Holley Sniper VS Carb Dyno test (750/850 CFM Carbs)

The best back to back comparison i've done! Holley Sniper X-flow vs 750/850 carbs.
Same engine, same day, same timing, same AFR, same coolant temps! Here are the results
Holley Sniper X-Flow 8 Injector (900 CFM)
Holley 750 CFM Carb (mech secondary)
Holley 850 CFM carb (mech secondary)

Is it fuel distribution? atomization? or inlet temp? Let me know in the comments

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[ntwtransam]

A high quality well set up and tuned carb is very hard to beat.

[IlPinnacolo]

The distance the fuel travels is what everyone thinks is the reason carbs make more power than port EFI, but as we see in TBI vs Carb tests the Carb still makes more power. The reason is because the carb atomizes better than fuel injection. In efi the fuel is pressurized and relies on the droplets accelerating out of the nozzle(s) to shear the droplets apart. The opposite happens in a carb, the pressure of the air acting on the fuel is decreased. This is what makes the fuel move from the main well out of the booster. What happens when the pressure on a liquid decreases? It gets closer to its boiling point for a given temperature. You could boil fuel at 0 degrees with a low enough pressure. As this pressure decrease happens the fuel's surface tension decreases and this allows air from the emulsions to aerate the fuel more easily. The fuel is also cooled; (adiabatic cooling) in the same but the opposite way that compressing something makes it hotter. So now you have cooler fuel with low surface tension that has been pre aerated exiting the booster. As it exits the booster, the airspeed through the booster is extremely high, higher than the airspeed through that sniper throttle body because of the venturi effect from the carb throat, compounded by the booster venturi discharging into the lowest pressure region of the carb throat. This is what creates the suction to draw the fuel, in addition to speeding up the air. This fast moving air then shears the aerated, cool, and low surface tension fuel into fine droplets.
You are most likely seeing the result of that in your lower end power numbers because the airspeed through the TBI is not high enough to counteract the coarse fuel introduction from the injectors. As air speeds up, some shearing action improves the atomization and also exposes the fact that a throttle body will flow more than a carb when you don't level the playing field by accounting for boosters and venturi reducing the flow area. This is why you see less of a high rpm difference on a single plane manifold vs a dual plane.
TL, DR: fuel introduction location is a tiny difference compared to how the fuel is atomized to begin with. Carbs win.

[andysteele]

People mistake throttle response for torque output. The slight lag that it takes for the air to pull fuel from the carb vs instant fuel with the smallest toe wiggle. Another factor is throttle return spring tension. I know it sounds dumb, but a lighter pedal feels faster to most people, myself included.

[pockets]

The sniper throttle bodies have 1:1 linkage. That’s why they feel like they have more low end power in the car. All carbs are progressive linkage. You can make them 1:1 though.

The carb atomizes fuel better, as well as giving a colder fuel charge to the engine because of the airflow through the carb.
Whereas the fuel injection is not using the air to pull the fuel and atomize it.
Engine Masters has tested this many times.

[classicwefi]

I like both carbs and EFI, I have the Holley stealth ram on the 400 in my camaro its nice to have fine control over the fuel and timing, but i love how simple the quick fuel 750 double pumper is on my chevy truck, a little time with the wide band meter and some jetting it runs just as good as the EFi with the exception of cold starts .

[bobfalfa]

Not surprising at all, every EFI to carb swap I've ever done the vehicle picked up everywhere and throttle response improved. The only thing I can really say about EFI is it's ease of tuning on a boosted application. Even then, with the technology we have available now you can easily pinpoint on a carb what you want/need to do. There are systems that will control everything except the carb but still inform you what you need to do, essentially an EFI system without the EFI. A carb is far less complicated than most ppl (younger) think. Tbh, sometimes I think the only reason carbs get hate is because younger guys who are so use to seeing everything on a computer screen can't function unless a device is telling them how.

[bryanst.martin]

As you say it depends on the application. EFI in marine applications is stellar. No fumes hanging out in your bowl, I mean boat... Instant starting too.
Carbs found a significant enhancement with the annular discharge venturi boosters. Carbs also have infinite ratio variation due to the fact that they are mechanically adjusted through air pressure/ vacuum signal, where as EFI must be calculated then applied. Carbs suffer from large overlapping cams weakening the low end vacuum signal, and the EFI just reads the data and injects X amount of fuel and bypassing the problem. Carbs also suffer fuel evaporation and occasional issues with hot fuel lines causing vapor lock, and also fuel vaporizing in the body/manifold when off and hot. The other issue with carbs is fuel level in the bowls on steep angles or high lateral G forces and harsh terrain the vehicle encompasses. Considering these variables a good EFI tends to win everyday. But if the ECU craps itself, you won't be fixing it in the desert. No clear winner here. It just depends.
Great post and question.

