Loss of torque with EFI?

[GARY C]

Gary, What are you wanting to change?

Would kind of like to reduce the delay of the drive by wire and stop it from dropping so much timing when it shifts and possibly the shift time and firmness but the timing issue my help that as well.

I won't tell you what you should and should not want, but when the OEMs cut timing or throttle like that during a shift, it's so the trans can shift without being under load. Transmission life goes up dramatically when you do that. The trans guy I'd go to said that it is not uncommon to see transmissions with 200k miles on them and you can still see the printing on the frictions.

But yeah, I think for your vehicle, if you have the 6 speed, it gets expensive to go in there (at least with HPT) because the trans controller is separate from the engine controller, so it gets licensed separately.

Yes it is the 6spd, I doubt I will change anything on it, I thought about something like a bully dog tuner but I don't think it would be worth it. I can always use the manual mode and thumb shift and pretend like I am driving a F1 car.

[cleveland]

Could it be Magazine propaganda, maybe that is why they made little mention of the torque loss. I agree with the previous poster if the correct carb had been chosen to begin with it could have been tuned in a couple of hours at worst. We tune all kinds of carbs and EFI and have even done some swaps and redynoed. If the correct carb is chosen and then correctly tuned the carbs make more power ever time,the correct booster in the carb is huge. Magazines are about advertising and they use their platform and exposure to push their narrative, Holley wants you to spend money on their EFI stuff so this magazine gives them the platform to push their narrative. You see any one with a little drive and research can tune and modify a holley style carb, creating your own EFI system is much more difficult. InLibertyDan

[MadBill]

.... I can always use the manual mode and thumb shift and pretend like I am driving a F1 car.

Wouldn't that be the Digital mode?

[Brian P]

Could it be Magazine propaganda, maybe that is why they made little mention of the torque loss. I agree with the previous poster if the correct carb had been chosen to begin with it could have been tuned in a couple of hours at worst. We tune all kinds of carbs and EFI and have even done some swaps and redynoed. If the correct carb is chosen and then correctly tuned the carbs make more power ever time,the correct booster in the carb is huge. Magazines are about advertising and they use their platform and exposure to push their narrative, Holley wants you to spend money on their EFI stuff so this magazine gives them the platform to push their narrative. You see any one with a little drive and research can tune and modify a holley style carb, creating your own EFI system is much more difficult. InLibertyDan

Have you expressed these findings to relevant Formula 1 and MotoGP teams? I'm sure they would be interested

(Can you explain why they wouldn't be interested?)

[paulzig]

You see any one with a little drive and research can tune and modify a holley style carb, creating your own EFI system is much more difficult. InLibertyDan

Doesnt the same go for EFi a bit of drive and research and you can setup your own system... ?

Why is it more difficult, anyone could pick out all the parts for an EFi system with a few hours research, and maybe asking some questions and go from there...

[Cutlassefi]

You don't have to be a rocket surgeon to see a short duty cycle percentage means erratic A/F homogeneity resulting in a higher percentage of dry air entering the cylinders.

Holley recommends a minimum engine size etc on that bigger TBI for that very reason.
Someone also mentioned injector timing. short of shutting off half of the injectors below a certain point, inj timing means nothing on a TBI system.
For years I've contended that at slower rpm's the pulsing of the injector just won't have the same effect as the more steady stream of fuel from a carb. In the upper ranges I believe it's not as much of an issue.

[ChargerST]

From David Vizard's book "Chevy Big-Blocks - How to build Max-Performance on a budget":

Port-injection systems are the way to go, but they’re not cheap. A fuel injector installed at a manifold location close to the cylinder head port seems like a big step forward over a carbureted system because it has the capability of ensuring an even cylinder-to-cylinder mixture distribution. In principle, that may be so, but with the current injector designs, such an injection point is usually too close to the intake valve, which results in a below-par mixture quality entering the cylinder.

The ideal point to introduce fuel to the air seems to be 12 to 15 inches from the valve. Although it is a very inconvenient situation, it is not insurmountable, but it introduces manufacturing problems.

