner lids wont fit I had to get a 1/2 spacer the float bowls are huge as a matter of fact the whole carb is big but sure works great . the new air cleaner is from crate insider.com flat base that has a velocity stack style base . they say 20 hp gain on just about anything .check them out .
Thanks!
My 1.5” drop base is designed like your 2” and clears everything on my carb.
I’ve looked but can’t find a 2” of that design.
I tried an aftermarket L88 2” but it interfered with the double pumper carb.
I’ll try a couple different ones when my hood is permanently installed so I can try and squeeze a 4” filter element on which would give me an additional 1/2” between the base and the lid.
So, given the air filter element top lids add turbulence when paired with the normal round filter, would it be logical to suggest adding a air filter element top lid and reducing the side filter size (from 3" to 2" lets say) improve airflow characteristics when paired with a drop base (comparing 2" side filter with 3" side filter both using the air filter top lid)?
Originally Posted by leigh1322
You got the basics right Walter, but not the numbers
A 752 HP engine lost huge HP with almost every air cleaner, except for none or a velocity stack.
They used it's 1100 CFM of airflow to really show big numbers.
But that is not real world.
Who in their right mind would put a single snorkel air filter on that engine?
Very few of us would even put a 752 HP engine in a C3, and it won't fit under the hood without severely choking it off anyway.
Those that do (Rothamn et al) run a huge 4" extended height L88 hood, that looks almost like a pro-stock setup. And they still have height troubles.
My race buddies 800-1000HP BBCs run dyno optimized 8-9" tall intakes! 5 inches taller than mine.
Those of us with more moderate engines, and desiring to keep stock hoods, are much more height limited.
400 to 500 HP is really pushing that "space" envelope.
On a 400 HP engine, and it's much more moderate airflow needs of around 700 cfm, the stock 2.0" drop open element air cleaner still costs 12 HP over nothing at all.
But it fits and it looks great!
Going with a 1.5" lesser drop base adds the most HP possible back to that system, it gives back 5 of those HP, and likely still fits under the hood. With the same 3.0" high paper element. It also raises the lid, which helps straighten the air flow. And gives more room over the choke horn. There are only 7 HP left to be recovered. It should have 3/4" clearance. This may be the strongest combination we can fit under our hood!
Adding a K&N filter really does nothing of consequence, they proved in back to back dyno tests, it only added 1 HP back. And according to other independent filtration test, it filters much worse, maybe by 30% or so. I do not like that trade-off. K&Ns marketing results are much stronger, but our 14x3 air cleaner system is pretty good to start with, so airflow gains are tough to come by.
Going to a 4.0" tall filter, on the same base, also did not help as much as I expected. it only gained 3 more HP back. Yes it raised the lid, but without raising the base also and consequently having two changes at once, and straightening the air flow out some more, it had a minimal impact. It is a huge 33% increase in surface area. Yet it shows less than a 1% increase in HP.!?!? This is why we run dyno tests. Common sense failed us here. That lack of response means our 14x3.0" high filter is big enough. BTW that will not fit under a C3 hood anyway now with the 1.5" drop base, and the taller base is worth more anyway, like 5 HP. The 4.0" looks cool, and satisfies common sense, but the dyno proved that a "taller" drop base was worth more. It would look good, and it may fit under a stock hood, with a 2.0" drop base, but hood clearance will be real tight. Like 1/4" or less. I know of one guy who even dropped his motor mounts 1/4" -3/8" to make this combo work.
Also contrary to popular belief, the dyno showed adding a K&N top filter to a system that already has a round filter, actually costs HP. Only 1 HP, but it does not help. When the side filters were tapped off, and only the top filter was used, that system did have strong results. It added 10 of the 12 lost HP back. What this proved was that straightening out the airflow path is very important to HP, and much more important than other factors like air cleaner height, or filter media.
The one extra thing that can help even more is moving the base up to a flat base, which actually has a 1/4" rise lip. That does add another 5 HP over the 1.5 drop, or 10 HP over the 2.0 drop. You are now within 2 HP of no air cleaner. But it will not fit under a C3 hood, with a 3" air cleaner, by a lot.
One combination that they did not test, would the flat base with a much shorter air filter, which may fit under the hood if you go with a 2.0" high filter. The lid would only be 1/2" to 1.0" higher than the stock drop base. I would love to see a dyno test on this combo. It may fit under the hood. The advantage of the higher flat base towards straightening the airflow may just help more than the disadvantage of less filter area. But with out a dyno test, or a A-B 1 variable comparison, we will never know. I guess I'll just stick with a 1.5" or 2.0" drop base.
Another test they did not make was a 3.5" high filter on a 2.0" drop base. It should fit, there should be enough room. Common sense would say the extra filter area should help, and raising the lid over the choke shorn should help. But based on the 3.0 vs 4.0" comparison, and only a 3 HP gain there, I would not expect very much help. Maybe 1 to 2 HP.
I am certainly not changing my BB hood, not for 12 HP!!!
So, given the air filter element top lids add turbulence when paired with the normal round filter, would it be logical to suggest adding a air filter element top lid and reducing the side filter size (from 3" to 2" lets say) improve airflow characteristics when paired with a drop base (comparing 2" side filter with 3" side filter both using the air filter top lid)?
No, if you have room for 3" use it. If you have room for 4" use it. You don't intentionally use 2" if you have room for taller.
Lower than 3" on a 2" drop base puts the lid way too close to the carb inlet.