[davelewis]

The carb has a venturi effect increasing the air speed cools the charge, Carbs, mechanical injection and efi all have there place I'm lucky to get to work with all of them.

[martyjohnsonozarkoutdoors]

I have a stock 5.3 ls. With a 4 barrel intake. I tried 5 different carbs on that thing and never got it to run right off idle.
Brand new old stock quadrajet, new 600 vac sec holley
New summit Brand 750 and a old dirty 600 vac sec that worked good on a 350 in my camaro.
And a old holley 650.
It ran great with every carb once it past the off idle dead spot. The old holley I pulled off my 350 in my daily driver truck. It didn't have a dead spot on the 350 engine only on the ls. I have been hotrodding and building engines and tuning carbs for over 40 years. I have never had a problem getting the dead spot out of a carb before. But that ls beat me down. I gave up and put a sniper on it. And no dead spot. Instant throttle response. It doesn't seem more powerful and it doesn't get better mileage driving it with the sniper. But the dead spot is gone. So that was a win.

[DiyAllaroundguy]

Can't beat the sound of long tube headers and carburetor combo

[harleysgarage]

Thanks for this video, I would like to see a track comparison also! I had a FITech unit that ran flawlessly for about 2 months and then it died, replaced it with a FAST unit that ran really inconsistently for some reason. Ended up just selling the truck. I like carbs and factory fuel injection, done messing with this stuff for my daily as I spend lots of time in remote areas and I don't trust the reliability of these aftermarket units where I live.

[hayaboosta]

The EFI TB does seem to have better throttle response and tip in. Sequential EFI does feel that way as well. That might be what is being felt as having "better low end torque" but from off idle to may be 2k rpm? The TBI performance resembles carb performance more than your normal port injection.

[topro]

You can fix the low speed torque output on the EFI with "pump shot" my EFI system has that option under advanced settings. I believe the sniper 2 has it too. You can also fix that mid range torque dip with a laptop. My system allows it and I believe the sniper 2 does. I do love the simplicity of carbs and I can tune them very well. I just got tired of draining fuel during the summer and cleaning them out for winter time. My EFI setup come winter I put a fresh 5 gallons in with some Lucas and it fires right up. Runs perfect. I do miss tuning carbs though, it was the best part to me.

[stalegiverhaug]

We may all agree that the EFI makes a better and more stable AF ratio during the rpm range than a carburetor.
But how big deal is that, if the motor simply don't need that level of accuracy on the AF ratio to make it's optimum amount of power?

I think it boils down to what we prefer to puzzle around with: carb or EFI?

My personal choice is carb, but others might feel more comfortable with circuit cards, sensors and a laptop.
Each to his own.

[RonaldLewis-pyyt]

Always like your videos, I gotta Ole drag car runs a 1050 Holley after a clean up pass it works fine and runs very consistent. Ole truck had tbi i converted it to Qjet 2 and its electric choke works great for me!!😊😊

[tangledline]

I have the ACE killshot-this was based on everything else on my big block. Carbs will always have a warm spot in my heart like points over HEI..lol.

[gusferguson]

A well tuned carb (and especially a 1:1 race carb) will out perform an EFI. But a well tuned carb on Tues. may not be well tuned on Wed. especially for us folks that have drastic weather changes where we live. I like both EFI and carbs for their pro qualities. If it's a race car and you know how to tune it.... Go carb for sure. If it's a hot rod that you take out from time to time during different times of year and conditions and you don't want to mess with tuning it every time.... Go with EFI if you can afford it. That's my take on things.

[coolkid]

Fuel efficiency and easier starts are two of the reasons I prefer efi. I think it’s worth the slight cost of power.

[AlfonsoGudino-lf]

I have always heard from other people that carbs are more responsive off the line. This is back in the day when the guys were putting Vortech or Paxton supercharges in the 5.0s to run 10 seconds.

[Carl_Jr]

I have the Atomic 2 on my 71 Camaro. I switched over from a Holley 650DP. The biggest difference between the Atomic 2 and the Sniper is the Atomic 2 actually has what simulates down leg boosters in the center of each of the bores of the throttle body. It's really cool. The sad part is, since the Sniper 2 was released it looks like MSD is discontinuing the Atomic 2. 😢

Anyway, the Atomic 2 is flow rated at 865 CFM compared to the Holley's 650 CFM. I noticed a huge change in throttle response. I believe part of that is due to the Holley carburetor having progressive linkage which the Atomic 2 does not. When you blip the loud pedal with the Atomic 2, all 4 throttle bores open immediately. I had to purchase that throttle lever extension they sell for the Sniper and modify it to fit the Atomic 2 to help reduce the tires spinning on every single launch, on the street. And I have a 3, 000 stall converter! 😮 It was annoying.

Honestly, though, I do kind of miss the simplicity of the carburetor.