fuel injected SBC vs gas mileage

Discussion in 'Engine Topic' started by dutch73camaro, Sep 5, 2017.

  1. dutch73camaro

    dutch73camaro Veteran Member

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    hi guys,

    i have a 73 camaro i'm building,

    i still don't have an engine so i'm reading a little bit about the options
    i prefer a fast SBC ( about 500 hp ) because of the prices / simplicity / and the amazing sound

    unfortunally the gas prices here are high in the netherlands, about 7 dollar a gallon ( €1.60 per liter ) and LPG is here about 90 cent in euro.

    is an fuel injected sbc also alot more efficiënt like an lsx engine ?
    and what about the bbc engine's ?

    the car is for me not a daily driver but a fun car.
    but i like to drive.
     
  2. ULTM8Z

    ULTM8Z Veteran Member

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    The transmission and gearing will play into it heavily.

    With 3.42 differential, overdrive transmission, lockup torque converter, and a ~400 hp 350, I'm pulling 26-27 mpg highway (cruising at ~2300 rpm at 70 mph). With a carburetor and the same transmission/rear-gear setup I was getting 21-22.

    Without the OD and carburetor, I could get about 15 highway (crusing around 3200 rpm at 70 mph).
     
  3. dcozzi

    dcozzi Veteran Member

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    With a GEN 1 SBC, fuel injection and an overdrive transmission will be key elements for better mileage.

    An LS will likely be better for mileage.
     
  4. badazz81z28

    badazz81z28 Veteran Member

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    Efficiency has many variables.

    #1 an engine that produces a lot of power requires fuel......Fuel is the stored energy (Meaning you want good mileage, drop the displacement and power)
    #2 Maximum utilization of the fuel turns into efficiency (Air to Fuel ratios is key). This is where computer controlled fuel injections helps. It doesn't stop there though, overall engine design helps fuel efficiency.
    #3 Engine RPMs, if you can drop RPMs of course the engine will burn less fuel (Gear ratios and Overdrive transmission)

    IMHO....If you want power and fuel efficiency, I would look into a small modern engine with Turbos. Other then that, if you want big cubes N/A, the LS will be more efficient then any design before it and its more then because it's fuel injected, its like I said design.

    A fuel injected SBC with good rear gears and an overdrive transmission will go a long ways, but not miracles. I could get about 15-18 with my 400hp SBC on a freeway road trip.
     
  5. dutch73camaro

    dutch73camaro Veteran Member

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    i'm offcourse not looking at economy only,
    but now i can make a choice why not try to get it better

    i really want an overdrive transmission.
     
  6. Lowend

    Lowend Administrator. .a car, a man, a maraca. Staff Member Lifetime Gold Member

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    A properly done EFI engine will almost always do better on fuel economy than it's carburated counter-part.
    The knock sensor and timing control you get with EFI allow the engine to run WAY more lean than is safe with a carb and a weighted distributor.

    An LS will tend to produce better fuel mileage than a traditional smallblock mostly because the cylinder heads are so much more efficient.
    With the Crate engine LS3's getting so cheap, I think you're probably on close for overall costs with a 500HP EFI Gen 1 smallblock
     
  7. ULTM8Z

    ULTM8Z Veteran Member

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    Yeah and it can make that kind of power while not sacrificing good street manners.

    If I had to start from scratch, I'd go LS in a heartbeat. But since my car is already set up for Gen 1 SBC and EFI, most likely I'll just do a 427 SBC later and get my big power that way... no need for the hassle of a LS swap when all I want is around 500 hp and 427 can do that easily.
     
  8. dcozzi

    dcozzi Veteran Member

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  9. ULTM8Z

    ULTM8Z Veteran Member

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  10. Cooldawg

    Cooldawg Veteran Member

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    Don't care for the LS looks, but you probably wouldn't need to open the hood very often. My opinion:

    Driver: LS
    Looker: Gen 1
    Best of both: Gen 1 FiTech or Holley EFI

    I'm still struggling with a decision (and need to unsee that WP hybrid block, BTW), but aside from the carb in my Yamaha 9.9 kicker, I won't own another, EVER. I could buy another kicker for what I've spent having that PO... rebuilt.
     

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