TBI cam duration

[rr]

Thanks for the info Walt, this solves the problem of getting enough
fuel into the engine. When I get some time I'll be putting a TBI
on to complete the conversion. Need to install the fuel delivery
system first.

BobR.

For peak driver boards, the 332 group has a schematic & layout.

Walter Sherwin wrote:

> >
> >I've wondered about doing this (rasing the fuel pressure). Did
> >GM do anything to the new TBI's  to hold the additional pressure
> >without leaks? Or, are we safe doing it to the older ones? (89-91)
> >
> >Thanks for the gm #'s.
> >
> >BobR.
> >
>
> Other than the regulator change, I can't see any significant difference
> between the old/new TBI's, in terms of sealing.  Have not yet seen any leaks
> at 30psig TBI pressures.
>
> I've operated the 454 "17084304"  (service P/N 17112560)  injector as high
> as 70psig on the bench, for extended periods of time.  The bench has a steel
> holder block, into which the stock injector and stock upper/lower O-rings
> are placed.  Have never observed leaks.  Also, have never observed leaks
> even when dead heading the injector against 140psig, during the leak test
> procedure built into the bench controller.
>
> One caution specific to "old" 454 TBI's, in the face of increased operating
> pressures................check the engraved numbers on the injectors.  If
> you have part number "5235231" injectors, then you should replace them with
> the part number listed above.  This particular injector seems a bit "iffy"
> at 30psig, and deviates from predictable flow quite strikingly at 40+psig.
>
> Here's a couple of other TBI numbers that I've found to be tolerant of
> increased pressures................."5235206"  (service P/N 17112493) used
> in various 5.7litre TBI applications, good through to 70psig, and gives
> around 180'ish pounds per hour each at 30psig....................medium duty
> [90'ish pounds per hour each,ed]

> truck TBI injectors (service P/N 17112202) used in all  6.0/6.6litre
> governed TBI gas engines, good to around 80psig, and gives around 80 pounds
> per hour each at 30 psig or 150 pounds per hour each at 80psig.  The really
> cool thing about the medium duty truck injectors is that they are physically
> much smaller than the conventional TBI injectors, and they are easy to
> package in tight places.
>
> All of the above was with one 4/1 amp peak&hold driver per injector.  To
> date, I have not tested any other TBI injectors :(
>
> Walt.