Loss of torque with EFI?

[RevTheory]

I'd sure like to hear about what you find, Carl.

[In-Tech]

No problem, I'll share what I find.

[Newold1]

Any good well tuned port or inlet injected EFI system will pull at or equal performance than a carbureted engine system from idle up to near WOT. What the heck does 2500 rpms and up have to do with it! You need to work with good EFI before you make a statement like that!
The effective powerband of any engine can be radically different from another EFI or Carb and its the effective powerband range and location that determines how that engine will accelerate from any given rpm under load.

[gmrocket]

I'll be testing a carb against a port injection set up for the Race Engine Challenge this year.

The port set up didn't make as much low end TQ as the carb before...going to give it another try. HP peak was within 1 or 2

The new set up will have a new and better carb as well.

I remember years ago when the EMC only allowed carbs...the EFI guys on here were crying foul!!! It was crazy,, they said the only reason the EMC wouldn't allow EFI was because it would be a sweep by the EFI guys and that would look real bad on the carb manufacturers and sponsors

It was a grand conspiracy against EFI

Well, when they did allow EFI to compete against the carbs...that sweep never happened.. and it's still not happening

[GARY C]

I'll be testing a carb against a port injection set up for the Race Engine Challenge this year.

The port set up didn't make as much low end TQ as the carb before...going to give it another try. HP peak was within 1 or 2

The new set up will have a new and better carb as well.

I remember years ago when the EMC only allowed carbs...the EFI guys on here were crying foul!!! It was crazy,, they said the only reason the EMC wouldn't allow EFI was because it would be a sweep by the EFI guys and that would look real bad on the carb manufacturers and sponsors

It was a grand conspiracy against EFI

Well, when they did allow EFI to compete against the carbs...that sweep never happened.. and it's still not happening

Thats what I have seen with the exception of boosted applications.

[gmrocket]

So what do the EFI guys think the problem is?

It's not a bias one way or the other on the builders choice,, they want the most points to win..

You would think the carb is the underdog just do to the fact you don't have enough time in the competition to pull the bowls and make jet changes... i did three last year in the 45 minutes allowed , while making some pulls between each one..it was still slightly off

With port EFI I would think you can make hundreds of changes in 45 minutes, even during a pull. Your fuel grid is right there on your laptop...

[Walter R. Malik]

At wide open throttle ... it is not good to try and best mother nature for sheer power.

Maybe that will change sometime in the future but, not today.

[Mike Laws]

At wide open throttle ... it is not good to try and best mother nature for sheer power.

Maybe that will change sometime in the future but, not today.

[MadBill]

... you don't have enough time in the competition to pull the bowls and make jet changes... i did three last year in the 45 minutes allowed , while making some pulls between each one..it was still slightly off...

Sounds like a good application for those conversion kits with elbows that screw into the metering blocks to point the jets up, accessible with a locking screwdriver through sight plugs threaded into the top of bowl.

[Walter R. Malik]

... you don't have enough time in the competition to pull the bowls and make jet changes... i did three last year in the 45 minutes allowed , while making some pulls between each one..it was still slightly off...

Sounds like a good application for those conversion kits with elbows that screw into the metering blocks to point the jets up, accessible with a locking screwdriver through sight plugs threaded into the top of bowl.

Carburetors with electronic feedback are/were available. Remember the Holley "Mile-A-Dial" which could richen or lean a carb air/fuel ratio with simply the twist of a potentiometer ...? Never was further pursued after the 80's. Along with the feedback Quadrajet.

[MadBill]

DV reported great success with the Holley system: near-instant tuning to half-jet precision...

[jmarkaudio]

Seems this discussion will be going on for a long time to come. Tuner has put it best, carburetors meter fuel in a continuous stream, and changes as the needs change instantly. Injection meters in pulses and at low speeds very short ones, making the air fuel mix inconsistent. A homogenous mix make more power, requires less fuel, and less timing. I have a customer that recently switched from an extremely large carb (another carb builder) that wasn't calibrated well at parts of it's operation to a high end injection, and lost 50 HP... 650" at 1500 HP.

[CGT]

You would think the carb is the underdog just do to the fact you don't have enough time in the competition to pull the bowls and make jet changes... i did three last year in the 45 minutes allowed , while making some pulls between each one..it was still slightly off

Why all the jetting at the EMC? Short on tuning time prior to the contest?

[gmrocket]

You would think the carb is the underdog just do to the fact you don't have enough time in the competition to pull the bowls and make jet changes... i did three last year in the 45 minutes allowed , while making some pulls between each one..it was still slightly off

Why all the jetting at the EMC? Short on tuning time prior to the contest?

That and I waited till the last minute..plus,,Headers were changed slightly, cam advanced 5, lash change, thinner oil and added a carb spacer...it was also brutally hot and muggy at the competition..

[Tuner]

You would think the carb is the underdog just do to the fact you don't have enough time in the competition to pull the bowls and make jet changes... i did three last year in the 45 minutes allowed , while making some pulls between each one..it was still slightly off

Why all the jetting at the EMC? Short on tuning time prior to the contest?

That and I waited till the last minute..plus,,Headers were changed slightly, cam advanced 5, lash change, thinner oil and added a carb spacer...it was also brutally hot and muggy at the competition..

In weather that was 100 F, 28.4", 100 % humidity, I have dropped six Holley jet sizes in a carb that was previously tuned at 55-60 deg. F, 30.2" baro, 40 % humidity.