5.3 Dyno Values: 07-09 Vs 2010

[music]

Not sure why, but look at the difference Hypertech measured stock. Not trying to advertise for them (I have not used their product), but their stock numbers for the two motors is very interesting, and do not match what GM reports in their literature (almost identical values @ crank). The two differences on the newer model would be VVT and the 6L80e. The other (obvious) difference is different measurements on different dates (and possibly even an updated or different machine). Interesting...

 

2007-2009 5.3L

http://www.hypertech.com/PerformanceGraphs...kSUV___5_3L.pdf

 

2010 5.3L

http://www.hypertech.com/PerformanceGraphs...GM_TruckSUV.pdf

 

Edit: didn't know where to post this?

[DwayneJ]

I don't trust companies like this dyno testing or magazines for that matter. I have been able to identify specifically how tests were manipulated in some cases.

 

That said the fact the 6speed lacks a 1:1 gear means the tranny gearing tested was not the same between the two tests.

 

The 4L60E the 6speed replaced dates back to the 80s as a 700R4. I would strongly suspect reduced hp to turn the 6speed was a priority in the redesign.

 

A different dyno can play a HUGE role in numbers too, use some cheap POS like "land and sea" and they produced grossly inflated numbers where a good loading dyno like a Superflo or Mustang will produce lower number. I also did not see whether the corrections applied for weather were SAE or STD. Lots of people like STD correction because it is a higher number, but these days the proper standard is SAE.

 

My experience lies mostly with the mid 90s Caprice/Impala, Tornado did a dyno test with one of those on TV, the guy watched the readout as he ran the car and on the before test held the throttle back a little, in the after test it made what a bone stock car actually made, about 220hp to the wheels(260 at the crank). One magazine did a Granatelli MAF test and if you read with an open mind they admitted they changed the air filter at the same time and that the old one "might have been original". Well gee no wonder the car picked up power when they put a junk part on it, they replaced a plugged air filter.

 

FWIW the Hypertech has been documented to SLOW DOWN the LT1 stuff I usually play with.

[music]

Thanks Dwayne. I have *zero* experience w/ chassis dyno measurements, and hadn't really thought too much. Looking at a bit of info on it just now (good 'ol Google), I can see the range of variables involved and the large uncertainty introduced by machine design and operator decisions. Apparently, an automatic must be run at a speed where WOT doesn't cause a downshift, but I have no idea how they do that? The minimum speed to prevent a WOT downshift on the 4L60 in 3rd would be over ~140 mph (under load). 4th on the 6L80 would be worse. How do they keep the TC locked and "in the same gear" at WOT under load?

[vettelovralexand]

Thanks Dwayne. I have *zero* experience w/ chassis dyno measurements, and hadn't really thought too much. Looking at a bit of info on it just now (good 'ol Google), I can see the range of variables involved and the large uncertainty introduced by machine design and operator decisions. Apparently, an automatic must be run at a speed where WOT doesn't cause a downshift, but I have no idea how they do that? The minimum speed to prevent a WOT downshift on the 4L60 in 3rd would be over ~140 mph (under load). 4th on the 6L80 would be worse. How do they keep the TC locked and "in the same gear" at WOT under load?

 

Most people are forced to use 2nd gear on the 4l60 and roll into the throttle or use EFI or HP tuners to lock the transmission in gear with the TC locked as well. When my truck was dyno'd the throttle was rolled upwards until finally hitting 100% barely past 3500 RPM, but 3rd gear was used (manual mode to prevent an upshift) instead of 2nd because we had no tuning sofware available to lock the gear or the torque converter.

[DwayneJ]

Yeah basically you need to play with tranny programming to get a good clean 3rd gear pull with the 4L60E. I never locked the converter on the dyno, not that I have spent much time with my car on the dyno. Locking will give a higher HP number but rarely will you actually lock the converter at WOT. The only real reason to do that would be if say at the dragstrip you would otherwise be shifting into OD just before the finish, lockup can buy you a little more time before the shift.

[Jrs580]

I think the new truck dyno looks like it does because they have to retard the timing so much for the engine to be able to run E85.