LT1 Based Engine Tech 1993-1997 LT1/LT4 Engine Related

question on tach and tune

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Old Jan 6, 2009 | 01:52 PM
  #1  
Slick_Sammy's Avatar
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From: Radford, VA
question on tach and tune

i have put a very mild tune on my 94Z (done by me on Tunercat)... i have all the stock parameters in there as far as max rpm and fuel cutoff at rpm, max RPM WOT shift points... However, this thing still shifts at (according to the tach) 6k rpm, maybe 6050-6100. I don't hear or feel any fuel cutoff or rev limit being hit so I am guessing my tach is just off like 400 rpm on the high end.... is that normal? it has 3.73 gears, a shift kit but i have kept the line pressure at stock and shift points are firm b/c i have set the 1-2, 2-3, 3-4 shifts up to be a little higher partial throttle than normal. pretty sure my tune is on-target. any thoughts? thanks! just kind of bothers me seeing it hit the red on the shifts.

Oh, and I will mention this gauge cluster is the one that only goes to 110 mph as i think it was not factory equipped with Z rated tires (also had MPH limiter on it which i removed). Not sure if that would affect the tach rpm reading or not.

Last edited by Slick_Sammy; Jan 6, 2009 at 02:01 PM.
Old Jan 6, 2009 | 03:38 PM
  #2  
WS6T3RROR's Avatar
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From: Engineerland
Factory tach is a piece of junk, trust a datalogger like freescan or datamaster is even better. When I make a run down the drag strip my peak rpm is usually about 7k on the logger. My tach needle spends much too long stuck on the peg , apparently in its world anything past 6200 is 7k. My tach in particular is very accurate at low speed though just gets over excited when the engine is wound up.
Old Jan 6, 2009 | 04:10 PM
  #3  
Slick_Sammy's Avatar
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From: Radford, VA
yeah, i was doing some reading and looks like most are off 200 rpm or so. i be mine's at least 300. i tried some logging with one of the free tools and it didn't seem to work too well. i have the weird Rev.B calibration that was out in 94 on a small percentage of cars, which may be the problem, i dunno. thx.
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