Posi Rear?

[John Day]

Hello from Abilene, TX.
I own a 19 Yukon XL SLT with a L83 - 5.3L, SID VVT, AFM ALUM GM: 6 SPD, HMD, 6L-80 TRANSMISSION: REAR AXLE 3:08 RATIO. My buggy has 34000 miles on it and runs like a top right now.
In short I own a 7700 lb pig.

So, my question is this, where do I start with bolt on power?
I want to keep the same "QUIET" ride and add some power to the rubber. I'm not talking about super chargers or any of that stuff. I want to improve drivability and add "SOME" power.
Any ideas will be greatly appreciated.
I"m 65 years old, my racing days are behind me. Driveability and "SOME" more horses.

Different Rear end gears?
CAI is ordered.
Headers, but I want to keep my "QUIET", so I need muffler ideas too.
I'll put bigger brakes on her in another 30-40K.
Never owned a "chipped" vehicle, except stock.

Thx for any help

I'm getting over CV and pneumonia right now. Yall say a prayer for John if led. Really attacked my lungs, spent one overnight in hospital with Atrial fabulation, Pulse was 180 for about 10 hours, not fun! Doing much better now. Keep pushing. M A G A

 

[swathdiver]

So, my question is this, where do I start with bolt on power?

Prayers sent on high John. GMCs should all come with the G80, check your RPO sheet, this is the combo locker/limited slip. Go for 3.42 or 3.73 gears and get a BlackBear tune. Headers will make it loud up front, you'll probably be happy enough with the extra 35+ horses and the gearing.

If you have E85 stations around, you can add the components from the 2015s and instantly be able to burn the corn which is free horsepower. A standard L83 picks up 25 horses burning E85 over gasoline. Torque surpasses 400 foot pounds too.

Glad you're still with us, that Wuhan Flu is no joke if not caught early for those of us with other ailments. My oldest daughter had it and it barely slowed her down.

 

[John Day]

Prayers sent on high John. GMCs should all come with the G80, check your RPO sheet, this is the combo locker/limited slip. Go for 3.42 or 3.73 gears and get a BlackBear tune. Headers will make it loud up front, you'll probably be happy enough with the extra 35+ horses and the gearing.

If you have E85 stations around, you can add the components from the 2015s and instantly be able to burn the corn which is free horsepower. A standard L83 picks up 25 horses burning E85 over gasoline. Torque surpasses 400 foot pounds too.

Glad you're still with us, that Wuhan Flu is no joke if not caught early for those of us with other ailments. My oldest daughter had it and it barely slowed her down.

Swat driver, thx for the kind words. My wife and I both had it. Mine just turned into pneumonia because of that's what God, I Am wanted I guess. Back to the Truck, I got my RPO from this site and I've attached the sheet for my engine. I'm not sure if I have to add anything for the E85, if so when u get a chance take a look. Thx for the help!!!! Happy Thanksgiving!!!! Stay safe and tote, it ain't over!!!

 

[Joseph Garcia]

x2 on the tune. Black Bear Performance is a favorite here in the Forum, but there are also other tune options available out there.

But for the money, and not having to tear down and rebuild your motor, you can't beat a tune. And, there is REALLY a very noticeable difference in performance, both in motor responsiveness and in transmission shifting effectiveness, after the tune.

 

[John Day]

Well I will look to black bear for Christmas.
So. CAI on order
Tune. Very stupid on that.
Headers? If I dont change muffler will headers help?
Then changing rear end gears? I have the 3.08’s in there now according to RPO.
Some talk to me about rear end gears. Positrac of course but just want to put some more horses on the ground. Something to loosen up the beast just a little. I don’t tow anything but my fat butt!

Happy thanksgiving to all.
Jd n Abilene

 

[swathdiver]

I've attached the sheet for my engine. I'm not sure if I have to add anything for the E85, if so when u get a chance take a look.

Well I will look to black bear for Christmas.
So. CAI on order
Tune. Very stupid on that.
Headers? If I dont change muffler will headers help?
Then changing rear end gears? I have the 3.08’s in there now according to RPO.
Some talk to me about rear end gears. Positrac of course but just want to put some more horses on the ground. Something to loosen up the beast just a little. I don’t tow anything but my fat butt!

Happy Thanksgiving John.

If you have a yellow gas cap or a yellow sticker inside the fuel door if you are capless, you are good to go for E85. I keep thinking 6.2 and pickups.

CAI isn't going to do much either other than add more noise when you push the go pedal. Your rear axle is a Salisbury 12-bolt 9.76 axle with 1410 u-joints, very strong.

These are the guys that made them for GM, they are the OE supplier:

https://demandaam.com/axle-results?vm=GM&q=9.76"+12+Bolt+-+Rear+Axle

You'll need a new carrier and of course the ring and pinion and associated hardware. I know of a guy up in Amarillo and Texas Speed is down in Georgetown, both about 3 hours from you that can do the work right the first time. But that is just based on reviews and watching their youtube videos! I'm sure there's a competent crew in Abilene too, especially if there is a drag strip nearby. For many axles, they do make adapters that allow one to use 3.42 and lower gears on a carrier designed for 3.08s but these do not stand up to... don't want to say abuse, but maybe heavy use or spirited driving are a better choice of words.

