GM ECU 1227730/47: basic questions

[Shannen Durphey]

I've been watching this thread closely.  Just a word of warning, the grind of the cam
is as important as the duration.  I went with 215deg at .050" on my crossfire
conversion and now I can watch the ecm throw extra fuel pulses out everytime the
vacuum gauge drops fast at idle.  I have put two older intakes on newer heads and I
just elongated the center holes then cut out tapered washers on a band saw.  Worked
fine and looked ok too.
Shannen

sfg wrote:

> Kevin Vannorsdel wrote:
> >
> > Another entry level question...
> >
> > I am wondering why go with a Holley/Howell configuration instead of getting
> > something from say- Turbo City (Big TB and a GM computer) that seems cheaper
> > and similar in performance (??)   ?
> >
> > Also- please post what you learn from your questions with Howell (if you don't
> > mind).    Thanks!
> >
> > ________________________________________________
> >   Kevin Vannorsdel     IBM Arm Electronics Development
> >     408-256-6492                Tie 276-6492     kv at us.ibm.com
> >
> > owner-diy_efi at coulomb.eng.ohio-state.edu on 11/05/97 07:14:48 AM
> > Please respond to diy_efi at coulomb.eng.ohio-state.edu @ internet
> > To: diy_efi at coulomb.eng.ohio-state.edu @ internet
> > cc:
> > Subject: Re: GM ECU 1227730/47:  basic questions
> >
> > John Zarli wrote:
> > >
> > > sfg wrote:
> > > >
> > > > John Zarli wrote:
> > > > >
> > > > > sfg wrote:
> > > > > >
> > > > > > I am using the 1227730 ECU and have a few basic questions:
> > > > > > 1. since it is so common, where might I find the disassembled code?
> > > > > >    (I'm using the EPROM 16139544 '87 K5 Blazer: manual trans, TBI)
> > > > > > 2. Is the memcal a fuse-link type ROM?
> > > > > > 3. Which application parameters are contained in the memcal?
> > > > > > 4. I have noticed ref to a "P" suffix on the p/n. Meaning?
> > > > > > 5. Is its driver circuitry capable of operating with the combined
> > > > > >    load of 8 injectors wired in parallel?
> > > > > > 6. Will it run a ZZ4 GM engine (24502609) (with the 10185071 camshaft)?
> > > > > > I know this is a lot of info, but since this ECU is so popular, answers
> > > > > > may benefit many people on this list. TIA   Steve
> > > > > Steve, stay tuned....I should know #6, whether a TBI system can support
> > > > > a ZZ3 (10185071) camshaft within a few weeks. roller rockers are going
> > > > > in now. Almost done.  Note that the alum heads on a complete zz3/zz4
> > > > > engine are the old style bolt pattern....I've heard different opinions
> > > > > regarding enlarging the bolt holes on newer manifolds to fit those
> > > > > heads.
> > > > John, what are you using for injection? TBI or port? Enquiring minds
> > > > need to know. Also, my GM service parts list (shows all the components
> > > > in a matrix for the ZZZ, ZZ1,2,3,&4) lists an intake manifold
> > > > (10185063) as "dual bolt pattern" with EGR and applies to ZZ3 and
> > > > ZZ4 only. I'll stay tuned....    steve
> > > Steve, visit the GMGOODWRENCH website & you can download the GM
> > > Performance parts catalog (free). It has a wealth of info. The ZZ4 is a
> > > great deal, but as it applies to newer engines...the dual bolt pattern
> > > is referring to the carb mounting. The intake manifold has an egr
> > > passage but the heads do not (go figure?) Also the head to intake bolts
> > > are old style, middle bolts on new manifolds are at a different angle
>
> Kevin,
> re my phone call to Howell Engine Developments Inc (810-765-5100) today:
> They said:
> 1. PROM, and Holley 4bbl TB *is* available w/o ECU; $600 for TB and $150
> for PROM. (ouch)
> 2. 215 deg duration, .5" lift cam is max for speed density system
> (how does lift enter into this equation????) I didn't ask......
> 3. adaptor cable: Holley round-to-GM weather pak) is avail.
> 4. They thought Crane had a good roller cam to  get the 235 deg dur-
> ation of the ZZZ engine down to 215 deg. (Crane "CompuCam")
> 5. 7730  or 7747 ECU both OK to use.
> 6. use 55 lbs/hr injectors for small block
> 7. GM ECU drives the 4 Holley injectors directly w/o external stuff
>
> BTW, I later found an article which features the same thing I'm
> considering: Holley 4bbl TBI on a GM ZZZ 10134338 crate motor, using a
> GM ECU! see "Popular Hotrodding" December, 1993. Article has good
> detail.
>
> Holley 4bbl TBI vs Edelbrock #3502 port injection:
>
> I also visited the Summitt Racing (Akron, OH) retail store and put the
> Holley 4bbl under scrutiny. The Edelbrock p/n 3502 was not in stock so
> I couldn't see it.
> the Holley TBI:
> 1. TPS is p/n 219R32A looks same as GM, w/weather pak connector
> 2. IAC is p/n 53030657 (a GM #???)
> 3. TB has built in thermistor (mounted in heat shrink)
> 4. has 3 vacuum ports: spark, full, and PCV
> 5. Holley ECU uses EEROM (if anyone is interested)
> 6. 3 CFMs avail: 650, 700, 900 (use the 900 on ZZZ??)
> 7. "fuel pressure: 15 psi" so said the flyer
>
> the cost of the Howell stuff would be close to the Edelbrock #3502 PFI
> system! Decisions decisions....!
> Steve