What did you do to your NNBS GMT900 Tahoe/Yukon Today?

[Rocket Man]

How did those rear links twist like that?

You must mean the lower control arms? I think someone put a floor jack under them and jacked the truck off the ground.There was no other damage around them, so they didn’t bounce over some concrete barrier or anything. It’s all I can think of.

Nice work @Rocket Man .
You need some shorter sway bar end links for the front.

Lowering Control Arm Sway Bar Endlink with a 1.75 inch Spacer

djmsuspension.com

I ordered some Energy Suspension, shortest they have. I think they’re the same length.

Energy Suspension- 9.8122R END LINK SET WITH HARDWARE,Red https://a.co/d/b2fXM5Z

 

[j91z28d1]

What's it from?

the hybrids. gm says it saves 2hp or something like that. oil pressure specs are much higher too. normal ls min spec is like 7psi hot at 1000 rpm. these min spec is 36psi at 1000 rpm hot.

I forget the 2 engine codes, ones LFA or something like that. Basically a ls2 with afm and odd cam.

 

[mikez71]

Neat. I'm guessing the 2hp savings is at 6000rpm, since it's pushing more pressure at idle?

 

[j91z28d1]

Neat. I'm guessing the 2hp savings is at 6000rpm, since it's pushing more pressure at idle?

no clue haha. Just gm release literature. no details and never seen any dyno tests.

makes sense but if it is at 6k only, doesn't make a lot of sense for a hybrid. I can't imagine anyone is racing around in their hybrid suv haha. mine might have seen 6k twice since I got it. I was guessing it was in the range of the epa test cycles.

 

[Charlie207]

Just ordered some black fender flairs. Gotta love road salt.

 

[Scrappycrow]

a variable displacement ls oil pump.

fins inside instead of gears, and I don't see any pressure bypass. how it changes displacement, I have no idea.

A piston moves the outer ring, causing the outer ring to become more eccentric or less eccentric relative to the shaft. If the ring and shaft were perfectly concentric, there would be no pumping, and as eccentricity increases, the volume of each "compartment" increases, thus increasing output.

BTW, what you are calling "fins" are known as "vanes" in this type of pump.

 

[the_tool_man]

I've been having a weird issue lately. I'll remote start the Tahoe, then when I get in and turn the key on, I get a 'service charging system' message. I turn the Tahoe off and restart it with the key and the error goes away. This issue only happens when I use the remote start but of course, not every time. I have a 250amp Mechman alt, new battery, and really expensive cables. The Tahoe also will drain the battery if it sits more than 3 days. Have any of you guys ever heard of this?

I've had a similar "Service Charging System" message periodically. At first it occurred only when I remote-started it. But eventually it would happen other times, even while driving. I isolated it to either starting or idling for long periods in traffic. I did all the usual things; cleaned terminals, checked grounds, had battery and alternator tested, etc. Finally, I decided to replace the alternator on the hunch that since the message only appeared when the alternator was turning slowly, that it was the cause. Sure enough, I haven't had the message pop up since.

 

[the_tool_man]

Driving to work this morning, I hit a pothole on the interstate, and shortly thereafter got a "Low Tire Pressure" warning. Sure enough, the left rear tire was reading 13psi. I figured I got a pinch flat from the pothole. I slowed to 45, hoping to limp it to an exit about 5 miles away so I wouldn't have to swap the spare on the side of the interstate. Then about 3 miles later, the pressure went back to 35psi, like nothing happened. I watched it all the way to work, and it crept up a couple more psi, as you would expect, as the tire warmed up (it got down to 48degF at home last night). I've had TPMS sensors fail before, presumably due to the battery dying. When this happens, the DIC reads "--". But I've never had a sensor give a false pressure level before. How common is that? I guess it would be prudent to manually check tire pressures every so often just to make sure the system isn't falsely telling you everything is okay.

