Generally, yes. I can't imagine someone towing in 4wd mode for long distances, so of course, the exhaust and compression braking would be applied to the rear axle with the exhaust braking force being significantly greater than compression braking.
2021 Tahoe Braking performance?
- Thread starter jboeckler
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NIevo
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At this point I believe he is trolling and not entirely sure how any vehicle system works
SSGUNNER
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Then explain how it works.At this point I believe he is trolling and not entirely sure how any vehicle system works
NIevo
Full Access Member
An exhaust brake literally uses your exhaust to create back-pressure in your engine to slow the rotating mass down, has nothing at all to do with brakes.
Correct.
My point was that on 1 ton HD pickup trucks, the rear brakes for SRW and DRW configurations tend to be similar if not identical. However, most 1 ton DRW HD pickup trucks have diesel powertrains which may have the advantage of exhaust braking.
The exhaust braking is generally applied to the rear axle because most people will tow in RWD mode for their transfer case instead of 4WD. But it also makes sense to apply that braking force to the the rear axle because the rear axle would be loaded with the pin/tongue weight of the trailer. The static weight distribution for a loaded 1 ton DRW HD pickup would be even more biased to the rear of the vehicle compared to most passenger vehicles on the road today.
You would not want to have the exhaust braking force be applied to the front axle in this application.
Likewise, I'd be wary of towing at max GCWR for a 1 ton DRW HD pickup trucks without exhaust braking from a diesel powertrain. I think you could easily overwhelm both the tow vehicle and trailer brakes on mountain passes without exhaust braking at max GCWR for a 1 ton DRW HD pickup.
Going back to load transfers under braking and cornering.
They are related to the center of gravity height. So a front engine front drive, front engine rear drive, mid engine rear drive, and rear engine rear drive would all experience similar load transfers if their mass, CG height, tire grip and wheelbase are the same.
Obviously how much load transfer is related to acceleration. So stickier and grippier tires alter the amount of weight transfer you can have.
The only main difference is really the starting and final percentages. For example if a front engine front drive car has a static weight distribution of 60/40 and the rear engine rear drive car has a static weight distribution of 40/60 with identical weight, wheelbase, and CG height, they would both induce X% weight transfer. Let's suppose that's 15%.
Under threshold braking, the front engine front drive car may end up at 75/25 and the rear engine rear drive would end up at 55/45.
If you've ever driven really well balanced cars on the track, you'd notice how well balanced a 911 GT3 is under threshold/maximum braking. It damn near feels like a 50/50 weight distribution under threshold braking.
Now, the 911 GT3 static weight distribution varies from 39/61 to 40/60 depending on the generation.
They are related to the center of gravity height. So a front engine front drive, front engine rear drive, mid engine rear drive, and rear engine rear drive would all experience similar load transfers if their mass, CG height, tire grip and wheelbase are the same.
Obviously how much load transfer is related to acceleration. So stickier and grippier tires alter the amount of weight transfer you can have.
The only main difference is really the starting and final percentages. For example if a front engine front drive car has a static weight distribution of 60/40 and the rear engine rear drive car has a static weight distribution of 40/60 with identical weight, wheelbase, and CG height, they would both induce X% weight transfer. Let's suppose that's 15%.
Under threshold braking, the front engine front drive car may end up at 75/25 and the rear engine rear drive would end up at 55/45.
If you've ever driven really well balanced cars on the track, you'd notice how well balanced a 911 GT3 is under threshold/maximum braking. It damn near feels like a 50/50 weight distribution under threshold braking.
Now, the 911 GT3 static weight distribution varies from 39/61 to 40/60 depending on the generation.
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I have Yukon 22 with less than 1000 mile, went downhill a mountain that is 10 miles long. I found it very difficult to stop or get the Yukon to slow below 20 mph. I had to use low gear to help and I got a waring message on the cluster saying that brakes are over heating, comparing it to Nissan armada 2017, the Armada was light years better in the same situation. I was really scared I will not make it safely. good thing I was not towing a trailer.
I will not trust it again until I figure out what's wrong.
I will not trust it again until I figure out what's wrong.
Admittedly, 911's have evolved dramatically over the years, and Porsche has continued to refine their typical Macpherson strut front suspension to now double wishbone on the latest GT3. (At what price? $165k+ or something?) The 911 weight distribution hasn't really changed much over the generations given the rear engine/rear drive configuration, but the diabolical lift throttle oversteer of the earlier 911's has been pretty much engineered out. (especially with all of the stability control options) I have driven various cars on a number of road courses. (e.g. Mid Ohio, Watkins Glen, Nelson.) Specifically Corvette, Camaro, Toyota MR 2, a number of 911, Caymen and Panamera cars. The Porsche I found that was the most balanced and fun to drive quickly, was the Caymen. Obviously the mid-engine configuration (along with my old MR 2) gave them a very low polar moment and incredible handling. You can definitely feel the weight of the big 6 rear engine hanging out the back going into a corner, even on a new 911 variant. I have been behind a number of older 911's where the driver went into a corner too hot and lifted...not a pretty sight when they swap ends. Fortunately I only ever saw one roll over.
In any case, we have totally lost sight of the OP's original braking question on his new Tahoe. (non towing situation) I stand by my original statement, that he would notice a huge benefit in braking performance from a more robust front braking system, without touching the rears. 6 Pot stationary calipers, and if his wheels allow, another inch or so larger diameter rotor. All the other stuff is nice to talk about, but will offer him little benefit in his application.
In any case, we have totally lost sight of the OP's original braking question on his new Tahoe. (non towing situation) I stand by my original statement, that he would notice a huge benefit in braking performance from a more robust front braking system, without touching the rears. 6 Pot stationary calipers, and if his wheels allow, another inch or so larger diameter rotor. All the other stuff is nice to talk about, but will offer him little benefit in his application.
