Large P&H Port Injectors

[Walter Sherwin]

Hi Clay,


At the time of your original post none of us knew exactly what your expected
BBC power level was or even what type of fuel you intended to run,  which is
why I tried to outline to you what your proposed 105's would give you with
"gasoline" and then asked you at the same time to expand upon your
assumptions if they seemed to differ.

In light of your subsequent posts, I agree that your application would be
best suited by a roughly 80 #/Hr port injector (assuming a maximum 80%
injector duty cycle and 0.6bsfc).   You had mentioned the 160's in your
original post which is why I had commented on them.  160's can be made to
work quite well on very large displacement/power BBC's (several examples of
which roam the tracks & streets around the southwest end of this province).
But again, in light of your recent posts,  I feel that the 160's are not for
you!

I am in the process of trying to gather together my old flowbench notes for
you, as related to a series of four different larg'ish port injectors
ranging from 75-160 #/Hr @ 3.0 bar, accompanied by photo images of the
injectors in action.  My photo scanner friend was tied-up today, so I'll try
again tomorrow.  As soon as I get everything ready I'll post a message to
DIY and place a 'ZIP file in the incoming directory.  The photos are from a
hand held camera (can't afford stroboscopic equipment) but they do
effectively give you an idea as to the various plume patterns and their
applicability to your injector targeting & distribution expectations.

When considering the Bosch vs Rochester P&H's, my choice is still the Bosch
injector, for many of the reasons stated earlier.  There are two other
important factors which I did not state at that time.  1) The Rochester's
are not tolerant of substantially increased fuel pressure.  On a hot day,
with a 4/1 amp driver, do not expect to operate a Rochester at much over
about 55 psig without fear that it will fail to open against the prevailing
internal hydraulic pressure.  Whereas,  I have been able to operate some of
the Bosch injectors as high as 140psig, which allows a huge window of tuning
opportunity down the road without having to fork over considerable $$$ for
new injectors.    2) At low base pulse widths, with a 4/1 amp driver,  the
Rochester's exhibit more irregularity and nonlinearity IMHO.

As for staged injection, if your particular ECU/software package easily
accommodates this feature, then by all means make use of it!  On the other
hand, if your package does not, then you will have to rely upon your own
means to build custom electronics and fudge the software tables.  This can
either represent an interesting challenge, or a PITA, depending upon your
background and outlook.

Yes, some of the Bosch Motorsport injectors are available in stainless steel
form (either internally or externally or both) for use with alcohol based
and other nasty fuels.  However, even though your application is for marine
use sounds like you as using "gas" which should be compatible with normal
non-SS injectors.  Hopefully you don't have that much water in your fuel :)

More info to come on the specific injectors.  As soon as it congeals I will
advise.....



Walt.






>---------------------------------------------------------------------------
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>
>Date: Mon, 31 Jan 2000 09:24:42 -0800 (PST)
>From: Anthony Buccellato <clayb at sonic.net>
>Subject: Re: peak and hold injectors
>
>Hey Walt,
>
>Thanks for the info. I don't need 160 lbs/hr units, not sure how that
>ended up in the thread. I calculate I currently need 76 lbs/hr with a high
>BSFC, as I understand boosted applications sometimes exhibit. I would
>prefer to get closer to 100 lbs/hr to allow some room for future
>improvement.
>
>Checking with the injector companies has shown me it's either Rochester or
>Bosch Motorsport. Rochester is appealing, due to low cost, I've found them
>for $62 for 82 lb units. I've heard Bosch is better, and some of their
>units are even offered in stainless steel, big plus for us boaters.
>
>I really want to avoid staged injection, at this point. Cost, complexity,
>etc. High PW resolution should do me fine at an idle, I figure.
>
>If you've got injector pattern pics, please send them. Any further insight
>on Bosch vs. Rochester would be welcome, as well as suggestions for
>reasonably priced suppliers, would be great. Thanks.
>
>- - Clay
>
>Oh yeah, please comment on "Rochester isn't as precise"
>

>------------------------------
>
>Date: Mon, 31 Jan 2000 13:21:21 -0800 (PST)
>From: Anthony Buccellato <clayb at sonic.net>
>Subject: re: Lots of snips from BBC with 160 lb injectors
>
>Hi Carl,
>
>I didn't mention 160 lb. I need 80 - 100 lb. I currently produce "only"
>800 HP, but plan to purchase injectors capable of 1000 - 1100 HP. Gotta
>look ahead. I plan to run both pump and aviation gasoline, depending on
>the occasion. Would like stainless steel due to the marine environment.
>
>Walt says the Rochester units may have a little better sensitivity at
>short pulse widths, a big bonus for idle quality. If I can locate a good
>supplier at a reasonable price, I'll try and find a 90 lb model to
>purchase.
>
>If you have any input re: BBC application, fire away, I would be glad to
>hear it. Once concern I have is finding good weld-in fittings for my
>manifold. I would like to find a "positive" retention system to hold the
>injectors secure against boost, initially 8 - 15 psi, but potential for up
>to 20 psi down the road.
>
>Thanks,
>
>- - Clay
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