4.10 gears installed last Saturday

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Notquik, as you know, going from your 3.31's to 4.10's will be very noticable. Your 12.94 is good for the mods you have. What tires was that with?

Dan, I'm a road racer also, it's been a difficult choice which way to go with the car. Drag or road race. I already have other drag cars and the Mustang fits into large sedan in the auto-X club I race with. So I beleive it will be very competitive. The straights on the road race tracks in the NW are not long enough for me to run out 4th gear with the 4.10's. But that was a consideration when I decided to go 4.10.
 
OK.....

Can someone comment on these gears for me (the 4.10s)?

I really never go to the drag strip (1x since I've had the car). I've auto-x'd 2 times last year....and I would do that again before the drag strip.

My car would most likely stay N/A for the next 5 years. I would only be adding basic bolt-ons and perhaps a Roush Stage 3 suspension (road racing more than drag, etc).

What are the RPMs at 70-ish mph? I typically cruise at 70-75 on the highway. I need to avoid 1750rpm due to the drone of my Roush mufflers.

I have 3.55s now, and was thinking 3.73s would give "some" change, and not kill gas mileage. I would like to do a 5,000 mile road trip this summer too, btw. Detroit to California and back, via Route 66. Would 4.10s blow up the rear end?

Thanks!
 
OK.....

Can someone comment on these gears for me (the 4.10s)?

I really never go to the drag strip (1x since I've had the car). I've auto-x'd 2 times last year....and I would do that again before the drag strip.

My car would most likely stay N/A for the next 5 years. I would only be adding basic bolt-ons and perhaps a Roush Stage 3 suspension (road racing more than drag, etc).

What are the RPMs at 70-ish mph? I typically cruise at 70-75 on the highway. I need to avoid 1750rpm due to the drone of my Roush mufflers.

I have 3.55s now, and was thinking 3.73s would give "some" change, and not kill gas mileage. I would like to do a 5,000 mile road trip this summer too, btw. Detroit to California and back, via Route 66. Would 4.10s blow up the rear end?

Thanks!

I have 4.10's and the factory 235/50/18 tires. 60 mph = 2100 rpm's. 70 mph = 2450 rpm's. 80 mph = 2800 rpms. The drone of your mufflers will not be an issue on the highway. 4.10's will not hurt the rear end (tires and axles are still moving the same speed regardless of gearing).

4.10's are great for N/A GT's and make daily driving wonderfully entertaining. 5th gear becomes usable, instead of lugging down like the stock gearing. A long road trip will be fine with 4.10's thanks to the overdrive in your transmission.

You won't really notice any difference between 3.55's and 3.73's, so that would be a waste of money. You've gotta change at least two steps to really "feel" a difference (i.e. 3.55's to 3.90's, or 3.31's to 3.73's).
 
I have 4.10's and the factory 235/50/18 tires. 60 mph = 2100 rpm's. 70 mph = 2450 rpm's. 80 mph = 2800 rpms. The drone of your mufflers will not be an issue on the highway. 4.10's will not hurt the rear end (tires and axles are still moving the same speed regardless of gearing).

4.10's are great for N/A GT's and make daily driving wonderfully entertaining. 5th gear becomes usable, instead of lugging down like the stock gearing. A long road trip will be fine with 4.10's thanks to the overdrive in your transmission.

You won't really notice any difference between 3.55's and 3.73's, so that would be a waste of money. You've gotta change at least two steps to really "feel" a difference (i.e. 3.55's to 3.90's, or 3.31's to 3.73's).

Your car is an automatic. Mine is a 5-speed manual. Does that factor in for anything different?
 
Dan, I'm a road racer also, it's been a difficult choice which way to go with the car. Drag or road race. I already have other drag cars and the Mustang fits into large sedan in the auto-X club I race with. So I beleive it will be very competitive. The straights on the road race tracks in the NW are not long enough for me to run out 4th gear with the 4.10's. But that was a consideration when I decided to go 4.10.

There's a lot of considerations like that. One of my closest tracks is Texas World Speedway, and the front strait on that is long enough to get over 140. But something to keep in mind is the difference between from 3.90 to 4.10 (or similar) is that same as going from 285x40x18 to 285x35x18. So you can do a decent amount of gearing which just your tires.
Dan
 
Interesting comment about tires and effective gearing. Never heard anyone make that comment, but it makes sense. I plan on sticking with a pretty normal setup. I'd probably run 18s with a 275 (all corners)...in a 40-45 series sidewall (or whatever is normal for that width).

My car is first and foremost a daily driver. Second, a street "enthusiast," :rolleyes:, third, an auto-x'er, fourth, a drag strip runner....and last, a road circuit car.

Eventually....and hopefully...I can keep this car for another 25 years and make it a project car, but until then, it will be bolt-ons mostly and enjoyed daily.

I really just don't want to kill the daily driveability or sacrifice a nice long road trip. 2500rpm at 70 isn't really that high, but it sounds louder than what I'm used to. My Civic Si (circa 1999) ran 4,000rpm at 80 with the stock 5-speed trans. That was kinda fun....LOL
 
I have 275/40/18 tires and with the 4.10 gears my RPM's at 75 are 2550. At 70 MPH the RPM's are about 2200. I did lose roughly 2 MPG at 75 MPH that might be an issue for some people. I would never go back to the 3.55 gears unless I put forced induction on the car.
 
Interesting comment about tires and effective gearing. Never heard anyone make that comment, but it makes sense. I plan on sticking with a pretty normal setup. I'd probably run 18s with a 275 (all corners)...in a 40-45 series sidewall (or whatever is normal for that width).

Gearing and tire height are directly related. On the dyno with my stock 235/50/18 tires (27" tall), I redlined in 4th gear at 114 mph. At the dragstrip with shorter 275/40/17 drag radials (25.7" tall), I redline in 4th gear at 109 mph, so I have to shift into 5th at the track (I trap at just shy of 112 mph). So, a taller tire for the track, or dialing back the gearing to 3.90's or 3.73's would probably make my car slightly quicker by avoiding that last shift.
 
Just my 02 here, but my Bullitt has 3.73s and turns 3000 rpm at 90 ish, which is more than I would like, and it sees steady 80ish cruises more than I imagined on the interstate.

I love the Bullitt acceleration, but this is my dd, and has 22000 miles since Apr 09. Also love teh 22+ mpg overall.

I think 4.10s would be painful on the highway.
 
thank you for your insight, I can't remember the last time I drove 90 mph steadily...heh....my highway driving is about 65 mph and very seldom 70mph...I rack miles up like yourself though, I was out of warranty in 13 months :( My next tire will also be a 305-35-20 so it'll be a bit taller than I have now which will also take away some of the gear for highway driving.
 
My car's 3rd birthday is coming up and I wanna get her something special! I was thinking the 4.10s since I haven't taken the plunge yet. However, I'm looking and I came across that I might lose 2 mpg with the install? I'm loving my MPG right now and am averaging 21+. But I keep hearing gears, gears, gears. So my questions are if I'm going to do the gears, where is the best place to get them (price)? Also what's the difference in the FRPP and the FRPP A gears? I saw some other links as well which had a kit vs just the ring and pinion. Do I only need the kit if I'm going to do the install myself?

Here's a link to a set I found on ebay. http://cgi.ebay.com/ebaymotors/05-0...c0.m245&_trkparms=72:1171|65:12|39:1|240:1318

Look like they might be a good buy. Thoughts?
 
Just a thought: giant wheels (20") look cool but slow you down. My stock 18 inchers turn more revoultions for every turn of the driveshaft. My 3:55's could be faster than 3:90's or 4:10's with bigarse wheels.