Beat that dead horse again! clarification PLUS new

[Shannen Durphey]

gmecm at efi332.eng.ohio-state.edu wrote:
> 

> I'm curious if anyone is running the stock ECM ('89 Firebird L98, or rather
> B2L) with GM's ZZ3 cam (208/221 @ 050, 474/510 lift, 112 LSA) as well as the
> stock TPI induction.  I'm wondering if this combination will at lest be
> driveable until I can get into learning ECMs.  Also has 10.2:1 compression,
> up from 9.4:1 stock.  Any comments?
Well, mostly rumor.  I've heard reports that the zz3 + tbi is a
driveability nightmare.  This from people running that combo.  I've
asked for stories at various times regarding this engine and efi, and
haven't gotten many good ones.  There might be more computer friendly
cams out there.  You might ask this question on an F-body list or a
Vette list, as somebody must have tried to run the complete package.  
Shannen
 
> Steve
> 
> -----Original Message-----
> From: Brent Obermiller [mailto:ober_b at sssnet.com]
> Sent: Saturday, October 30, 1999 1:19 PM
> To: gmecm at efi332.eng.ohio-state.edu
> Subject: Re: Hello/Beat that dead horse again! clarification
> 
> BluVette wrote:
> >
> > OK guys, let me reword the original message and clear up a few points
> along
> > the way.
> >
> > I designed and built and engine. I designed the cam. ACCORDING tot he CAM
> > GRINDER and HIS computer, that cam is good for 600-650 HP, with all other
> > factors taken into consideration such as heads and the rest of the
> > modifications done. *I* limited the engine with 30# injectors, so if there
> > was any possibility of the stock computer, with a chip in it that has
> > already been modified for the supercharger.  I'm a mechanic, not an
> > electronics engineer. Please, whenever possible, put your replies into
> > laymens terms, and that would help a bunch!  :o) Thanks.
> > Now, back to my original problem. When the engine hits 5400 rpms, it just
> > stops. I was told on another list that the computer limits the rpm's at
> 5400
> > on a stock L-98 enine in 1989. BEFORE the modifications, with only the
> > supercharger, it did the same thing. I really need to spin this engine up
> to
> > at least 6000....so, does the computer limit the rpm's at 5400 or is
> > something else doing it?  It did it with the old stock injectors, and i
> > would have thought that the engine would lean out at a higher rpm with the
> > new 30# injectors.
> > Next problem is the idle. It is hunting between 500-700 rpms. The cam is
> on
> > the radical side, along with custom made full roller 1.6:1 rockers. I HAVE
> > to raise the idle up to about 800-850 rpms, as it dies right now when
> coming
> > to a stop about 1/2 the time, especially when the engine has been running
> at
> > WOT, and then letting off the gas, it dies almost immedatly.
> > I am sure that there are other factors to take into consideration that I
> may
> > not be aware of as of yet. The engine is also equiped with water/alcohol
> > injection, just ahead of the throttle body to help eliminate detonation,
> and
> > that combined with the lowered compression ratio has done a GREAT job, and
> > no knock or detonation is apparent, even under full boost conditions, so I
> > don't *think* that the advance curves need to be played with any more than
> > they may have already been altered by the custom chip that is already in
> > place.
> >
> > Someone on the list suggested swapping out the computer with one from a
> > turbo GM car. Good idea, but, just HOW would I go about this, and is it
> > compatable with an 89 Corvette onboard systems already in place?
> >
> > Inquiring minds want to know :o)
> >
> > Thanks to everyon that has been involved in this thread to this point,
> > pleasae be patient and I will get up to speed.   TIA!
> > -Barrett
> > SCAR Corvette & Performance
> > 1010 W. Hwy 131, Clarksville, IN  47129
> > (812) 941-0839
> > bluvette at scarcorvette.com
> > www.scarcorvette.com
> 
> I read somewhere that the Tuned Port intake is only good for a certain
> rpm range (5300rpm being the top).  The runners are something like 22"
> long.  Also the air box volume is supposed to limit the rpm's of an
> engine.  Have you considered the Accel box intake?  If I'm way off here,
> help me, I'm a TBI person and have only read a lot about TPI.
> 
> -Brent
>  "A little knowledge is a dangerous thing"