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#1 |
![]() Join Date: Nov 2010
Location: Japan
Posts: 30
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Hi.
I am a new owner of a ZR-1(1991) and am enjoying it every weekend. I am very happy now ![]() BTW, please let me ask you a beginner question. I would like to know whether the rear end of my ZR-1 is normal or not. When I accelerate my ZR1 to 7000 rpm with 5th gear, the GPS speedometer reads 223.9 km/h(about 140 mph). Is this normal? Is the max speed of ZR-1 accomplished by 6th gear? I am wondering if the rear end ratio of my ZR-1 is normal or not. *the rear tires are Nitto NT555(315/35-17). *the original speedometer reads about 219 km/h(136 mph) at 7000 rpm with 5th gear. Thanks in advance. Y. Honda 1991 ZR-1 Last edited by gorgeousgeorge; 11-08-2010 at 04:04 PM. |
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#2 |
Join Date: May 2005
Location: Leesburg, VA
Posts: 2,713
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7,000 in 5th gear would be about 200mph (320kph) with stock gearing. That would suggest you have around a 5:1 rear gear ratio. Some Jeeps use the D44, so there are probably some pretty extreme gears available out there.
It sounds like your speedometer has been corrected properly, though.
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Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img] |
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#3 |
Join Date: Apr 2009
Location: Prather, CA
Posts: 809
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It's possible his tach isn't reading correctly also.
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[IMG]http://i13.photobucket.com/albums/a292/bdw18_123/_zr1netforumsigphoto.jpg[/IMG][B] 1990 Corvette ZR-1 [/B][I] White/Flame Red, #2299, mostly stock, 144K miles.[/I] -Cams timed to the '93-'95 405HP LT5 stock timing. -IAT sensor relocated to below front bumper. -Haibeck hoops installed in airduct. -OBX cat-back exhaust. [COLOR=DarkRed][B](SOLD - December 2012 [/B][/COLOR][COLOR=DarkRed][B]:hello:)[/B][/COLOR] 1993 Corvette Coupe Black/Black, 6-speed (SOLD - October 2009 :hello:) |
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#4 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
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Wow! That would be some serious rear gears. Mine with stock 3.45 hits 181mph at 7100 rpm,s.
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#5 |
![]() Join Date: Nov 2010
Location: Japan
Posts: 30
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Thank you for your interesting replies!
![]() I understand that 140 mph at 7000rpm in 5th gear is NOT normal for ZR-1. The problem would be that the rear end ratio is not normal or the tachometer is not correct. I think I have to inspect the rear end ratio at first. Does the method below work well to inspect the ratio? 1. lift the car up. 2. mark a dot with chalk on circumference of the propeller shaft. 3. mark a dot with chalk on the rear tire wall. 4. rotate rear tire and drive the propeller shaft. 5. count the number of rotation of the tire required to have the propeller shaft make one complete rotation. I am not a gearheaded guy ![]() Thank you! Yoshi Honda 1991 ZR-1 |
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#6 |
![]() Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
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Hi! Yes that will work to get you a very close approximation of the gear ratio,
![]() Tom
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1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
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#7 | |
![]() Join Date: Dec 2004
Location: Luling, TX
Posts: 97
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I believe your tach is off too. You should be over 200 @ 7100 with 3.45 in 5th gear. At least mine was. Curtis
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Curtis Ward 91 ZR-1 #364 RIP |
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#8 |
Join Date: Mar 2009
Location: Orlando, FL
Posts: 1,828
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My bet is inaccurate tach
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#9 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
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My tach is off now. Corey even said it was off in the high direction 1000rpm's. Now it reads 8000 at 181mph which to me says 7100 is about right for that speed.
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#10 | |
![]() Join Date: May 2010
Location: Japan
Posts: 3,573
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Craig
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Craig "ZR-1 NO KA 'OI" "ZR-1 ICHIBAN" 1995 #228 Black/Black with Dunn Heads ZR-1 owner since September 2003 ZR-1 Net Registry Founding Member #0074 NCM Lifetime Member #2048 ![]() |
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