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aardvarcus · 09-10-2018, 02:42 PM

Funkhoss,

Thank you, you pointed out a glaring issue that I should have known about. My engine reads RPMs off the alternator, which has been switched out and probably has the wrong pulley size. All the RPM numbers I have given up until know are based from the instrument cluster reading, which I now calculate is 20% too high. Reverse engineering off Michelin’s 656 rotations/mile, 4.10 gears, and 0.726 overdrive I am sitting at 1791 RPM @ 55 and 2280 RPM @ 70, so much better than I thought. I also just did the gear tooth counts and confirm the early overdrive is .726, the late overdrive is 0.745 and the potential early/late hybrid overdrive is 0.643. I now show for the hybrid transmission 1635/2080 at 55/70 respectively, and down to 1208/1537 with 3.42 gears so much closer to what you had calculated than my previous estimation. So thanks again.

Everyone,

My prior tank was down a bit but my last tank was a new record at 24.4 MPG. I have also noticed much variability with my hill coasting speeds, must be wind or other factors, so I won’t rely on that anymore. I have some service work I need to do to replace a few items, I need to get that taken care of soon. I am in the middle of a garage cleaning/reorganization project right now, I need to get that completed so I can get the patient back into the operating room.

09-10-2018, 02:42 PM	#146 (permalink)
aardvarcus Master EcoModder Join Date: Apr 2012 Location: Evensville, TN Posts: 676 Deep Blue - '94 GMC Suburban K2500 SLE 90 day: 23.75 mpg (US) Griffin (T4R) - '99 Toyota 4Runner SR5 90 day: 25.43 mpg (US) Thanks: 237 Thanked 580 Times in 322 Posts	Funkhoss, Thank you, you pointed out a glaring issue that I should have known about. My engine reads RPMs off the alternator, which has been switched out and probably has the wrong pulley size. All the RPM numbers I have given up until know are based from the instrument cluster reading, which I now calculate is 20% too high. Reverse engineering off Michelin’s 656 rotations/mile, 4.10 gears, and 0.726 overdrive I am sitting at 1791 RPM @ 55 and 2280 RPM @ 70, so much better than I thought. I also just did the gear tooth counts and confirm the early overdrive is .726, the late overdrive is 0.745 and the potential early/late hybrid overdrive is 0.643. I now show for the hybrid transmission 1635/2080 at 55/70 respectively, and down to 1208/1537 with 3.42 gears so much closer to what you had calculated than my previous estimation. So thanks again. Everyone, My prior tank was down a bit but my last tank was a new record at 24.4 MPG. I have also noticed much variability with my hill coasting speeds, must be wind or other factors, so I won’t rely on that anymore. I have some service work I need to do to replace a few items, I need to get that taken care of soon. I am in the middle of a garage cleaning/reorganization project right now, I need to get that completed so I can get the patient back into the operating room.