4bbl Intake efi Conversion
Thread Starter
Instructor
Joined: Jun 2003
Posts: 183
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From: Gordonville MO
4bbl Intake efi Conversion
Anybody had a dual plane RPM type converted to efi?
Wondering if the torque curve changes, really shouldn't.
How about anybody that's tried an Ebock efi with the single
plane - what's your torque like about 2k to 4k compared to
a dual plane?
Thanks
Oh, anybody know where this can be done at a reasonable
cost? I've seen some on the net, but they want $500 just
to do the work and provide the bungs and fuel rails on your
manifold!
Wondering if the torque curve changes, really shouldn't.
How about anybody that's tried an Ebock efi with the single
plane - what's your torque like about 2k to 4k compared to
a dual plane?
Thanks
Oh, anybody know where this can be done at a reasonable
cost? I've seen some on the net, but they want $500 just
to do the work and provide the bungs and fuel rails on your
manifold!
Race Director
Joined: Sep 1999
Posts: 11,361
Likes: 383
From: Plano TX
Re: 4bbl Intake efi Conversion (macx)
Why not get one that is already done? Holley, for instance, sells a kit with everything you need except the ECU (in case you want to use a different one), or just the intake if you prefer that.
With port EFI there's no reason to use a dual plane. The dual plane design was used to create a strong signal for a carb at low engine speeds. Port EFI has no need for a vacuum signal to pull fuel so there's no drawback to using a single plane intake.
With port EFI there's no reason to use a dual plane. The dual plane design was used to create a strong signal for a carb at low engine speeds. Port EFI has no need for a vacuum signal to pull fuel so there's no drawback to using a single plane intake.
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
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St. Jude Donor '06-'10, '13
Re: 4bbl Intake efi Conversion (zwede)
:iagree: What he said.
Le Mans Master
Joined: Apr 2000
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From: B'Ville NY
Cruise-In III Veteran
St. Jude Donor '05
Re: 4bbl Intake efi Conversion (BSeery)
:iagree: Good advice Zwede :yesnod: . You really won't save any $ having an intake converted to EFI. The kits that are out are pretty good deal. I think the Holley intake can be port matched to a 1206 intake gasket also ;) .
Team Owner
Joined: Jul 1999
Posts: 65,492
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From: Orange Park Florida
Re: 4bbl Intake efi Conversion (macx)
Funny you mention that very topic, as I did a project in my garage over one winter 91-92 I think, putting computer DPFI on an old Pontiac 455 engine in my '70 Lemans/GTO convertible.....picked up about 3-4 mpg and about doubled the instant torque available when mashing the pedal....that damn car FLEW....great tow car too, jerk a boat over the mountain to the river at amazing speeds....really layed us back the kids loved it, really fun at WOT with the top down....;-)))
the machining of the intake was done at a local machine shop, and so I had to plumb the injectors....really hard to do on the dual planes as the injectors have to be aimed directly at the intake valves....so the problem is with the differant heights, the injectors needed a dedicated pipe run to each one....
so my install looked like one hell of a kludge, but it worked fine...I had a 1000 cfm t-body where the carb used to sit....the moan was fantastic....
much louder than any Qjet....dunno why, just WAS.....
probably because the thing would just open up and the injectors went into open **** mode.....whereass a Qjet might still be partly closed on the secondaries is all I can think of.....
had a 25 gallon caddy tank in the thing....
GENE
the machining of the intake was done at a local machine shop, and so I had to plumb the injectors....really hard to do on the dual planes as the injectors have to be aimed directly at the intake valves....so the problem is with the differant heights, the injectors needed a dedicated pipe run to each one....
so my install looked like one hell of a kludge, but it worked fine...I had a 1000 cfm t-body where the carb used to sit....the moan was fantastic....
much louder than any Qjet....dunno why, just WAS.....
probably because the thing would just open up and the injectors went into open **** mode.....whereass a Qjet might still be partly closed on the secondaries is all I can think of.....
had a 25 gallon caddy tank in the thing....
GENE
Thread Starter
Instructor
Joined: Jun 2003
Posts: 183
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From: Gordonville MO
Re: 4bbl Intake efi Conversion (mrvette)
Hmmm - I realize the dual plane design helps with the carb signal.
But doesn't it also help with torque? The old Heimholz effect (aka "ram tuning" to stuff more air into the cyl at lower speeds w/longer runners - irregardless of whether there's fuel in the air or not) How about the diff in low-mid range throttle response between a short runner large plenum LT1 and a long runner TPI?
But doesn't it also help with torque? The old Heimholz effect (aka "ram tuning" to stuff more air into the cyl at lower speeds w/longer runners - irregardless of whether there's fuel in the air or not) How about the diff in low-mid range throttle response between a short runner large plenum LT1 and a long runner TPI?
Race Director
Joined: Sep 1999
Posts: 11,361
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From: Plano TX
Re: 4bbl Intake efi Conversion (macx)
Yes, good 'ol Helmholz is still valid. Longer runners improve low end torque. I guess I'm not really the one to ask. I have 454 so the torque is more than I need at any rpm. I cruise in 5th gear at 1000 rpm and it is totally effortless.
But I would say that although ram tuning is still valid with EFI, a single plane is usually used and tuning is accomplished by changing plenum volume.
But I would say that although ram tuning is still valid with EFI, a single plane is usually used and tuning is accomplished by changing plenum volume.
Team Owner
Joined: Jul 1999
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From: Orange Park Florida
Re: 4bbl Intake efi Conversion (zwede)
[QUOTE]Yes, good 'ol Helmholz is still valid. Longer runners improve low end torque. I guess I'm not really the one to ask. I have 454 so the torque is more than I need at any rpm. I cruise in 5th gear at 1000 rpm and it is totally effortless.
But I would say that although ram tuning is still valid with EFI, a single plane is usually used and tuning is accomplished by changing plenum volume.
I think you mean runner volume....plenum has little to do with tuning, doesn't it??? unless I missed something somewhere along the line....
GENE
But I would say that although ram tuning is still valid with EFI, a single plane is usually used and tuning is accomplished by changing plenum volume.
I think you mean runner volume....plenum has little to do with tuning, doesn't it??? unless I missed something somewhere along the line....
GENE
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