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The problem with EFI conversion over keeping carburetors

Started by deathsled, June 08, 2023, 05:35:01 PM

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deathsled

"Low she sits on five spoke wheels
Small block eight so live she feels
There she's parked beside the curb
Engine revving to disturb
She's the princess from his past
Red paint gold stripes damned she's fast"

FL SAAC

I truly never knew Mario ( a.k.a. Captain Lou Albano ) was a gear head   !
Home of the "Amazing Hertz 3 + 1 Musketeers"
I have all UNGOLD cars
I am certainly not a Shelby Expert

deathsled

"Low she sits on five spoke wheels
Small block eight so live she feels
There she's parked beside the curb
Engine revving to disturb
She's the princess from his past
Red paint gold stripes damned she's fast"

pbf777

     You've got to be really bored, with absolutely nothing of any importance that needs doing, to sit thru that!  At least not until you've had a couple of alcoholic drinks first!   ::)

     Scott.

deathsled

Quote from: pbf777 on June 08, 2023, 08:30:39 PM
     You've got to be really bored, with absolutely nothing of any importance that needs doing, to sit thru that!  At least not until you've had a couple of alcoholic drinks first!   ::)

     Scott.
That sums up my situation upon listening. But it did dissuade me from going the efi route.
"Low she sits on five spoke wheels
Small block eight so live she feels
There she's parked beside the curb
Engine revving to disturb
She's the princess from his past
Red paint gold stripes damned she's fast"

pmustang

I read again and again about these systems fixing issues. I spoke to a guy with a spectacular Mach one in PA last month. Said he just installed a Sniper system and it was great BUT!  There always seems to be a but. Something about the Tach causing issues with the system.

Hear the same type of thing again and again.

69 GT350 Vert

Love my sniper EFI.  I've had it for 5 years and it is the best mod I ever made to any classic car.  If you have a marginal engine with vacuum leaks or an exhaust leak you will have lots of trouble with EFI.  If you don't install it properly and don't know what AFR means, stick with the 100 year old carb technology.  If you want perfection with cold start and throttle response, EFI might be for you.

Royce Peterson

Lots of folks in my club have gone that way. Big trouble. Breakdowns constantly.
1968 Cougar XR-7 GT-E 427 Side Oiler C6 3.50 Detroit Locker
1968 1/2 Cougar XR-7 428CJ Ram Air C6 3.91 Traction Lock

69 GT350 Vert

Many do have problems if they have the ECU control timing with the hyperspark distributor, which is prone to rfi/EFI.  I stuck with my autolite distributor with pertronix and it works great with my factory tach. Fuel percolation and vapor lock is eliminated even with low boiling temps of E10 fuel.  Holley quality control on the sniper is poor currently based on what I read in the sniper forums. My 5 year old unit has been great.

crossboss

Even old school Holley's have issues. "Why is my carb always leaking?" Holley has always had the reputation for being a "Calibrated fuel leak". That said, once its set, and correctly rebuilt, it will/should be fine. Sniper EFI is not perfect. When an aftermarket conversion is made for a 'universal' across the board usage, there are bound to be issues. In my view, only an OEM set up will be reliable. Just me.
Past owned Shelby's:
1968 GT-350--Gold
1970 GT-500--#3129--Grabber Orange.
Current lifelong projects:
1969 Mustang Fastback/FOX chassis, 5 speed, 4 wheel discs, with a modern Can-Am 494 (Boss 429), Kaase heads, intake with a 1425 cfm 'B' Autolite Inline carb, ala Trans-Am style
1968/70 Olds 442 W-30

Side-Oilers

Current:
2006 FGT, Tungsten. Whipple, HRE 20s, Ohlin coil-overs. Top Speed Certified 210.7 mph.

Kirkham Cobra 427.  482-inch aluminum side-oiler. Tremec 5-spd.

Previous:
1968 GT500KR #2575 (1982-2022)
1970 Ranchero GT 429
1969 LTD Country Squire 429
1963 T-Bird Sport Roadster
1957 T-Bird E-model

69 GT350 Vert

Tony's video makes several good points.  He's right about the heat from mechanical fuel pumps being attached to a 220 degree engine block being mostly the cause for high fuel temperatures.  The problem is that storing 6 to 12 ounces of E10 fuel in the carb's fuel bowls just doesn't work without percolation.  The boiling point of ethanol fuel is too low.  With 58 psi of fuel pressure and no fuel storage on top of the heat sink, percolation and vapor lock is not a problem with EFI.

I couldn't solve percolation problems with a carb because my 351w has high performance mods that cause increased heat.  My gt350 feels like a gt500 based upon the ease of being able to spin both tires for 25 feet with half throttle from a dead stop with an FMX. I owned a 68 KR for 21 years with a well tuned cobra jet and my gt350 is almost as powerful as the KR was.  My car runs way better with EFI.

69 GT350 Vert

My Sniper EFI just failed and needs a new oxygen sensor driver and ECU.  My car started randomly stalling and I barely made it home.  I'm switching back to a carburetor.  EFI gave me 5 good years but I no longer trust it on my Shelby.

deathsled

Quote from: 69 GT350 Vert on June 21, 2023, 08:23:25 AM
My Sniper EFI just failed and needs a new oxygen sensor driver and ECU.  My car started randomly stalling and I barely made it home.  I'm switching back to a carburetor.  EFI gave me 5 good years but I no longer trust it on my Shelby.
A carburetor can be tuned to cooperate at the side of the road.  EFI makes that prospect difficult if not impossible especially for a novice such as myself.
"Low she sits on five spoke wheels
Small block eight so live she feels
There she's parked beside the curb
Engine revving to disturb
She's the princess from his past
Red paint gold stripes damned she's fast"

Drew Pojedinec

"I want to use EFI because it is easier to tune." -some guy with an AOL email address (probably)