Carb Vs. EFI for Cam Lope

[cv2065]

Anyone know if EFI noticeably takes the lope out of an aggressive cam? I've looked up and listened to a few videos, which does a terrible job at duplicating sound accurately. I have a desire for EFI, but not at the expense of my car shaking. :)

[scrubs]

I have a carb, but have heard lots of EFI vehicles with cams that sound...like they have aggressive cams.

[BEAR-AvHistory]

A number of "ghost cam" programs are available for FI engines especially those with fully electronic valve controls like the Coyote. I run a simple street performance 93 octane program as my daily driver. I also have a ghost older cam program that emulates the 427 race motors. Takes about 10 minutes to switch between them with a hand held device.

[Jeff Kleiner]

It makes no difference. The "ghost cam" thing is for Coyotes with variable valve timing.

Jeff

[GoDadGo]

Thanks for posting this thread, because I'd really like to hear from folks that have successfully run a Holley Sniper or EFI other throttle body system on a push rod V8 over 360 Cubes with a camshaft that has a LSA of 110 that is also a bit on the aggressive side from a lift and duration perspective.

[cv2065]

Thanks for posting this thread, because I'd really like to hear from folks that have successfully run a Holley Sniper or EFI other throttle body system on a push rod V8 over 360 Cubes with a camshaft that has a LSA of 110 that is also a bit on the aggressive side from a lift and duration perspective.

Hey GDG. You hit the nail on the head and where I was going. I wasn't sure how a 427 with an aggressive cam handles EFI. I think an LSA of 112 to 114 is optimal for EFI, but anything below that might have issues? For myself, I'm going to fall in the 112-114 range, but even then, wasn't sure how the cam lope is reduced by the computer, if at all. I hear LS3's all of the time that sound incredible with EFI, but Ford's seem to be hit or miss, at least what I've listened to. Ghost tunes for Coyotes are cool, but not for me.

[cv2065]

It makes no difference. The "ghost cam" thing is for Coyotes with variable valve timing.

Jeff

Thanks Jeff. So you are saying that cam lope is not impacted by EFI? I'm hoping that's the case but have not been able to directly compare.

[GoDadGo]

What Cha Think CV?

Last night I was at our Monthly Cruise Night and folks kept telling me that I'd be much happier switching to EFI over my AVS Edelbrock 800 which runs fine; however, their cars had much milder combinations with minimal lope and lacked performance.

I'm running the Comp Cams XR288HR and it is rather mild grind, but not a good candidate for EFI because of the 110 LSA. My combo is 10.2 compression (383 SBC) Tall Port Iron Eagle heads which flow better than the World Products Sportsman-II's or any other Standard Port Heads. While EFI sounds intriguing, I don't think moving over to EFI is an option because my camshaft LSA won't pair well with most EFI systems.

Shown below are those camshaft specs & 350 SBC dyno data:

Comp Cams XR288HR
https://www.compcams.com/xr288hr

Steve

[Jeff Kleiner]

Thanks Jeff. So you are saying that cam lope is not impacted by EFI? I'm hoping that's the case but have not been able to directly compare.

Correct, however with that said you can have a poorly tuned carb (or EFI) that will spit, sputter and sound like a nasty cam at idle but really it’s just running bad. Example; take a carb car with a manual choke and close it about 3/4 of the way and it’ll sound like a Pro Stocker at idle (until it fouls the plugs and dies:p).

Jeff

[Mike.Bray]

393W with 579 Lift, 286 advertised duration intake, 300 advertised duration exhaust, and 114 degrees lobe separation. Borla stack EFI.


https://youtu.be/Q_5fTdGFakQ

[cv2065]

393W with 579 Lift, 286 advertised duration intake, 300 advertised duration exhaust, and 114 degrees lobe separation. Borla stack EFI.


https://youtu.be/Q_5fTdGFakQ

Thanks Mike. Those stacks are awesome! What idle speed are you set at? I couldn't see it in the video.

[Mike.Bray]

Thanks Mike. Those stacks are awesome! What idle speed are you set at? I couldn't see it in the video.

850 when warm.

[J R Jones]

The cam determines valve time and duration and without variable cam timing, the cam can be optimized for low, mid or high RPM at the expense of other speed performance.
The carb or EFI both try to provide the appropriate air/fuel ratio throughout the RPM range. EFI has tune advantages. You can not fix a high RPM cam that lopes at idle with carb or EFI.
Ghost tunes are for exhaust noise and simulating a lumpy cam. The ghost tune sacrifices performance and fuel economy. One should speculate that a ghost tune may not be good for engine durability.
jim

[cv2065]

The cam determines valve time and duration and without variable cam timing, the cam can be optimized for low, mid or high RPM at the expense of other speed performance.
The carb or EFI both try to provide the appropriate air/fuel ratio throughout the RPM range. EFI has tune advantages. You can not fix a high RPM cam that lopes at idle with carb or EFI.
Ghost tunes are for exhaust noise and simulating a lumpy cam. The ghost tune sacrifices performance and fuel economy. One should speculate that a ghost tune may not be good for engine durability.
jim

Thanks Jim. So if I have the exact same radical cam in two identical 427 engines (LSA 112-114), but one is carb'd and the other EFI, I won't be able to tell the difference between the two from a cam lope perspective?

