Ok, i have been wanting to dyno my truck for awhile now, and today i finally had the time to go get it done. The shop is Colvin Automotive here in Austin, they have a Dynojet in floor dyno, not sure what model.

Truck is a 2003 ECSB with the 5.3L/4L60 with 85K miles.

Mods on my truck:

Banks Cold Air Intake Kit
Pacesetter LT'S and ORY
Stock cat back pipe with a Dynomax Ultraflow Muffler 2.5 in/out
05+ efans and 34" rad with a nelson performance harness to control them.
Custom Blackbear Performance Tune.

Truck has stock 3.42 and stock 255/70 16 tires also. First run was done in 3rd, but at only 4600 it hit the 120 speed limiter, second run was in 2nd and the numbers were better, but I'm going to use the first run numbers since it was done in 3rd and its more realistic.

It only got to 4600 but put 244 RWHP and 298 RWTQ, and you can see when it hit the 120 MPH limiter it was still pulling so i think if it had been able to get to 6K the power would be well over 250, maybe close to 260, but again i don't want to speculate and will just go with these numbers as my baseline. Also temps were like 103 in the dyno cell with 21% humidity, not ideal by any means.

Ill get the print out scanned in and posted up in the new few days for all to see.


Next I'm going to install a ported TBSS intake and 90mm TB with no other changes and see exactly what the swap is worth and will post up my results.

The numbers are what i was expecting, as these truck are in the 225 range for a stock 5.3L. Feel free to post up your thoughts.

 

Kinda low for the mods IMO, but the conditions were a big factor I would think. In stock trim back in the day my 5.3/4l60e made 257/281. I would think if you pulled past 4600 your HP would get much closer to mine but with all your mods looked like you gained 19 ft/lbs of torque. Be interesting to see how you would of fared on a cooler day and take it past 4600 rpm.

 

Yeah, def not ideal conditions today for sure, it was hot as hell in the dyno and they only had one small fan on the floor in front of the truck. Next time i go back ill make sure that the speed limiter is alot higher so i can get a couple good 3rd gear pulls out of it.

 

What driveshaft do you have on it? If it's aluminum it'd be foolish to take the limiter off.

 

What were the 2nd gear numbers?

 

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I haven't gotten under my truck very much, but mine has the 2 piece shaft, so I'm pretty sure its steel and not aluminum.

 

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I was looking at the graph, and the numbers on the 2nd run were actually lower on the torque, the HP was the same at 244 and tq was 270, and temp in the dyno was 103 on the first and 104 on the 2nd run.

 

That's a huge torque difference!!

 

Yeah, im thinking the heat in the dyno room was killing my numbers pretty good. I got 2 runs for 50 bucks, so i dont think thats to bad, but i may look around town and see what other dynos there are, not sure it it really makes any differance.

 

why is an aluminum ds a problem above 120 mph?