I prefer a custom tune over a canned tune, I personally met up with BlackBear and he tuned my truck from the passenger seat while I drove and followed his instructions. Updates are free for life. So if I change gears or tires, he'll update the tune to recalibrate and account for those changes performance wise. Diablo has canned tunes and also does that too, Lew is his name. @kbuskill

 

[John Day]

Happy Thanksgiving John.

If you have a yellow gas cap or a yellow sticker inside the fuel door if you are capless, you are good to go for E85. I keep thinking 6.2 and pickups.

CAI isn't going to do much either other than add more noise when you push the go pedal. Your rear axle is a Salisbury 12-bolt 9.76 axle with 1410 u-joints, very strong.

These are the guys that made them for GM, they are the OE supplier:

https://demandaam.com/axle-results?vm=GM&q=9.76"+12+Bolt+-+Rear+Axle

You'll need a new carrier and of course the ring and pinion and associated hardware. I know of a guy up in Amarillo and Texas Speed is down in Georgetown, both about 3 hours from you that can do the work right the first time. But that is just based on reviews and watching their youtube videos! I'm sure there's a competent crew in Abilene too, especially if there is a drag strip nearby. For many axles, they do make adapters that allow one to use 3.42 and lower gears on a carrier designed for 3.08s but these do not stand up to... don't want to say abuse, but maybe heavy use or spirited driving are a better choice of words.

I prefer a custom tune over a canned tune, I personally met up with BlackBear and he tuned my truck from the passenger seat while I drove and followed his instructions. Updates are free for life. So if I change gears or tires, he'll update the tune to recalibrate and account for those changes performance wise. Diablo has canned tunes and also does that too, Lew is his name.
@kbuskill

EXCELLENT, I HAVE CAPLESS GAS PORT.
CAI IS BOUGHT, BUT WILL B RETURNED.
FOR THE REAR END I THOUGHT IF I JUST CHANGED MY GEARS UP SOME I COULD GET SOME MORE UMMPH. IT SEEMS LIKE I HAVE TO MAKE IT GO. I DON'T KNOW IF CHANGING GEARS IS THE WAY TO GO OR NOT. GOTTA DIG SOME MORE ON THAT.
I HAVE ALWAYS DRIVEN A RAM 5.7 FOR THE LAST 13 YEARS (4 OF THEM ALL NEW AND RAN LIKE A RAM). JUST USED TO THE GO.
DEFINITELY GONNA DO A TUNE PROBABLY IN AMARILLO. IF U HAVE LEWS NUMBER PASS IT ALONG, YOU GUYS HAVE BEEN GREAT, THX FOR ALL THE HELP.

HAPPY THANKSGIVING.

 

[swathdiver]

EXCELLENT, I HAVE CAPLESS GAS PORT.
CAI IS BOUGHT, BUT WILL B RETURNED.
FOR THE REAR END I THOUGHT IF I JUST CHANGED MY GEARS UP SOME I COULD GET SOME MORE UMMPH. IT SEEMS LIKE I HAVE TO MAKE IT GO. I DON'T KNOW IF CHANGING GEARS IS THE WAY TO GO OR NOT. GOTTA DIG SOME MORE ON THAT.
I HAVE ALWAYS DRIVEN A RAM 5.7 FOR THE LAST 13 YEARS (4 OF THEM ALL NEW AND RAN LIKE A RAM). JUST USED TO THE GO.
DEFINITELY GONNA DO A TUNE PROBABLY IN AMARILLO. IF U HAVE LEWS NUMBER PASS IT ALONG, YOU GUYS HAVE BEEN GREAT, THX FOR ALL THE HELP.

HAPPY THANKSGIVING.

Amarillo is where Precision Transmission is and they can change your gears. You'll definitely wake up the 5.3 with a 3.42 or 3.73 gear set!

 

[John Day]

Prayers sent on high John. GMCs should all come with the G80, check your RPO sheet, this is the combo locker/limited slip. Go for 3.42 or 3.73 gears and get a BlackBear tune. Headers will make it loud up front, you'll probably be happy enough with the extra 35+ horses and the gearing.

If you have E85 stations around, you can add the components from the 2015s and instantly be able to burn the corn which is free horsepower. A standard L83 picks up 25 horses burning E85 over gasoline. Torque surpasses 400 foot pounds too.

Glad you're still with us, that Wuhan Flu is no joke if not caught early for those of us with other ailments. My oldest daughter had it and it barely slowed her down.

James if I go to the different gears will I have to change the entire rear end?

 

[kbuskill]

Here is Lew's info...

http://www.diablewtune.com/package_deals.html

I went this route because I already had a Diablo Sport tuner.

If I didn't have the Diablo tuner I would probably go with Black Bear Performance because they have more options in the tune.