Little_Mata

I recently put a Stage 2 Texas speed camshaft in my 5.3 Silverado and I went to get it tuned. I went to a local shop who does dyno tuning, about 8 hours and $625 later I got my truck back with the dyno sheet. According to the sheet my truck made 270 horsepower and 267 lbft of torque which is below stock. The motor is from a 2004 Tahoe and it only has about 115,000 miles and it has great compression, long tube headers, upgraded valve springs and the cam. Did I get ripped off or is this normal for the tuning process?

Atomic

iTrader: (42)

That doesnt seem right...did the tuner say anything about it? How does it drive? Did you do a before run by chance?

Little_Mata

the tuner never told me anything about it they pretty much sent me home and called me when it was finished, it drives like a normal truck but the shift points are a little low In the rpms and the shift pressure feels a little high from first to second, I did drive the truck before the tune and it felt great with all the shift points and pressures and it felt like the acceleration was a little better before the tune

1FastBrick

iTrader: (17)

First off, Every Dyno reads differently. What brand was the dyno?

There was no before and after results? They didn't tell you or show you what the gain was from stock?

2nd. The factory ratings where at the crank, not the wheels.

Little_Mata

the brand was called “dyno jet” and no they didn’t give me a before and after sheet it was just the results after the tune, and that does make much more sense that the number is recorded at the crank and not the wheels

allenk4

Interesting that the Dyno shop didn’t provide a graph with baseline and post-tune numbers for torque, hp, etc.

295 at the crank w 20% drivetrain loss is 236hp at the wheels for a 4-Wheel Drive.

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- The Vortec 5300 L59 (VIN code "Z") is a flexible fuel version of the LM7. The 2002-2003 made 285 hp (213 kW) and 320 lb⋅ft (434 N⋅m), while the 2004-2007 L59s made 295 hp (220 kW) and 335 lb⋅ft (454 N⋅m).

L59 applications:

• 2002–2006 Chevrolet Tahoe/GMC Yukon

Is it possible that you have the older 5.3L (LM7) was rated at only 270hp at the crank. With 20% drivetrain loss, that leaves you with 216hp on the Dyno.


Can you post a photo of the sheet that provided you?

infam0us1

Probably wanted to tune it first and not do a base pull with the new cam in it.

arthursc2

iTrader: (5)

wow..... lmao

My 02 5.3 L59 rated at 295 put down a whopping 204whp bone stock. That exact same motor with 190k on it makes 302 now; cam/intake/long tubes/exhaust.

Your numbers arent low, your understanding of a dyno, factory ratings and exceptations are too high

270whp is a gain of at least 50whp over factory, no doubt

Nick99Chevy

My bone stock ‘04 2wd put down 242, 260 back when it was new.

arthursc2

iTrader: (5)

But to recap; (aside from dyno differences, altitude differences, tire size differences, gear ratio differences, drivetrain configuration and motor wear), your 242whp dyno was still lower than the stock rated output of 285/295 (depending on fuel options), correct?

Thats the point Im trying to make to the OP. Factory rated output is never seen at the rear wheels unless you have an "underrated" vehicle such as a C8, Terminator, TT-RS; etc. So yes, some cars do lay down damn near their rated crank horsepower to the wheels. GM trucks from yesteryear do not fall into that category, at all. They never have. They consistently dyno 25-30% less whp than rated crank output