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

[iamdub]

on that note why did gm make so many different mounts for a ls. ugh, a Gen 1 sbc used the same clam shell mount from 1960 to 1990 and never failed. just sagged a little.


on a cost note. I replaced my c6 mounts after I tore one and fluid went everywhere for less than tahoe mounts lol.

people be crazy with prices.

I can see them changing the design to combat sagging. Maybe the rest is packaging? All I can offer is that I learned there are two different versions of mounts for the GMT800 trucks. They look identical, but one is more "heavy duty" for the 4WD and maybe trucks versus the wagons (SUVs). Maybe it's a stiffer rubber? They're designated by a strip of red paint on 'em. It's what my bro's truck had and what I put back on it.

 

[mikez71]

I swear they're the same as a standard GMT800 mount. Or, a GMT800 mount would work just the same. Does anyone know any different?

if its anything like gm alternator part numbers you're probably right!

Some ebay listings show the same mount for various gmt800 and gmt900 trucks. The gmt800 mounts look different than the h3 (though very similar) so I never did order one to compare.

Looking at pictures, I feel the gmt800 mount maybe a tiny bit shorter than the H3 mount...

 

[j91z28d1]

You mean on the Gen 4 trucks with AFM, yeah?




You can't beat GM up too badly over it. The EPA has steadily been tightening down on them to improve the fuel mileage of their SUVs. I think they eked by the standards set forth and released the first iteration of AFM prematurely. They revamped it with considerable reliability improvements around 2010. All considered, the risk of having a first or second generation of AFM still far outweighs any benefits it'd ever return. They just needed the engines to achieve X efficiency in whatever operational testing environments the EPA demanded. Us end users seem to rarely ever experience those operating environments.

as I understand it that's not exactly how it worked or at least a very generalized version.

the epa standards are an average across your fleet. trucks also having an offset factored in based on weight. this is why they kept high mileage small cars around. they needed the mileage to offset the trucks they sold. any mileage these trucks get above 15mpg in the city is just a inter class marketing battle. chevy marketing against Ford type thing. gm has always seemed to go mpg while Ford went throttle mapping. you test drive a Ford and that sells you. you do your research and you buy a chevy.

every notice just about every truck gets the same mileage. give or take a few here and there. a 4.3 v6 blazer was rated at the same mileage as a suburban and full size truck. size and weight be dammed.

then jump to say vans and there's a different standard.

on a side note, check a Toyota mini van.. thing weighs as much as my suv. has the same tow rating as my yukon but gets 30mpg. because it has to to complete in its class.

I'm sure there's more to it but it sure feels like all the manufactures loosey agree what mileage they need to build each segment to and then do it as cheaply as possible.

the epa gets a lot of blame cause it's an easy boogy man. but the devil is always in the details.

go check the date when the last administration lifted the mileage requirements, the trucks didn't start getting less mpg they just cut the little car market that was being propped up to meet epa standards.

 

[j91z28d1]

I can see them changing the design to combat sagging. Maybe the rest is packaging? All I can offer is that I learned there are two different versions of mounts for the GMT800 trucks. They look identical, but one is more "heavy duty" for the 4WD and maybe trucks versus the wagons (SUVs). Maybe it's a stiffer rubber? They're designated by a strip of red paint on 'em. It's what my bro's truck had and what I put back on it.

I like the idea of the fluid filled ones for the smoothness. they lasted over 100k miles on my c6 and that's a manual tranny spinning tires and banging gears with 315s on the back. I don't see how these trucks are so ******* mounts. a few of you race around but I bet most of us never go over half throttle more than once a month.

 

[89Suburban]

 

[RooTBeeRthe1st]

Post in thread 'Finally posting a "build" thread. The progression of my stupidity.' https://www.tahoeyukonforum.com/thr...ogression-of-my-stupidity.129351/post-1800142

 

[swathdiver]

every notice just about every truck gets the same mileage. give or take a few here and there. a 4.3 v6 blazer was rated at the same mileage as a suburban and full size truck. size and weight be dammed.

I think you're on to something there! When our trucks were new, the EPA gave the FlexFuel vehicles an MPG rating of 59 miles per gallon for CAFE standards. When that expired, GM quit offering them as FlexFuel vehicles.

 

[swathdiver]

I think they eked by the standards set forth and released the first iteration of AFM prematurely. They revamped it with considerable reliability improvements around 2010.

 

[j91z28d1]

View attachment 405025

ahh the first 4,6,8 I believe right?


I seem to remember the north star was supposed to be able to 50 miles without coolent by pumping just air thru some cylinders while running, effectively becoming air cooled.

sadly that Northstar is better left forgotten thou.


you guys every see the guy that build a running prototype in his back yard of using valve lift as the throttle? I saw a video somewhere years ago, it was some kinda wedge variable ratio. it idled as super low lift and then as rpm went up it added valve lift. no clue if it's true, but I heard gm bought it off him for next to nothing telling him he was going to be famous, only to shelf the project never to be heard from again. no clue if that's real, but I saw the Saab patent and prototype for variable compression ratio head, it was supposed to be ready for production till gm brought a controlling interest in Saab and said it wasn't profitable tech at this time.

 

[j91z28d1]

on a oil note, amsoil released two new oils today, both geared towards hybrids.

something about more additives for condensation and faster pickup for all the stop starts. might be marketing but my volt might run a few times a month and only for a few minutes, and this yukon stop starts like 100 times a day. seems I'm their target audience except both call for 5w30 and they only offer it in 0w16 and 0w20.

I've been wanting to try the 0w20 on the yukon for a while thou.

