Need opinion on gear ratios
Melting Slicks
Joined: Apr 2002
Posts: 3,019
Likes: 0
From: down that one road next to that big tree
Re: Need opinion on gear ratios (LT4BUD)
limited to 6300 they won't work for the power your making you need to hit at least 6500-6600. actually you'd have to try it, programs are close but actual tire size varies. maybe the 3:90 isn't a bad idea for you. i'm doing a 4:10 personally but i have 7,000 rpm capibility and also less power than your making using n02 so the mph is a little lower.
Drifting
Joined: Jul 2000
Posts: 1,661
Likes: 4
From: Phoenix, Arizona
Re: Need opinion on gear ratios (owensLT4)
No personal experience with NOS, but 4.10s make the LT4 the PERFECT daily driver. They should have come that way. Mileage may be lower, but 6th gear is usable, and you didn't buy a LT4 for mileage anyway, did you? :) I can get 25 if I cruise at a steady 75. I get 20.5 or so pulling my tire trailer to races in CA and NV. One thing - you will enjoy hearing your exhaust at WOT more often :blueangel:
Racer
Joined: Jan 2002
Posts: 341
Likes: 1
From: Cave Creek AZ
Re: Need opinion on gear ratios (LT4BUD)
ttt
LT4BUD, If I plug the 2765 in as my base at 60 I come up with the same numbers that you do. So I need to find out exactly what rpm I'm turning at 60. I understand the circumference calculation but I like to get actual real world data. I guess I need a scanner. Thanks.
OwensLT4, If you can come up with rpm in 4th gear at say 60mph with the tires that you will be racing with, then you can easily calculate speed with different rear ratios. As you and others have said you don't want to have to shift into 5th. That would drop you down too far in your power band for a very short time at the end of the quarter. Plus I would expect that your mph may increase after you change the gears. :)
LT4BUD, If I plug the 2765 in as my base at 60 I come up with the same numbers that you do. So I need to find out exactly what rpm I'm turning at 60. I understand the circumference calculation but I like to get actual real world data. I guess I need a scanner. Thanks.
OwensLT4, If you can come up with rpm in 4th gear at say 60mph with the tires that you will be racing with, then you can easily calculate speed with different rear ratios. As you and others have said you don't want to have to shift into 5th. That would drop you down too far in your power band for a very short time at the end of the quarter. Plus I would expect that your mph may increase after you change the gears. :)
Safety Car
Joined: Jul 2001
Posts: 3,524
Likes: 1
From: Pinellas Florida Misfit
Cruise-In III Veteran
Re: Need opinion on gear ratios (NavyVet)
I have driven a 3.90 car and a 4.10 car... both are very nice gears for the M6 NA motor. I would not add any more gear if you run the bottle...
Safety Car
Joined: Sep 2000
Posts: 3,524
Likes: 4
From: Hinckley Ohio
Re: Need opinion on gear ratios (lead_foot)
lead foot
Your 25.9" height converts to 778 vs the 801 revs per mile. I just took a quick look at the BFG site and it looks like they no longer make the T/A in 285/40ZR17, so I couldn't check the data. But The Revs per mile are at a given speed (45mph), so at higher speeds I'm sure the tire grows a little. I like your idea of real world data that accounts for things like speed, tire pressure, rim size, etc.
It looks like replacement tires in the original size for std suspension LT4's are going to get limited.
Your 25.9" height converts to 778 vs the 801 revs per mile. I just took a quick look at the BFG site and it looks like they no longer make the T/A in 285/40ZR17, so I couldn't check the data. But The Revs per mile are at a given speed (45mph), so at higher speeds I'm sure the tire grows a little. I like your idea of real world data that accounts for things like speed, tire pressure, rim size, etc.
It looks like replacement tires in the original size for std suspension LT4's are going to get limited.
