DIY_EFI Digest V5 #57

Shane Buss shaneb at ev1.net
Wed Feb 9 16:40:42 GMT 2000


Very good information.. Holley calls these injectors 80#, but you are saying
they are actually 85. Good to know. I'm going to use 2 of them on a 670CFM
unit.  I decided against the 700cfm unit or 900cfm unit because i think they
are overkill.  Do you know what the stock fuel pump off my 92 firebird 305
tbi can support as far as the holley 670 with 85#?

Thanks,
Shane
(currently 2-65# injectors. 8.75 in the 1/8 running lean, 225 crap tires,
dying tranny)
-----Original Message-----
From: Walter Sherwin <wsherwin at idirect.com>
To: diy_efi at diy-efi.org <diy_efi at diy-efi.org>
Date: Wednesday, February 09, 2000 10:30 AM
Subject: Re: DIY_EFI Digest V5 #57


>
>Shane;
>
>The #85 injector that I mentioned below is in fact the same thing as what
is
>oft referred to as the "#80" injector.  In either case this is the injector
>which comes standard from Holley in the 900 CFM 4bbl TBI, injector P/N
>250R-51A, service P/N 522-26.
>
>The #85 actually flows about 85 pounds per hour of fuel @ 15psig (Holley's
>rated pressure).  It will slip into your smaller TBI injector housing pod.
>When four of these injectors are housed and fed via the pod passages, and
>driven via four 4/1 amp P&H drivers, you can usually get about 310 pounds
>per hour of maximum fuel flow.
>
>I would aim to calibrate your setup at a pressure somewhere between
>12-15psig.  Any less pressure, and the injector spray quality is really
>"globbery".  15-18psig will get you more volume, which in your case you
>don't need.  Over 18psig, and you risk hydraulic shut down of the
injectors.
>
>I don't know if you intend to purchase new or used injectors, but here's a
>tip that will save a lot of headaches when either buying used,  or
>performing regular maintenance at a later date.  Measure the resistance of
>each of the four injectors, from the very tip of one terminal post to the
>very tip of the other terminal post.  The spec is 1.3 ohms +/1 0.1 ohms.
>Now measure the resistance of the same injector, from the cylindrical
collar
>that appears to sheath the terminal post to the other collar around the
>other terminal post.  The resistance should be identical to what you just
>measured above.  If not, there is an electrical resistance and/or break
>between the collar and the terminal post somewhere.  If you look at the
>mating connector, you will see that the connector terminals engage over the
>outsides of the collars, and that current must flow through the collars in
>order to enter the terminal posts and windings of the solenoid.  I've been
>caught by this a couple of times myself.  Sometimes a dab of solder at the
>collar/post interface will fix this problem.  Sometimes not.
>
>
>Walt.
>
>
>
>Date: Tue, 8 Feb 2000 17:35:02 -0600
>From: "Shane Buss" <shaneb at ev1.net>
>Subject: Re: Holley TBI Injectors VS Pressure
>
>about about the 80# injectors? i'm about to get some of those
>
>
>- -----Original Message-----
>>Shane;
>>
>>The Holley B2 TBI injectors do not typically like a lot of static fuel
>>pressure.  I have never tested the #65's myself, but I have extensively
>>tested the #85's on my flow bench.  According to what I've read & heard,
>>both are constrained by the same limitations.  The basic problem is
>>associated with the fact that the internal ball and pintle rod are
>>magnetically "coupled", and that the internal hydraulic differential
forces
>>(a product of increased fuel pressure) can become sufficient to separate
>the
>>two elements and cease flow entirely.
>>
>>With a 4/1 amp driver, the #85's are happy puppies at 15psig when hot.
>>Roughly 18psig is the upper hot operating limit, with same.  Cold, on the
>>bench, the #85s will operate irregularly above 20'ish psig and will
>>completely shut-off at 26psig.
>
>
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