New Personal Best - 2015 Sierra 6.2

slowfive0 · November 15, 2015

2015 Sierra 1500 cc/sb 4x4 Denali - 6.2/8 speed.

Very happy with this truck. It's quiet, smooth, powerful & gets amazing fuel economy!

It's completely stock and weighs 5700lbs. My race weight was 6000lbs. Temps today were mid-40's / 50% humidity.

My best pass was 13.77@99mph. Best 60 foot was 1.91.

Leave at 1200rpm in "4wd Auto" --- "TC" Off, then switch back to 2wd after launch.

8secpumpgasdad · November 16, 2015

That beats my 13.86 @ 98.15. My shuts off just before the end @ 98 by my spedometer. I quess yours doesn't? Do you have the max tow package?

slowfive0 · November 17, 2015

What ambient temp was your run made on? How much do you weigh? Crew cab or double?

No, mine is a Denali so I couldnt get the max tow unfortunately. It has the 3.23.

I hit the limiter pretty hard hence the reason (I assume) it overun the 98mph limiter by 1 mph. I was thinking about that later and wondering what it would run without that stupid limiter. My guess is 13.65-13.70 at 100-101. Pure speculation on my part though ?

sahls01gmc · November 17, 2015

Does it actually disengage without letting off the gas?

Nice time BTW....wow!

slowfive0 · November 17, 2015

Thx.

I'm going to say yes. Because for one, If I leave it engaged longer the acceleration feels a little sluggish. I dont feel that using my normal launch technique.

Also, on my last pass I disengaged it literally on the launch (oops lol) and it spun a tad. The truck had already started to move out but I got a little excited and turned the knob just a few feet from the line. Probably not good for it lol.

sahls01gmc · November 17, 2015

As if drag racing is good on any vehicle! It sounds like it does disengage, but I bet it uses a lot of "force" to do that since pressure is being applied to it.

slowfive0 · November 17, 2015

I went back and looked at all my runs this day and I'm going to say I think it would have run 13.70-13.75 at 100 if the limiter hadn't kicked in. Pure speculation based off of prior run mphs and increments.

It was also interesting that hot lapping didn't seem to affect it much. Heat soak (shutting off engine for a little bit then trying to make more passes) yes. At one point I let it cool down for 2.5 hours. Went out and cut my best 60ft (1.916) but was slower et wise across the board (.022 at the 1/8 & .035 at the 1/4) then my best pass. Weird thing is the 1/8 mile mph was .33 mph higher (then my best pass) but the 1/4 mph was 1.29 mph lower. Any my best pass that day came with me pulling right back around and making another hit! Weird. Maybe tables in the computer (how much timing/fueling for a given IAT) or maybe when I released it out of 4wd auto? I don't know buts it's fun to think about it. Can't wait to do some more

What ambient temp was your run made on? How much do you weigh? Crew cab or double?

No, mine is a Denali so I couldnt get the max tow unfortunately. It has the 3.23.

I hit the limiter pretty hard hence the reason (I assume) it overun the 98mph limiter by 1 mph. I was thinking about that later and wondering what it would run without that stupid limiter. My guess is 13.65-13.70 at 100-101. Pure speculation on my part though

I went back and looked at all my runs this day and I'm going to say I think it would have run 13.70-13.75 at 100 if the limiter hadn't kicked in. Pure speculation based off of prior run mphs and increments.

It was also interesting that hot lapping didn't seem to affect it much. Heat soak (shutting off engine for a little bit then trying to make more passes) yes. At one point I let it cool down for 2.5 hours. Went out and cut my best 60ft (1.916) but was slower et wise across the board (.022 at the 1/8 & .035 at the 1/4) then my best pass. Weird thing is the 1/8 mile mph was .33 mph higher (then my best pass) but the 1/4 mph was 1.29 mph lower. Any my best pass that day came with me pulling right back around and making another hit! Weird. Maybe tables in the computer (how much timing/fueling for a given IAT) or maybe when I released it out of 4wd auto? I don't know buts it's fun to think about it. Can't wait to do some more

What ambient temp was your run made on? How much do you weigh? Crew cab or double?

No, mine is a Denali so I couldnt get the max tow unfortunately. It has the 3.23.

I hit the limiter pretty hard hence the reason (I assume) it overun the 98mph limiter by 1 mph. I was thinking about that later and wondering what it would run without that stupid limiter. My guess is 13.65-13.70 at 100-101. Pure speculation on my part though

I went back and looked at all my runs this day and I'm going to say I think it would have run 13.70-13.75 at 100 if the limiter hadn't kicked in. Pure speculation based off of prior run mphs and increments.

It was also interesting that hot lapping didn't seem to affect it much. Heat soak (shutting off engine for a little bit then trying to make more passes) yes. At one point I let it cool down for 2.5 hours. Went out and cut my best 60ft (1.916) but was slower et wise across the board (.022 at the 1/8 & .035 at the 1/4) then my best pass. Weird thing is the 1/8 mile mph was .33 mph higher (then my best pass) but the 1/4 mph was 1.29 mph lower. Any my best pass that day came with me pulling right back around and making another hit! Weird. Maybe tables in the computer (how much timing/fueling for a given IAT) or maybe when I released it out of 4wd auto? I don't know buts it's fun to think about it. Can't wait to do some more

What ambient temp was your run made on? How much do you weigh? Crew cab or double?

