she went in under the knife
she went in under the knife
lets say a quick prayer... the hd truck is at the shop getting the gears installed.... finally gonna figure out if the 4:56 gears are a win or they suck.. will post results... 
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From: NY
Why would one do that? Just for increased acceleration?
Wouldn't that over rev the engine
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From: Houston and College Station, TX
Yup
Yup
It was recommended by Jim at JDM though, so we'll have to see. I'm predicting like 3.5k RPM at 70 mph or something crazy. It's gonna have so much *** down low though, he won't be able to keep rubber on the rears!
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From: Broken Arrow, OK
Lol, I think 4.10's is about the most I'd go on the stock tire size, but I like my highway mileage with the 3.55's.
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From: Joplin MO
You can't overrev the engine - there's a RPM limiter.
With 4.56's and 31's, a gear calculator says 70 mph in OD is 2422 RPM and in 3rd direct is 3460 RPM. Even accounting for unlocked torque converter, that's no big deal at all. A Triton will run at 5000 RPM all day long.
With 4.56's and 31's, a gear calculator says 70 mph in OD is 2422 RPM and in 3rd direct is 3460 RPM. Even accounting for unlocked torque converter, that's no big deal at all. A Triton will run at 5000 RPM all day long.
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its not bad i had a 01 silverado 4.8 v8 and ran 31in tires 265/70/17s for a while with a canned tuner and 4.56s, ran great and i acutally got pretty good gas mileage. i was turning out roughly 2100 rpms at 70 it pulled my boat great too it was the best thing i ever did, op you should have no problems with it just make sure to follow all the break in periods. i went from 3.23s to 4.56s my truck probably had a heart attack with that much change
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From: Houston and College Station, TX
What calculator are you using? This one?
http://www.ringpinion.com/Calculators/Calc_RPM.aspx
Because 4 different ones just placed my 70 MPH RPM at ~2500 and it's actually 2000 RPM at 74 MPH. 3.55s
Last edited by KMAC0694; Feb 19, 2014 at 07:06 PM.
Ok, here we go... The gears are awesome... Not near as bad on the highway as I thought.. At 70 it was running about 2400-2500.. At 80 it was 2800-2900.. Very comfortable cruising.. The bottom end torque was great ... Gonna have to get Jdm to tweak shift points, bangs out the rev limiter in the 1-2 shift at wot... 4:56 did sound crazy, but Jdm was spot on with the recommendation ... However did find out today that my inter cooler pump quit working,,, that could explain some of the strange power differences I had been feeling... The connector on the motor was corroded... Pulled the pump cleaned it up, fixed connector all is well... One of Jdm' s reasoning behind the 4:56 was the heavy 22" tire/ wheel combo.. .. I thought it was going to be just silly from a dig, but it's just seems to fit... I would say its a win...
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From: Joplin MO
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Last edited by KMAC0694; Feb 21, 2014 at 02:49 AM.