 

[Doubeleive]

Driving to work this morning, I hit a pothole on the interstate, and shortly thereafter got a "Low Tire Pressure" warning. Sure enough, the left rear tire was reading 13psi. I figured I got a pinch flat from the pothole. I slowed to 45, hoping to limp it to an exit about 5 miles away so I wouldn't have to swap the spare on the side of the interstate. Then about 3 miles later, the pressure went back to 35psi, like nothing happened. I watched it all the way to work, and it crept up a couple more psi, as you would expect, as the tire warmed up (it got down to 48degF at home last night). I've had TPMS sensors fail before, presumably due to the battery dying. When this happens, the DIC reads "--". But I've never had a sensor give a false pressure level before. How common is that? I guess it would be prudent to manually check tire pressures every so often just to make sure the system isn't falsely telling you everything is okay.

I have had them read lower pressure when the battery gets weak, will say 14, 20, etc when it is really normal 36

 

[mikez71]

A piston moves the outer ring...

Can't see piston in picture, thanks for the explanation!

Looking online, some pumps just have a spring to adjust pressure, but some are computer controlled as well.

 

[Rocket Man]

I believe I’m going to need some extra adjustment in my camber adjustment plates after lowering mine. It looks like Belltech makes one that allows for 3* of adjustment but looks like it doesn’t come with bolts and it’s about $140. Does anybody have experience with any kits like this for lowered vehicles that allow for extra adjustment to correct positive camber? I want to have the hardware on hand so when I take it in to the alignment shop they can install it.

 

[89Suburban]

I believe I’m going to need some extra adjustment in my camber adjustment plates after lowering mine. It looks like Belltech makes one that allows for 3* of adjustment but looks like it doesn’t come with bolts and it’s about $140. Does anybody have experience with any kits like this for lowered vehicles that allow for extra adjustment to correct positive camber? I want to have the hardware on hand so when I take it in to the alignment shop they can install it.

Chris @iamdub elongated the slots in his frame to get some extra adjustment.

Growing up doesn't have to suck

Did a full brake job. The front pads were worn to the squealer tabs and rotors were worn so much they had a ridge about 2mm high around the outer edges. I'm really disappointed in the cryo-tempered StopTech rotors. Maybe the Hawk LTS pads are too aggressive for them? Oh well, I got 50K miles...

www.tahoeyukonforum.com

 

[Rocket Man]

Chris @iamdub elongated the slots in his frame to get some extra adjustment.

Growing up doesn't have to suck

Did a full brake job. The front pads were worn to the squealer tabs and rotors were worn so much they had a ridge about 2mm high around the outer edges. I'm really disappointed in the cryo-tempered StopTech rotors. Maybe the Hawk LTS pads are too aggressive for them? Oh well, I got 50K miles...

www.tahoeyukonforum.com

Thanks, that also answers another question I had- do I need to do anything extra to install the belltech kit. I’ll need to elongate those or have the alignment shop do it. The place I’m taking it does all kinds of custom work like this, especially for the 4 wheel guys. I might have them do it. I wont have a place to work on it in a couple days anyway since my driveway will be replaced.

 

[j91z28d1]

A piston moves the outer ring, causing the outer ring to become more eccentric or less eccentric relative to the shaft. If the ring and shaft were perfectly concentric, there would be no pumping, and as eccentricity increases, the volume of each "compartment" increases, thus increasing output.

BTW, what you are calling "fins" are known as "vanes" in this type of pump.

ahh vanes, yes. you'd think I'd know that lol.

the offset makes sense. I found a short clip of one apart. seems the spring controls the volume, no ball and spring bypass style of the gears.



I can only guess that's why it's full bore at idle speed and has 40 something psi. it hasn't it the spring set point yet and the spec is much higher in the manaul. so you know if it's damaged/worn out or not. my guess is it's actual more load on the engine at idle than the gear pump at low speed and lower psi. but these trucks don't really idle, well aren't meant to. anything below 10-20mph the engine is off. so idle load probably doesn't matter. but that 1500-3k range this thing lives it's life at, it can throttle back to run the oil pressure where the gear style pumps more and more with higher rpm and the bypass valve in the pump and pan have to flow enough to keep up.

