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Dyno'd my Stock Z06

2257 Views 20 Replies 13 Participants Last post by  Lew
My car has about 3K miles on it and I got it about 2 months ago. The only mod is a B&M. I dyno'd today at 330RWHP and 330RWTQ (SAE corrected). It pulled the EXACT same on each of the three pulls.

How does this compare with others? We had an Autotap on it while it ran and noticed it had 4 degrees of knock retard. Any idea why?
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Frank, unfortunately, at least in past releases of the "viewer" software, it excludes many of the features that are evident with the actual dynojet equipment installed in the shop. I don't know why they exclude them but it is not very useful without them.

What would be nice is if we could have a forum just for dyno results. Far too often those of you that post your dyno results do not provide any supporting information, like whether or not the #s are "corrected", what rpm at the peaks, mileage, engine temp, etc.

I am also very interested in the "shape" of the HP and TQ curves and the amount of "smoothing" applied to those curves.

Picture images of actual graphs provided by the Dynojet shop would be ideal. Such as in case of FRC Tom's dyno results (see his post in this tread), which shows a lot of these details.

On "modified" cars it is also important to see if there were any tradeoffs in the power band. In Tom's case, his results look very good and mods did not adversely affect low to mid range power characteristics.

Unfortunately, most dyno operators do not bother to capture the low end torque & power characteristics much below 2500 rpm. With as much torque as the LS6 makes even down low, it would be interesting to measure at so-called "cruising" speeds at around 1500 rpm or even lower. It's just a matter of initiating the test at lower rpm and then triggering the capture buffer built in to the Dynojet software a bit earlier during the roll on test.
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Interesting. If I apply the normalized drive line loss factor of 14.3% derived from the 1st car (Netjunkie), to the last (Rwdyryd), and both cars are stock, then these cars differ (mathematically), as follows.

At normalized loss factor of 14.3%:

Netjunkie's LS6 @ 3k miles = 385 hp
Rwdyryd's LS6 @ 2k miles = 397 hp

Another way to look at the same comparison, is to derive the loss factor in the opposite way. By so doing, then the "normalized" loss factor becomes 11.6%, a more conservative figure, and perhaps more realistic.

At normalized loss factor of 11.6%:

Netjunkie's LS6 @ 3k miles = 373 hp
Rwdyryd's LS6 @ 2k miles = 385 hp

Another approach would be to average the two calculated loss factors which results in 13%.
(Some people believe the loss factor is as high as 16 or 17%). Then the comparison between these two cars becomes:

Netjunkie's LS6 @ 3k miles = 379 hp Rwdyryd's LS6 @ 2k miles = 390 hp

Applying a 13% (average) LF to a corrected dyno measurement of 335rwhp equates to 385hp at the flywheel. A lot of the numbers we have seen posted on this board higher than
that are from "modified" cars.

However, an essential piece of information that could help to explain differences in dyno measurements of stock Z06s is missing and poorly compensated for by the dyno measurement system. It is internal engine operating temp at the time of each test. A good approximation of this temp is the coolant or oil temp in the block. What the dyno instrumentation monitors and factors into its compensation algorithm is the OAT. This is "roughly" equivalent to the MAT, which is somewhat pre-heated to a higher temperature which the dyno cannot accurately determine.

What all this is getting at is the relative importance of doing dyno testing at a "controlled" or nominal engine operating temp. Then, for comparison purposes, either for the same car that is subsequently modified, or between cars that are 100%stock, Dynojet measurements in terms of peak values are more relavent.
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