[Gmecm] Chevy 350 Carburated to TBI / TPI?
Aphelion79
aphelion79
Sat Jan 13 05:42:32 UTC 2007
Oh okay so the 2bbl TBI was stock, that clears that up... :) I figured
the 4bbl was some fancy thing by Holly... thanks for all the information
everyone, I'm still lost as to what a "CAL" is when I was asking about
the Transmission earlier:
"If you are going to use a TH400 transmission, you will want to find
a wiring harness from a truck equipped with the TH400 and use a CAL from
a TH400. If you can't find the CAL, let me know and I can tell you
which one I used that I uploaded to the server several years ago."
Beau Blankenship wrote:
> The 17-41 adapter is what I used on my Edel. Performer intake to adapt the
> TBI. The bores are 2" (Big-block/ProJection size). The stock TBI has smaller
> bores. Not a problem, but something to be aware of if you are considering an
> upgrade later (or even now if you find a 454 TB in the parts-yard). But,
> then if you found one of those, you could get its adapter (which is heated).
> The 4-bbl was a Holley thing. I'm sure someone here has tried adapting it to
> a GM ECM, but it is a bit more work than sticking a stock TBI on there. More
> tuning, wiring, possibly a different ECM, injector drivers, etc. Don't worry
> about finding one of those in a parts-yard. You probably won't.
>
> Beau
>
> -----Original Message-----
> From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On Behalf
> Of Aphelion79
> Sent: Thursday, January 11, 2007 9:57 PM
> To: gmecm at diy-efi.org
> Subject: Re: [Gmecm] Chevy 350 Carburated to TBI / TPI?
>
> Also,
> http://www.holley.com/types/Commander%20950%20and%20Pro-Jection%20TBI%20Serv
> ice%20Parts.asp
>
>
> Part #: 17-41
>
>
> Commander 950 and Pro-Jection TBI Service Parts
>
> <http://www.holley.com/types/Commander%5F950%5Fand%5FPro%2DJection%5FTBI%5FS
> ervice%5FParts.asp>
>
> Is this the correct one for a Chevy 350?
>
> Also, I have a 4-barrel carburetor on there... I see that Holly makes a
> 4bbl TBI... is this "normal" (i.e. stock? more power than the
> carburetor?) I also don't see an adapter for the 4bbl TBI... Although if
> 2bbl is stock and is what I'm going to find at the Junkyard, please let
> me know not to worry about the TBI being 4bbl or 2bbl!
>
> Aphelion79 wrote:
>
>> Not to sound ignorant, however much I may be on the topic, what
>> exactly is a CAL?
>>
>> Jake Tucker wrote:
>>
>>> Bob,
>>> If you are going to use a TH400 transmission, you will want to find
>>> a wiring harness from a truck equipped with the TH400 and use a CAL from
>>> a TH400. If you can't find the CAL, let me know and I can tell you
>>> which one I used that I uploaded to the server several years ago. The
>>> TH400 uses an electric solenoid for the kick-down on the transmission.
>>> On a carb, this is activated by a simple switch that is below the gas
>>> pedal and senses full throttle. On a TBI system, it is controlled by
>>> the computer, which allows you to change the set point. You can
>>> probably re-pin a harness that doesn't have this wire, but that's a
>>> little more difficult. Look for an orange wire that is by itself, near
>>> the firewall on the drivers side. The TH350 and manual trans versions
>>> of the TBI system will not have this wire. The TH350 uses a mechanical
>>> cable for the kickdown, and obviously the manual trans doesn't do
>>> anything.
>>>
>>> Jake
>>>
>>> -----Original Message-----
>>> From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org] On
>>> Behalf Of Aphelion79
>>> Sent: Thursday, January 11, 2007 4:13 PM
>>> To: gmecm at diy-efi.org
>>> Subject: Re: [Gmecm] Chevy 350 Carburated to TBI / TPI?
>>>
>>> Ok, so that means I will need the distributor from the truck that I pull
>>>
>>> the TBI, harness, and ECM out of (and all accompanying sensors) as
>>> well right?
