TBI cam duration

[CSH-HQ]

Just for dumb ideas, if your running a TPI level of fuel pressure, why not 
use a vac referenced fuel pressure regulator, a set of P+H 4/1, and a 730.
Then just consider it a wet manifold TPI.  If running a single plane I don't 
see where the firing rate of the injector would be as critical (please note
I have my CSH, with chinstrap on).  Specifically I looking at a cross fire 
set of TBs on a vintage Smokey Ram manifold.  Only real advantage is when 
using diacom.  OK, better/more tables, then 747 in a way.

On a similiar not has anyone tried just clearing as many tables out of a 730 
that aren't used for off-road applications?.
Grumpy



At 07:27 AM 11/7/99 -0500, gmecm at efi332.eng.ohio-state.edu wrote:
>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.
>