04-12-2017 | #31 |
Join Date: Jul 2016
Location: Bloomington, MN
Posts: 127
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Re: Speed at WOT ?
Im having this same issue and found this thread thru a googl e search. I have a 1991 ZR-1 with 68k miles. It has Borla exhaust so its possible it has 4.10s. With the tach reading 7000 rpm I'm at ~100mph in 3rd gear. I did the HVAC test and the tach is off ~300 rpm but it doesn't seem like 300 rpm would make a 20mph difference. I guess the only way to be sure is jack the rear up and count driveshaft revs?
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1991 ZR-1 #520 Arctic White/Gray |
04-12-2017 | #32 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,700
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Re: Speed at WOT ?
Do you have a GPS? Compare that to your speedo.
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
04-12-2017 | #33 |
Join Date: Jul 2016
Location: Bloomington, MN
Posts: 127
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Re: Speed at WOT ?
Did that too. Speedo is accurate. Also, the shift light does come on when the tach reads 7k.
Sent from my XT1080 using ZR-1 Net Registry mobile app
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1991 ZR-1 #520 Arctic White/Gray |
04-12-2017 | #34 |
Join Date: May 2007
Location: Chicagoland, IL
Posts: 9,700
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Re: Speed at WOT ?
At a steady 70mph ctuise, what's ur rpm?
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[SIGPIC][/SIGPIC]Former Membership Chairman Former ZR-1 Registry - BOD 1972 Corvette 4speed base Coupe SOLD long time ago 1984 Corvette Z-51/4+3 SOLD 1992 Corvette ZR-1 Aqua/Gray #474 SOLD 1992 Corvette ZR-1 Black Rose/Cognac #458 2014 Honda VFR Interceptor DX |
04-12-2017 | #35 |
Join Date: Jul 2016
Location: Bloomington, MN
Posts: 127
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Re: Speed at WOT ?
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1991 ZR-1 #520 Arctic White/Gray |
04-12-2017 | #36 |
Join Date: Aug 2012
Location: Ellicott City, MD
Posts: 1,697
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Re: Speed at WOT ?
I have 4.10's and at 70 MPH I am about 1900 RPM.
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Charlie __________ Dredgeguy WAZOO Member 1992 Bright Red/Black ZR1 #246 Dana 4:10 gears Polished LT5 by Haibeck Polished Fikse FM5's with Michelin Pilot Sport 2 Stainless Works headers and cats with Corsa |
04-14-2017 | #37 |
Join Date: Jul 2016
Location: Bloomington, MN
Posts: 127
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Re: Speed at WOT ?
The tach reads 1900. I checked using the HVAC readout and engine speed at 70mph is 1650.
What controls the shift light? The tach or the ecm? Sent from my XT1080 using ZR-1 Net Registry mobile app
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1991 ZR-1 #520 Arctic White/Gray |
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