Quote:
Originally Posted by ChrisM3
Great results on so few mods! At what point do you think port injection is necessary? Wondering what the ceiling is power/ET/MPH wise on say 109 octane unleaded versus 93 all without PI.
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Quote:
Originally Posted by chris3g
Port injection won’t be needed on race gas with stock turbos or likely even with upgraded turbos, the factory fuel system is very capable. It’s only needed with high ethanol content and power in excess of 750whp on ethanol.
With piggyback solution the limits are probably a bit lower since there is no control over the fueling.
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Trust me, I spent over $2,000 on MS109 exploring the limitations of the stock fuel system. Believe me when I tell you JB4 has different limitations than what you see with flash-tuned applications, haha.
I ran 10.00s, 10.01, and 10.02 multiple times on MS109. The fuel system was so on the ragged edge, that I could only manage 1 clean run every 3-4 without trims going open loop and getting lean cut. You can see in this 10.00s timeslip how it's moving great for the 1/8th mile, but then loses power on the big end when trims started freaking out. This would have been a fast one, otherwise!
With E50, the car traps 138mph+ on less boost. Based on the data from my ~100 runs, it looks like optimal boost for JB4 on E50 is considerably lower than on flash-tuned cars, at 28.6psi. I found that to be the peak of the bell curve. Any more or any less, and the car went slower.