[Gmecm] Re: injection acronyms, injector placement

[davesnothereman at netscape.net]

GM 5.7, 6.2, and 6.5 are 3 common examples of indirect injected 
engines.  Injection timing is critical... prechamber expansion is part 
of the total timing.

I agree with the comment about band-aid methods.  But I've seen it work 
well enough to produce 800HP from a 6 cyl engine.  In some cases there 
simply are no methods to make ecm based changes, or there are no 
injectors that can be used.  The GM 2.2 used from '92 to '97 uses a 
one-off injector which cannot be easily upgraded.  Certain Northstar 
and Quad 4 ecm's are still not "user tunable."  Do you tell someone to 
forgo boost for an indefinite amount of time, or do you design and 
install a band aid system which produces acceptable results until the 
"right" way to tune becomes available?

I think you're right that many turbo kits don't include the proper 
tools, and that the people installing these kits don't understand what 
it takes to make a good add-on system.  Adding forced induction should 
not include pouring in enough fuel to quench combustion.  Convering to 
boost should entail adding the proper amount of fuel combined with 
decreased spark advance.  The correct add-on tools do exist, the 
overall desire seems to be lacking.

For every high tech solution, there is prehistoric thinker ready to 
throw it out the window.

Zaphod

-----Original Message-----
From: William Lucke <william.lucke at highspeedlink.net>
To: gmecm at diy-efi.org
Sent: Sat, 13 May 2006 22:22:03 -0400
Subject: [Gmecm] Re: injection acronyms, injector placement

   I've never heard of a diesel that didn't have direct injection... I 
thought that was a staple of diesel operation in order to ensure that 
the combustion event occured at the proper time... like spark timing on 
a spark ignition engine. Which ones weren't direct?

 > From: davesnothereman at netscape.net
 > Subject: Re: [Gmecm] Understanding injection system acronyms
  > > Yep. Injection type depends on placement of injectors, not number 
of > throttle plates. Diesels have either indirect or direct injection 
and > no throttle plates.
  > > Individual throttle barrels may need a common connection for MAP > 
reference to work with a speed density system.
 > > Zaphod
 >
  I'm aware that the ricers do it... It's my opinion that extra 
injectors with a turbo kit are just a bandaid because the turbo kits 
that include extra injectors do not include correct engine management 
(this applies no matter how pretty the billet aluminum housing is... 
it's still a billet aluminum bandaid). I was referring to well setup 
and correctly managed engines that are just too big for single injector 
per cylinder (like 3,000 HP alcohol burners running 40# of boost on 
10:1 compression).

 > From: davesnothereman at netscape.net
 > Subject: Re: [Gmecm] Understanding injection system acronyms
 > > -----Original Message-----
 > From: William Lucke <william.lucke at highspeedlink.net>
 > To: gmecm at diy-efi.org
 > Sent: Sat, 13 May 2006 19:32:38 -0400
 > Subject: Re: [Gmecm] Understanding injection system acronyms
  > > > In extreme racing engines, particularly dragsters, it is 
possible to > run both PFI and TBI at the same time... PFI supplies 
fuel at idle and > low throttle and when the PFI injectors get maxed 
out, the larger TBI > injectors start spraying. This allows the latent 
heat of vaporization > of the fuel to cool the intake charge and 
supplants the need for > intercooling in alcohol fueled forced 
induction cars.
  > > It's not just extreme racing engines. The ricer crowd will add > 
injectors pre TB when adding a turbocharger to a N. A. engine. New > 
cars, old tricks.
 > > Zaphod

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