I can only imagine gm going thru all the hassle to design this pump. had to be more reason than the quoted 2hp. wonder if it did a better job of keeping oil pressure up during the 100s of starts and stops a day these engines see. auto stop is very aggressive. it will shut the engine off any time it can under 30mph. nothing like today's starter based auto stops.

the LT engines use the vane style, but with a pwm signal from the ecm to adjust pressure. I guess so it doesn't idle at unneeded high pressure these do.

interesting stuff. I'm going to have to see how much wear the old pump had after 170k miles. seems like the vanes wearing down would be a down side of this kinda pump.

still left wondering how it would work in a performance engine like a ls3. but there's no aftermarket manufacturers of them, and gm quit making them years ago. what's out there on shelves is all that's left. luckily they are still cheap thou. and what I find, it you put a standard pump on a hybrid it throws low oil pressure warning non stop. don't believe anything oil pressure related in the ecm is adjustable with hptuners on these ecm's.

 

[kbuskill]

Thanks, that also answers another question I had- do I need to do anything extra to install the belltech kit. I’ll need to elongate those or have the alignment shop do it. The place I’m taking it does all kinds of custom work like this, especially for the 4 wheel guys. I might have them do it. I wont have a place to work on it in a couple days anyway since my driveway will be replaced.

Hey Mark,

I assume this is the kit you already found... Belltech Alignment Kit - 4951.

You just reuse your factory bolts and nuts, and yes you need to elongate the holes slightly. The instructions should come with the kit. A rasp type bit on a 90° die grinder makes pretty quick work of it.

 

[Charlie207]

Now I kinda want to get another rig to lower for the warm months.

 

[Rocket Man]

Hey Mark,

I assume this is the kit you already found... Belltech Alignment Kit - 4951.

You just reuse your factory bolts and nuts, and yes you need to elongate the holes slightly. The instructions should come with the kit. A rasp type bit on a 90° die grinder makes pretty quick work of it.

Actually,no. That’s not what comes up; Belltech says the only kit for my truck is the 4957 which comes with offset bushings and bolts and is 3x more $. But in the pictures you can see it uses the same adjustment plates. You’re saying the 4951 kit works, I know who I believe. I’ll order that one. Thanks.

 

[kbuskill]

Actually,no. That’s not what comes up; Belltech says the only kit for my truck is the 4957 which comes with offset bushings and bolts and is 3x more $. But in the pictures you can see it uses the same adjustment plates. You’re saying the 4951 kit works, I know who I believe. I’ll order that one. Thanks.

The offset bushings way over correct for a 4/6 drop. At least with 2" drop spindles.

I'm not sure how low you would need to go to need that much adjustment. Maybe if you were rolling on 13X7 reverse offset Daytons.... lol

 

[CMoore711]

Just ordered some black fender flairs. Gotta love road salt.

Damn…

Ive been putting time and $ into my ‘13 Escalade ESV and it’s coming along great.

I don’t mind that it’s 13 yrs old with 177K miles; But the entire time in the back of head I just dread if/when the body panels start to rust. So far no signs even behind fender liners and back side of rocker panels. Members on here refer to rust as cancer and that’s a great analogy; Because some vehicles get it and some don’t with zero correlation to age or mileage.

 

[Scrappycrow]

Can't see piston in picture, thanks for the explanation!

Looking online, some pumps just have a spring to adjust pressure, but some are computer controlled as well.

After looking at various pics of the pumps on line, I must've been thinking of another variable-displacement vane pump, because you are correct -- there's no piston, just a spring. The spring works against the output pressure from the other direction on the outer wall on the outer ring, pivoting on a pin on the side opposite the spring.

The pump in the 6L80 is arranged similarly:

https://imgur.com/x2NofrI