4.10 gears - ideal for highway driving?
- Thread starter paulk
- Start date
70 mph at 4.10's will put you at approximately 2600 rpm, versus aproximately 2000 rpm with stock 3.27's. I have 4.10's and my Cobra is my daily driver. Also, only thing I need to do now is aluminum driveshaft installation, have driveshaft vibration at highway speeds because of increase rotation from gear change. From others on this board, this appears to be a very normal change with installing 4.10 or higher gears. I think 4.10's are just fine, have excellent reponse at the throttle now, no hesitation or slow pickup.
I do 80mph at 3000 rpms w/ my 4.10's on my 01 cobra. I don't mind it, but I don't drive it all year or everyday
see thats to high, thats why i wouldn't want to break into the 4 series if i change gears. Yeah theres a performance incentive, but gas prices are very high and if you drive these cars the way there meant to be driven then your already suffering enough, no need to suffer much more. Thats why i'd maybe go with 3:73's or 3:90's i know its not a big change but its enough, hopefully.
what are you 4.10 guys at rpm wise around 85-90?
Is it safe that I drive in 4th gear on my stock gears on the 01 cobra hittin 80MPH? For some reason I dont like driving on high way in 5th gear, 4th gear better accelerates, i usually hit 3k-3.5k doing that and love the sound
Why would it be "unsafe" to drive in 4th gear? You are simply putting more strain on engine, cruising for duration of time at higher rpm. When I am cruising for distance, I try to stay at lowest rpm as possible, just don;t putting unnecessary strain on the engine and tranny. With my 4.10's, when driving around town doing 45-50, I drive in 5th gear, just being conservative I guess. I plan on making my car last as long as possible. But, this is just my preference. If I need to accelrate, well, with the 4.10's on the highway, I can stay in 5th and punch it pretty good and get right up. But, if I really want to accelerate, drop into 4th and have fun.
Wow, do some research on the topic first then ask some questions that were just answered about two weeks ago. Go with at least 4.10's. Even if you drive for 2 hours everyday on the highway. Its not that big of a difference in mileage. If you want better gas mileage get a honda
paulk said:
paul,
if you drive in 4th gear everywhere (like I USED to), then either 4.30s.
@70mph my car is about 2600 RPM in 5th gear with 4.30s.
If you have an 01, then 4.10s may be easier. I believe I have read that 4.30s and higher require some modification to something on the differential to get them to fit (maybe the cross pin that holds the internals of the differential together). 4.30s fit fine on the 99 differentials (28-spline axles), but 4.56s would require some modification.
Or maybe I just misunderstood what was posted, though.
You guys getting 4.10's are going to wish you went with 4.30's after about two weeks post gear swap. Really, 3K is not a lot of strain on these high strung engines. Do you really need to go 80 everywhere anyways?
You are just used to the factory "economy" gears keeping the rpm's down to nothing. If you are doing a gear swap to 4.10's then you might as well just bite the bullet and get 4.30's.
You are just used to the factory "economy" gears keeping the rpm's down to nothing. If you are doing a gear swap to 4.10's then you might as well just bite the bullet and get 4.30's.
This subject has been beat to death many many times. Don't fear the gear. The 4.6 DOHC runs it coolest at 3000 rpm according to the proving ground guys. I have had 3.27, 4.10, 4.30, and 4.56 gears. I am keeping the 4.56s but I have the D&D T56 with the 2.97 first gear and a .62 6th.
I put together a spreadsheet to figure out the different cruising speeds and punch rpms at street speeds. It has calculations for 4th, T56 6th, and the T45 5th. There are also worksheets for the Viper Spec T56 and the 03 Cobra T56.
I will not go back to the 4.10s, there is not enough difference in cruising speeds between those and the 4.30s. Actually it is only about 140 rpm difference at 80 mph. If I go to a blower I will jump up to the 4.30s. Just for the heck of it 4.30s will run you through the traps at 125 on 26.4 tires, jump up to 11.50 26x17 ET Streets and you can blast the traps at 132.
BTW. I still get ~22 mpg at highway speeds with the 4.56s and about 16 in town. In town I can't seem to keep my foot out of it.
Here is a link to the sheet:
http://members.cox.net/99venom/Gear_Chart.xls
I put together a spreadsheet to figure out the different cruising speeds and punch rpms at street speeds. It has calculations for 4th, T56 6th, and the T45 5th. There are also worksheets for the Viper Spec T56 and the 03 Cobra T56.
I will not go back to the 4.10s, there is not enough difference in cruising speeds between those and the 4.30s. Actually it is only about 140 rpm difference at 80 mph. If I go to a blower I will jump up to the 4.30s. Just for the heck of it 4.30s will run you through the traps at 125 on 26.4 tires, jump up to 11.50 26x17 ET Streets and you can blast the traps at 132.
BTW. I still get ~22 mpg at highway speeds with the 4.56s and about 16 in town. In town I can't seem to keep my foot out of it.
Here is a link to the sheet:
http://members.cox.net/99venom/Gear_Chart.xls
Last edited:
lemosley01 said:
You have to buy a new crosspin when switching to 4.56's but 4.30's are fine.
not a problem, dio it daily. lost about 40 miles to the tank.
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