>>>
>>> Also one more thing I've thought of...
>>> How does the TH400 transmission work with the stock carburetor? Does it
>>>
>>> have anything to do with it? If so, how does this work with the TBI?
>>> I've only messed with manual transmissions in my lifetime, never worried
>>>
>>> about autos! =)
>>>
>>> Thanks for all the help, thats about all I can think of that I'd have
>>> problems/concerns about!
>>>
>>> Jay Vessels wrote:
>>>
>>>> Hi there!
>>>>
>>>>
>>>>> I was wondering if the TBI systems used on the '87+ Truck 350s were
>>>>> fuel only, or did they control timing as well?
>>>>>
>>>> They controlled the timing as well, through the distributor ignition
>>>> module.
>>>>
>>>>
>>>>> On the GM 151 4cyls I've had experience with they used a computer
>>>>> controlled timing curve (basically the same idea as a vacuum advance,
>>>>>
>>>>> I.E. the computer has NO idea where the timing is in relation to
>>>>> the crankshaft)
>>>>>
>>>> The ECM doesn't have absolute position of the crank, but it does
>>>> have relative position in that it trusts that the distributor is set
>>>> at a particular static timing position, and it adjusts from that.
>>>> Since it
>>>>
>>>> is not doing individual cylinder timing adjustments and is not doing
>>>> sequential fuel injector firing it does not need to know exactly where
>>>>
>>>> the crank is.
>>>>
>>>> I also know of other types of engines using complete timing
>>>>
>>>>> control where the use of a crankshaft positioning sensor / knock
>>>>> sensor is used...
>>>>>
>>>> Many GM DIS systems don't provide crank position to the ECM. The
>>>> ignition module has that data but doesn't pass it on since the ECM
>>>> doesn't need it.
>>>>
>>>>
>>>>> Also, for an O2 sensor, do you need one for each "side" of the
>>>>> engine? (Where as my previous knowledge is I4 and I6's, I only have
>>>>> one exhaust manifold! =D )
>>>>>
>>>> For this system (older TBI) there is only one sensor.
>>>>
>>>>
>>>>> Also these systems are all OBDI, because to my knowledge OBDII didn't
>>>>>
>>>>> start up until 1996? (Dunno where I got that year from, but for some
>>>>>
>>>>> reason it comes to mind, lol.)
>>>>>
>>>> Right on both counts.
>>>>
>>>> Jay Vessels
>>>> 1982 Chevrolet S-10 Sport, 2.8V6 TBI
>>>> 1984 Chevrolet S-10 Blazer Sport, 2.8V6 (TBI pending)
>>>>
>>>>
>>>>
>>>>> Thanks for the support everyone!
>>>>>
>>>>> Jake Tucker wrote:
>>>>>
>>>>>> Bob,
>>>>>> The Carter is a square bore, just like a Holley. As a matter of
>>>>>> fact, I believe the only stock spread bore carb was a quadrajet
>>>>>> (although that was almost all GM 4 barrel carbs). Holley, and
>>>>>>
>>> others,
>>>
>>>>>> do make a spread bore replacement, but the OEM carbs that weren't
>>>>>> quadrajets were all square bores.
>>>>>>
>>>>>> Jake
>>>>>>
>>>>>> -----Original Message-----
>>>>>> From: gmecm-bounces at diy-efi.org [mailto:gmecm-bounces at diy-efi.org]
>>>>>>
>>> On
>>>
>>>>>> Behalf Of BNRVL at aol.com
>>>>>> Sent: Tuesday, January 09, 2007 11:45 AM
>>>>>> To: gmecm at diy-efi.org
>>>>>> Subject: Re: [Gmecm] Chevy 350 Carburated to TBI / TPI?
>>>>>>
>>>>>>
>>>>>>
>>>>>> Hello , what is the bolt pattern for 69 Corvette Carter carb. ??
>>>>>>
>>>>>> thanks
>>>>>> Bob Norville
>>>>>>
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