Which is faster carb or Fuel injection?
 

All things being equal in a stocker, lift, valve, piston, head, etc.. what would be faster a carb or fuel injection?

Don't worry Dennis I am having a cigar, backing off. lol

Re: Which is faster carb or Fuel injection?
 

Here we go. LOL

Re: Which is faster carb or Fuel injection?
 

OK, I will bite... Too hot to do much more here right now. :)
Never ran fuel injection on a race car, so I sure can NOT offer "facts" on back to back test.

My response below is directed to a stock eliminator setup.
With "all else equal" including "expert" tuners of both carbs and injection, I would say that fuel injection would be faster.
Reasons: You can tune each cylinder much more accurately with injection. The programming is there to change the fuel load to each cylinder. With a good data collection system, and egt on each tube, you can tell what each cylinder is doing with each change, and level them out. You can set the fuel curve, taking temperatures, flow, rpm, etc. into the mix. This makes a smoother motor, and should make more power overall.
Even the best carb tuner is subject to the flow of the intake, to take the fuel load to the cylinders. Just not going to be as accurate, as having the ability to inject directly into the runner, so it is not impacted by the other cylinders in an open intake. Yes, we can corner jet a Holley, etc. but still not like having the ability to inject into each cylinder, and change it thru the rpm range.

There is my two cents... please adjust for inflation as needed!

Ken

Stock 412

Re: Which is faster carb or Fuel injection?
 

Come'on Joe thats an easy one, even for you.

No more cigars or lake house for you.

And you better be at my BBQ this year, & bring the shirts, XL & 3XL. to ATCO.

Re: Which is faster carb or Fuel injection?
 

Ok Joe Lol . And what shirts is Pete talking about?

Re: Which is faster carb or Fuel injection?
 

Ken that makes sense and thank you for the mature response. This is not a loaded question, I was looking in the guide and saw 2 cars same class basically the same specs except carb vs FI.

My "friends" pick on me for being thoughtful, lol.

Is the torque higher in an FI motor due to the FI or are there other factors cause them all to leave harder than carb motored cars?

Re: Which is faster carb or Fuel injection?
 

From everything I have read over the years, a carb at wide open throttle can make about the same power as EFI. (if not more)

However, EFI engines can be dialed in easier for the optimum air/fuel ratio throughout the entire rpm range, thereby making better average torque numbers.

Neither has a clear cut advantage, in my opinion.

Re: Which is faster carb or Fuel injection?
 

Alan got this one.

Re: Which is faster carb or Fuel injection?
 

Besides blueprint specs take a look at the intake potential and carb size vs. the throttle body, plenum and runners. There may be some differences. If you could estimate actual air flow available at the port would be big.
Fuel injection could have an advantage in having fuel introduced close to the back of the valve vs. being carried in suspension with the air stream.

With injection being able to control AF Ratio through the operating RPM range should be an advantage. Most systems will allow you to define RPM range in each cell but the amount of cells in the table is limited. Most are 400 or 500 RPM per cell. Think about the RPM range an engine operates in high gear. In low gear the time spent in each cell is minimal and controlling fuel is difficult.
Theoretically sequential vs. batch fire should have an advantage along with individual cylinder timing, etc. The real word variable is the operating RPM range, time spent in each cell, speed of the processor and speed of the injector.
Theoretically speed density / closed loop should be optimal vs. open loop or Alpha-N when the air fuel table is optimal. But it may not.

What I've come to understand is a carb will make more peak HP while EFI will make a flatter curve. Would average HP be similar?

Re: Which is faster carb or Fuel injection?
 

That's tellin 'em Frank. lol

Re: Which is faster carb or Fuel injection?
 

With or without the AHFS?

Re: Which is faster carb or Fuel injection?
 

Bill: I was comparing two motors, two different cars same HP and basically same specs with the only difference being carb vs EFI.

The FI cars leave harder in lower HP cars then the carb cars, I am not sure in higher HP cars because they all leave hard.

Looking at slower cars in my older age...

Re: Which is faster carb or Fuel injection?
 

Joe Didn't you go a 10:92 in H/SA at Atco this year? How fast do you want to go? I don't see many older Fi cars going 1:23 under. You just have to much time on your hands. Barry

Re: Which is faster carb or Fuel injection?
 

That's tellin 'em Spanky.

Re: Which is faster carb or Fuel injection?
 

Brother Parker, you taught me everything I know.... but not everything you know about going fast. Your vette is still sleeping, when are you going to wake that thing up????

I lost something at Lebanon Valley and can't find it, thinking keeps me young.

