Edelbrock TBI Conversion

[Ward]

Its not just TBI Batch fire, all GM V8's run in batch fire up till the LT1,
LS1 engines. that is right bank then left bank.

The only demonstrated benifit of sequential fire is emmissions at idle are
marginaly improved.

Severel of the TBI systems fire every 12.5 msec in some power ranges.

as to injector and cid size . it can be set at address $02B4 in the 1227747
ECM, the value for 5.7l is 135 decimal. this is for a 7.71 grams/sec TBI
injector or 15.42 total.

for a sinble port injector 2.33 grams/sec the value at $02b4 would be 112
decimal.

Ward...


On Thu, 10 Jun 1999 12:56:00 +0000, jweir at att.net wrote:

> Ok, thats why I asked.  I was under the impression that 
> with a batch fired system, it fired half the injectors 
> and them fired the corresponding cylinders which on a 6 
> cylinder would be 3 ignition events before it fired the 
> other half of the injectors..
> 
> So are you saying that with every ignition pulse (at the 
> coil) there is an injector event.. ? 
> 
> Maybe I need a basic course in how a TPI batch system 
> works...
> 
> I understand that I need to keep the injector sizes/fuel 
> pressure and such relative so I am still getting the same 
> ammount of fuel vs. the TBI
> 
> Jason
> 
> --
> 88 Wrangler - 155K miles and counting
> 258 I6, 4.0 head, Cherokee header, 2 1/2 exhaust with 
> high flow cat & Flowmaster
> GM TBI, Crane 260H Cam
> TJ Fender Flares
> http://home.att.net/~jweir
> CNC 4X4 Member - http://cnc.4x4.org/
> 			
> 			
> > Jason Weir wrote:
> > 
> > > 
> > > TBI
> > > 
> > > 1 injector fires for every cylinder firing.
> > > 8 cylinders firing means 8 injector events, alternating 4 per
injector
> > > 
> > > Edelbrock 7747 TPI Setup
> > > 
> > > 1 injector fires for every 4 cylinders firing
> > 
> > Huh???
> > 
> > > 8 cylinders firing means 2 injector events. 2 groups of 4 alternating
> > 
> > 4 injectors fire for every ignition pulse
> > 
> > > 
> > > So my question did Edelbrock just put a divide by 2 after each
original
> > > TBI driver and use that to trigger a secondary driver that fed the
> > > injector groups?  This is the only way that I can see how they might
> > > have made it work?  Any other ideas..
> > > 
> > > This brings up my application question.  When we are dealing with a
V8
> > > things are easy its a divide by 2.. But what if I wanted to do the
same
> > > thing on a 6 cylinder?  Now I have 6 injector events that I need to
turn
> > > into 2.  Its not as easy to make a divide by 3.  Has anyone heard of
a
> > > chip that could do this.. Customizable to do a divide by x, with just
> > > jumping pins or resistance to pins or whatever.
> > 
> > You're getting some strange numbers here.  Alternating batch systems
> > fire 1/2 of the injectors per ignition event, when in synchronous
> > mode.  The fuel pressure, injector size, and fuel map work together to
> > prevent creating a rich condition.  To prevent large amounts of
> > remappingin your case, the 3 port injectors together should flow as
> > close to the same amount of fuel as one TBI injector as possible.   
> > > 
> > > Any ideas???
> > Start looking up injector flow rates.
> > Shannen
> > > 
> > > BTW I am running a TBI right now but I've got the Multi-Port manifold
> > > just waiting till I can get the electronics figured out..  I know I
> > > could just swap the ECM to a V6 TPI computer but thats the easy way
and
> > > them I have to learn a new ECM all over again, just when I almost
have
> > > my 7747 setup running great.
> > > 
> > > Jason
> > 





_______________________________________________________
Get your free, private email at http://mail.excite.com/