icyshark

I was first told that my car was 560whp 495wtq.
Another shop said my car was only 490whp.

Here is my mod list:
dual racing valve springs
stainless steel ls7 exhaust valve
mls ls7/7.0L head gasket
front seal
front cover gasket
cloyes timing chain and gear set
camshaft
ls rocker trunion kit
ls7 valve guides
american racing headers w/ titanium coating
american racing high flow X pipe
r&r heads
r&r cam
ported intake manifold
ported throttle body
5 angle valve job
clean and assemble heads
cnc heads
mill heads
install and hone valve guides
install trunion
muffler mod exhaust
airaid intake

I'm confused. Please let me know if I am a victim of fraud.

Thank you! Happy Holidays!

Z2Z

That is a very large difference in numbers. That said, you can never expect the same car to make the same numbers on different dynos. A car wont even make the exact same number in a single dyno session. Literally EVERYTHING is a factor on a dyno run: ambient temperature, humidity, barometric pressure, elevation and of course dyno type and calibration.

All that considered, 70whp is a HUGE difference. How long between the runs? Is your car running well? Have you noticed any loss?

For example, when I had my last car done it made 518rwhp on the in house dyno. About a year later I was at a "dyno meet" with a bunch of Honda friends. Of course they all wanted to see what the "big bad Z06" could really put down. The car made 509rwhp. I feel that it was a perfectly reasonable difference in rated power.

One more thing. There have been guys that made 490+ with just basic bolt-ons and a tune. I would be weary of the second dyno.

Z.06

Are both sets of whp/wtq corrected to the same atmospheric pressure/temperature conditions? or is one or more of the sets at actual conditions? Were the higher whp/wtq numbers from a run with the knock controls surpressed, ie was this the final road tune? I had a shop try to tell me and brag about these numbers on my car, rather than the final tune with all of the engine nannies in place. In my view this is fraud.

Forum members might be better able to tell you what whp/wtq they think your car should be able to put down if you can also provide the camshaft specs and how much if any the compression has been raised by milling the heads as well as who dyno-tuned the engine. The result one actually gets is more than just a list of the parts employed.

Nowanker

The title actually says it all... chassis dyno numbers are unreliable.
Some brands are known to be stingy, some generous. But that is quite a spread...
Cam specs?

atljar

Post both graphs. Correction factors play a big role, as does dyno brand. If the high reading was a dynojet and the low a mustang/eddy current style, then seems about right to me

Unreal

Could be as simple as different brand dyno, corrections or even bad gas. Dyno is just a tool. Don't worry about the numbers.

icyshark

Thank you all very much for your kindness and help.

The higher dyno read was done on 12/15/12.
The lower dyno read was done on 2/5/13.

I am not sure of the cam specs, but it seems like a pretty strong cam.

Thank you!

dcamick

Similar work 06 Z

557.48 Max Power
490.72 max torgue

October runs in Charlotte, NC

Best,
dcamick

TRSCobra

Take it to the drag strip and see what it traps in the 1/4 mile. You'll have a better idea of your power with that.

REDZED2

Dynos mean dick all. Ask my buddy.

icyshark

This sounds very similar to mine. What mods differ on your end?

Thank you for your help!

icyshark

With the first dyno read, what should my 1/4 mile time be?

TRSCobra

132-135ish I believe.