[64speed]

So I was watching one of the hotrod shows that comes on the motor trend network and they were comparing the sniper with a double pumper on a Chevrolet performer RPM air gap and a regular Torker II and the results were shocking. They found that the open plenum of the design made less power than the RPM with the sniper. I would think the Torker with it’s easy path to the runners would make more power and that’s why I bought the Torker. Anyone seen this in real life? Not interested in changing anything in my motor but I was just thinking to future builds. The RPM beat the Torker on every test carburetor or sniper.

[Tom Vaught]

Do not understand "real life" vs Testing on a Hot Rod Show. Wasn't that a "real life dyno test"?

That being said, the RPM Intake (Chevy or Pontiac) was always a very good Dual Plane intake.
The physics of how the air and fuel from a Double Pumper Carb and Sniper unit travels thru the intake runners/plenum to get to the individual cylinders does not change.

The Dual Plan has nice even pulses of fuel/air to the two different intake planes.
The Torquer style intakes as well as most single plane intakes has the fuel and air mixture violently going back and forth between the runner inlets.

The Sniper electronic fuel metering does nothing when your nice clean air/fuel mixture (from the carb booster or the booster on the Sniper) gets 'disorganized" when inside the plenum. That is why the dual plane intake is a much better street type intake and typically will make more power across the entire power band. Hot Rod Open Plenum intakes might be better on some of the high rpm points.

Just Basic Physics documented again on a TV Program or Internet Video.

Tom V.

["QUICK-SILVER"]

This video out for free on you tube yet?

If results were shocking it sounds like the engine was purpose built for a dual plane intake.

FWIW Don't let chevy testing influence your plans for a Pontiac build.

Clay

[Formulajones]

Every single plane I've ever used or tested worked better with a spacer, didn't matter if it was a mild or wild build.

Betchya if they put a super sucker on that single plane intake the results would have been vastly different.

[pastry_chef]

Originally Posted by 64speed

Chevrolet performer RPM air gap and a regular Torker II

SBC?
I've never known anyone who uses a SBC Torker2. Not the intake to have.

Also finished dead last in this test.
https://www.hotrod.com/articles/19-s...-intakes-test/

[tom s]

I have had 2 experience with back to back testing on a true everyday type driver with single plane to dual plane intakes,one on a 455 440ish HP engine and the other a 366 RA V 450 HPs engine.The 366 with the single plane was a little soft on the bottom end(huge ports) and the AFRs were all over the place.Holley vac secondary 780.On the highway at around 2000 they were 17-1 and up and down the gears all over the place.Put a factory dual plane on,AFRs on the highway went to stable 12.5-13-1 and were more stable up and down the gears.The 455 had a street dom and were in the 15s on the highway and better than the 366 up and down the gears.Changed to a E performer and solid 12.5 13 on the highways and more stable up and down the gears.IMO direct port injection and a single plane would shine on the street.This was a hard test as the stick shift car has a final rear of about 2.11 and all the driving in from off idle to max of 2000 and much done at around 1500-1700.Because of the TA upper and lower pans no spacer of any kind could be tried.FWIW.Tom

[Schurkey]

The TBI forum I look at has, in general, a very favorable opinion of single-plane manifolds WHEN USED WITH TBI.

Note that many aftermarket TBI systems also ship with a single-plane manifold.

The TBI, unlike a carb, does not rely on manifold signal (vacuum/velocity) to draw fuel. How the manifold handles that fuel (wet flow within the manifold) is dependent on the manifold design, runner configuration and size, etc.

[pokey1]

Not sure what difference that direct port vs throttle body would be but last winter when I was putting the EFI on my 467 I went with throttle body and had a dual plane intake (performer RPM) on the motor and was told it would work but I should cut the divider like an air gap so it could equalize between the 2 sides so the fuel could atomize better. The dual plane would work this way but could cause other small issues or hesitations. I went with a single plane (northwind) intake and my performance improved from the bottom end RPM's all the way through the top end.

[64speed]

I in my layman’s mind just thought that a single plane while probably lower on torque off idle would see more even distribution with the Torker over the performer RPM. I have a one inch four hole spaced mainly to cure the snipers dreaded whistle but hopefully it will do some good to. We will see in a few years

[Lee]

I put a FAST EZ 2.0 on a mild 350 sbc ('72 El Camino) a few years ago. It had the Edelbrock Performer EPS (newer revision of the Performer, square-bore only design) for an intake. I had it running pretty well, and strapped it to the chassis dyno. I tested it with and without a 2" open spacer - the HP and TQ graphs were virtually identical.


On my '73 T/A clone, I have the FAST XFI Sportsman efi system on it. I've ran both a Performer and a Holley Street Dominator on it. I really can not feel any difference in driving around, between the two. The hood scoop fits better with the Performer, so that is what is on it right now. A series of unexpected things have kept me from being able to do any dyno testing for the last year, but I hope to be able to put the car on the dyno next spring, and test a few different intake manifolds.

[jerry455]

I think because the TBI works very similar to a carburetor, where there is an air/fuel mixture, that the dual plane works better in most street applications than a single plane. If you are using multi port system where the injector is at the entrance of the head than there will only be air in the manifold.

[Steve C.]

From the internet, and regarding underhood heat.....

