RPM VS Air Gap
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Instructor
Joined: Apr 2003
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From: Neenah WI
RPM VS Air Gap
Looking at two intakes for my 69 350/350 L46 motor.
I originally debated between the Edelbrock proformer and the proformer RPM, decided the RPM was better even with needing to put on a drop air filter.
Now I discovered their is a Proformer RPM Air Gap model that is to allow cooler air to the motor. Pricing isn't that different.
Any suggestions on this. I know cooler AIR is better but can it run too cool as to not allow the fuel to vaporate properly. I already have this issue with my edelbrock torquer intake. My motor runs cool 170 - 190 degrees.
I originally debated between the Edelbrock proformer and the proformer RPM, decided the RPM was better even with needing to put on a drop air filter.
Now I discovered their is a Proformer RPM Air Gap model that is to allow cooler air to the motor. Pricing isn't that different.
Any suggestions on this. I know cooler AIR is better but can it run too cool as to not allow the fuel to vaporate properly. I already have this issue with my edelbrock torquer intake. My motor runs cool 170 - 190 degrees.
Thread Starter
Instructor
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From: Neenah WI
Re: RPM VS Air Gap (comp)
Never drive it in the winter.
April - October is about all that Wisconsin allows.
Outside temp range from 45 - 95 degree days through out the summer. Normal is 75 - 80 when I have it out the most.
Got pricing the Air gap is $68 more, am I going to see these dollors in performance vs the RPM.
Any one have compairing numbers on these.????
April - October is about all that Wisconsin allows.
Outside temp range from 45 - 95 degree days through out the summer. Normal is 75 - 80 when I have it out the most.
Got pricing the Air gap is $68 more, am I going to see these dollors in performance vs the RPM.
Any one have compairing numbers on these.????
C6 the C5 of tomorrow
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From: Twin Cities Minnesota
Re: RPM VS Air Gap (69Sting)
IMHO
you don't have enough engine for the RPM Airgap. It flows better than the non airgap one if I remember right.
There isn't much temperature diff tween the two
Air gap is mostly for looks:smash:
You'll be very happy with the performance og the performer...
[Modified by 427V8, 12:13 PM 12/1/2003]
you don't have enough engine for the RPM Airgap. It flows better than the non airgap one if I remember right.
There isn't much temperature diff tween the two
Air gap is mostly for looks:smash:
You'll be very happy with the performance og the performer...
[Modified by 427V8, 12:13 PM 12/1/2003]
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From: eville in
Re: RPM VS Air Gap (427V8)
427 probably right about not enough engine mods. the have a performer
air-gap . i look at it like this at operating temp. i can leave my hand on air-gap standard intake gets to hot to leave. i'd rather have my face above the
stove than on it..
air-gap . i look at it like this at operating temp. i can leave my hand on air-gap standard intake gets to hot to leave. i'd rather have my face above the
stove than on it..
Melting Slicks
Joined: Jan 2003
Posts: 2,804
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From: OKC Oklahoma
Re: RPM VS Air Gap (69Sting)
I don't think that the AirGap will have anything to do with engine cooling. It only cools the intake charge for more horsepower. The cooling of the engine has nothing to do with the intake. (not in this post anyway)
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From: Neenah WI
Re: RPM VS Air Gap (79VetteMike)
I am not looking for cooling the engine.
Just woundering if I would vaporize the fuel enough if the air gap puts cooler air in. that would mean the temp to vaporize the fuel would be lower as well. Since I run cool already would this lower temp hurt the fuel vaporization process. That was the only reason I mentioned the engine temp.
Sounds like if I had a larger motor or more heavily modified the Air Gap would show some difference but since I run only slightly modifications the Air Gap would be just spending more money for the same result.
Just woundering if I would vaporize the fuel enough if the air gap puts cooler air in. that would mean the temp to vaporize the fuel would be lower as well. Since I run cool already would this lower temp hurt the fuel vaporization process. That was the only reason I mentioned the engine temp.
Sounds like if I had a larger motor or more heavily modified the Air Gap would show some difference but since I run only slightly modifications the Air Gap would be just spending more money for the same result.
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From: Waterford Mi
Re: RPM VS Air Gap (69Sting)
Just for those who are wondering. I got this from there web site:
Intake Frt. Rear Height
Performer #2101 (3.50+4.60)/2 = 4.05
Performer Air Gap #2601 (3.72+4.92)/2 = 4.32
Performer RPM #7101 (4.00+5.30)/2 = 4.65
Performer RPM Air Gap #7501 (4.20+5.25)/2 = 4.725
Intake Frt. Rear Height
Performer #2101 (3.50+4.60)/2 = 4.05
Performer Air Gap #2601 (3.72+4.92)/2 = 4.32
Performer RPM #7101 (4.00+5.30)/2 = 4.65
Performer RPM Air Gap #7501 (4.20+5.25)/2 = 4.725
Le Mans Master
Joined: Jun 2003
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From: Not Correctly Restored Stingray Fla.