Seems to me that in most cases the proximity of the injectors to the valve is the culprit for the loss of torque.. (at least for port injection)

[Brian P]

From David Vizard's book "Chevy Big-Blocks - How to build Max-Performance on a budget":

Port-injection systems are the way to go, but they’re not cheap. A fuel injector installed at a manifold location close to the cylinder head port seems like a big step forward over a carbureted system because it has the capability of ensuring an even cylinder-to-cylinder mixture distribution. In principle, that may be so, but with the current injector designs, such an injection point is usually too close to the intake valve, which results in a below-par mixture quality entering the cylinder.

The ideal point to introduce fuel to the air seems to be 12 to 15 inches from the valve. Although it is a very inconvenient situation, it is not insurmountable, but it introduces manufacturing problems.

Seems to me that in most cases the proximity of the injectors to the valve is the culprit for the loss of torque.. (at least for port injection)

That's why the higher-end systems use an injector at the airbox end of the intake runner pointed straight down the runner.

The production sport bike systems use two injectors per cylinder, one close in downstream of the throttle (individual throttle per cylinder!) aimed at the intake valve for idle and part throttle driveability and emissions, and another one in the airbox aimed at the bellmouth.

For racing applications where the rules constrain them to one injector per cylinder, it's the one in the airbox, but they're not concerned with emissions, cold-starting, smooth idling at 700 rpm, etc.

[ChargerST]

That's why I asked earlier (got lost somewhere in the thread) if someone has already thought about combining a TBI with port injection. Of course you would need to have a software to balance both systems e.g. move injection bias from port to throttle body with increasing rpm.

[Warp Speed]

That's why I asked earlier (got lost somewhere in the thread) if someone has already thought about combining a TBI with port injection. Of course you would need to have a software to balance both systems e.g. move injection bias from port to throttle body with increasing rpm.

It's being done all the time.

[Walter R. Malik]

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.

This is the benefit of EFI in a street car

The carb cure for the time frame spent is to further develop or just bring back the "feedback" electronic, dashboard adjustable carburetors. Same time frame for changing required air/fuel ratios.

[Tuner]

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.

This is the benefit of EFI in a street car

The carb cure for the time frame spent is to further develop or just bring back the "feedback" electronic, dashboard adjustable carburetors. Same time frame for changing required air/fuel ratios.

Spec class, rules are strict about the carb and do not allow such folderall.

[Mike Laws]

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.

This is the benefit of EFI in a street car

The carb cure for the time frame spent is to further develop or just bring back the "feedback" electronic, dashboard adjustable carburetors. Same time frame for changing required air/fuel ratios.

https://www.theengineblock.com/kn-elect ... ssic-ride/

I've got experience with both. K&N's deal equals a feedback carburetor on steroids.

[GARY C]

This is the benefit of EFI in a street car

The carb cure for the time frame spent is to further develop or just bring back the "feedback" electronic, dashboard adjustable carburetors. Same time frame for changing required air/fuel ratios.

https://www.theengineblock.com/kn-elect ... ssic-ride/

I've got experience with both. K&N's deal equals a feedback carburetor on steroids.

When you add the cost of K&N's ECI on top of a custom carb the cost of a true FI system doesn't look so bad.

[Roadknee]

You don't have to be a rocket surgeon to see a short duty cycle percentage means erratic A/F homogeneity resulting in a higher percentage of dry air entering the cylinders.

Holley recommends a minimum engine size etc on that bigger TBI for that very reason.
Someone also mentioned injector timing. short of shutting off half of the injectors below a certain point, inj timing means nothing on a TBI system.
For years I've contended that at slower rpm's the pulsing of the injector just won't have the same effect as the more steady stream of fuel from a carb. In the upper ranges I believe it's not as much of an issue.

I tuned a Holley Stealthram EFI on a SB 400 backed by a 200R4 trans in a 3200 Lb car. It ran out of injector with 24 pph injectors. We swapped in Holley 36 pph injectors and lost 0.5-1 mpg at highway cruise.