[rodneybutler]

I didn't read through all this, but I have dynoed 20 plus engines with EZ efi with the Performer RPM intake. Makes the same torque and HP as carb. These are hyd roller 550 to 575 hp engines. Intake works well with the given rpm range, 6000 max. Lunati hyd roller lifters float at 5900 anyway. More hp and rpm, I use EZ multiport and Torquer II with just enough injector to support the power. Smaller injectors atomize better than larger. 36 lb pico inj atomize very well. 44 lb not so good. Have to run more timing to make the same power as smaller injectors. Hope this helps.

[David Holmberg]

Excellent info, thanks Rodney!

[Skip Fix]

Engo reversion as you said will be no different based on the intake dual vs single just different with port injection vs carb/TBI at the top of the plenum as the fuel mixture is being introduced lower in the tract.

"Why would the engine produce more torque with a (generic) dual plane intake than a (generic) single plane intake in a tbi-engine? i.e. why would the tbi act exactly the same as a carburator? (remember the tbi does not need a vacuum signal to pull fuel from the booster as a carburator would)"

Runner length-now if both had similar runner length and similar plenum size would be a wash. That is the variable assuming carb and TB and intakes are giving the same mixture and AFR. I would agree with you a single plane probably a little better more equal fuel distribution cylinder to cylinder as "generally" the runners are closer to the same(now a T1 or Tomahawk/Holley they are not the same front to rear like a T2 or Victor.


Rodeny thanks for the input. The 36 lb Picos support a 550 hp motor? Have you all used the regular taller injectors with more size selection in the Torker EFI and just raised to TB with a spacer to clear to fule rails and add more plenum?

[rodneybutler]

36 lb injecters support 575 hp no problem. More if you jack the fuel pressure to 55 psi. A little harder on fuel pumps, but atomizes even better. 44 lb are the tall ones, but don't run a spacer. Most of my street customers want low profile to run a stock hood.

[projectfolly]

Thanks for all the input guys. Its given me a lot to ponder!

[Fishin2Deep4U]

Originally Posted by Skip Fix

Rodeny thanks for the input. The 36 lb Picos support a 550 hp motor? Have you all used the regular taller injectors with more size selection in the Torker EFI and just raised to TB with a spacer to clear to fule rails and add more plenum?

Another option is ls3 injectors. Readily available and with a small adapter, work great. I don't like the pattern of the picos.

Dave

[Engo]

Originally Posted by Skip Fix

Runner length-now if both had similar runner length and similar plenum size would be a wash. That is the variable assuming carb and TB and intakes are giving the same mixture and AFR. I would agree with you a single plane probably a little better more equal fuel distribution cylinder to cylinder as "generally" the runners are closer to the same(now a T1 or Tomahawk/Holley they are not the same front to rear like a T2 or Victor.

Runner lenght is of course important in any engine. But to say that any dual plane intake is better than any singel plane due to runner lenght is not even a remotely correct statement. What is a good runner lenght is specific to each engine. A dual plane intake (typically) has unequal lenght runners with unequal cross sections. Not good, compared to most singel plane intakes from a runner lenght perspective.

The one (and only) specific reason that a dual plane intake can produce more low end power on a carburated engine compared to a singel plane intake is that the dual plane intake, with its two plenums, has a better vaccum signal to the CARBURATOR to pull fuel out of it.
That one (and only) reason is a moot point on a TBI engine as it does not need a vaccum signal to pull fuel, because fuel is injected.

Therefore there is no (generic) reason to use a dual plane intake over a singel plane intake on a TBI engine.

[Fishin2Deep4U]

The generic reason to use the dual plane intake is exactly as you stated. Improved vacuum response at low rpm. Out does not matter how fuel is metered if the cylinders are not filling efficiently.

So yes, generally speaking, a carb and tbi act similarly. And both typically perform better on the low end with a dial plane intake. Port injection tolerates single planes far better as you are only metering and moving air.

Dave

[Engo]

Originally Posted by Fishin2Deep4U

The generic reason to use the dual plane intake is exactly as you stated. Improved vacuum response at low rpm. Out does not matter how fuel is metered if the cylinders are not filling efficiently.

No I did not say that!

It is the vaccum signal needed to PULL fuel from the carb that makes the dual plane better at low rpms for a CARBURATED engine. SO it is all about fuel metering.

Cylinder filling is not a generic reason for using a dual plenum intake at all.