Re: RPM VS Air Gap (redwingvette)
I will tend to disagree with 427vette, If I am not mistaken!!! The air-gap has longer runners which is always better (if you make the needed carb. adjustments) more air + more fuel = HP. Also the "slight" cooler temp below the carb. is much better. Just think a certain % of the air/fuel mixing is happening OUTSIDE the intake valley. You might not feel it on your "face"but I'm sure there is a difference in temp. Just to go to an exteme, look at the "big boy" fabricated intakes..... Long runners & air-gap"S" between the runners and everything!!!!
Le Mans Master
Joined: Oct 2002
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From: Silver City NM
St. Jude Donor '05-'07
Re: RPM VS Air Gap (lotahp)
But IS it really "slight cooler temp below the carb"? There used to be (may STILL be!) a manifold that had a little scoop cast in front of it to move air through it to cool it off. I think a lot of this stuff is like fishing lures. Made to catch the fisherman instead of the fish. The aluminum manifold WILL be cooler than cast iron, but what REALLY needs to be cooled down is the air flow coming INTO the carb and all the way down to the combustion chamber.
If you pulling air into the carb from the surrounding engine compartment, then you are defeating the air gap or any other manifold that has open space underneath it.
A lot of heat is STILL being radiated up from the engine to the bottom of that air gap manifold. I think the only REAL way you would cool the runners would be with one of the high rise single planes like the Dart, Holley Strip Dominator, or Brodix. No exhaust crossover and no water passages except for the very front. With a manifold like that and cold air induction via a hood scoop or cowl induction, you are REALLY making a difference in the density of the air getting to the engine.
Don't forget, the "big boys" get their air from OUTSIDE the car!
Dep
[Modified by Dep, 3:59 PM 12/1/2003]
If you pulling air into the carb from the surrounding engine compartment, then you are defeating the air gap or any other manifold that has open space underneath it.
A lot of heat is STILL being radiated up from the engine to the bottom of that air gap manifold. I think the only REAL way you would cool the runners would be with one of the high rise single planes like the Dart, Holley Strip Dominator, or Brodix. No exhaust crossover and no water passages except for the very front. With a manifold like that and cold air induction via a hood scoop or cowl induction, you are REALLY making a difference in the density of the air getting to the engine.
Don't forget, the "big boys" get their air from OUTSIDE the car!
Dep
[Modified by Dep, 3:59 PM 12/1/2003]
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From: eville in
Re: RPM VS Air Gap (Dep)
i didn't compair the air-gap to a iron man. it was to at stock GM alum. intake
and yes IF i go fishin' i put something on the hook,, not just throw it in the water. also use outside air not under hood(easy 80 plus deg. cooler)
and yes IF i go fishin' i put something on the hook,, not just throw it in the water. also use outside air not under hood(easy 80 plus deg. cooler)
Drifting
Joined: Dec 2002
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From: New Zealand
Re: RPM VS Air Gap (69Sting)
I too had a Torker single plane and ditched it for the Performer because the Torker is for high end applications (2500-6500RPM) and the Performer is good for idle to 5500rpm.....I chose the Performer because I am only interested in street cruising and low end torque........I operate from idle to 4000RPM, so I don't want an intake that kicks in outside my rev range......
I panned on the Performer RPM because it's outside my range (1500-6500RPM) and the idea that this dual plane acts like a single plane sounded like :bs to me.......
I panned on the Performer Air Gap because this is a high rise dual plane and although good from idle to 5500RPM, there was doubt in my mind that it would fit under the hood even with a drop base and a 2.5" filter......plus the idea that Edelbrock has adopted the design from their Victor Series race single plane intakes makes me think that they're experimenting and I'm the guinea pig........more :bs :bs
The Performer Air Gap may offer a denser charge, but how many tenths of a second is that going to knock off if you're cruising????? And Dep is right.....if you want cold air, bring it from the outside......
My vote is for the basic Performer......hope this helps :cheers:
I panned on the Performer RPM because it's outside my range (1500-6500RPM) and the idea that this dual plane acts like a single plane sounded like :bs to me.......
I panned on the Performer Air Gap because this is a high rise dual plane and although good from idle to 5500RPM, there was doubt in my mind that it would fit under the hood even with a drop base and a 2.5" filter......plus the idea that Edelbrock has adopted the design from their Victor Series race single plane intakes makes me think that they're experimenting and I'm the guinea pig........more :bs :bs
The Performer Air Gap may offer a denser charge, but how many tenths of a second is that going to knock off if you're cruising????? And Dep is right.....if you want cold air, bring it from the outside......
My vote is for the basic Performer......hope this helps :cheers:
Le Mans Master
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From: Not Correctly Restored Stingray Fla.
Re: RPM VS Air Gap (standup)
YO GUYS!!!! We all know a "chick" with an AIR-GAP is awesome and breaths alot better :lolg: :lolg: So it must be great for your Corvette to have an AIR-GAP also!!! :lolg: :lolg: :lolg:
Pro
Joined: May 2001
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Re: RPM VS Air Gap (Dep)
But IS it really "slight cooler temp below the carb"?
A lot of heat is STILL being radiated up from the engine to the bottom of that air gap manifold.
