Input or advice from others on cam swap for 6.2L 2011 Yukon Denali

[hagar]

I hear you, but that’s exactly what I did, and it’s working great for me. I’m not trying to debate anyone here. I’m just saying that I have never seen any evidence of what the actual power gains are for VVT at lower RPMs. I hear lots of hand waving and wows, but there seems to be two sides to this issue, and no clear resolution with data.

You mis understood me, unless you kept your vvt system and installed a non vvt cam. I have done lots of vvt deletes, it used to be all I did automatically for years. I meant there is a reason people don't put a non vvt designed cam into a vehicle and still retain the vvt system. A vvt cam is designed differently than a non vvt cam. My point was that tooley advancing and retarding a non vvt cam that wasn't designed for the system, isn't a very good control for an experiment on the benefits of a vvt system.
It is just the internet, I might not even have a car for all you know, just telling you my above average experience from 20 years of building and tuning efi vehicles.

 

[Geotrash]

You mis understood me, unless you kept your vvt system and installed a non vvt cam. I have done lots of vvt deletes, it used to be all I did automatically for years. I meant there is a reason people don't put a non vvt designed cam into a vehicle and still retain the vvt system. A vvt cam is designed differently than a non vvt cam. My point was that tooley advancing and retarding a non vvt cam that wasn't designed for the system, isn't a very good control for an experiment on the benefits of a vvt system.
It is just the internet, I might not even have a car for all you know, just telling you my above average experience from 20 years of building and tuning efi vehicles.

Got it. Thanks for clarifying. That makes sense. I still wish there was a good set of data points for an otherwise similar cam between VVT and non-VVT to be able to isolate just how much gain it really offers down low.

 

[hagar]

This thread is a great resource that I wish I'd had when I did mine a couple of years ago. I'm still happy with the setup I landed on though. Cam Motion Stage 2 truck cam (3-bolt), Chevrolet Performance LS7 lifters with BTR beehive springs and moly pushrods. Just finished a 2500 mile camping trip through the northeast pulling our 7500 lb camper, and never ran short on power anywhere. On a few long grades when I had to downshift to 3rd, I had to keep my foot out of it or it'd keep accelerating.

Side note: I have never been able to find a chart or performance data for VVT vs non-VVT at lower RPMs where it's supposed to be most effective, so I'm still skeptical of its benefits outside of fuel mileage. I also have a 2007 XL Denali that still has the stock cam and VVT and the 2012 with the 3-bolt cam will outrun it off the line pulling the same camper, all the way through the rev range. On the same highway entrance ramp near my house, I'm 10 mph faster merging onto the highway with the 2012 than I am with the 2007 when towing. The only significant difference is the cam. And both are Black Bear tuned for premium fuel.

What cam is in the 2012?

 

[hagar]

Got it. Thanks for clarifying. That makes sense. I still wish there was a good set of data points for an otherwise similar cam between VVT and non-VVT to be able to isolate just how much gain it really offers down low.

Here is a back to back test with just a stock cam. The thing about the aftermarket vvt cam is it still pulls super hard down low, much harder than stock does. I don't doubt your 2012 pulls harder than the 2007 if the cam is aftermarket. More power pulls harder for sure. That's not to say it wouldn't be even better if it was a vvt aftermarket. The key is you are super happy with the cam, I am sure it works great!

GM Gen IV VVT Dyno Data

Since its release, the benefits of GM Gen IV Variable Valve Timing (VVT) technology have been unknown to the performance aftermarket. Mast Motorsports recently conducted testing during the development of our L92 turnkey crate engine package to determine the performance gains of the GM Gen IV cam...

www.pro-touring.com

 

[Geotrash]

Here is a back to back test with just a stock cam. The thing about the aftermarket vvt cam is it still pulls super hard down low, much harder than stock does. I don't doubt your 2012 pulls harder than the 2007 if the cam is aftermarket. More power pulls harder for sure. That's not to say it wouldn't be even better if it was a vvt aftermarket. The key is you are super happy with the cam, I am sure it works great!

GM Gen IV VVT Dyno Data

Since its release, the benefits of GM Gen IV Variable Valve Timing (VVT) technology have been unknown to the performance aftermarket. Mast Motorsports recently conducted testing during the development of our L92 turnkey crate engine package to determine the performance gains of the GM Gen IV cam...

www.pro-touring.com

Wonderful! That’s exactly what I’ve been looking for, thank you! And if I’m understanding you correctly, an aftermarket cam ground specifically to take maximum advantage of VVT can have even more gains? That’s terrific.

It was also my understanding that the phasing was pretty binary - either fully advanced or fully retarded, but it seems that’s not the case?

 

[Geotrash]

What cam is in the 2012?

It’s a Cam Motion Stage 2 Truck Cam specifically for the 6.2:

 

[hagar]

Wonderful! That’s exactly what I’ve been looking for, thank you! And if I’m understanding you correctly, an aftermarket cam ground specifically to take maximum advantage of VVT can have even more gains? That’s terrific.

It was also my understanding that the phasing was pretty binary - either fully advanced or fully retarded, but it seems that’s not the case?

The cam angles are in a large table that references both engine rpm and load, there is full control from idle to red line, there are also separate timing tables that modify spak from the normal base timing based off the various cam angles. That is why you see the peak power finish the exact same, yet the difference below is very uniform in its gains up until that point. So that pull starting at 2 thousand rpm would be retarded 18 degrees, then at 2200 it might be -17 degrees, then at 2400 it might be -16, and so on, until it reaches the point where the cam being locked static, is at, and they become the same power.
And yes, an aftermarket version follows the same pattern, just in a higher amount. The peak power from a vvt 2 l92 tsp cam will be around 80 hp more than stock, but it's average power follows suit along the path to that peak power.

 

[Geotrash]

The cam angles are in a large table that references both engine rpm and load, there is full control from idle to red line, there are also separate timing tables that modify spak from the normal base timing based off the various cam angles. That is why you see the peak power finish the exact same, yet the difference below is very uniform in its gains up until that point. So that pull starting at 2 thousand rpm would be retarded 18 degrees, then at 2200 it might be -17 degrees, then at 2400 it might be -16, and so on, until it reaches the point where the cam being locked static, is at, and they become the same power.
And yes, an aftermarket version follows the same pattern, just in a higher amount. The peak power from a vvt 2 l92 tsp cam will be around 80 hp more than stock, but it's average power follows suit along the path to that peak power.

Fabulous! The heads on the L92/L94 flow so well that it's silly not to take full advantage of it.

Well, I suppose there is nothing keeping me from going back to VVT someday. I don't welcome the prospect of tearing back into it, so I'll probably leave it as-is for some time. But it's great for others to have this info to make more informed decisions with as they go, so thank you for taking the time to share your expertise and knowledge with us! I'll update my cam swap thread with this info also as I know a lot of people have referred to it in making their decisions.

 

[donjetman]

I like to see the guys on MotorTreads "Engine Masters" tackle this:
https://www.motortrend.com/plus/show/engine-masters/645/

 

[JPS0284]

BTW, my number one trade of customers is HVAC guys, there must be some sort of correlation there if a guy thought hard enough about it.

Lol must be. So I’m getting ready to make the order but I’m a little confused which would be the better choice since I’m not going to be changing out the torque converter….yet.. What would you go with? (I plan on getting a set of the Johnson lifters as well)
1.)TSP L92 Stage 1 216/228 .600”/.600” 113LSA
2.)TSP L92 Stage 2 220/232 .600”/.600” 113LSA
3.)TSP L99/L92 Stage 2 212/218 .600”/.600” 112LSA