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| [GMCnet] EFI conversion [message #366253] |
Fri, 20 August 2021 21:51  |
Oliver Moore
Messages: 21
Registered: March 2018
Karma: 1
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Junior Member |
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My Rochester on my Dick Patterson engine seems to work perfectly. But, as
an inveterate tinkerer, I am tempted to replace it with EFI. I would
appreciate input from those who have gone EFI. Here are some questions:
Is it a DIY installation?
When you add in the high pressure fuel pump, return line etc what is the
total cost?
Should you replace the distributor as well?
What is the fuel savings at 55 and 70 mph.
Many thanks
1973 Glenbrook
Patterson Stage II engine
Thorley headers
Alcoa wheels
Honda 6kw Genset
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| [GMCnet] Re: EFI conversion [message #366256 is a reply to message #366253] |
Fri, 20 August 2021 23:47  |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Oliver,
WE sell ALL the Throttle body units and receive feedback.
If your looking for better mileage with improved performance only the
Howell based with EBL ECM and full electrical distributor will work . Don't
lrt the two barrels think it slows you down.
MSD, Sniper,FiTech and others Perform well, but does not have the full
distributor control plus acquiring replacement parts are very limited.
On Fri, Aug 20, 2021 at 7:52 PM Oliver Moore wrote:
> My Rochester on my Dick Patterson engine seems to work perfectly. But, as
> an inveterate tinkerer, I am tempted to replace it with EFI. I would
> appreciate input from those who have gone EFI. Here are some questions:
> Is it a DIY installation?
> When you add in the high pressure fuel pump, return line etc what is the
> total cost?
> Should you replace the distributor as well?
> What is the fuel savings at 55 and 70 mph.
> Many thanks
> 1973 Glenbrook
> Patterson Stage II engine
> Thorley headers
> Alcoa wheels
> Honda 6kw Genset
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
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Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] EFI conversion [message #366257 is a reply to message #366253] |
Sat, 21 August 2021 00:40 |
Scott Nutter
Messages: 782
Registered: January 2015
Location: Houston/San Diego
Karma: 4
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Senior Member |
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Jim K speaks the truth.
The bolt on throttle body EFI kits are best for reliability(compared to a carb).You will not get better fuel mileage versus a well tuned carb. Just a more reliable fuel delivery system than a carb. The bolt on EFI’s will love Dick Patterson’s distributor. Or, at least mine does.
If you want better MPG, then you will need the Howell setup with the distributor that is controllable.
My numbers are old, but…..
1. Carb $350?
2. MSD EFI master kit $1,200?
3. Howell with controllable distributor $3,000?
Then put labor on top of that…..but Jim K has it all. I got my MSD master kit from him.
Scott.
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI
Houston, Texas
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| [GMCnet] Re: EFI conversion [message #366258 is a reply to message #366257] |
Sat, 21 August 2021 04:37 |
johnd01
Messages: 354
Registered: July 2017
Location: Sacrameot
Karma: -1
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Senior Member |
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I get about 8 MPG, what should I expect from the Howell with a controllable
distributor?
Will that fix my vapor lock problems?
On Fri, Aug 20, 2021 at 10:40 PM Scott Nutter wrote:
> Jim K speaks the truth.
> The bolt on throttle body EFI kits are best for reliability(compared to a
> carb).You will not get better fuel mileage versus a well tuned carb. Just a
> more reliable fuel delivery system than a carb. The bolt on EFI’s will
> love Dick Patterson’s distributor. Or, at least mine does.
>
> If you want better MPG, then you will need the Howell setup with the
> distributor that is controllable.
>
> My numbers are old, but…..
>
> 1. Carb $350?
> 2. MSD EFI master kit $1,200?
> 3. Howell with controllable distributor $3,000?
>
> Then put labor on top of that…..but Jim K has it all. I got my MSD master
> kit from him.
> Scott.
>
>
> --
> Scott Nutter
> 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final
> drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
> installed MSD Atomic EFI
> Houston, Texas
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
*John Phillips*
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Johnd01
John Phillips
Avion A2600 TZE064V101164
Rancho Cordova, CA (Sacramento)
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| Re: [GMCnet] EFI conversion [message #366261 is a reply to message #366253] |
Sat, 21 August 2021 08:59 |
Silvernort
Messages: 95
Registered: June 2019
Location: Rock Springs, WI
Karma: 0
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Member |
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I'd like to add to the "what's involved?" list for EFI:
Is an accumulator tank a necessity, nicety, or unnecessary?
How do you plumb one in? Does the return line go to it or main tank? Where is the best place to put it? Where do the fuel pumps go?
