Finally Caved
FTE Leadership Emeritus
Joined: Jul 2002
Posts: 42,561
Likes: 421
From: Long Island USA
I think what you're getting is, well, it's hard to describe, but what I call the engine's "spinup time".
The engine can only spool up so fast in terms of RPMs. Anything that holds back the spinup of the engine produces more torque (turbo). So, a higher gear (3.73) produces a certain amount of acceleration. 4.30's allow the engine to spin up faster. BUT - the engine is only spinning up at a certain rate. With 4.30's, the spinup rate limits the acceleration.
With gas engines, advancing the timing helps the spinup time.
The engine can only spool up so fast in terms of RPMs. Anything that holds back the spinup of the engine produces more torque (turbo). So, a higher gear (3.73) produces a certain amount of acceleration. 4.30's allow the engine to spin up faster. BUT - the engine is only spinning up at a certain rate. With 4.30's, the spinup rate limits the acceleration.
With gas engines, advancing the timing helps the spinup time.
Freshman User
Joined: Oct 2007
Posts: 35
Likes: 0
From: San Diego, CA
Originally Posted by i eat hybrids
k7, when are u doing ur lift?
I just finished my rack for my bikes. Still need to run my wiring and build my new tail lights.. No, not new as in replacing the OEM ones, just new as in my rack sticks out from the back of my truck 5' and needs it's own tail lights.
I am going to install the rear springs I have from a 4x4 Ex and see what kind of lift that gives me over the stock 2x4 springs. Then I will probably move forward on deciding which lift I am going to get for the front. I am more than likely going to go with the Fabtech Performance lift.. either the 4" or the 6" Not sure which yet.
It might be a couple months before I am going to actually pull the trigger..
I'll post some pics after this weekend with the bikes loaded and unloaded on the new rack.
Laughing Gas
Joined: Jun 2005
Posts: 1,009
Likes: 1
From: Colorado
That is surprising. You said the lower gears made it more powerful as well as less powerful.
The new gears would change the shift points some and make it react differently until it 'learns' new shift points. I understand diesels do better at low to mid rpms, not high end as gassers but i would never have guessed it would be too much as many run 4.30s with stock tires...almost sounds as something was amiss, like torque converter not locking or something.
I only lead you astray from your initial feelings cuz I did not want you to be upset without much change...should be easy to sell gears for partial recovery...
The new gears would change the shift points some and make it react differently until it 'learns' new shift points. I understand diesels do better at low to mid rpms, not high end as gassers but i would never have guessed it would be too much as many run 4.30s with stock tires...almost sounds as something was amiss, like torque converter not locking or something.
I only lead you astray from your initial feelings cuz I did not want you to be upset without much change...should be easy to sell gears for partial recovery...
Oh and the F450 with 7.3's come stock with 4.88 gears... it will pull more weight but it wont set any speed records and you will be turning hi RPM's if you try doing much over 70 or 75 mph
My 4700 international has a 4 speed auto (no OD) and 4.10's with 39" tires it turns about 2500+rpms at 75. OD drops the RPM's by about 30% from direct drive 1:1 ratio
Elder User
Joined: Nov 2008
Posts: 517
Likes: 0
From: Wash DC/ Westminster, MD
Now what you've all been waiting for...(especially i eat hybrids 
)
Stock:
Lifted with stock tires
8/16/07 Lifted but with 305s obviously the wrong tires for this lift. This pic is proof enough that those rear SD blocks were a bad idea:
8/16/07 Later today with the right tires 315/15/16 BFG All-Terrains :
The man that I am in debt to for this all:
To me the rear end looks way too high, so once my wallet recovers I'm going to get it leveled if not just slightly higher than the front. Special Thanks goes to igotoneforya and i eat hybrids as these were the people who inspired and supported me throughout this lengthy process. Now there are three of us with lifted 2wd trucks. Thanks again guys.
Comments and suggestions are more than welcome......
)Stock:
Lifted with stock tires
8/16/07 Lifted but with 305s obviously the wrong tires for this lift. This pic is proof enough that those rear SD blocks were a bad idea:
8/16/07 Later today with the right tires 315/15/16 BFG All-Terrains :
The man that I am in debt to for this all:
To me the rear end looks way too high, so once my wallet recovers I'm going to get it leveled if not just slightly higher than the front. Special Thanks goes to igotoneforya and i eat hybrids as these were the people who inspired and supported me throughout this lengthy process. Now there are three of us with lifted 2wd trucks. Thanks again guys.
