So we sold our '03 Z06 to justify buying a more expensive house... Picked up an '02 Denali and had to tinker. I went with Chokemasters (I mean Flowmasters) new cat-back for the Denali/Escalade. Then I bought the Hypertech Powerprogrammer III.

Off to the Dyno at AZ DynoChip.

With "tune" in place: 280awhp/308awtq
With "stock setting" put back on: 280awhp/310awtq

So, pretty much the same. I called Hypertech, they were, of course shocked! They swore up and down that the 6.0 motor I have had one of the biggest gains they'd seen, around 28awhp and 32awtq (plus or minus). Their test truck made around 236hp and then 264 or so with the tune. So mine is showing as quite a bit higher either way (and it's all-wheel drive).

One thing to note: My A/F was around 12.2 with the Hypertech.
A/F on the "stock" setting was around 14.0. Actually was at 16.1 @ 2800 and slowly dropped.

Maybe the hi stock HP/TQ was there because it was too lean? Not sure... Strange to see then #'s so close.

One thing the Hypertech did do is extend the power from the low 5200rpm shift point to 5900 (where I set it) and changed the shift firmness so that it doesn't bog and detune at each shift. BIG differnces there for sure. But the lack of power gain, and the difference in A/F ratios was very strange. Usually an aftermarket tune will set your A/F higher than stock. This actually corrected it.

Anyone else have this kind of experience?

 

Pretty interesting results. Did you happen to have any sort of scanner hooked up to see the actual timing events and knock retard? Were there non-peak gains with the hypertech?

That 280 number isn't too far off what some 6L trucks are making. With the catback, I'd say thats about right.

 

It was a "tailpipe" sniffer for the A/F ratio. No scanner. There really were no gains across the board. On the stock program, at the 5200rpm shift point, the power would dip down, say, 15hp. With the shift point set to 5900, there was no dip in power during the shift and the power curve continued out to the 5900rpm and only dropped off about 20hp from the PEAK power of 280awhp at around 5200rpm.

There is no doubt the truck is now faster, but mostly due to the firmer shifting (no loss of power) and extension of the power (out to 5900 where I set it).

Me, and Hypertech, are baffled by the ZERO power gain across the board. This is on the 93 Octane setting. Why the A/F was SO high stock, I'm not sure. Hypertech said they always see a leaner graph than stock.

So 280hp is about correct running through all-wheel drive? Or is that with 2-wheel drive?

Next I need an intake. Then I'll retest both "Hypertech" and "Stock" again but with an intake this time. Then again, I'd rather find a nice used Supercharger!

 

Did you dyno before the tune? Maybe the previous owner had a programmer on it also. Did you reset the PCM after you took the tune off? I think you never got entirly back to the stock settings.

 

im sure one of these two things happend

 

No, the truck was bone stock.

1. I put the Hypertech program on first. Ran the dyno.
2. I put the truck back to stock, let it cool to about the same temp as I started, then dynod again.

As far as resetting the PCM, Hypertech said this was not necessary. To show that it WAS set back, I have the dyno showing the truck shifting at the stock 5200rpm, the dip in power at the shift, and the 108 (or whatever it was) Governer. With the program I set: 5900rpm shift, firm shifting, and a 128rpm governer.

Don't forget the HUGE difference in A/F from stock to Hypertech. Hypertech being fatter and more where it should be, and stock showing way too lean. This was the case with my '00 SS as well, far too lean bone stock. Thus the pinging in the SS in the hot weather.

I'm not saying you're wrong, just giving the facts. I'm still shrugging my shoulders. The Hypertech did EVERYTHING it was supposed to, changed all teh different aspects, yet showed no gains in HP or TQ...

 

Pretty much. I bought a HPP-III for my '03 5.3 and all I noticed after installing it was detonation. When I called them and asked for dyno graphs for an 03, it was apparent that they knew there was little gain because it took two calls to finally get them to send me the graphs. When I got it, it only showed a 4 hp gain for 87 tune and a 7 hp gain for 93 tune. About the same for torque also (and I'm sure they picked their best results to send me). I removed it and got a custom tune. Big difference!

 

Strange. That's exactly opposite of what I show. My A/F went DOWN (less chance for detonation/pinging/etc) from the factory tune.

 

I think there was too much timing advance.

 

Yep, for sure. The Head Tech at Hypertech told me they add timing which increases the A/F ratio which in turn adds power. Why stock was higher than with the Hypertech in my case baffled him...