In a wet-flow system, a mixture of air and fuel coarses through the intake-manifold runners; in port systems, the fuel is administered at the end of the intake-manifold runner just prior to entry into the cylinder head. The laws of physics dictate that for every 10 degrees Fahrenheit of change in the temperature of the charge, there will be a corresponding effect of 1 percent to the specific output of the engine-raising the charge air temperature will decrease power; cooling it will have the opposite effect. Wet-flow manifolds enjoy the advantage of cooler charge air temperatures created by the vaporization of the fuel. When changing from a liquid to a gaseous state, this transformation will consume some of the heat from the intake tract. Dry-flow manifolds do not benefit from the latent heat of vaporization.

The results of this phenomenon cause fuel-injected engines to be affected more by higher ambient temperatures and underhood heat. EFI racers know that a bag of ice on the plenum after every run is essential to obtain maximum performance. For this reason, the latest in engine technology from Detroit utilizes intake manifolds fabricated from thermoplastics such as DuPont Zytel, a material relatively impervious to heat. Thus, underhood or ambient temperatures have less of an effect on the specific output of the engine. Chevrolet’s new LS1 and many other engines use this technology.

With this in mind, a throttle-body-mounted air filter may look trick, but it ingests preheated underhood air from the radiator and the engine compartment. The best-running EFI cars breathe cold air from a ram-air kit. Mustang 5.0L engines are very susceptible to an idle instability when an open-element air filter is attached to the end of the mass airflow (MAF) meter. The turbulence created by the engagement of the clutch fan causes pockets of low- and high-pressure air entering the MAF sensor, technically referred to as fan wash. This creates idle instability, especially if the engine is fitted with a performance camshaft. A simple sheetmetal shrouding will effectively isolate the air filter from this turbulent air.



.

[JLMounce]

I currently run a Tii under my Fitech and previous to that I ran a P4B. The car ran well with both intakes. By checking plugs I can state that at least in my situation, the Tii distributes fuel more evenly than the P4B did.

I can't comment on power because the heads and cam changed along with the intake, so it's not an apples to apples comparison.

It's also possible that the head and cam change may have also effected fuel distribution between the two manifolds as well. I'm just reporting my observed evidence.

FWIW the TBI manufacturers basically all state to run whichever manifold you'd typically run for your combination with a carb.

[Formulajones]

Originally Posted by JLMounce

I currently run a Tii under my Fitech and previous to that I ran a P4B. The car ran well with both intakes. By checking plugs I can state that at least in my situation, the Tii distributes fuel more evenly than the P4B did.

Interesting you say that. That's typical of many dual plane intakes. Usually I stagger jet a carb to compensate for that. I guess you cant change injector pulse width individually on these throttle body tunes...?? So I assume that's a tuning feature we lose when switching from carb to throttle body style fuel injection.

We used to increase injector pulse width on cyl #7 when tuning LS engines. It was interesting that even with a big plastic open intake and multiport fuel injection, #7 cylinder still ran lean on those engines.

[JLMounce]

Originally Posted by Formulajones

Interesting you say that. That's typical of many dual plane intakes. Usually I stagger jet a carb to compensate for that. I guess you cant change injector pulse width individually on these throttle body tunes...?? So I assume that's a tuning feature we lose when switching from carb to throttle body style fuel injection.

We used to increase injector pulse width on cyl #7 when tuning LS engines. It was interesting that even with a big plastic open intake and multiport fuel injection, #7 cylinder still ran lean on those engines.

The systems are batch fire, so there's no real injector timing at play. Pretty much the same you get with the venturi effect, it's just offered via opening the injector.

Now I didn't really think about this until you brought this up just now, but with FiTech you have the ability to change injector flow rates in the software (should you upgrade to larger injectors). Considering you can do this for each individual injector, you could conceivably "trick" the computer into providing more or less fuel to a given bore by altering the injector flow rate in the software.

This would allow you to do exactly what you were doing with the individual jets in the carb. It would take some trial and error and reading of plugs to get it right. If I'm thinking about this correctly, if you wanted to lean out specific cylinders, you would add injector flow rate to the injectors associated with the throttle bores for cylinders that are too fat. You'd go reverse if you need to fatten up a cylinder or two.

This could be useful for people that run boosted applications with hats that may direct airflow un-evenly. Add some fuel to the rear throttle bores to compensate.

[Formulajones]

Interesting, it really sounds like the Fi-Tech software is more refined then some of the other offerings.

[JLMounce]

Originally Posted by Formulajones

Interesting, it really sounds like the Fi-Tech software is more refined then some of the other offerings.

They all pretty much do the same thing. The Holley VE table is much larger than the FiTech table, which means less interpolation.

I would assume that you could do the same thing with the holley software assuming it gives you the ability to change injector flow rates. If they are saying, no and we need to service the unit ourselves to change injectors, then probably not.

I've only seen screen shots of the holley software though, so I can't verify anything accurately there.

I'm also guessing at the functionality I listed above. People have been doing stuff like that to fool software for a long time, so theoretically, it should work. But practical application doesn't always sus out that way.

[Formulajones]

So far I haven't gotten answers relating to that subject on the Holley systems. So I'm thinking not, which is a bummer. If it were more tunable I don't think they'd have so many setups with narrow HP windows.

[Tom Vaught]

Mark at Luhn Performance went thru the Holley EFI school and has all of the tuning of the system books so he might be a good resource for one person to contact him.

He will have no time to explain the Holley system to 20 different phone calls on the phone.

Just my input on the Holley calibration/system question.

Tom V

[hgerhardt]

The SBC TBI from the '80's-90's had a single-plane. Wonder if that was to maximize turbulence in the plenum (as Tom indicated) to reduce emissions and enhance driveability or if there was another reason.