Comments and suggestions are more than welcome......where are the pics?
Cargo Master
Joined: Nov 2008
Posts: 2,332
Likes: 2
From: Summit, MS
Pictures on photobucket do not expire. He either deleted them or moved them. I still have photos on photobucket with valid links from over 5 years ago. You just have to leave them alone.
Thread Starter
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FTE Leadership Emeritus
Joined: Sep 2003
Posts: 12,242
Likes: 758
From: Houston, Texas
But Yellowsled, any questions you have don't be afraid to PM or e-mail me. I can practially write a book on lifting these trucks....
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New User
Joined: Nov 2009
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I know all of the kits say that the biggest tire you can run is a 35, but I love the look of the 4X4 X/Superduty with the 6"-7" lift on 37s (I assume they are about 2" higher than the 2wd stock)... Any way to squeeze an extra inch or two out of the 2wd to comfortably clear 37s?
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FTE Leadership Emeritus
Joined: Sep 2003
Posts: 12,242
Likes: 758
From: Houston, Texas
Just looked at this thread again after awhile and just noticed your question...
You can probably get away with 37s with a 6 inch lift kit like mine, people always keep asking me if I'm going to go with 37s at some point and I never did. Simply becuase 35s look good on my truck and finding a 35 inch tire is easier than finding a 37 inch tire.
You can probably get away with 37s with a 6 inch lift kit like mine, people always keep asking me if I'm going to go with 37s at some point and I never did. Simply becuase 35s look good on my truck and finding a 35 inch tire is easier than finding a 37 inch tire.
Cargo Master
Joined: Feb 2005
Posts: 2,837
Likes: 1
Hope y'all don't mind me reviving an older thread, but I am looking at regearing and this thread really has my head spinning. I used the calculator from 4-lo mentioned earlier in this thread and was convinced that the 4.30 gears would be best for me. I am trying to get my RPMs up for towing, closer to 2200 rpms or so between 65 - 70 mph. My truck is used mostly for towing my 14000lb 5th wheel, with some in-town errands to Lowes, etc. I have 33" tires (or 285/75/16's). If I go with the 4.30's, are the things the OP talked about being a problem something that can be adjusted in tuning? I just don't think 4.10's will be enough of a change for my purposes. If you can't tell, I'm very confused. Thanks for the input.
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FTE Leadership Emeritus
Joined: Sep 2003
Posts: 12,242
Likes: 758
From: Houston, Texas
Hope y'all don't mind me reviving an older thread, but I am looking at regearing and this thread really has my head spinning. I used the calculator from 4-lo mentioned earlier in this thread and was convinced that the 4.30 gears would be best for me. I am trying to get my RPMs up for towing, closer to 2200 rpms or so between 65 - 70 mph. My truck is used mostly for towing my 14000lb 5th wheel, with some in-town errands to Lowes, etc. I have 33" tires (or 285/75/16's). If I go with the 4.30's, are the things the OP talked about being a problem something that can be adjusted in tuning? I just don't think 4.10's will be enough of a change for my purposes. If you can't tell, I'm very confused. Thanks for the input.
My thoughts on this: If you stay with 285s, then 4.10s would be more than accurate for what you're looking to accomplish. I say this because from 1999-2007, certain F-350 Super Duty DRW came equipped with 4.10 gears from the factory (as would some V10s with 4.30 gears) as they were specifically meant for towing.
They usually ran 265s or 285s and would typically turn around 2100-2300 rpms at highway speeds. They wouldn't get much for fuel economy with a load behind them, but the trucks could get down the road much easier.
I feel that 4.30s would be overkill for your situation, especially if you plan on staying with 285s. This is only a suggestion based on my personal experience with gearing, make sure and check with a few shops and see what the consenus is.
Cargo Master
Joined: Feb 2005
Posts: 2,837
Likes: 1
Thanks for your input. Yes, I am still very confused and have even gone so far as to start considering trading up to an F350. I have gotten a lot of varying feedback with regards to the gearing change. My question is, in the end, is there a noticeable difference between the 3.73 you had and the 4.10 you have now?