Edelbrock single plane (Victor Jr) vs dual plane (Air-Gap) intake manifolds on the same engine in a dyno test at Westech Performance. Plus a test of the Air-Gap vs Regular dual plane intake manifolds. This is an episode I edited.
Pontiac guys have known this for many years. Except we only cut down the back half of the divider so the secondarys take advantage. Test have been done on this with regular performer and Qjets and that lil trick will definitely add power and smooth everything out.
I have run several engines with the regular Performer RPM 4150 and a 1” open spacer. They look factory and run well. My last engine was a 468 BBC with a Comp Cam’s hydraulic, similar to the Edelbrock RPM hyd. camshaft. We added a 1” open spacer, under a Holley 850 HP and made 537 hp. This was with a mechanical water pump, NOT electric water pump, but what you typically see on a street car. All run through 2” Hooker Comp headers, 3” full exhaust to rear bumper. In a 3,925 lb. ‘66 Bel Air, weight with driver, in as driven on the street, except for 9” radial slicks, ran 11.51 @ 116.51 mph. This was with a Turbo Action 10” street converter (tight) with a flash stall of 3,800 rpm’s.
I have completed the same mods to my Performer RPM 1" spacer and milled divider and it works on my 383 stroker 350 with Victor Jr heads we also port matched the intake and a general clean up on the castings. Great job guy's and in idles sweet as.
Great test and very informative but its important to note that a change in cam profile such as something with more over lap for example can throw those results out the window and have a very different out come. There are many different factors to consider, and all engines and set ups should be tested individually. Keep up the good work and look forward to more testing on different combo's.
Exactly right. I decided to test the Air Gap over a well established single. Multiple carbs with each setup dialed in and found the more spacers added the better it ran but not close to the single. You can feel the torque go away above 5k. The Air Gap is on the shelf collecting dust. It ALL depends on the build and the chasis.
I used suck,squeeze,bang,blow as a answer to homework when I was going to Harley school in Phoenix in 93 too funny.Other students wrote pages on how a four stroke works all I wrote was those four words .He got a good laugh
an additional interesting comparison would be to put a plenum divider in the vic jr and also notch it the proper amount at the top and see how much, if any, low and midrange torque the vic jr can gain on the air-gap dual plane. it would also show if the divider in the vic jr would cost some high rpm hp.
Great info guys !!!, I just built a 355 SBC, AFR 195 and a solid roller 242/248 @ 0.050 with 570 lift, Victor Jr, 10.7CR and 750 carb, we made 481 and 428 fts lbs. I have a video on my youtube page. It's in a manual car so very spongy below 4000 rpm, we were thinking of going the Air gap to fire up the bottom end a bit. This video has help alot. Cheers from Australia . Mario
Great video. Really wanted to see the 1 inch spacer on the air gap rpm though. that's what's going in my 383 next week so hopefully makes a difference over the regular rpm in my setup
Keep in mind the reason for the air gap is to keep fuel temps cooler...so for my money the air gap is my choice on cruise night, cross country, or towing. Pontiac did this on all it's factory V-8's.
A single plane intake will always make more hp than a dual plane intake. Just at a higher rpm. This is a very old video, but I recall them doing the test again on Engine Masters and of course the single plane won.
chief slap a ho from the slap a ho tribe on my 383 small block Chevy I ran the air gap RPM for a little over a year and loved it, but after speaking to my cam Builder we installed a single plane Jr Victor intake. lost zero throttle response or lower end torque...but gained mid-range and upper horsepower at least by 20whp...car is a pleasure to drive around town, idles great and puts you in the seat when I hit the pedal..
I have a 347 sbf. I had a Victor Jr. also and car ran perfect. I changed to a funnel web single plane and it is kind of like a super victor in a way with height and it is a happy engine. Had a 327 sbc with a dual plane in the past and switched over to a victor jr and it screamed. After that just preferred single planes over dual planes for a street strip car.
chief slap a ho from the slap a ho tribe right on! Yeah I'm sticking to the Victor jr. As well. Especially after seeing the graphs showing no loss and more horsepower.👍
I had the same reaction , "I wanna see this " ........We have a lathe big enough in our shop but would use the mill , which is what he obviously meant to say , lol .
Something that rarely gets covered in these tests is carburetor changes and tuning. A larger CFM, Annular boosters and tuning would change quite a bit of the outcome. The AirGap wouldn't be able to utilize the extra air volume but would be much more in line with recommendations for the Victor Jr. This type of testing is "step one" of dozens of tests needed to draw the multiple conclusions on these setups. Using the same carb and no tuning is like using the same tires on both a quarter mile vehicle and on a road course! Great video but lets see the other 98% also.
Yeah I would definitely say it's early engine Masters, but then again I would say engine Masters is one of the best. There's so many other channels that just are complete nonsense and dragged out all the unimportant stuff and fast forward of all the important stuff because they're afraid it may be conceived as boring. If you need fake reality TV drama go watch the Kardashians, but for some of us who actually like the in depth technical stuff that may not be so dramatic to watch but is actually informative. I just wish that there was more engine Master episodes. I haven't seen a new one in a while. Roadkill is okay but I'm definitely a fan of engine Masters.
Used all of these one time or another agreed dual planes are impressive especially on heavy drivers, also used the jnr tall version in a very mild 350 z25 isky 10.5 comp glide 3500 convertor 4.50 and 28 " tires 3 years 11.os best 10.85 Sydney dragway cold night.
I'd love to see a old vintage Torker Manifold vs. Torker II, RPM Performer and a Air Gap RPM Performer. I'm a big fan of the Torker on a SBC, with the right combination of parts, it kicks ass on the track and street...
look at the intake manifold ports with a gasket to see if Manifold and head come even close to matching. I found the RPM is perfect port matched to the heaed wher as the Vict Jr and Super Vic really need port work at openings
haha that's awesome! I've been looking for a video like this for SSSOOOOO long, thanks guys, i'm actually putting a Performer RPM manifold on my 283 later on this week =]
Air gap is to keep hot oil off of the underside of the intake heating the incoming air charge. The single plane only starts to work after 6k. That cam is actually very large and high compression is not your typical street rod. Your results would have been more dramatic had your cam and compression ratios been more mild.
Sounds a bit better than what I'm trying to do. Going brodix ik200's, solid roller 241/247 @.05 w/ .570 lift, Edelbrock performer RPM air-gap, 10.6 CR 750 Holley DP and looking for a M22, m21 or t-56 to throw behind it. Really find the cam hilarious. Going a little tight on quench with mine about .038. Hoping to make 400/400 minimum anything over that would be a bonus.
Is spacer open or 4-hole? Also thoughts about using a phenolic spacer instead of aluminum to reduce heat to the carb or Holley Sniper. I’m planning on using Holley Sniper with Air Gap on my 383 sbc.
What are the dimensions for the divider relief you milled on the RPM manifold? Depth, length and was this centered or offset? Curious if this would also help the regular performer manifolds.
depends on the vehicle you're putting the engine into. A TORKER 2 intake manifold is not designed for heavy vehicles. I have one that one a 350 in my truck and its sluggish in the low end, but i will say it does make some AWESOME power in the top though. I am going to switch back to the performer after watching this though.
I have an offenhauser 360 intake for a sbf laying around. The machine work you did to the divider in the middle is similar to how the offey is setup from the factoy. it has like a 3/4"x3/4" square knotch out of the top of the divider.
i think on the performer intake i would have used the spacer from edelbrock that takes a square bore carb to a spread bore manifold and tried that it just seems to match the plenum from the design of the spacer so no air is leaking (whistling)and the gasket doesnt get saturated with gas like i seen when you had the open hole spacer which seems to work with wot pills or racing but for daily driving in stop and go isnt the way to go..just my experience.
The victor junior was for race cars, back in the 80’s they didn’t make that other intake I’m sure there’s plenty of intakes better than the victor jr. out there today
Eric, what would be the benefits of running the dual plane over a single plane for street / racing . I am wanting to get one of the Chinese copy’s of an Edelbrock air gap manifold but I can seem to find a copy of the performer rpm air gap. And the only air gap copy I can find is the Victor Jr. air gap copy.
With that parts list, it should have made more power. I've seen 350s with hydraulic rollers and modified vortec heads make as much or more power than this engine.
Why did he say he needed to add an "adapter plate" to use a holley 4150 on the Performer RPM Qjet manifold? The RPM Qjet is drilled for both carburetors already?
So what you guys basically were saying, and correct me if I'm wrong; but if I add a 1" spacer on top my Performer RPM AirGap intake. I can squeeze a bit more horse power in on my power curve? Please tell me yes. I'll get a spacer right now.
my experience with the airgap is very poor cold weather performance. she loves hot and humid air though. going with a non air gap for this new engine. this is a street car, drive it e ery day so I'm hoping the Wieand street defender, or whatever it's called, I bought will help. gasoline has to vaporize guys, so some heat is necessary on these street cars for driveability. yeah I'm giving up volumetric efficiency but, unfortunately, I can't drive at WOT the whole way to work. I bet it's just the vaporization though. wondering if my propane engine will solve this type of issue.
+james myers I'm not sure how it'll perform on a mopar block but I'm sure it couldn't be much different. mine's all stock minus the bolt ons but I could definitely tell it had more umpf in the mid
I am using the Holley Terminator EFI system on my 400 Firebird. Mild cam bored etc. I have the Edelbrock RPM dual plane manifold. I am experiencing a tip in stumble at lights an I think it could be from the divider in the middle of the manifold. Can I expect to alleviate my issue as well as get a bit more out of it if I mill out an air gap on my manifold? Do not think I have enough clearance to do a spacer as well.
Man! I just bought a Holley 750 double pumper and the Edelbrock air gap intake for my 383 with vortec heads from a 99 Escalade. I want to know the 1" spacer difference!? Please?!
