| [GMCnet] Howell TBI injector information [message #73644] |
Fri, 12 February 2010 15:53 |
emerystora
Messages: 4442
Registered: January 2004
Karma:
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Senior Member |
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For those of you using the Howell TBI system I have some new
information about the injectors.
When I first bought my Howell system several years ago it came with
Holley injectors. Several other people bought them at about the same
time including Gene Fisher and Al Chernoff.
If you are still using the Holley injectors you are fine. The are
about 80 poubds per hour rating at about 13 psi.
I found that Holley had discontinued those injectors when I was on a
trip and one of my injectors went bad. I had to rent a car and drive
about 350 miles round trip to pick up a Holley injector that a Speed
shop had in stock. That was before I started towing a car with me
At that time I spoke with Troy at Howell and he told me that they
could supply a retrofit injector holder with GM fuel injectors. I
believe I paid about $250 for the kit which included two injectors.
However, after installing it I found that I just didn't have the power
to get up hills like i used to. I increased the fuel pressure to
about 19 psi and my engine ran better.
When I recently tried to determine which injectors I now had it
appeared that they ;might be GM 402-037 injectors used in GM 4
cylinder engines of 2.2 to 2.5 liter capacity.
Of course these engines only used one injector whereas the Howell kit
uses two.
This morning I called Troy at Howell and he said the injectors that
they get from Holley are 85 pound per hour (PPH) injectors for a 6
liter engine.
That would only be about a 366 ci engine rather than a 455 ci engine.
i pointed this out to Troy and he just said it runs fine for the 455
the way they have programmed the chip.
I was still a bit concerned about this so in late morning I contacted
Holley to get some information about the injector that is currently
being supplied by Howell and I asked them if they had the GM part
number for it..
Here is the reply i got back from Hollley:
> Sorry, Do not have GM part # available to me. Our Sales # is 522-43.
>
> 60PPH @12psi, 85PPH @ 21PSI.
>
> WW
So, in order to have the flow rate for the larger GMC motorhome engine
(a GM 454 uses two 80 PPH injectors) it would be necessary to step up
the pressure on the throttle body.
As I said above, those of you ;that are using the original Holley
injectors (which have two prongs on the top) should not have a problem
but those using the Howell system with the GM injectors (which have
the prongs enclosed in a right angle connector pointing to the front
of the throttle body) l would have to increase the fuel pressure to
get the same flow of fuel.
I know there have been discussions about raising the fuel pressure on
this net in months past and when I had reported that I was using 19
psi I had several people tell me that was too much pressure.
It appears it all depends on which injectors you are using.
Emery Stora
77 Kingsley
Santa Fe, NM
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