A lot of heat is STILL being radiated up from the engine to the bottom of that air gap manifold.
When I take her for a quick spin, yes, the runners and carb are cool to the touch, -does this make "noticable" extra power... probably not.
When I take her for a 30 min. run or more, the carb is hot to the touch, just like if the air-gap wasn't even there.
Maybe on a bracket racer who ices down the manifold before a 1/4 run can benefit from the air-gap, but on the street, the runners and carb will eventually get soaked with heat too.
BTW, just in case you haven't heard all the buzz, you will have to do some creative work with an RPM manifold to get hood clearance. Easy stuff like a drop-base air cleaner, re-routing vaccum lines/ fittings, maybe a thin carb spacer and such.
Le Mans Master
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From: Not Correctly Restored Stingray Fla.
Re: RPM VS Air Gap ('75 383 ElkGrove)
You guys need to understand, a lot of little, minute things do ADD UP. No you are not going feel the difference with your hand. When that engine warms up, IT'S HOT ALL OVER. But if you can raise the ionizing (if that's correct terminology) out of the engine valley and make 50, 75, maybe even 100 degrees cooler it helps. Tell me, by touch, can you tell the differnce between 175 degrees and 225 degrees??? Of course not. But again all these very little things add up and helps the engine run more efficient and get the most power out of what you got.!!!!! Without a temp gauge, you couldn't tell if the engine is running 175 or 205 and I know my engine wiil run alot better at 175.
Le Mans Master
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From: Silver City NM
St. Jude Donor '05-'07
Re: RPM VS Air Gap (lotahp)
I think you are dealing in "fractionally" better performance. As in MAYBE getting 1 or 2 extra horsepower from running a tiny bit cooler. A better improvement would be some form of external intake of air to the carb.
Then you will have a NOTICEABLE increase in performance. Don't forget, the air blowing UNDER that carb isn't coming from OUTSIDE where it's nice and cool. With the hood closed on a warm day, that measureable difference will be a LOT less. Certainly NOT 30 degrees of temp. If you REALLY want to cool things off where it counts put a spacer between the carb and manifold. Chevy sells a metal plate that goes under the carb to reflect away heat (heat RISES you know) :)
Dep
Then you will have a NOTICEABLE increase in performance. Don't forget, the air blowing UNDER that carb isn't coming from OUTSIDE where it's nice and cool. With the hood closed on a warm day, that measureable difference will be a LOT less. Certainly NOT 30 degrees of temp. If you REALLY want to cool things off where it counts put a spacer between the carb and manifold. Chevy sells a metal plate that goes under the carb to reflect away heat (heat RISES you know) :)
Dep
Team Owner
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From: eville in
Re: RPM VS Air Gap (Dep)
allways run ''fresh air'' only time i don't is when it's well below freezing. and
if i wasn't trying to have it run as well as possible i'd take some timing out,
just so i could run junk gas
if i wasn't trying to have it run as well as possible i'd take some timing out,
just so i could run junk gas
Le Mans Master
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From: Not Correctly Restored Stingray Fla.
Re: RPM VS Air Gap (Dep)
[QUOTE]I think you are dealing in "fractionally" better performance. As in MAYBE getting 1 or 2 extra horsepower from running a tiny bit cooler. A better improvement would be some form of external intake of air to the carb.
Then you will have a NOTICEABLE increase in performance. Don't forget, the air blowing UNDER that carb isn't coming from OUTSIDE where it's nice and cool. With the hood closed on a warm day, that measureable difference will be a LOT less. Certainly NOT 30 degrees of temp. If you REALLY want to cool things off where it counts put a spacer between the carb and manifold. Chevy sells a metal plate that goes under the carb to reflect away heat (heat RISES you know) :)
I WILL REPEAT MYSELF !!!!! Alot of little things WILL ADD UP.
No you will not feel 1,2 or 3 horsepower gain. I bet you wont even feel a 10 horsepower gain!!!! the manufacturers (in 99% of the time) do not do this for nothing. That is why there is TESTING. Hey, if you get 2-3 hp here, and 3-5 hp there, and another 3-5 here and get "the mother" tuned right IT ALL ADDS UP. That's what we call "TWEAKED"!!!!!! :rofl:
Then you will have a NOTICEABLE increase in performance. Don't forget, the air blowing UNDER that carb isn't coming from OUTSIDE where it's nice and cool. With the hood closed on a warm day, that measureable difference will be a LOT less. Certainly NOT 30 degrees of temp. If you REALLY want to cool things off where it counts put a spacer between the carb and manifold. Chevy sells a metal plate that goes under the carb to reflect away heat (heat RISES you know) :)
I WILL REPEAT MYSELF !!!!! Alot of little things WILL ADD UP.
No you will not feel 1,2 or 3 horsepower gain. I bet you wont even feel a 10 horsepower gain!!!! the manufacturers (in 99% of the time) do not do this for nothing. That is why there is TESTING. Hey, if you get 2-3 hp here, and 3-5 hp there, and another 3-5 here and get "the mother" tuned right IT ALL ADDS UP. That's what we call "TWEAKED"!!!!!! :rofl: