Home » Public Forums » GMCnet » Converting to FI - Port or TBI
| Converting to FI - Port or TBI [message #107666] |
Mon, 06 December 2010 09:41  |
tze73
Messages: 13
Registered: August 2010
Location: Montreal, Quebec
Karma: 0
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Hi, I'm in the process of converting to FI on a 455. I found a 2bbl iron manifold from a 70 olds 98 that is in good shape and bored out the carb base to 2" for a TBI from a gm 454, it is a bit higher than the original but I think I can fit it without raising the hatch. I already have the TBI, which I was going to control with megasquirt. I also have a set of port injectors from a ford 460. Now i'm thinking maybe I should go to port injection to try to squeeze out another point or two of fuel economy. Is it worth the extra work. (bore manifold, fuel rail, plumbing etc.) Opinions?
[Updated on: Mon, 06 December 2010 09:41] Report message to a moderator |
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| Re: [GMCnet] Converting to FI - Port or TBI [message #107668 is a reply to message #107666] |
Mon, 06 December 2010 09:58  |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Bill Bramlett, one of the best mechanics I've EVER known, converted his
Cad500 from TBI to Port, using an already port equipped manifold. His
advice to me when I was considering my options was to forget port injection
since the benefits over TBI were not worth the effort, expense, or increased
complexity.
Several other netters are just finished or in the process of flying in the
face of that advice, however, so there may be other opinions.
If I WERE going to make the conversion you propose on a 455, I sure wouldn't
use a high rise manifold though; I've lived with the raised hatch you'll
inevitably need & REALLY didn't like it. I'd use Gary Rockwell's aluminum
manifold since it has bosses to bore for the injectors.
JMHO,
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Mon, Dec 6, 2010 at 10:41 AM, kp <kpattington@yahoo.ca> wrote:
>
>
> Hi, I'm in the process of converting to FI on a 455. I found a 2bbl iron
> manifold from a 70 olds 98 that is in good shape and bored out the carb base
> too 2" for a TBI from a gm 454, it is a bit higher than the original but I
> think I can fit it without raising the hatch. I already have the TBI, which
> I was going to control with megasquirt. I also have a set of port injectors
> from a ford 460. Now i'm thinking maybe I should go to port injection to try
> to squeeze out another point or two of fuel economy. Is it worth the extra
> work. (bore manifold, fuel rail, plumbing etc.) Opinions
>
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Converting to FI - Port or TBI [message #107669 is a reply to message #107666] |
Mon, 06 December 2010 10:03 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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By the way, let me know if you want to join GMCMH-EFI, where most of the
detailed EFI discussions are conducted.
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Mon, Dec 6, 2010 at 10:41 AM, kp <kpattington@yahoo.ca> wrote:
>
>
> Hi, I'm in the process of converting to FI on a 455. I found a 2bbl
_______________________________________________
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Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: Converting to FI - Port or TBI [message #107679 is a reply to message #107666] |
Mon, 06 December 2010 12:18 |
tgeiger
Messages: 518
Registered: February 2006
Location: kansas city
Karma: -1
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Senior Member |
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I'm in the same ball park, although I think I want to stick with the TBI system. I've read some calibration issues with some TBI's, I don't know if this is from the TBI kits that are sold strictly for the GMC or if it's from guys that are putting togehter their own TBI systems. Can someone comment on this?
I was considering the Howell system for mine, when I pulled the money together.
Tom Geiger
76 Eleganza II
KCMO
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| Re: [GMCnet] Converting to FI - Port or TBI [message #107683 is a reply to message #107679] |
Mon, 06 December 2010 12:32 |
Ken Henderson
Messages: 8726
Registered: March 2004
Location: Americus, GA
Karma: 9
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Senior Member |
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Tom,
All your questions have been, or will quickly be, answered on our GMCMH-EFI
Google Group. You can visit it at http://groups.google.com/group/gmcmh-efi
<http://groups.google.com/group/gmcmh-efi>Pay particular attention to the
"Pages" and "Files" sections, which contain material we feel it's important
to have readily available.
Let me know if you want me to sign you up (or do it yourself and I'll
approve the request).
Ken H.
Americus, GA
'76 X-Birchaven w/Cad500/Howell EFI+ & EBL
www.gmcwipersetc.com
On Mon, Dec 6, 2010 at 1:18 PM, tom geiger <tgeiger@burnsmcd.com> wrote:
>
>
> I'm in the same ball park, although I think I want to stick with the TBI
> system. I've read some calibration issues with some TBI's, I don't know if
> this is from the TBI kits that are sold strictly for the GMC or if it's from
> guys that are putting togehter their own TBI systems. Can someone comment
> on this?
> I was considering the Howell system for mine, when I pulled the money
> together.
> _______________________________________________
>
_______________________________________________
GMCnet mailing list
List Information and Subscription Options:
http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
Ken Henderson
Americus, GA
www.gmcwipersetc.com
Large Wiring Diagrams
76 X-Birchaven
76 X-Palm Beach
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| Re: [GMCnet] Converting to FI - Port or TBI [message #107688 is a reply to message #107683] |
Mon, 06 December 2010 13:34 |
jimk
Messages: 6734
Registered: July 2006
Location: Belmont, CA
Karma: 9
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Senior Member |
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Stick with a unit that most people use, as the tech support is easier to get.
We have 2 people retained to help or customers when they have any
problems with the units they purchase from us.
We reccomend the Howell unit. Base price $1,025.00
On Mon, Dec 6, 2010 at 10:32 AM, Ken Henderson <hend4800@bellsouth.net> wrote:
> Tom,
>
> All your questions have been, or will quickly be, answered on our GMCMH-EFI
> Google Group. You can visit it at http://groups.google.com/group/gmcmh-efi
>
> <http://groups.google.com/group/gmcmh-efi>Pay particular attention to the
> "Pages" and "Files" sections, which contain material we feel it's important
> to have readily available.
