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4.10 Gear Speed/RPM Video

22K views 63 replies 15 participants last post by  Mile high JDF 
#1 ·
im glad u made that video... it definatley makes me wanna stay away from 4.10's for a highway driven car. im gonna assume you have stock injectors.. i definatley cant afford that kinda 65-70mph rpm with 30lbs inj.

if i had a 6spd i think i would be all over it.

again, thanks for the video.. it clarified things for me
 
#2 ·
Excellent idea! :good::good:
 
#4 ·
Oh, and just to add to this. 4.10 adds about 300-400rpm on a stock gear of 3.27 with the tremec 3650 5speed. So 3.73 will be slightly less than this but still a relatively noticeable difference. I'd guess in the 200-300rpm increase range. City mpg will go up if you short shift, and hwy mpg will only go down by 1-4mpg.

The reason people seem to see such bad gas mileage is because it's so hard to not stand on it all the time. And third and fourth gear finally do something so hwy and interstate driving is much more fun! When I stay in the throttle I can get down to 12-15mpg. Lol

It's so worth it.
 
#6 ·
For the most part yes, you can always have a heavy foot and get lower mileage, but for the most part you will see an increase in normal city traffic.
 
#8 ·
ColeJohnson said:
That is correct. But if you love the sound of your car in higher RPMs.. Your MPGs can always dip way down. But if you behave yourself it does increase city mpg. :]
Well the thing I hate the most about the stock gears is, it feels like 3-4 has no power in it. Just wondering if its worth the swap if I do get worse mpg. My 02 GT is a daily driver right now.
 
#13 ·
tigercrazy718 said:
another thing to point out: from my research if your ever gonna supercharge with a roots or twin screw type blower, 4.10s are gonna be pretty brutal. no 1st gear at all lol. idk about centrifugal sc's tho
Good point. It's said that if you go forced induction at all, really, then you should stick with something more like a 3.55 or even stock 3.27.
 
#16 ·
Everyone seems to be really scared about changing out their stock 3.27 gear with a steeper gear like 3.73, 3.90, or 4.10. I elected to go big or go home and went with the 4.10s. And I'm so happy I did! Here's a video to put to rest all the stories about how terrible the gas mileage is and how much it affects your car... This is a video of me on the interstate running at 65mph, 70mph, 75mph, and finally 80mph. The speedometer and RPM gauge is all correct thanks to my tuner.

Don't fear the gear! 4.10 is amazing!

4.10 Gear RPM/Speed Example Video - YouTube
Also I would like to add that for an automatic-equipped vehicle, the RPMs with the 4.10 gears will be 100-200 lower than a manual-equipped vehicle. This kinda goes for all gears. So while a popular choice for manual cars is a 3.73, people whom have autos will feel a similar gain in power from a gear much steeper like a 3.90 or 4.10.

---------- Post added at 01:33 PM ---------- Previous post was at 01:25 PM ----------

Also I would like to add that for an automatic-equipped vehicle, the RPMs with the 4.10 gears will be 100-200 lower than a manual-equipped vehicle. This kinda goes for all gears. So while a popular choice for manual cars is a 3.73, people whom have autos will feel a similar gain in power from a gear much steeper like a 3.90 or 4.10.
And one more thing! People say that the steeper gear you get, the less top-end you'll have in terms of MPH. This is completely false in so many ways- especially if you have a brain and can think. With a relatively stock car, you reach 5th gear at around 105mph if you're going all the way through the RPM band. Then when you shift into 5th with stock 3.27s, your RPMs hit around 2k-2.5k. The powerband is around 3k+, but seeing as how 5th is an overdrive gear, it's very difficult for your car to get into peak RPMs around 4k-4.5k and you usually end up hitting maybe 110 then acceleration almost stops.

However, with 4.10s, at 105 I hit 5th gear and my RPMs are already right over 3k, and then soon they're over 4k and I'm going around 125, then at 5k I'm at 135, and I've gotten up to 143mph at around 5.5k. When I had stock 3.27 I was maybe getting 120 if I was lucky. With the steeper gears, the engine is allowed to work at a more efficient RPM and doesn't get bogged down.

So yeah... The only downside to steeper gears is:
1) Lower MPG(but only barely if you drive nicely)
2) You burn out a lot
3) First gear becomes pretty useless.

Upsides:
1)Accelerate like a bat out of hell (versus stock gears)
2) You burn out a lot
3) Your engine works at more optimal RPMs in pretty much every gear
4) City driving is easier because it takes less effort to start rolling
5) Passing on HWYs and Interstates is fun/safe again.
6) There are more, but I gotta get going to work. Lol Can't wait to drive my car!!
 
#17 ·
Good stuff/good Info, thanks for that Info.

As you have probably read, I have the 4.10's with an Automatic and I am thinking of getting the "Saleen" SuperCharger on mine, what's your opinion on that setup/choice?? I've read resently alot of opinions on Gears and SuperChargers, particularly the First and Second Gear being useless, do you think I will have that problem????:confused:

Also I would like to add that for an automatic-equipped vehicle, the RPMs with the 4.10 gears will be 100-200 lower than a manual-equipped vehicle. This kinda goes for all gears. So while a popular choice for manual cars is a 3.73, people whom have autos will feel a similar gain in power from a gear much steeper like a 3.90 or 4.10.

