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Old 07-14-2010, 03:51 PM   #1
hopelessredneck
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Question EFI or CARB

So im in the middle of planning a rebuild on my 454 for my 1978 GMC C25 and am at a crossroads on weather to keep it carborated and add a edelbrock RPM airgap or switch over to efi with an edelbrock kit im working with a 1980's 2bolt main block and stock heads but plan to upgrade heads at a later date
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Old 07-14-2010, 04:51 PM   #2
Low87
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Re: EFI or CARB

Efi ftw
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Old 07-14-2010, 05:57 PM   #3
68GMCCustom
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Re: EFI or CARB

for a driver where mileage and a solid running motor w/o hiccups is more important then power....efi.
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Old 07-14-2010, 06:23 PM   #4
PushnFords
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Re: EFI or CARB

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Originally Posted by 68GMCCustom View Post
for a driver where mileage and a solid running motor w/o hiccups is more important then power....efi.
+1 except depending on the carb and efi setup the power could be more with either one.
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Old 07-14-2010, 07:14 PM   #5
RandyP
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Re: EFI or CARB

EFI and never look back.
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Old 07-14-2010, 07:59 PM   #6
68GMCCustom
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Re: EFI or CARB

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Originally Posted by PushnFords View Post
+1 except depending on the carb and efi setup the power could be more with either one.
well most tests show more "peak" power with a carb up high... and in many cases down low...where as the efi is better in the midrange, where a street engine lives.
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'68 GMC short step - '09 LY6 6.0L crate motor w/mods, '12 crate 4L85e w/billet 3k stall Circle D, 3.73 posi 12 bolt, DynaTech f-swap headers, 3/4 drop, handling mods, etc. - my toy
'72 Chevy LWB C-10 Highlander - 350/350 ps/pb/tilt/ac - not original but close
'84 Cadillac Fleetwood Brougham - white w/white vinyl top, red leather interior - family heirloom
'06 Chevy TrailBlazerSS - LS2 - little black hot rod SUV - my DD
'13 Kia Optima - wife's econo-driver

my '68's powertrain and chassis build
A surprise phase - carb to efi
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Old 07-15-2010, 12:17 AM   #7
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Re: EFI or CARB

EFI - it will take a bit of planing and work, but you will never look back.

//RF
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Old 07-15-2010, 01:47 AM   #8
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Re: EFI or CARB

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Originally Posted by rfmaster View Post
EFI - it will take a bit of planing and work, but you will never look back.

//RF
True, and well worth the time!
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Old 07-15-2010, 05:49 AM   #9
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Re: EFI or CARB

The Edelbrock TBI - to - MPFI kit seems to work fairly well, but isn't very tolerant of big cams and heads (sort of like stock TBI). Haven't heard much about the Holley Pro-jection kits.

Megasquirt is more work up front, but is more tuneable, and being Windows - based, is a lot more user-friendly for most.
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Old 07-15-2010, 07:13 AM   #10
BigBlocksRule
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Re: EFI or CARB

It depends on what you want to do with the truck.
EFI can work great - IF it's tuned correctly. Same can be said for a carb.
Check out the price difference with tuning time included, then decide if it's worth it. How much the truck will be driven would determine it for me.
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Old 07-15-2010, 10:32 AM   #11
glock35ipsc
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Re: EFI or CARB

Efi!!
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Old 07-15-2010, 12:01 PM   #12
willett
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Re: EFI or CARB

cARB!


BRAAAAP
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Old 07-15-2010, 03:41 PM   #13
GmtGmt
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Re: EFI or CARB

Quote:
Originally Posted by BigBlocksRule View Post
It depends on what you want to do with the truck.
EFI can work great - IF it's tuned correctly. Same can be said for a carb.
Check out the price difference with tuning time included, then decide if it's worth it. How much the truck will be driven would determine it for me.
x2
i personaly love carbs but i dont mind EFI on a DD but again its down to if you have the money and dont care the price or if you want to save alot of $$$ in the years to come its a personal couise i think i have heard a EFI 454 only goes 15MPG tops on highway and maby 8-10 in town idk what a Carb does
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Tonight mine pulled a few cars out of snowbanks, and is sitting in my driveway, icicles on the grille, wheels just white cakes of snow, buried up to the lug nuts in powder, straps and chains wrapped around the bumpers, the outline of the wipers clear in 4 inches of snow on the windshield... A tired warrior of the 1980s in a world of low profile tires, front wheel drive, and plastic bumpers, where people stay in their houses until snowplows move the offending substance from their paths, too helpless to travel without AAA and chains and salt, clearing their windows with longhandled brushes while gently stepping around in the snow trying to stay nice and dry.

