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Old 02-08-2008, 05:24 PM
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FastMover FastMover is offline
Old Boomer Techie
 
Real Name: BobB
Location: Pacific Northwest (WA)
Hybrids: '07 TCH (Titanium)
Posts: 531
Post Re: ICE RPM questions for those with a ScanGauge

Quote:
Originally Posted by SPL View Post
FastMover — For a road speed of 50 miles per hour, and for the ICE rpm's that you cite at this road speed, I compute quite different values for MG1's rpm using my formulas (from the thread "Heretical Mode" post #40):
  • ICE = 1450 rpm => MG1 = -684 rpm (Heretical mode)
  • ICE = 1550 rpm => MG1 = -324 rpm (Heretical mode)
  • ICE = 1650 rpm => MG1 = +36 rpm (Normal mode)
We really must try to resolve this discrepancy, which has cropped up before. If I am wrong, I'd like to correct my formulas; and if you're wrong I'm sure that you'd like to do likewise. I've clearly explained the derivation of my formulas in the thread cited above. They are deduced from Toyota's published gear ratios for the TCH. In the interests of accuracy and transparency, please tell us your formulas and their derivation!

Stan
OK Stan, just for you.

Attached is my little spreadsheet toy. At 50 miles per hour, 1450 RPM, it gives -1202, and at 1650, it gives -482.43. It is based on published gear ratios and data in all cases, and cross-checked against the P311 Service Manual data (the "Sanity Checks") . The highlighted areas are inputs, and you can play with it to discover some things. For example, at 121 miles per hour, MG2 is turning faster than 10K, and closer to 15K. To keep MG1 under 10K you need to have at least 1550 ICE turn, irrespective of any torque loads. (It will always be much higher at that speed, as we all know.) Interestingly, if you take the ICE to the redline at 6250, mg1 will also be in tolerance, but turning positive.

Either way, we should know sometime this month, I have the frequency sensors working now on MG2 and MG1 power leads, and should be able to read them directly on the triple tach. I have also attached the RPM/Frequency curves for the triple tach as some asked if I could get the resolution.

RFB
Attached Files
File Type: xls Gears3.xls (22.5 KB, 14 views)
File Type: xls TCH Triple Tach Counter Calcs.xls (42.5 KB, 12 views)

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It is the ignorant among us that will eventually destroy us all.

Last edited by FastMover; 02-08-2008 at 05:44 PM.
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