First hand fuel economy benefits of aftermarket EFI?

[ken4444]

Does anyone have any first hand experience showing that an aftermarket EFI system like FiTech or Holley Sniper provides any fuel economy improvements over a carburetor?   I understand the benefits of EFI, and the manufacturers seem to completely avoid making any claims about improved MPG, which I'm sure they do for legal reasons.  My 454 as expected gets really bad fuel economy.  I don't want to assume that an EFI would be a magic fix.  I know there many factors that influence MPG.

So, I'm wondering if anyone has seen real world MPG improvements with these systems, and what numbers you have seen.

[ken4444]

No takers on this?   I did find one reply to the same question about the Holley Sniper EFI 550-511K at Summit Racing:

https://www.summitracing.com/parts/sne-550-511k/questionsanswers/?page=2

Of course they're going to reply that it improves MPG, but no specific numbers are provided.

[Stewart G Griffin]

i'm guessing 10% improvement over carb----maybe.   And a large part of that may be due to more accurate/efficient warmup?

[ken4444]

i'm guessing 10% improvement over carb----maybe.   And a large part of that may be due to more accurate/efficient warmup?

10% seems reasonable.  If anything that's a good number to work with:  10% of 10 MPG is only an additional 1 MPG, so that's no big improvement when the economy is so bad to start with.

Also, to detect a 10% improvement, one would have to measure their MPG pretty accurately beforehand.

[bd]

Having driven down that road with Edelbrock MPFI, you will feel improved torque production from the motor in which you will indulge.  At that point improved mileage becomes theoretical.   

[fitz]

  One of the shows on the Velocity network installed a sniper FI system on a 69 camaro this past weekend.
  It was the typical tv show install where the whole install took about 5 minutes to slap it on.  They didn't go into details on the cars drivetrain but they were quick to say that the mpg's should go from "about" 10 mpg's to "about" 20 mpg's.  Sounds a little optimistic to me.

[zieg85]

Does anyone have any first hand experience showing that an aftermarket EFI system like FiTech or Holley Sniper provides any fuel economy improvements over a carburetor?   I understand the benefits of EFI, and the manufacturers seem to completely avoid making any claims about improved MPG, which I'm sure they do for legal reasons.  My 454 as expected gets really bad fuel economy.  I don't want to assume that an EFI would be a magic fix.  I know there many factors that influence MPG.

So, I'm wondering if anyone has seen real world MPG improvements with these systems, and what numbers you have seen.

I investigated TBI for my 85 C20 with a 454.  At the time I was comparing the TBI of 1987 to mine.  What I found out is that a properly tuned quadrajet did better for mpg that a TBI.  It could be the way I drive but 13-15 is what I used to get regularly.  I have a 4 speed and a 3.21 gear out back.  I also keep the rpm's down and usually in 4th by 35 mph

[ken4444]

..They didn't go into details on the cars drivetrain but they were quick to say that the mpg's should go from "about" 10 mpg's to "about" 20 mpg's.  Sounds a little optimistic to me.

..What I found out is that a properly tuned quadrajet did better for mpg that a TBI

Thanks for the details.  All good information.

Part of me says that for the sake of public service I should run my own test.  I would have to get quality MPG numbers for a while and then install the Holley Sniper EFI and get quality numbers with that.  Only after gathering my own data would I know the EFI truth for my truck and driving style.

I read the whole Holley Sniper install manual and it's pretty detailed.  It has advice to ensure quality electrical connections such as getting power directly from the battery terminal and using soldered connections instead of vampire taps.  Clearly the manual is a result of their technical support people taking the same calls over and over about the same problems and same shoddy installation work

[Coasting2aStall]

You might see a little improvement but rarely enough to justify the price those systems bring.  A properly sized and jetted carb is going to do nearly as well.  Assuming you have good cam and distributor advance curve.  The devil is in the details and most people ignore some important details on carb system.

Fuel injection will give a little better control thus bit more power and fuel economy, all other things equal.  It truly is superior for cold starts if properly setup and maintained.  But it isnt the magic panacea to all ills.  Read my posts in the MPG, part2 thread.  Lot people making assumptions about carbs have never driven a pristine unmolested pre-pollution era carb car.  Night and day compared with the carb cars in pollution era with the goofy cams and all the add on nonsense.

[ken4444]

.. But it isnt the magic panacea to all ills.

I was reading the documentation for the Holley Sniper EFI and that might been where I read that (paraphrasing), "a poorly-running engine isn't to be magically fixed by replacing the carb for an EFI."

Night and day compared with the carb cars in pollution era with the goofy cams and all the add on nonsense.

When I bought my 1985 Jeep CJ a decade ago, I got a quick lesson on that generation of elecronically-controlled carburetors. The Carter BBD that was originally put on my Jeep (258 AMC inline 6) used a stepper motor to push a mixture metering pin in and out to fine tune the mixture.  It worked good enough when new, but after 25 years the whole system was a problem.  I ended up replacing it with a new genuine Weber 38 carburetor which gave the engine new life and has been trouble-free for many years.  While that system was OK for its time, clearly it was not something that could compete with the EFI systems that were being developed.

Anyhow, thanks for the comments.  The more I read and learn, the more I realize that EFI has benefits but is to magic fix for fuel economy.

[Coasting2aStall]

I looked some at SNIPER 2300 2BBL.   Its a nice package if you want TBI conversion without hassle.  Fits anything that a Holley 2300 2bbl carb fits.  Or Ford/Motorcraft/Autolite 2100 carbs which I prefer over the Holley. Be interesting and fun to experiment with it.  Alas on practical side,  wouldnt be worth the money to me.   I think one of those programmable ignition boxes be more practical though I do understand this SNIPER does ignition and injection.  Since Sniper self adjusts, wonder how it decides on an advance curve.  Distributor advance curve is the difficult thing to adjust accurately without electronics. 

[Irish_Alley]

if it was me (be frugal as some would say) and i want a tbi conversion i would opp for one off a tbi 350. save a lot of money and it would be a bolt on deal with a system that was made for our trucks