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Old 07-15-2010, 03:47 PM   #14
swb85
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Re: EFI or CARB

Coming from a guy who owns and tunes both:

If you're going to keep it relatively stock and/or plan all of the engine modifications at one time, then I'd go EFI. If you're going for a little more wild combo and/or plan to add modifications to the motor slowly over time as budget allows, then I'd go carb. Obviously carb will be significantly less costly.

Every single change you make to an EFI motor requires changes in the tune. If you've got the software/knowledge to do this yourself then it's no big deal, but many people do not. Almost everybody can change jets in a carb and twist a distributor.

There's new "self tuning" EFI solutions on the market now, although I have no direct experience with those so I can't do more than speculate.......I do have extensive late-model EFI experience, and a simple MAF based system with wideband o2 feedback *should* work just fine without much user input on mild-ish motors. But you gotta pay to play!
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Old 07-15-2010, 03:54 PM   #15
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Re: EFI or CARB

here are some links.
cant go wrong here.
im going with stock efi once i have to replace my motor (w/stock 350)


http://www.affordable-fuel-injection.com/

Im hearing positive stuff from fast

EZ-EFI® from FAST™
http://www.fuelairspark.com/ezefi/default.asp
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Old 07-15-2010, 04:15 PM   #16
piecesparts
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Re: EFI or CARB

I have been considering the EZ EFI for my 383 stroker setup. I am just considering what would be the best way to connect the tanks with the fuel pump. I get 15 MPG with the carb, but the EFI should make that more efficient, not to mention a larger power band capability.
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Old 07-15-2010, 07:07 PM   #17
rfmaster
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Re: EFI or CARB

Quote:
Originally Posted by swb85 View Post
Coming from a guy who owns and tunes both:

If you're going to keep it relatively stock and/or plan all of the engine modifications at one time, then I'd go EFI. If you're going for a little more wild combo and/or plan to add modifications to the motor slowly over time as budget allows, then I'd go carb. Obviously carb will be significantly less costly.

Every single change you make to an EFI motor requires changes in the tune. If you've got the software/knowledge to do this yourself then it's no big deal, but many people do not. Almost everybody can change jets in a carb and twist a distributor.

There's new "self tuning" EFI solutions on the market now, although I have no direct experience with those so I can't do more than speculate.......I do have extensive late-model EFI experience, and a simple MAF based system with wideband o2 feedback *should* work just fine without much user input on mild-ish motors. But you gotta pay to play!
MAF = Mass Air Flow
You mean MAP (Speed density) used on in early EFI systems. MAF sensors can temperamental and GM had hard time keeping early TPI cars running well. They ditched MAF sensor and switched to MAP (in F-Body) until MAF sensor technology matured to be robust enough.

A stock BBC TB, with dynamic fuel pressure modification (VAFPR) and optimized ECM (EBL) tuning can provide enough air flow (about 640 CFM) and fuel (a pair of 80 or 90 lb-Hr injectors at 20+ PSI) to support up to about 360 to 370 HP. The problem with most stock BBC is that these engines were choked with tiny cams, puny heads and restricted exhaust systems from the factory.

Like previous posters have stated - there is a learning curve associated with EFI tuning. But there is also a real world performance win since ECM tuning allows greater flexibility under a wide range of conditions. Also, camshaft and head selection is critical and careful consideration to an engine - drive line combination should be given before starting this project.

It all depends what you plan do with your rig.....

//RF
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TBI retrofit completed (2007-07-29)
New 383CID (+030) 08-304-8 9.5:1CR x36,005 (2012-12-17)
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Old 07-15-2010, 07:11 PM   #18
Davidmichael
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Re: EFI or CARB

I just got my first EFI square, and it's EFI all the way for me.
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