---------- Post added at 01:33 PM ---------- Previous post was at 01:25 PM ----------



And one more thing! People say that the steeper gear you get, the less top-end you'll have in terms of MPH. This is completely false in so many ways- especially if you have a brain and can think. With a relatively stock car, you reach 5th gear at around 105mph if you're going all the way through the RPM band. Then when you shift into 5th with stock 3.27s, your RPMs hit around 2k-2.5k. The powerband is around 3k+, but seeing as how 5th is an overdrive gear, it's very difficult for your car to get into peak RPMs around 4k-4.5k and you usually end up hitting maybe 110 then acceleration almost stops.

However, with 4.10s, at 105 I hit 5th gear and my RPMs are already right over 3k, and then soon they're over 4k and I'm going around 125, then at 5k I'm at 135, and I've gotten up to 143mph at around 5.5k. When I had stock 3.27 I was maybe getting 120 if I was lucky. With the steeper gears, the engine is allowed to work at a more efficient RPM and doesn't get bogged down.

So yeah... The only downside to steeper gears is:
1) Lower MPG(but only barely if you drive nicely)
2) You burn out a lot
3) First gear becomes pretty useless.

Upsides:
1)Accelerate like a bat out of hell (versus stock gears)
2) You burn out a lot
3) Your engine works at more optimal RPMs in pretty much every gear
4) City driving is easier because it takes less effort to start rolling
5) Passing on HWYs and Interstates is fun/safe again.
6) There are more, but I gotta get going to work. Lol Can't wait to drive my car!!
 
#19 ·
KATO said:
Good stuff/good Info, thanks for that Info.

As you have probably read, I have the 4.10's with an Automatic and I am thinking of getting the "Saleen" SuperCharger on mine, what's your opinion on that setup/choice?? I've read resently alot of opinions on Gears and SuperChargers, particularly the First and Second Gear being useless, do you think I will have that problem????:confused:
Honestly with an auto you might get away with it.. Especially if you pick and choose your races.
 
#20 ·
Thanks Cole, and tigercrazy, i've heard and spoken to a few people, and they said that with my Automatic and the 4.10 Gears, that I would be OK.
 
#21 ·
KATO said:
Thanks Cole, and tigercrazy, i've heard and spoken to a few people, and they said that with my Automatic and the 4.10 Gears, that I would be OK.
Yeah, like I said you should be able to get away with it. You're just going to have to learn how to control your car's acceleration from a dig. But that experience comes with time. It's gonna be a really fun car!
 
#22 ·
I just swapped in 4.10's from the factory 3.27's. I have an automatic. I wanted 3.73's but my brother insisted I go at least a full turn higher to feel the difference. I do 2 hrs of highway driving every day. I can finally use my Overdrive.

Sent from my SGH-T989 using Mustang Evolution mobile app
 
#23 ·
GOOD

That's good. I have absolutely no complaints with mine. Worlds of Fun to drive.:thumb:
 
#24 ·
Hey Cole you're running those 305/40R18s right? What's the revs per mile on those. My recent highway trip had me running 2700rpms in 5th (T45) on a 244/45R17 snow tire. 65 runs 2200ish.
 
#25 ·
I haven't got to drive it much with the 305s because since getting them I parked it for a complete rebuild. But when I had a similar height 295 I was around the same RPMs. Except I was around 2.5k at 70-75. I cruise at 65 however and turn for around 2.1-2.2k pretty regularly. Doesn't really hurt the 'ole wallet bad at all. I didn't even notice the difference really. Haha
 
#28 ·
So I went on a nice cruise and decided to check my RPMs at each speed Cole did. I have a 245/45R17 tire but I'm not 100% sure how accurate my speedometer is right now, it might still be calibrated for the 315s. But here's some pictures I took while driving. I absolutely love my 4.10s by the way.
 

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#35 ·
I'd really like to see a difference of the 4.10 gears with a change in tire. I'll be getting 4.10s for my car soon (already ordered the gear kit) and i have 285/35-18, and later plan to upgrade to 305/40-18 tires, it would be cool to see the difference in rpm alone.
 
#42 · (Edited)
One thing I'd like to point out here that might make this video a little deceptive. Cole has a 2002 GT. From 02-04 ALL 5 spd Mustangs got the T-3650 with a .62 overdrive vs the .68 overdrive in any other 5 spd. The .62 5th in the 02-04 3650s is the same overdrive as the 6th gear in the Terminator.

So for those of you that have the 02-04 3650 or have swapped to one or a T-56 that will be mostly accurate give or take since the stock tach is not exactly dead on. For those of you with a .68 overdrive which was every T-5, all T-45s, early run 3650s and 05-10 3650s, you have a .68 final drive too so tack on about 200-250 RPM @70mph.

With that said, don't fear the gear. If you are a NA 2V and want to accelerate quickly at LEAST 3.73s are required. I kind of wish I had 4.10s currently but the car is getting a IRS swap anyway so it won't matter in a few months what is in there now.

A GREAT site for calculating RPM is here. Go to the bottom, stock tire size is 25.6 and I just listed what the final drive ratios are above. If you have a 4R70W your final drive is .70. Going to a 27" tall tire and if you need a new trans going to the 3650 with the .62 overdrive are both good ideas IMO. Makes for a very nice highway cruiser even with 4.30s in there.
 
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