Small TBI question (of my own)

[Pat Ford]

George Bearden wrote:
> 
> I have a Suzuki Samurai and it is my daily driver, though increasingly I
> have tilted the 'compromises' towards the off-road driving I do.  I have
> done a lot of mods for off-roading, and a buncha engine mods but I still
> have the stock electronic carb.
> 
> I am interested in a fairly cheap & available EFI.  Suzuki uses a TBI
> starting in the early 90's but some report that it is fragile and eats
> ECM's off-roading, and they are *expensive*.
> 
> I have been considering a small GM TBI unit and have been reading all I can
> find on the topic.  I'd appreciate any suggestions for books that offer
> good info on these TBI units.

Jason Weir had a webpage about a similar system into a J**P

> 
> There is one fella I heard about who used one off of a 2.5L Sunbird
> successfully (the Suzuki is 1.3L).  Which leads me to a couple of questions
> I have been playing with.  If the TBI's tables are appropriate for a 2.5L
> engine, how well will it run in open-loop and WOT? 

 That will work but there is FREE tuning software for the gm ecms (
winbin
amongst others)

> The fella who did the
> swap reportedly has his running well.  He has lowered his fuel pressure and
> I am guessing this is to bring the amount of fuel delivered closer to
> stoich.  But with stock fuel pressure will it 'learn' to deliver the
> (approximately) correct mixture in open-loop?  I don't know which year
> model or ECM he used, but I guess I don't really care as I am attempting to
> determine for myself which would be a good candidate.  I don't know much
> about these.. I am wondering if the smaller single-throat TBI's used BLMs,
> and if so, will they have this effect?  Is it desirable in light of my
> application to attempt to find an ECM that uses BLMs?

 most gm ecms have a "learning mode" that will gradually bring the
system close to what you want. The problem with altering the fuel
pressure is that you will need to drop the pressure close to 50% ( 1.3 ~
50% of 2.5)

 I have a complete efi system out of pontiac 6000, a neigbour was
sending the car to the wreckers, and I bought the harness, computer,
intake, coil pack for $100 that should be where you start.

goto the DIY-EFI page (www.diy-efi.org) then enter the gmecm website.

> 
> My goal is to have more power, better driveability, better running at
> severe camber angles, and an attractive replacement for the tempermental
> stock carb and fragile stock TBI.

 Same reasons I did the gm efi on my 61 landrover! ( I also got rid of
the 
D$mn lucas distributor)

> 
> Regarding Ron Schroeder's previous question:
> > Why is WOT open loop?  Wouldn't it be better to be
> > closed loop or is feedback response an issue?
> 
> I understood the answer that was given but was unsatisfied.  Here's the
> deal:  My Suzuki is waaay under powered.  But this can be a good thing, I
> mean, you can blithely hotrod like crazy right in front of the cops, no
> problem.  Go through the gears, engine screaming, exhaust wailing, scream
> of tortured metal.. no..no.. just kidding.. anyway, a quick look at the
> speedo shows you are just now reaching 40mph!  On a road trip with a slight
> head wind, you may run at full throttle for hours.  Or it seems like hours.
>  One might say the electronic carb drops  out of closed loop at full
> throttle in order to richen the mixture a bit to give a larger safety
> margin, maybe less possibility of detonation?  More cooling?  More power?
> Well, as I think about it, since my tweaked engine has considerably more HP
> than stock I have the same output at part throttle that the stocker does at
> WOT.  And my engine holds together at high rpm WOT operation too.  So.. I
> believe I am subjecting my engine to much greater thermal and mechanical
> stress than a stocker ever achieves.  So.. I feel that at least for the
> stock engine, the open-loop for WOT isn't needed.  And I wonder if I need
> it for my engine.  Am I missing something here?
> 
> I am actively soliciting your input!
> 
> Thanks
> George Bearden
> 
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