Torn between two different intakes

At first I thought of the air-gap as just nice marketing, but now I'm really wondering.

I know an intake manifold gets pretty hot not matter where you touch it, and I didn't see seperating the runners making that much of a difference, but now I'm wondering if this is the case.

Infact, if (for some weird reason) you wanted to heat the intake charge, you would do what every conventional intake manifold does. Pass the fresh air/fuel right by the hot engine oil and coolant.

BUT the air-gap has a gap here. Not sure why this wasn't produced before the air-gap. It seems like a simple concept.

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If you have a conventional intake manifold oil and water flow next to it acting as a heat source for the intake manifold. The intake charge would then flow along this heated aluminum.

With the air-gap the hot oil/water would heat the bottom of the intake and would have to radiate heat up to towards the carb. So heat would have to flow through the surrounding air to heat the plenum.

BUT the runners of the air-gap still touch the lower portion of the manifold. This would only allow heat to conduct its self up the intake manifold.

I would say it WOULD SEEM the air-gap should make for a 'slightly' cooler intake charge, but would it be neglideable? I don't know.

If anyone has a pryometer laying around and both intakes please take some readings for me!?

Aside from that I only have information like this,

http://www.fordmuscle.com/phpBB/viewtopic.php?topic=20690&forum=1

Where someone claims to have went from 13.7's to 12.9's by installing a RPM air-gap.

I'd like to get some before/after intake runner temps if I do decide to go with the air-gap.






No one on the board like paying too much for something that can be had cheaper and does the same thing (unless you pay to take your car to the dealership). So, this leads me to thinking is the air-gap worth the difference in increased price?

I'm leaning towards yes, but if you have any further reasoning or any source that you would like to quote... please contribute.

The intakes I am looking at are:

http://store.summitracing.com/partdetail.asp?part=EDL%2D7116

http://store.summitracing.com/partdetail.asp?part=EDL%2D7516

(ALSO BOTH INTAKES ARE AVAILABLE FROM
www.cnc-motorsports.com in an off brand)


These are all for my 350HO Gm crate engine. Dyno sheets from carcraft for this engine can be found at

http://www.carcraft.com/projectbuild/116_0403_mail/index.html

This intake is for that motor with a 750 double pumper on it and 1.625" headers. The motor spins a 2400 rpm (cheap) B&M converter. It's geared with 3.42:1 gears and is 90% street driven.

So, it is marketing or is the air-gap any better than the vortec RPM?

Ben T.

If anyone has a pryometer laying around and both intakes please take some readings for me!?
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its not the air-gap making the gains in Torque/HP

its the runner length, cross-sectional area , and shape making the real gains


the Air-Gap does matter slightly, but its advertizing !


and the RPM Air-Gap intake is really that good as claimed
atleast in my dyno tests

with bone stock Cylinder Head flow/shape..maybe not so much gains or difference

with Cylinder heads with great valve job and a little bowl-porting and port matching...the RPM Air-Gap starts to make healthy gains compared to similiar style intakes

the Victor Jr just starts to pull away at 4500 rpms from RPM Air-Gap intake on most 355 cid engines

the RPM Air-Gap is better 4500 rpms and lower

the Victor Jr is dead even at 4500 rpms
and climbs higher above 4500

depends on what your application is ??

the RPM Air-Gap dual-plane will love 750-780 cfm carb

if an engine didn't have a hood, the whole air gap design might be more effective aye? I have the RPM Air Gap on my engine and I'm glad to say it's clearing the hood with a good drop base and 2.75" air filter.:) Pulls clean to 6500+ as advertized.

http://www.popularhotrodding.com/enginemasters/0301phr_rmouse/

That article is on Dan Crower's engine entry in PHR's Engine Masters Challenge. They made some pretty impressive 3000-6500rpm average HP/TQ numbers using L98 Vette heads and an RPM Air Gap!:eek: The Dyno files are here: http://www.popularhotrodding.com/enginemasters/dynopulls/

Download that SuperFlow program to view ALL of the dyno results. Well worth it. I spent a lot of time looking at the numbers and going back to see what parts were used, etc. Kinda fun for a gear head.:bow:

544hp/518TQ...It definately didn't win and was roughly 65HP shy of the winner and a couple ft-lbs but cost wise That is a street happy killer of a small block.

Denny,

Good comparison, but the Crower motor was a stone compared to Beck and Shermans Chevy motors.

Beck had the GMPP Fastburn heads and a RPM Air Gap intake and he finished in 3rd. Sherman used a Super Vic and won. If you overlay Sherman and Beck you will see where the Super Vic makes more power.

Now Sherman had a more expensive motor, AFR 215's and about $20K to duplicate fully. Beck had a very reproduceable motor that worked like a champ and turned out to be a better motor than the Crower boys entry.

If you look at the 2nd place guy Storlien, he worked heavily on heat reduction and keeping heat out of the intake area.

I know when we dyno tested our motor I did heat readings on the intake to make sure the motor was consistant before we did a pull. While running even at idle the intake temp was 110degs in the dyno cell, if you shut the motor down for a "cool down" you increased the intake manifold temp from 110 to 140-160, so the air moving thru the intake helped keep it cool.

Now heat helps the vaporization of the fuel in the air , but a good intake will help prevent fuel drop out. The colder intake will keep the air fuel charge denser containing more oxygen and in turn requireing more fuel which means more power.

In my book the air gap design is a fundemental part of good intake design, along with good dry and wet flow characteristics along with the right cross section and runner lengths for the motor. Anything you can do to keep the intake charge dense and cool makes HP for you.

I have to agree and disagree with Larry on the RPM Air Gap vs. the Super Vic arguement. The Engine Masters contest works solely on a 2500-6500rpm scale and maximizing the average TQ and power there, the contest has proven that the strongest motors use a single plane design. IMHO that's because the intake makes power for you in th 4000-6500rpm range and the dual plane hurts that range while the lower 2500-4000 rpm range is effected by DCR, carb, valvejob, cam and port size more than anything and in a cube restricted class those things are super vital to making power numbers down there. At least that's what I have found.

On top of that.... even with a big 1-2 split in gears like a 4L60 (yes I have the joy of being young enough not to worry about PGs!) will drop from 6500-4000 so all you have to do is get the puppy to launch hard as a street car and you are going to gain more from the single plane since the motor only see's below 4000 in 1 gear all though it is the most important gear. On street tires I would say it's the least important RPM range to make power in unless you don't have enough power and have too much weight. Not enough power is something I don't really worry about! lol

Bret

I have to agree and disagree with Larry on the RPM Air Gap vs. the Super Vic arguement.
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Bret ,

in my previous Post it was

Victor Jr. -VS- Rpm Air-Gap

and not ;

Super Victor -VS- Rpm Air-Gap :)