>
> Let me know if you want me to sign you up (or do it yourself and I'll
> approve the request).
>
> Ken H.
> Americus, GA
> '76 X-Birchaven w/Cad500/Howell EFI+ & EBL
> www.gmcwipersetc.com
>
>
>
> On Mon, Dec 6, 2010 at 1:18 PM, tom geiger <tgeiger@burnsmcd.com> wrote:
>
>>
>>
>> I'm in the same ball park, although I think I want to stick with the TBI
>> system. I've read some calibration issues with some TBI's, I don't know if
>> this is from the TBI kits that are sold strictly for the GMC or if it's from
>> guys that are putting togehter their own TBI systems. Can someone comment
>> on this?
>> I was considering the Howell system for mine, when I pulled the money
>> together.
>> _______________________________________________
>>
> _______________________________________________
> GMCnet mailing list
> List Information and Subscription Options:
> http://temp.gmcnet.org/cgi-bin/mailman/listinfo/gmclist
>
--
Jim Kanomata
Applied/GMC, Fremont,CA
jimk@appliedairfilters.com
http://www.appliedgmc.com
1-800-752-7502
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Jim Kanomata
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jimk@appliedairfilters.com
www.appliedgmc.com
1-800-752-7502
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| Re: Converting to FI - Port or TBI [message #107699 is a reply to message #107666] |
Mon, 06 December 2010 17:19 |
George Beckman
Messages: 1085
Registered: October 2008
Location: Colfax, CA
Karma: 11
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Senior Member |
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| tze73 wrote on Mon, 06 December 2010 07:41 |
Hi, I'm in the process of converting to FI on a 455.
<snip>
Now i'm thinking maybe I should go to port injection to try to squeeze out another point or two of fuel economy. Is it worth the extra work. (bore manifold, fuel rail, plumbing etc.) Opinions?
|
I agree with Ken that the GMCMH-EFI group is where you will find excellent information and help. However for those just wondering, I have a couple of points to think about as you consider starting down this road.
1) Fuel Injection is not going to get you 15 mpg. We are working at this and doing better than before but not as well as we hoped.
2) Many with EFI (Electronic Fuel Injection) have found that spark control (by the computer) is huge in this undertaking. Howell makes solid kits and I am happy with mine. However, they proudly say that you can use your HEI distributor with their kit. And that is right. But after almost 20K miles with EFI, I find more results in spark. Getting the spark at the right time is huge. (Of course vacuum and weights can do this, also) Being able to tweak spark tables is helpful on so many fronts: pinging, mpg and responsiveness.
3) Some GMC guys don't want to play with spark tables and fuel tables and that is understandable. A number of fellows have some good setups (bin files) that they are willing to share.
4) Howell, Affordable and Megasquirt all adapt to our existing manifold. Any manifold that is even a tiny bit higher is going to rub... my 74 grazes the deck with the original manifold.
5) Some of the setups are static, meaning you get it, put it on and it runs pretty well. I know Affordable and Howell both are willing to help you tweak your bin file setup if you find it is not quite what you want; you send the chip to them and they tweak it. However Megasquirt and an EBL add-on to the Howell type computer allow us to make changes easily and literally while on a trip. This is not necessary, but if you like to "tune" your carb and your distributor, you will want to twiddle with the EFI and both EBL and Megasquirt make that pretty easy... and you do it without lifting the hatch.
6) If your travels take you to different elevations you will appreciate the benefits of EFI. We live at 145 feet and our coach starts and runs beautifully at 8,000 feet and at home.
Lastly, there is no silver bullet. There never was a 200 mpg carburetor that was bought up by Standard Oil. A carburetor that lean makes a mixture that won't explode with a spark plug. We push a lot of wind with our 12,000 lb rigs and that takes fuel. Gene Fisher has said you will get 8-10 mpg depending of whether or not you tow. Some EFI guys are starting to prove him wrong... by a few tenths... if conditions are right. These are averages of several fill-ups... not one "good tank". On the California to Du Quoin trip I averaged about 9.5 mpg. We were not towing. I drove about 62-65 most of the time. Yes, I could say we had many days of hard head winds. Whine, whine. I was in Colorado and New Mexico at high elevations. Whine, whine. In New Mexico for three days we used to coach like a car. Whine, whine. I got about 9.5.
'74 Eleganza, SE, Howell + EBL
Best Wishes,
George
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| Re: Converting to FI - Port or TBI [message #107821 is a reply to message #107699] |
Tue, 07 December 2010 13:34 |
roy1
Messages: 2126
Registered: July 2004
Location: Minden nevada
Karma: 6
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Senior Member |
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I seem to remember Fritz Slama got 12 miles to the gallon in a Cadillac powered 26 foot GMC back in the early 80's. As I remember it was some kind of a contest between GMC's. I don't remember if it was injected or carburated.
Roy
Roy Keen
Minden,NV
76 X Glenbrook
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| Re: Converting to FI - Port or TBI [message #107835 is a reply to message #107666] |
Tue, 07 December 2010 15:26 |
g.winger
Messages: 792
Registered: February 2008
Location: Warrenton,Missouri
Karma: 0
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Senior Member |
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I've stated this before, but the "Boss" gets 40 (FORTY)mpg on a 35mpg rated saturn. The secret is she hates the interstate and drives 55 on the backroads into town. If you were to remove the roof AC's, rack, ladder and pods and drove 45-50 I bet it could be done. Just an opionion. Tring to figure out how to remove my AC's now. Mr Anslett did it. Looks good,,,,,,PL
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