Gears & Axles Driveshafts | Rearends | Differentials | Gears | 12 Bolt | 9 Inch | Dana

Question about highway speed

Thread Tools
 
Search this Thread
 
Old 11-07-2007, 08:56 AM
  #1  
Teching In
Thread Starter
 
NkTyson06's Avatar
 
Join Date: Sep 2007
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts
Default Question about highway speed

Hi, I have a 98 v6 Camaro y87 and GU6 on the RPO list. My car came with 3.42's and they were replaced about 2 years ago. When I am driving on the highway at 74-75 mph with cruise control on, my rpms are steady 2400-2500. I have been reading the stickies above and people having been saying with the same gears I have that at 75-80 mph they are cruising at 1800 rpms. Is this because they have a v8 and with more power it doesnt have to struggle as much to move the car? Like because I have a 3.8 it has to push harder to move the car of the same weight? And ever since I had my 3.42's + rear axle replaced (with a used set) there has always been this woo woo whoo noise at highway speeds. It is not loud but it is "hearable" if that is a word lol. Its a dull noise I have been told it may be my tires. Once I upgrade my rims/tires I will see if it was them but I still feel strongly it is coming from the rear end. Sorry for the wall of text, but thanks for the help.
Old 11-07-2007, 09:11 AM
  #2  
Internet Mechanic
iTrader: (17)
 
BlackScreaminMachine's Avatar
 
Join Date: May 2005
Location: Wallingford CT
Posts: 9,831
Likes: 0
Received 2 Likes on 2 Posts

Default

People who rev 1800 rpms @ 75 mph have 6 speeds witha 0.50 6th gear ratio on a 3.42 gear.

If im not mistaken, your car didnt come with a t-56 6 speed, did it!? I thought its a 5 speed.
Old 11-07-2007, 09:59 AM
  #3  
Teching In
Thread Starter
 
NkTyson06's Avatar
 
Join Date: Sep 2007
Posts: 22
Likes: 0
Received 0 Likes on 0 Posts
Default

Mine is an A4. The Y87 package included the posi rear with 3.42 gears.
Old 11-07-2007, 02:14 PM
  #4  
Internet Mechanic
iTrader: (17)
 
BlackScreaminMachine's Avatar
 
Join Date: May 2005
Location: Wallingford CT
Posts: 9,831
Likes: 0
Received 2 Likes on 2 Posts

Default

then you have a .70 OD gear ratio

run the calculator....

http://www.f-body.org/gears/

26" tall tire, 3.42 gears, 0.70 OD, 6000 rpm redline @ 74 = 2300 rpms.

26" tall tire, 3.42 gears, 0.50 OD, 6000 rpm redline @ 74 = 1600-1700 rpms

You must have been reading about t-56 6 speeds

** please note with a Auto and a stock tach it may be off by 100-200 rpms.

Last edited by BlackScreaminMachine; 11-07-2007 at 02:26 PM.




All times are GMT -5. The time now is 07:52 PM.