Question about Howell conversion.

[rr]

esc wrote:
> 
> >If your talking about wanting to run a 4 barrel TBI, the only gm ecm I know
> >of to do that properly is the 1227749 wired as used in a 87 Sunbird Turbo.
> >  In some testing that I did, I was unhappy with the results of firing
> >injectors wired, in series parrarel.
> >  If you want to run a 4 barrel TBI, my suggestion is to run, a TBI ecm and
> >then make an injector driver board external to the ecm, to actually fire the
> >injectors.
> 
> Sounds like a can of worms I'de rather not open.
> 

Actually, Bruce is dead on here, go with a driver board. Wiring PnH
inj's
in series is stupid, you halve the voltage to each injector. You will
lose
all short duration opening control otherwise. I really can't understand
why aftermarkets do it.

> >  From what I've heard all the 4 barrels use the same butterflies, but
> >different injector sizes from rating to rating.   So the idea of selling
> >them by CFM is silly, when they all flow about the same CFM, and the actual
> >difference is gals/hour....
> 
> Mine is the 900CFM..uh, 4 85 lb/hour injectors.  Holley claims it is good
> for 500 HP at 15 PSI.
> 
> >  Next item, 4 ninety gal/hr injectors would support about 700 HP.
> >  I run 13s in a 3000#/350 CID car, with 2 two inch butterflies, if you
> >really need that much air (4-2" butterflies), I'd look further than a TBI...
> 
> I want to use my TBI because I put a lot of effort into the ram-air system
> on the car.  If I go with a port injection system (most anyway) I would
> have to scrap my ram-air, and maybe my hood.
> 
> >  If your needing that much air, then you have a bunch of cam, and might do
> >well using a 747 where you can go open loop at idle.
> 
> I do have a lot of cam 255 at 0.50 and 0.600 lift.  Would I need the
> external driver board you mentioned earlier to use the 747?

Yeaaa... I'd vote for "that's a bunch of cam".

> 
> >Cheers
> >Bruce
> 
> Eric
> esc at firstnethou.com
> If it breaks, make it stronger.
> If it doesn't, try harder.
> '68 Big Block Bird
> '69 Spitfire
> '82(sort of) Camaro


BobR.

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