It might even hit the choke tower, I think there is only 3/4" clear there with a 3"
To the guys using the edelbrock rpm air gap how do you like it and are you able to get 6500 rpm out of it I have another build going to start soon and might use it . thanks .
Lid design would impact the carb to filter lid measurement as well. I'm thinking more in terms of using all aftermarket parts.
An filter style lid would negate the impact of limited airflow to the carb (if the lid becomes very close to the carb), correct? Since air is now coming in from the top?
Hypothetically it seems the smaller side filter would minimize horsepower robing turbulence when using a filter style lid, given less air would come in from the sides (this is assuming the drop base size and filter size combination fit all other components).
Originally Posted by leigh1322
Lower than 3" on a 2" drop base puts the lid way too close to the carb inlet.
It might even hit the choke tower, I think there is only 3/4" clear there with a 3"
Lid design would impact the carb to filter lid measurement as well. I'm thinking more in terms of using all aftermarket parts.
An filter style lid would negate the impact of limited airflow to the carb (if the lid becomes very close to the carb), correct? Since air is now coming in from the top?
Hypothetically it seems the smaller side filter would minimize horsepower robing turbulence when using a filter style lid, given less air would come in from the sides (this is assuming the drop base size and filter size combination fit all other components).
Decades ago Holley performed tests. 3x14 is the way to go rather than a shorter one
In every "experiment" they do, their engine is breathing comfortable room-temperature air. You would not want your room to be the same temperature as what is found under the hood of a C3.
In every "experiment" they do, their engine is breathing comfortable room-temperature air. You would not want your room to be the same temperature as what is found under the hood of a C3.
Does the video say a 2" tall air cleaner is better than a 3" tall?
Does the video say a 2" tall air cleaner is better than a 3" tall?
I don't know. I didn't watch it either. But they do test one of those air cleaners with the filter in the lid.
And like many of their videos, there are a LOT of uncontrolled variables. Not only is a C3 engine compartment 100 degrees warmer, a C3 hood is right up against the top of the lid, so you are unlikely to get clean flow through the lid.
Does the video say a 2" tall air cleaner is better than a 3" tall?
That is exactly what I have done - having said that when the engine dyno figures were taken it was with an unfiltered velocity stack if I remember correctly - so other than perhaps putting the car on a rolling road 'now' I can't say if the 2" filter and filter top has a restrictive effect as compared with an unfiltered set-up in 'open air', given also that its all too close to the underside of the L88 style hood. The engine is in fact 'overcarbed' anyway with a 950 cfm DP.
I didn’t go back and watch the Engine Master’s video, but didn’t they tape up the sides of a 3” filter and just used the filter top?
If I remember it performed really well because the air flow was all in from the top and nothing coming in from the sides.
I also believe in this discussion early on that Lars commented on the airflow coming from both top and side was what caused the turbulence and was what made the filter lid a bad thing.
The front of my air cleaner is really close to the hood at the front of the lid but I have plenty of clearance starting a couple inches back.
My lid is completely flat but once the hood is permanently installed I plan to buy an oem style lid that is slightly taller towards the center of the lid to help create more distance between the carb base and lid bottom in the area directly above the carbs center.
I have a 1.5” drop base and a 3” tall filter which gives me 1.5” clearance.
With the oem style lid I might be able to increase the difference to 2.0” with is considered perfect.
I don't know. I didn't watch it either. But they do test one of those air cleaners with the filter in the lid.
And like many of their videos, there are a LOT of uncontrolled variables. Not only is a C3 engine compartment 100 degrees warmer, a C3 hood is right up against the top of the lid, so you are unlikely to get clean flow through the lid.
I never commented on that type of lid so not sure how I got dragged into that conversation. All I said is Holley tests from decades ago stated the 3" tall filter was the minimum height. It was way before a filtered lid existed.
I use the k&n tops air flow lids on all carbed vettes and find that they work better by letting more air in when I put a enclosed top on I had to turn the idle up it was so bad and then as soon as I went back to open lid rpm came back up and on I think it's power nation with the 2 guys one is younger and the other is older with a **** ton of pens stuft in his shirt pocket they did a test on engine with 500hp on a engine dyno and the top open lid was the best by a lot Im not trying to get into a big pissin match but just saying it works better for me .
that motor with a short team g intake makes over 650 hp
I never commented on that type of lid so not sure how I got dragged into that conversation. All I said is Holley tests from decades ago stated the 3" tall filter was the minimum height. It was way before a filtered lid existed.
I didn't mean to drag you into anything. Your post just reminded me that Engine Masters did a related test.
Originally Posted by 509 rat
I use the k&n tops air flow lids on all carbed vettes and find that they work better by letting more air in when I put a enclosed top on I had to turn the idle up it was so bad and then as soon as I went back to open lid rpm came back up and on I think it's power nation with the 2 guys one is younger and the other is older with a **** ton of pens stuft in his shirt pocket they did a test on engine with 500hp on a engine dyno and the top open lid was the best by a lot Im not trying to get into a big pissin match but just saying it works better for me .
that motor with a short team g intake makes over 650 hp
Thanks! I'd say your experience has more weight than most of the Engine Masters dyno test. Your car looks great on the track!
I'm disappointed with the reality that my AG can't really breathe as is!
I measured from the choke horn to the top of the filter w/straight edge.
Somehow 1 5/8 is not enough room to my inexperienced self.
I'm considering cutting a hole in the hood and running a 4" filter w/o drop base AC.
Your thoughts please?
they say 20 hp gain on just about anything .check them out .
