[Gmecm] Re: TBI injector schema vs. port injector schema

[Gary Evans]

The fueling strategies for a dry vs. wet manifold system are going to  
be very different. True, basic steady state VE theory will be the  
same, and you could probably get such a setup to run.

But AE, DE, cold start, warm soak restart, cranking fuel and PE  
(among other things) are going to be very different to account for  
the presence of fuel in the manifold under a variety of conditions. I  
doubt such a TBI/TPI hack job would ever run good enough to be  
mistaken for a factory tune.

That's what my common sense tells me... I could be wrong.

As evidence for this I would point out that GM felt it was necessary  
to write entire new calibrations for TBI vs TPI applications, not  
just change injector and VE constants.

If you are talking about running a 'TPI ecm' with a modified TBI cal,  
then yeah, I can see that working just fine. I am not aware of  
anything in the ECM hardware that would absolutely prevent it from  
being adapted to a TBI setup with proper electrical accommodations.  
But I think an '730 + $8D + TBI combo would pretty much suck for  
drivability no matter how much you tweaked the VE table.

Having said all that, you really should go ahead and try it and let  
us know how it works out. Seriously! Until someone gives it a go, we  
may never know. If you try it and report the results (good or bad)  
then we will all have learned something.

-Gary


On Jan 11, 2007, at 9:03 AM, William Lucke wrote:

> I know that the 730 can't drive more than one and that it would  
> need external drivers to run multiple LoZ injectors. I was just  
> wonndering if there was anything associated with the way the ECM  
> calculates pulse width and fires the injectors that wouldn't work  
> with TBI injectors.
>
> Common sense tells me that as long as the PCM is programmed with  
> the correct injector flow rate and the VE tables are dialed in that  
> there shouldn't be a problem.
> The one person who's told me otherwise seems content to be  
> demagogic and not bother to explain himself so I have to assume  
> that he's wrong and my common sense evaluation is correct.
>
>
>
> Will
>
>
>> From: Tomas Sokorai <tsokorai at minimania.org>
>> Subject: Re: [Gmecm] Re: TBI injector schema vs. port injector schema
>> On Thu, 4 Jan 2007 16:48:08 -0800 (PST), Chris Reynolds  
>> <red83brick at yahoo.com> wrote:
>>> Because you are going to alot of trouble to re-invent the wheel  
>>> so to
>>> speak.
>>>
>>>   The TBI injectors are driven with Peak and Hold drivers, the  
>>> 7730 lacks
>>> this style of driver.   The 165 MAF TPI ECM was however used with  
>>> TBI in
>>> the 4 banger S10s.
>> '730 & '727  *can* drive just one injector in P&H mode. Take a  
>> look at the 2.0 TBI app.
>> So if its a small TBI with one injector, I can't see why a 730/727  
>> can't be used there with no extra HW or hassles.
>> --
>> Tomas J. Sokorai Sch.
>
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