[cv2065]

850 when warm.

Wow, I thought it would be at least over 1K

[Railroad]

My experience with a more radical cam with carb has a choppy idle, due to low vacuum signal, which the carb cannot ideally provide a stable fuel ratio. I had this in a car built for my wife, supposedly. It was too rough at idle and sitting at a red light.
I put a throttle body EFI on the engine and it cleaned the idle and low rpm up like a factory grocery getter. Idle speed was much lower and efi could over come the idle low vacuum signal.
I am sure a cam can be aggressive enough that EFI would not entirely mask big numbers on a cam.

[Its Bruce]

I can't imagine there being any difference in idle quality between a carb and Sniper EFI's 4 barrel injection. It's the same thing aside from maybe better atomization from the Sniper, ie EFI offers improved idle. I could see bigger differences when comparing a carb to port injection.

FWIW, I love my idle chop.

[Fman]

Dart 427, Edelbrock PF4 EFI. I can't recall what cam was put in my engine, engine builder gave me the cam card info but it is tucked away somewhere. I would say definitely on the more "mild" side. I wanted it to be very drivable around the streets, idle is set around 850 RPMs. This video is with Gas 'n side pipes, I later on switched to the Gas 'n touring pipes.


https://www.youtube.com/watch?v=WzV11uZDsGA

[Kbl7td]

No offense, lots of bad advice in here. EFI will always dominate the carb in tuning capabilities. You can turn any wild cam on paper into something street worthy You can also turn a stock cam into a chop monster with a little clever timing tricks. My opinion, always choose the EFI. At this point we aren’t even talking basic tuning. Now with the Holley software you can add in traction control, etc all with the included software and some additional sensors.

[timspx]

Fact - Efi like sniper do not work well with long duration cams (238+ degrees of duration at .050.
More factors need to be taken into account such as single plane or dual plane intake, number of o2 sensors (how can one tell the full afr with one sensor in one bank?), and more. Stating Efi is always better than a carb is incorrect.
Please call Holley and carb companies such as pro systems and ask them questions. Get the facts.

I can tune a pretty damn good carb because I’ve been doing it for 40 years. I was almost going to do Efi in my current build but decided against it because of all the complexity of Efi with no benefit with a beefy motor. I like simple (occam’s razor).

Sorry - don’t mean to be cranky

[J R Jones]

I agree with Bruce and Tim. One should acknowledge that not all EFI is the same, as accurate, or as adjustable. A throttle body injection is similar to a carburetor in that it is fogging the top of a manifold with four injectors expecting the atomized fuel to find it's way to all eight cylinders equally, at the right time, and in the optimum proportion. Maybe.
Digital EFI positions injectors at each cylinder intake valve(s) and they inject at an adjustable point in the combustion cycle. Fuel amount is controlled as well. Yes Digital EFI can make the best of any running speed.
In the end, the adjustability of induction components and technician skill factor into tuning results.
jim

[BEAR-AvHistory]

Some pre-Halloween ghost stuff.

Back around 2011 FORD had an option called "the track key" for the BOSS engines. This was the original ghost cam. FORD never applied for a patent at that time.

Lund developed an early ghost tune based on FORD's work. Chris Rose @ BAMA got into the market using the SCT X4 handheld. I got an early tune from them. Use it only for shows & C&C's. Its not really suitable for daily driving. Some legal stuff where FORD told the tuners to stop selling their versions. It was thought FORD wanted to sell them itself. Never paid much attention to it. Maybe the new ones, if there are any new ones, are for daily driving.

My 93 octane street performance tune is more than enough to move the car smartly. My specific change in addition was to run the BOSS intake to kill some of the lower engine speed torque. That and slowing the throttle program makes hard launching the car a lot easier to control.

Anyway the key to the tune is the Coyotes TiVCT (Twin Individual Variable Camshaft Timing) feature with individual intake & exhaust camshafts in each cylinder head through software tuning can simulate the rough idle effect of a 60's race car. Just adding FI to an engine without some type of software valve control or an actual ghost cam will not automatically give you a Ghost Cam capability.

