Tuners,please confirm my suspicion: BW 366 .91 a/r going excessively rich above 24psi
#1
Tuners,please confirm my suspicion: BW 366 .91 a/r going excessively rich above 24psi
Hey tuners, I recently switched from a Garrett gt4094r w/106a/r turbine housing to a BW S366 with .91a/r housing. I have since adjusted my 4094r fuel map(perfectly tuned to 28psi) to the needs of the S366. Generally, I have had to add fuel to the boost map to maintain the same afr's as the 4094r, but the tunes are very close. This could be because I also did a refresh on the motor with new seals just before I add the new turbo. I am now beginning to tune high rpm above 24psi and the motor is running very rich as I reach 7500 and up. It still pulls without breakup, but not as hard, and gets very rich(below 10.1afr) above 7500.
Is this caused by the restriction of the .91a/r housing? Is this the expected result form choking turbine at high rpm?
Is this caused by the restriction of the .91a/r housing? Is this the expected result form choking turbine at high rpm?
Last edited by jetlude; 08-17-15 at 03:29 PM.
#2
rotorhead
iTrader: (3)
When you say it's running very rich, what happens when you reduce fuel injection pulsewidth at that high rpm and boost? A more restrictive turbine A/R means more residual gases and backpressure at very high speeds. This reduces the amount of fresh air that gets into the combustion chamber. However, the low speed turbine power increases. That means that you should be able to get more boost when you floor it in 5th gear at say 2000rpm.
#3
When you say it's running very rich, what happens when you reduce fuel injection pulsewidth at that high rpm and boost? A more restrictive turbine A/R means more residual gases and backpressure at very high speeds. This reduces the amount of fresh air that gets into the combustion chamber. However, the low speed turbine power increases. That means that you should be able to get more boost when you floor it in 5th gear at say 2000rpm.
Will the choking of the exhaust show richer condition because volumetric efficiency is reduced?
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