11-08-2010 | #1 |
Join Date: Nov 2010
Location: Japan
Posts: 30
|
A question about speed reading at 5th gear
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. |
11-08-2010 | #2 |
Join Date: May 2005
Location: Leesburg, VA
Posts: 2,713
|
Re: A question about speed reading at 5th gear
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.
__________________
Bob Saveland Former owner of #2517 [IMG]http://a.random-image.net/aurora40/vette.jpg[/img] |
11-08-2010 | #3 |
Join Date: Apr 2009
Location: Prather, CA
Posts: 809
|
Re: A question about speed reading at 5th gear
It's possible his tach isn't reading correctly also.
__________________
[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:) |
11-08-2010 | #4 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
|
Re: A question about speed reading at 5th gear
Wow! That would be some serious rear gears. Mine with stock 3.45 hits 181mph at 7100 rpm,s.
|
11-08-2010 | #5 |
Join Date: Nov 2010
Location: Japan
Posts: 30
|
The right procedure for inspect the ratio of rear end
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 and do not want to make any mistakes so I ask for the right procedure. Thank you! Yoshi Honda 1991 ZR-1 |
11-09-2010 | #6 |
Join Date: Dec 2004
Location: Jacksonville, FL USA
Posts: 4,645
|
Re: A question about speed reading at 5th gear
Hi! Yes that will work to get you a very close approximation of the gear ratio,
Tom
__________________
1990 ZR-1, Black/grey, #2233, stock. ZR-1 Net Reg Founding Member #316 & NCM member |
11-09-2010 | #7 | |
Join Date: Dec 2004
Location: Luling, TX
Posts: 97
|
Re: A question about speed reading at 5th gear
Quote:
I believe your tach is off too. You should be over 200 @ 7100 with 3.45 in 5th gear. At least mine was. Curtis
__________________
Curtis Ward 91 ZR-1 #364 RIP |
|
11-09-2010 | #8 |
Join Date: Mar 2009
Location: Orlando, FL
Posts: 1,828
|
Re: A question about speed reading at 5th gear
My bet is inaccurate tach
|
11-09-2010 | #9 |
Join Date: Aug 2008
Location: Houston 90 Red ZR-1
Posts: 2,320
|
Re: A question about speed reading at 5th gear
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.
|
11-10-2010 | #10 | |
Join Date: May 2010
Location: Japan
Posts: 3,577
|
Re: A question about speed reading at 5th gear
Quote:
Craig
__________________
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 |
|
Thread Tools | |
Display Modes | |
|
|