Re: Which is faster carb or Fuel injection?
 

Joe where have you been hiding. You going to Indy. We are thinking about it. If your not going I may run H. Barry

Re: Which is faster carb or Fuel injection?
 

Joe, I know what you meant...

Re: Which is faster carb or Fuel injection?
 

This is just our experience, but like has been said in previous post, if everything is apples to apples, their is no noticeable difference. Tuneability and the ability to squeeze out every little hundredth is a big plus for the F.I. The comparison on fuel readings off the Egts are not even close, and we have a pretty well tuned carb. You can get the F.I to somewhat flat line the target fuel curve, and you just are not going to do that with a carb.
We broke in, then dynoed our engine with a carb, and then a box manifold/F.I set-up, and lost 13 horsepower with the F.I. .. The carb was a 750 Q-Jet, but our combo uses the stock 48 mm tuned port (L-98) F.I throttle body, and those little bores suffocate a 350. I am guessing on a 305, the numbers would be closer as not as much air would be needed for good power.

Re: Which is faster carb or Fuel injection?
 

With my last engine we did a test to see if there was a big problem with my EFI setup and took off the tune port and put on a 350 manifold, not the best but good and a dyno Q-Jet and picked up 20 HP. Nothing else changed.

Re: Which is faster carb or Fuel injection?
 

Joe, on Bryan's 305 the carbureted combo made 20 more horsepower than the F.I. and made power at a higher rpm. The F.I. combo makes more torque and has a flatter torque curve. run at the same weight the carb is faster.

Re: Which is faster carb or Fuel injection?
 

Guys, the carb guys aren't going to believe you by they think there is magic in that ECU. LOL

Btw, that small TB is restrictor. It flows less air that a QJet. My friends with 350"s & carbs often run well past 8500 in the lights, some way past. Dave Layer, when I ordered my heads, told me a 350" would all done by 8200 RPM, of course he was correct. Smart man.

Re: Which is faster carb or Fuel injection?
 

Barry rumor has it that neither of us is the fastest H/SA in D-1 let alone at Indy. I am going to take a pass been a rough year. My ego can't take losing hahahaha. My money is on you if you go in H/SA. That is why I am looking for a soft EFI combo.

Re: Which is faster carb or Fuel injection?
 

I'm gonna take a stab at this. The Third Gen Camaros mentioned above have a manifold with relatively long runners, which will make more power down low, and perhaps explains why you observed a harder launch.
Q-Jet manifold that I assume Frank and Lee refer to have much shorter runners, and should make peak power at a higher RPM, which probably accounts for the higher peak HP observed.
If the comparison was made with identical manifolds and the same total area throttle body/throttle blades, and fuel curves both optimized to whatever extent possible, I'll argue that the FI has superior atomization, and should make a little more power at every increment.

Re: Which is faster carb or Fuel injection?
 

[QUOTE= That is why I am looking for a soft EFI combo.[/QUOTE]

Get a new Camaro or Mustang.
Or call Billy.

Re: Which is faster carb or Fuel injection?
 

[QUOTE=
If the comparison was made with identical manifolds and the same total area throttle body/throttle blades, and fuel curves both optimized to whatever extent possible, I'll argue that the FI has superior atomization, and should make a little more power at every increment.[/QUOTE]

Let's take an look at a ringer in the Mopar DragPak engine with the tall single plane and throttle body on top. Easily replaced with a carb. If the throttle body was flowed, a really good Holley was assembled to match, have a feeling that there would be little to nothing.

Don't think there is any way to compare EFI to Carb in a stocker apples to apples. If you look at the potential of the combination with it's HP rating then you have something to study. Not being a dedicated student it appears to be a new car or a slow car.

Re: Which is faster carb or Fuel injection?
 

Correct. My 5.9L DragPak uses the identical M1 single plane manifold that my 360 Magnum crate motor (w/ 750 Holley) had. They come with the bosses to be drilled for injectors. That being said, simply swapping carb vs EFI, even adjusting jetting/tuneups, is not as apples to apples as one would think. There are other variables involved in optimization for each.

Re: Which is faster carb or Fuel injection?
 

Joe if you find a soft EFI combo call me!

Re: Which is faster carb or Fuel injection?
 

Hot Rod mag did a comparison test about a year or so ago using an FI LS1. They swapped on the Edelbrock LS1 4-barrel manifold/carb and made more peak HP in every test. The torque curve was a lot peakier however. Of course the EFI system is infintely more tunable, so there's that... The results really surprised me, I thought the FI would be more efficient by design?

