Went from 3.90 to 4.10
03-19-2013, 11:33 AM
#1
Went from 3.90 to 4.10 I managed to get 30,000 miles out of the 3.90's (in the stock 10 bolt) before I broke the pinion. Ended up going with Motive 4.10's this time. Here are my initial thoughts:
1. They're just as quiet as the 3.90's.
2. They are much more lively on the street. My setup with 3.90's was already pretty low-end and mid-range friendly (moderate cam, 11:1 compression) however there still seemed to be a brief lull down low. That's now completely gone.
3. CORRECTED. You will lose some mph in 4th gear as a result of the change so be mindful of what mph you'll need to hit the traps in 4th. With a 6700 - 6800 redline and a 26.30" tire diameter, I should still be able to pull to 128-130 in 4th gear at the track.
4. Difference in gas mileage seems nominal. Do we really drive these cars for fuel economy?
5. This will have a real impact on traction. It always let loose in 1st even on the drag radials however that seems to be more severe and 2nd is an issue unless conditions are ideal.
In summary, I'm very pleased with the change. Was always fearful of going to 4.10's and a 3.73 seemed like a waste of time so I thought the 3.90 was a good compromise. In hindsight, I should've gone with the 4.10's years ago.
1. They're just as quiet as the 3.90's.
2. They are much more lively on the street. My setup with 3.90's was already pretty low-end and mid-range friendly (moderate cam, 11:1 compression) however there still seemed to be a brief lull down low. That's now completely gone.
3. CORRECTED. You will lose some mph in 4th gear as a result of the change so be mindful of what mph you'll need to hit the traps in 4th. With a 6700 - 6800 redline and a 26.30" tire diameter, I should still be able to pull to 128-130 in 4th gear at the track.
4. Difference in gas mileage seems nominal. Do we really drive these cars for fuel economy?
5. This will have a real impact on traction. It always let loose in 1st even on the drag radials however that seems to be more severe and 2nd is an issue unless conditions are ideal.
In summary, I'm very pleased with the change. Was always fearful of going to 4.10's and a 3.73 seemed like a waste of time so I thought the 3.90 was a good compromise. In hindsight, I should've gone with the 4.10's years ago.
Last edited by Midnight02; 03-21-2013 at 03:56 PM.
03-19-2013, 11:44 AM
#2
10 Second Club
iTrader: (8)
With my set-up 3.90's are much better. You can't always go by feel. Do you track times to back up your opnion? Topping out @ 115-118 sucks. You can't hardly get a good running bolt-on car threw the 1/4 at those mph's.
On contrary to what you and others have said 3.42 to a 3.73 is a major change.
On contrary to what you and others have said 3.42 to a 3.73 is a major change.
03-19-2013, 02:38 PM
#3
With my set-up 3.90's are much better. You can't always go by feel. Do you track times to back up your opnion? Topping out @ 115-118 sucks. You can't hardly get a good running bolt-on car threw the 1/4 at those mph's.
On contrary to what you and others have said 3.42 to a 3.73 is a major change.
On contrary to what you and others have said 3.42 to a 3.73 is a major change.
I agree that there's a real change in going from 3.42 to 3.73. Heck, the basis of this thread is the noticeable difference between the 3.90's and 4.10's; that's less of a gap than the 3.42 to 3.73 swap. Back when I made the decision to go with 3.90's it seemed like it wouldn't be worthwhile to go to 3.73's. In hindsight it would've been, however I still think taking the next step up to the 3.90's were the right call at the time.
03-20-2013, 07:58 PM
#6
Not arguing, just wondering what the thought process is behind that statement?
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03-21-2013, 03:54 PM
#8
Not sure how you are only getting 115-118? We have nearly identical setups (about as close as you can get without having exactly the same setup) and I definitely can get 128 out of 4th (if required). I usually shut down around 120 since that is about 6500, but what RPM did you setup peak at? Mine was 6550 with the LS6 intake, I assume yours with the FAST has got to be around 6700? Therefore, even if you did take your car to the strip, you still would be in 4th going thru the traps - and not be out of the powerband?
Not arguing, just wondering what the thought process is behind that statement?
Not arguing, just wondering what the thought process is behind that statement?
I was too conservative on my redline (6400) and had the wrong tire diameter (used the Nitto NT01 diameter of 25.35 instead of the 26.30 for my 555R II's).
Just re-ran the numbers and it looks like I could expect to get to 128-130 mph in 4th gear with the redline at 6700 - 6800. Feeling that much better about the 4.10's now!
03-30-2013, 11:32 AM
#9
I will be tuning my suspension at the track next weekend, do you think it would be worth my while to switch out from the 3.73-4.10's in a moser 12 bolt? (had traction issues before but have a few parts on that will help a lot with that)