No, mine is a Denali so I couldnt get the max tow unfortunately. It has the 3.23.

I hit the limiter pretty hard hence the reason (I assume) it overun the 98mph limiter by 1 mph. I was thinking about that later and wondering what it would run without that stupid limiter. My guess is 13.65-13.70 at 100-101. Pure speculation on my part though

8secpumpgasdad · November 18, 2015

What ambient temp was your run made on? How much do you weigh? Crew cab or double?

No, mine is a Denali so I couldnt get the max tow unfortunately. It has the 3.23.

I hit the limiter pretty hard hence the reason (I assume) it overun the 98mph limiter by 1 mph. I was thinking about that later and wondering what it would run without that stupid limiter. My guess is 13.65-13.70 at 100-101. Pure speculation on my part though

It was mid 50's when I ran 13.86 and mid 60's when I ran 13.97. Mine is a cc 4x4 with 3.23 gears and have added a pace edwards retractable tanneau cover and bed rug. My best 1/8 mile pass was 8.872 @ 78.89. The temp is supposed to be mid 40's this Sunday so I think I will try it again.

slowfive0 · November 18, 2015

Interesting. I went 14.07 at 96.X in mid 60 temps.

I can't wait to see your results in mid 40 degree temps! ? Kind of funny that a factory speed limiter could potentially hurt 1/4 mile performance. Hopefully, it doesn't impact u too much. Would love to see some 13.50's or 13.60's from a bone stock truck though!

Good luck

8secpumpgasdad · November 18, 2015

Interesting. I went 14.07 at 96.X in mid 60 temps.

I can't wait to see your results in mid 40 degree temps! Kind of funny that a factory speed limiter could potentially hurt 1/4 mile performance. Hopefully, it doesn't impact u too much. Would love to see some 13.50's or 13.60's from a bone stock truck though!

Good luck

Thanks. Sounds like our trucks are pretty evenly matched. A friend of mine has a Yukon Denali with a 6.2 8 speed and he ran consistent 14.0's the same night I was running 13.8s & 9's. I'm pretty sure he is heavier than me though which is why he was a tad slower. I'm trying to talk him into going Sunday to try to get a 13.

Boombastic · November 18, 2015

As I have stated in another forum,that is quite impressive. I am a bit sarcastic and do not mean to be. But my 14 Denali 6.2 ran 14.7 stock in the 1/4 and after adding a supercharger and giving it about 100 rwhp extra it ran 13.5 to 13.7 in the1/4. And coincidentally I have speedometer acceleration videos of my stock 6.2 6 speed goin 0 to 100 mph in low 15 seconds and another vid a 2015 highcountry 6.2 with the 8 speed running 0 to 100 mph in the mid 15 second range. So maybe you were lucky to get a really fast one. Either way, very nice run.

Sooperdave · December 3, 2015

2015 Sierra 1500 cc/sb 4x4 Denali - 6.2/8 speed.

Very happy with this truck. It's quiet, smooth, powerful & gets amazing fuel economy!

It's completely stock and weighs 5700lbs. My race weight was 6000lbs. Temps today were mid-40's / 50% humidity.

My best pass was 13.77@99mph. Best 60 foot was 1.91.

Leave at 1200rpm in "4wd Auto" --- "TC" Off, then switch back to 2wd after launch.

Another one in the 70's! Nice times!!

slowfive0 · April 5, 2019

4 hours ago, sealandsky said:

I'm curious as to your launch technique. Di you use 4WD auto? 2WD? Traction control on or off? I've only given my new Yukon Denali one hard launch from dead stop in the 3 months I've owned it and did it in 4WD auto with traction control "off". I should have switched to 2WD after initial launch but forgot and rode it in 4WD to a 1/4 or so. With TC off I did get some wheel spin on all 4 off the line, then a solid hook.

I was launching in 4wd Auto with the Traction Control turned off. Right after the launch, I would turn it back to 2wd. I would brake torque the converter to 1200rpm.

Still love the truck. Now, it has 142,000 miles Haha. Good luck and post ur results.

L86 All Terrain · May 13, 2019

On ‎2019‎-‎04‎-‎05 at 5:26 AM, slowfive0 said:

I was launching in 4wd Auto with the Traction Control turned off. Right after the launch, I would turn it back to 2wd. I would brake torque the converter to 1200rpm.

Still love the truck. Now, it has 142,000 miles Haha. Good luck and post ur results.

Mine will brake-boost up to 2,000 before the converter wants to pull through the brakes. No tire squeal. Maybe you can squeeze a bit more out of the 60 foot that way? Closest timer to me is 7 hour drive...

slowfive0 · May 13, 2019

Mine went slower doing that. Seemed like 1100-1300 area was the best. My guess would be that the engine is allowed to flash and hit the converter a little harder that way vs being stalled up or loaded up near its limit.