Cheers
Shane Harvey
1973 26' "Packer Backer", 1976 Palm Beach, 1965 Dart
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| Re: [GMCnet] EFI conversion [message #366263 is a reply to message #366253] |
Sat, 21 August 2021 10:26 |
Scott Nutter
Messages: 782
Registered: January 2015
Location: Houston/San Diego
Karma: 4
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Senior Member |
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8 MPG is pretty standard with a carb.
After 10,000 miles with the MSD and very accurate fuel calculations, I get 7.666 MPG. But that is with a very heavy coach, 2 ac’s, a pod, towing a tracker, with 2 bicycles off the back of the tracker. So basically a lot of aerodynamic drag….and our dash air is most always on. We are in Texas!
I am not a Howell expert(Jim K is) but I’ve heard you can get up to 11 MPG. So what is that. About a 20% improvement in MPG? So the Howell will eventually pay for its self. But how long will that take?
As far as the plumbing on the bolt on throttle body EFI kits. The sky is the limit as far as design. But there are 2 necessities on all systems. 1, a high pressure fuel pump(either in the tank, or inline). 2, a return fuel line(either to the tank or to the fuel fill neck).
MSD, Holley, and Fitech all have detailed information on installation on their websites. Someone mentioned a Accumulator tank. I believe that is a option with the Fitech.
Scott
Scott Nutter
1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final drive, Quad bags, Dave Lenzi super duty mid axle disc brakes, tankless water heater, everything Lenzi. Alex Ferrera installed MSD Atomic EFI
Houston, Texas
[Updated on: Sat, 21 August 2021 12:33] Report message to a moderator |
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| [GMCnet] Re: EFI conversion [message #366264 is a reply to message #366263] |
Sat, 21 August 2021 10:43 |
James Hupy
Messages: 6806
Registered: May 2010
Karma: -62
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Senior Member |
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I have a 78 Royale with a 403. Heavy coach. 3:70 final drive. I
consistently get between 8 and 9 mpg on major brand (Chevron. Texaco, Petro
Canada) gasoline usually 87 octane alcohol laced fuel.
In years past (before alcohol laced gasoline) I used to get
consistently 10 mpg.
My coach has a Quadrajet and HEI ignition with no dash A/C.
I think today's gasoline is more responsible for poor fuel economy
than any other factor.
Coaches that are Howell HEI/EBL equipped start and run very well.
Vapor lock is minimized. If spark is controlled with the computer, a 1-2
mpg improvement can be expected. But if you drive 55, you can also improve
your fuel consumption.
So driving habits are a factor in all this also.
Jim Hupy
Salem, Oregon
On Sat, Aug 21, 2021, 8:27 AM Scott Nutter wrote:
> 8 MPG is pretty standard with a carb.
> After 10,000 miles with the MSD and very accurate fuel calculations, I get
> 7.666 MPG. But that is with a very heavy coach, 2 ac’s, a pod, towing a
> tracker, with 2 bicycles off the back of the tracker. So basically a lot
> of aerodynamic drag….
>
> I am not a Howell expert(Jim K is) but I’ve heard you can get up to 11
> MPG. So what is that. About a 20% improvement in MPG? So the Howell will
> eventually pay for its self. But how long will that take?
>
> As far as the plumbing on the bolt on throttle body EFI kits. The sky is
> the limit as far as design. But there are 2 necessities on all systems. 1, a
> high pressure fuel pump(either in the tank, or inline). 2, a return fuel
> line(either to the tank or to the fuel fill neck).
>
> MSD, Holley, and Fitech all have detailed information on installation on
> their websites. Someone mentioned a Accumulator tank. I believe that is a
> option with the Fitech.
>
> Scott
> --
> Scott Nutter
> 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21 final
> drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
> installed MSD Atomic EFI
> Houston, Texas
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
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| [GMCnet] Re: EFI conversion [message #366265 is a reply to message #366264] |
Sat, 21 August 2021 11:39 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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There are lot of variables when it comes to MPG.
All I can tell you is that ignition timing is key to mileage and
performance.
Learned that as a kid working on my Mom's car.
I put on a triple carb set up and Mom always kept track of mileage.
Her only complaint was the roar noise when she had to put the pedal down to
pass.
One of key to why Patterson's distributor performance is his ignition
timing.
The EBL we sell has the best timing curve that has been developed by couple
of the GMC MH people in Oklahoma.
Those that purchase the EBL from the Manufacture lack the program we
install in ours that is for 403 or 455. Also have no clue that there is an
EBL for GMC MH.
