it's all about the 4.56's baby.

 

Hi Everyone,

Well it’s been awhile now since I had the new Precision 4.56 gears installed and I am still feeling somewhat disappointed?
I really, really expected a vast improvement in acceleration from stand-still take offs, more noticeable low-end torque, and better overall performance at WOT.

I expected much more from going with the stock 3.55’s to 4.56, but I am just am not feeling it?

I am really starting to think about it way too much because now I am starting to wonder if perhaps 4.10’s we mistakenly installed instead of the 4.56’s, but I know this could/would never happen with the well respected shop that I went with?

Do you think it would be worthwhile if I were to call the shop where I had this done and talk to my sales-guy/service manager and let them know that I am somewhat disappointed with the new gears?

I know I still need to purchase the Microtuner to fix the speedometer calibration & shift points, do you think that after I reprogram the PCM with the Microtuner I will be more happier with the gains?

Also, if after I reprogram the PCM with the Microtuner is there a way I can calculate what gear ratio I actually have installed by using the tire size/height, the speed at a particular rpm?

Thanks in advance for any and all replies.

 

DaMatRat,

You should be able to burn those tires from a standstill. Jack up the rear till both wheels clear the ground. With the vehicle in Neutral turn one wheel 1 complete turn. count the number of turns the drive shaft turns. Using a spot of tape or white paint or some sort of marker on the drive shaft makes counting the turns it makes easier. On turn of the rear wheel should make the drive shaft turn 4˝ turns. Actually it should turn 4.56 turns but 4˝ is close enough. If it turns only 4 turns you have the 4.10 gears.

JMC

 

MrTude,
I know when I installed my 4.30's a while back there was a vast improvement when I corrected the speedometer (I already had a Superchip and in my year, had to change the trans gear). The computer (thus timing) is directly affected by the speed you are traveling. Right now the computer thinks you are moving much faster then you actually are. Everything will be off including shift points.
Do what JMC suggested to check that you have the correct gears. Then do the computer correction.

 

Thanks guys for the replies/advice, perhaps this weekend I will try what you guys suggested to check the gear ratio.

 

MrTude,
Go with the tuner as soon as you get the chance!
Then get back to us.
What size tires are you running? I definitely noticed the the gear change more once I used the 1715 microtuner.

 

6” RCD suspension lift with 305/70/16 (33”) BFG Mud Terrains mounted on 16x8 Weld Racing "Outback’s'.

Mods other then the new 4.56 gear include: the AirForce 1 air-intake kit and the MagnaFlow #15609 cat-back system

I will definitely get back to you guys as soon as I purchase the MicroTuner and reprogram the PCM.