GM ECU 1227730/47: basic questions

Thu Nov 6 00:06:20 GMT 1997

Kevin Vannorsdel wrote:
> 
> Steve-  Thanks for the info!
> 
> If the Howell setup is that much...  why would you not want to investigate
> getting the whole thing (computer and all) from Holley?    In other words-
> what does the Howell setup offer over going all Holley  (besides being less DIY
> (grin))?  Maybe I better read that article!
> 
> The Edelbrock system is tempting-  I agree!    I am still investigating options
> available from Turbo City for my K5 Blaze.
> 
> ________________________________________________
>   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 02:02:21 PM
> Please respond to diy_efi at coulomb.eng.ohio-state.edu
> To: diy_efi at coulomb.eng.ohio-state.edu
> cc:
> Subject: Re: GM ECU 1227730/47: basic questions
> 
> 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
Kevin,
The MOST important thing to me is reliability. Therefore, GM ECU and
no other. Aftermarket companies do not have the resources to pour
the R&D into an ECU like GM has. There is a great deal of engineering
that goes into an electronic device which can withstand the temperature
variations, electrical transients, vibration, and miscellaneous abuses
(like booster cables!) that an ECU is normally exposed to. It also
takes evolution to arrive at a venerable design. None of the 
aftermarket products have arrived at this point, IMHO. Plus, OEM ECUs
are cheap from the wrecking yard! I'd consider the Edelbrock system
because it uses OEM ECU *and* OEM TB on a PFI set up. Steve