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Old 04-10-2013   #16
scottfab
 
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Join Date: Jan 2009
Location: Portland Oregon metro area (Washington side)
Posts: 3,193
Default Re: What say you, Graham?

Quote:
Originally Posted by XfireZ51 View Post
The "split BLM" issue is not unique to the LT-5. The LT-1/4s exhibit similar bank to bank differential. My suspicion, and that's all it is, is based on my experience w the Xfire motor. There you have a much simpler example of individual bank fueling. The fueling for that motor used twin TBIs in series. The "rear" TBI (left bank) had the regulator built in. I measured fuel pressure differential between the two TBI was .5psi. This was enough for GM to use staggered injectors of
63/65 # F/R to equalize fuel delivery. No other TBI injectors were available that would retain the stagger and deliver more fuel needed for higher hp. It became necessary to run individual fuel lines to each TBI so that equal size injectors could be used. So I am speculating that there may be a slight pressure drop at the left hand fuel rail due to the added distance fuel travels to reach it. Perhaps the use of injectors with different mechanical and electrical properties could also magnify the differential.
A way to isolate on this theory would be to re-route the fuel to the left side first. Painful to do but would be conclusive.
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