 

[gooffeyguy]

Not today, but yesterday (Saturday) drove it 539 miles mostly at 80 mph only stopping once for gas and potty break. Cargo area loaded to top of 3rd row seat back, 5 passengers.

 

[alpha_omega]

View attachment 405025

Looks like mine except brown instead of blue. Mine was a ‘77 sedan de ville w/ a 425.

 

[j91z28d1]

Looks like mine except brown instead of blue. Mine was a ‘77 sedan de ville w/ a 425.

never heard from anyone that's actually driven them. they were fwd right? how was that back then. all that tq

 

[iamdub]

as I understand it that's not exactly how it worked or at least a very generalized version.

the epa standards are an average across your fleet. trucks also having an offset factored in based on weight. this is why they kept high mileage small cars around. they needed the mileage to offset the trucks they sold. any mileage these trucks get above 15mpg in the city is just a inter class marketing battle. chevy marketing against Ford type thing. gm has always seemed to go mpg while Ford went throttle mapping. you test drive a Ford and that sells you. you do your research and you buy a chevy.

Honestly and obviously, I've never looked into it that deeply. No need or care to. But, "average across your fleet" seems ridiculous to me. Not doubting as I'm not surprised at all. Is it just a lazy way for the EPA to say "Brand A as a whole is more efficient than Brand B"? Yet, again, more credibility lost.

every notice just about every truck gets the same mileage. give or take a few here and there. a 4.3 v6 blazer was rated at the same mileage as a suburban and full size truck. size and weight be dammed.

I have. Also have personal experience with the 4.3 S-series versus my full size Tahoe. When I switched from my '02 S10 ex-cab to the Tahoe, I caught a little static on the S10 forums about the Tahoe being a gas hog. It gets the same MPG but it's faster, with more comfort and LOTS more room and capability.

then jump to say vans and there's a different standard.

on a side note, check a Toyota mini van.. thing weighs as much as my suv. has the same tow rating as my yukon but gets 30mpg. because it has to to complete in its class.

I'm sure there's more to it but it sure feels like all the manufactures loosey agree what mileage they need to build each segment to and then do it as cheaply as possible.

Like "bro code" to keep the playing field level and easier for everyone?

 

[iamdub]

View attachment 405025

DOD, yes. But is that atrocity even comparable?

 

[iamdub]

you guys every see the guy that build a running prototype in his back yard of using valve lift as the throttle? I saw a video somewhere years ago, it was some kinda wedge variable ratio. it idled as super low lift and then as rpm went up it added valve lift. no clue if it's true, but I heard gm bought it off him for next to nothing telling him he was going to be famous, only to shelf the project never to be heard from again.

Can't say I've ever heard of this. Not the same, but makes me think of the Koenigsegg Freevalve.

no clue if that's real, but I saw the Saab patent and prototype for variable compression ratio head, it was supposed to be ready for production till gm brought a controlling interest in Saab and said it wasn't profitable tech at this time.

Just looked up that SAAB engine. Interesting concept. Have you seen Nissan's variable compression engine?

 

[j91z28d1]

Honestly and obviously, I've never looked into it that deeply. No need or care to. But, "average across your fleet" seems ridiculous to me. Not doubting as I'm not surprised at all. Is it just a lazy way for the EPA to say "Brand A as a whole is more efficient than Brand B"? Yet, again, more credibility lost.




I have. Also have personal experience with the 4.3 S-series versus my full size Tahoe. When I switched from my '02 S10 ex-cab to the Tahoe, I caught a little static on the S10 forums about the Tahoe being a gas hog. It gets the same MPG but it's faster, with more comfort and LOTS more room and capability.




Like "bro code" to keep the playing field level and easier for everyone?

I think they call them Gentlemen's Agreements.

in reality it's borderline Monopoly practices but everyone does it.. if your airport has the big 3 airlines flying into it.. one will raise ticket prices 40$ for a few weeks, the other 2 will watch, if they don't see people making different decisions when buying tickets, they will all raise to match. if they do see it, they know the market is mostly Leisure routes and will lower back down. they are in competition, but not in the normal sense of it.. there's more than enough money to go around and after deregulation they learned pretty quickly they make more money when they loosely work together than when they fight each other to hard. they save that for slot access, they will fight to the death over that.(delta will run you into the ground before they give up atl lol) but once that's sorted out, it's all gravy. the gentleman's agreement is also say American has issues, they can book their passengers in open seats on the other 2 if they have them open at base costs.


across the fleet epa is because the manufacturers lobbied for it that way. it makes both sides look good, I'm sure the epa would want them to make each class as efficient across the board, but that's just not a profitable business practice. so you get an overall rating, kinda like crash standards for trucks are much lower than for cars because it costs more to make a 6k lbs truck perform as well in a crash test as a 2800lb car. just a lot more energy to get rid of. making trucks more expensive to build. the compromise is to rate them all differently so you can market both as 5 star ratings.

thing about the epa in reality is its a government agency and like all government agencies they are in the back pocket of lobbyist. it's good for business to have a Boogeyman to blame for 100k$ glorified minivans, but they run the show for real. the epa in no way is trying to put anyone out of business.

 

[swathdiver]

DOD, yes. But is that atrocity even comparable?

If memory serves, the same guy designed both systems.

 

[j91z28d1]

Can't say I've ever heard of this. Not the same, but makes me think of the Koenigsegg Freevalve.




Just looked up that SAAB engine. Interesting concept. Have you seen Nissan's variable compression engine?

I have a buddy that is a huge Nissan fan boy, like been to the tour in Japan lol.

I've heard of it, but didn't read to deep into it. the s15 I believe it was? probably better done than the Saab haha.

 

[avalonandl]

never heard from anyone that's actually driven them. they were fwd right? how was that back then. all that tq

No RWD.