[cv2065]

Dart 427, Edelbrock PF4 EFI. I can't recall what cam was put in my engine, engine builder gave me the cam card info but it is tucked away somewhere. I would say definitely on the more "mild" side. I wanted it to be very drivable around the streets, idle is set around 850 RPMs. This video is with Gas 'n side pipes, I later on switched to the Gas 'n touring pipes.


https://www.youtube.com/watch?v=WzV11uZDsGA

I'm getting a set of Gas N Pipes from Georgie as well. If you can find the cam card, that would help greatly.

[narly1]

I'm not sure if this will be helpful or not, but video of my 302 with an Edelbrock Proflo4 & Comp Cams XE264HR-14 running on the stand:


https://www.facebook.com/earl.anderson.18/videos/306017537745450/

Mufflers are stock Mustang take-offs.

Earl

[GoDadGo]

I did a lot of digging and learned a few things.
I'll keep my Carb and 110 LSA camshaft.
Great discussion that made me think.
Thanks for starting this thread.

[cv2065]

I did a lot of digging and learned a few things.
I'll keep my Carb and 110 LSA camshaft.
Great discussion that made me think.
Thanks for starting this thread.

I think that I may go carb again as well GDG!

[GoDadGo]

I think that I may go carb again as well GDG!

If I ever build another Factory Five, I think I'd stay with a carburetor too.
I'd likely upgrade go AVS-2 which came out a few years ago.
The standard AVS has the old down-leg primary boosters.
It works fine; however, I am running dual a feed line.

https://youtu.be/3npwfIOdKPc

[cv2065]

If I ever build another Factory Five, I think I'd stay with a carburetor too.
I'd likely upgrade go AVS-2 which came out a few years ago.
The standard AVS has the old down-leg primary boosters.
It works fine; however, I am running dual a feed line.

https://youtu.be/3npwfIOdKPc

I've always been a Quickfuel guy myself. They are nice out of the box and with a little tuning, start like EFI. But I will run a return line 'just in case' I change my mind down the road.

[nucjd19]

So glad to see you building another cv. You, Papa, GDG, Kleiner, Fman, and edwardb were my go to and my inspiration when I was building and even before I started my build. Agree with GDG. My carb has been rock solid from blue print. They dialed it in at a similar elevation to where I live and I have had zero problems with it. Just fires up to idle and runs. I love the lope on it too. Was just listening to it when I got back from a drive with my daughter.

[GoDadGo]

I've always been a Quickfuel guy myself. They are nice out of the box and with a little tuning, start like EFI. But I will run a return line 'just in case' I change my mind down the road.

Here is why I run an Edelbrock:
I totally suck at rebuilding and or tuning Holley or Holley Style carbs but do fine with Quadrajets and AFB (Edelbrock) style units.
It is sort of like stick welding for me because I suck at that too even though I went to trade school at night for a year.
Some times you just need to know your limits and accept them.

[cv2065]

Here is why I run an Edelbrock:
I totally suck at rebuilding and or tuning Holley or Holley Style carbs but do fine with Quadrajets and AFB (Edelbrock) style units.
It is sort of like stick welding for me because I suck at that too even though I went to trade school at night for a year.
Some times you just need to know your limits and accept them.

"Every man has got to know his limitations" - Clint Eastwood (Magnum Force):cool:

[Hoooper]

I did a lot of digging and learned a few things.
I'll keep my Carb and 110 LSA camshaft.
Great discussion that made me think.
Thanks for starting this thread.

No reason you cant run EFI on a 110LSA cam as long as you have control over the idle timing and AFR targets. Problem people run into when tuning big cams with lots of overlap on EFI is they keep trying to maintain 14.7:1 AFR, which is NOT right when you are running a big cam. Big cams with a bunch of overlap wont achieve full combustion at idle so they end up giving misleading O2 readings. The O2 only reads air and products of combustion, unburnt fuel doesnt read on the O2 so when you have a big enough cam that its going to always have incomplete combustion at idle, 14.7:1 AFR for the burnt portion of your mixture gets added to all the air that didnt get used in combustion but the fuel that did not get burned doesnt get counted, resulting in a lean O2 reading when the mixture is perfect. I run mine at 15.2:1 target AFR at idle, its not a HUGE cam but its 240/254@ 0.050", 0.688"/0.671" lift, 112 LSA solid lifter roller cam. With basically the same cam but turned into 110LSA you might need to target 15.5:1 AFR. Not really a big deal as long as you know what to do and you have the right EFI system or software to do it. Im not familiar with Sniper software but for OEM ECUs or most standalone ECUs thats perfectly manageable. With cams like that you tune idle just like with a carb, make adjustments until you achieve the highest vacuum reading. Its just a lot faster to make the adjustments when all you have to do is change digits on a screen.