Also ready availability of parts. The Howell based unit is mainly GM
components, so they are available from your parts store. Try that on the Fi
Tec, MSD,Sniper and others.
On Sat, Aug 21, 2021 at 8:43 AM James Hupy wrote:
> I have a 78 Royale with a 403. Heavy coach. 3:70 final drive. I
> consistently get between 8 and 9 mpg on major brand (Chevron. Texaco, Petro
> Canada) gasoline usually 87 octane alcohol laced fuel.
> In years past (before alcohol laced gasoline) I used to get
> consistently 10 mpg.
> My coach has a Quadrajet and HEI ignition with no dash A/C.
> I think today's gasoline is more responsible for poor fuel economy
> than any other factor.
> Coaches that are Howell HEI/EBL equipped start and run very well.
> Vapor lock is minimized. If spark is controlled with the computer, a 1-2
> mpg improvement can be expected. But if you drive 55, you can also improve
> your fuel consumption.
> So driving habits are a factor in all this also.
> Jim Hupy
> Salem, Oregon
>
> On Sat, Aug 21, 2021, 8:27 AM Scott Nutter wrote:
>
>> 8 MPG is pretty standard with a carb.
>> After 10,000 miles with the MSD and very accurate fuel calculations, I
> get
>> 7.666 MPG. But that is with a very heavy coach, 2 ac’s, a pod, towing a
>> tracker, with 2 bicycles off the back of the tracker. So basically a lot
>> of aerodynamic drag….
>>
>> I am not a Howell expert(Jim K is) but I’ve heard you can get up to 11
>> MPG. So what is that. About a 20% improvement in MPG? So the Howell will
>> eventually pay for its self. But how long will that take?
>>
>> As far as the plumbing on the bolt on throttle body EFI kits. The sky is
>> the limit as far as design. But there are 2 necessities on all systems.
> 1, a
>> high pressure fuel pump(either in the tank, or inline). 2, a return fuel
>> line(either to the tank or to the fuel fill neck).
>>
>> MSD, Holley, and Fitech all have detailed information on installation on
>> their websites. Someone mentioned a Accumulator tank. I believe that is a
>> option with the Fitech.
>>
>> Scott
>> --
>> Scott Nutter
>> 1978 Royale Center Kitchen, Patterson 455, switch pitch tranny, 3.21
> final
>> drive, Quad bags, tankless water heater, everything Lenzi. Alex Ferrera
>> installed MSD Atomic EFI
>> Houston, Texas
>> _______________________________________________
>> GMCnet mailing list
>> Unsubscribe or Change List Options:
>>
> _______________________________________________
> GMCnet mailing list
> Unsubscribe or Change List Options:
>
--
Jim Kanomata ASE
Applied/GMC, Newark,CA
jimk@appliedairfilters.com
http://www.gmcrvparts.com
1-800-752-7502
_______________________________________________
GMCnet mailing list
Unsubscribe or Change List Options:
Jim Kanomata
Applied/GMC
jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: [GMCnet] EFI conversion [message #366305 is a reply to message #366253] |
Tue, 24 August 2021 08:43 |
lqqkatjon
Messages: 2324
Registered: October 2010
Location: St. Cloud, MN
Karma: 5
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Senior Member |
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Everything on a GMC motorhome Can be DIY. but there are many coach's I see that you really wish someone did not DIY. I have also seen most work that was done by a Shop where the owner did not want to DIY, and the shop really should not be in the GMC motorhome fixing business either.....
EFI is not a stock OEM install setup, and every one is installed differently. There is no true manual for installing it, and every installer does something a little different.
EFI will give you better drivability, but don't count on better MPG.
in my opinion, 50% of the work to install EFI is figuring out how you want to supply the throttle body system with fuel. there are surge tanks, there are different methods of fuel return to the tanks. 1 pump? 2 pumps? put the pumps in the tank, put them on the inside of frame, outside of frame? filters, ect... it is a big puzzle to figure out, and there is no one correct answer.
it can be a DIY project, but it is not as bolt on and go as most seem to think. Even the holly spreadbore still needs a bit of work to get it on and going.
I personally installed a GM based system like the howell, and installed the EBL with timing control and I am very happy with that setup. This weekend I was around a coach that I believe it was one of the first coaches with the EBL ECU installed into it. I know this coach has been all over the USA it's whole life, and this coach engine was still running smooth.
it is a real benefit to know there are many GMC owners who have decades of experience with the same EFI system you have on your coach.... just my thoughts.
Jon Roche
75 palm beach
EBL EFI, manny headers, Micro Level, rebuilt most of coach now.
St. Cloud, MN
http://lqqkatjon.blogspot.com/
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