Re: Which is faster carb or Fuel injection?
 

Some really interesting results and good things that make you think here... which is why I replied to this post to start with.
I will have to try to find the Hot Rod article. Same type of apples to apples that Michael is talking about. My question, is the throttle body truely the same cfm as the carb?
Just hard to understand how on same cfm of air flow, the carb would make more HP, with the tuning ability of the FI cylinder to cylinder. NOT arguing, just trying to understand.
But then again, I have raced for years, and racing in the summer in TX... :) Never been very smart!

Ken

Re: Which is faster carb or Fuel injection?
 

Lee you guys ran one 10 years ago. It's light and can be FAST.

Re: Which is faster carb or Fuel injection?
 

I don't have the best comparision,but I'll throw it out there.
Dynoed 350 chevrolet w holley fuel injection can't recall name,had 950 throttle body w/injectors above throttle body,that is why I don't like this comparision,because injectors mounted in intake runners are advantage,I feel make EFI worthwhile, because of indvidual cyl. tunability, intake not effecting fuel flow,etc
Also this injection was limited on tuning,if I recall correctly had idle,mid and wot adjustments.
So with this being said I feel like you could call this system a electronic carb.

They dynoed almost identical, w/ the efi or carb,but he never could get efi to run on the track.
Mike Taylor 3601

Re: Which is faster carb or Fuel injection?
 

Every engine is nothing more than an air pump. Some better than others. It does not know or care how fuel is delivered. (In a perfect world)

When AFR and spark timing within the combustion chamber are optimal the engine will make max power. The burn is more important than the method of delivery.

Re: Which is faster carb or Fuel injection?
 

Ok Joe next question. Which is faster a real good metric 200 or a real good Pro Trans 350. Who's done that test before?

Re: Which is faster carb or Fuel injection?
 

Does anyone know what cfm a 48mmGM throttlebody flows? I would guess maybe 580cfm but this is a wild guess. I cant see how it would be close to a Q-jet's cfm. Just thinking out of the box but I would think the performance advantage of the efi would be a imediate throttle response with improved low rpm torque, with the carb making more total top end power while giving up some on the bottom end. The larger LS-1 or the drag pack efi I think would be superior to a carb in all rpm ranges. Just my $0.02. Don Jackson.

Re: Which is faster carb or Fuel injection?
 

well, seeing how a throttle body (port fuel setup) flows ONLY air and not a fuel/air mix, I can see a less cfm TB flow as much air as a Q-jet....just my opinion...


is a carb flowed "wet"?

Re: Which is faster carb or Fuel injection?
 

Don. The smaller throttlebody only flows air not a mixture.
I had a real hard time grasping throttlebody do's and dont's. I might not be right now. But the way I under stand it (simplified) the throttlebody is basicly feeding one cylinder (at max) at a time.
I had a 65mm throttlebody (probably over sized) on my 4 cylinder Neon and a box manifold feeding all 4 cylinders. I switched to 4 Individual Throttlebodies each one directly feeding a cylinder. Each throttlebody is 52mm. It took a long time to sink into my brain that this setup wasn't way to big. But it finally sunk in that the motor was only feeding one cylinder at a time (100%) and one throttlebody over each hole needed to be big enough to feed that cylinder.

Re: Which is faster carb or Fuel injection?
 

I'll Bite:
Would think the ET may be about the same but the Pro Trans will live behind engines where an M200 will not.

Re: Which is faster carb or Fuel injection?
 

If the 48mm throttle body was too small an LT-1 engine would likely run weak when built as a SuperStock engine....The throttle body would limit performance.....and thats what I thought when I raced one in Stock...

From the numbers I have seen those engines run in SS/IA or SS/JA or in a GT car......they run very well.....so I think the 48 mm throttle body's ability to move air can not be directly compared to a carb like a Q-jet that flows air and fuel....

Re: Which is faster carb or Fuel injection?
 

LT1 throttle body 783cfm at 28"
If I remember right it was 660 cfm at 20"

Re: Which is faster carb or Fuel injection?
 

If memory is right Holley is flowed dry @ 17''
Q-jet can't remember but some reason dry @ 12'' is coming to mind?
Have info on Q jet but have to dig out,but not tonight, well this morning.
I always heard Carter's ratings were wet flow #'s ?

Going back there was huge difference in tunnel ram w/660's vs Crower injection.
My Dad has Crower he bought new around 1970 back then cost $ 375.00 is what he always told me,he sent to Kinsler and had redone in late 80's cost about $3000.00

Mike Taylor 3601