Problem. Low HP Dyno c7

[kprog]

Hello, I have a C7 z51.
With exhaust downpipe and X pipe. both without catalyst.
KN replacement filter
And a Tune.
The truth is that the car works very well.
I have done several tests against a friend's C7. and even mine is a little faster.
Today I went to the dyno and I had a bad surprise.
I expected 15 or 20 HP more than stock. Stock is 466hp "supposedly according to the manufacturer" . Well, I was thinking about 490 hp or so.
The result was 442hp engine. and 317 to the rear wheels. with a torque of 585Nm
Why so little power? It is normal ?
The dyno is from the Maha brand. They are very prestigious.

grafica c7.jpg

[kprog]

I have done the typical test from 40 to 100 MPH.
first in one direction of the road and then just in the opposite direction.
I always get values between 5.6 and 5.7 sec.
It seems like a good time. Is it possible that the Dyno is bad in this case?

[edcmat-l1]

There are too many variables, including an unknown name brand dyno, and no data log, to give an accurate opinion. Without a data log we can't tell if the throttle blade is wide open, how much timing it has in it, what the reported torque is, what the AF ratio is (no wideband on the dyno) don't know what gear it's in, nothing.

[kprog]

repeart

[kprog]

There are too many variables, including an unknown name brand dyno, and no data log, to give an accurate opinion. Without a data log we can't tell if the throttle blade is wide open, how much timing it has in it, what the reported torque is, what the AF ratio is (no wideband on the dyno) don't know what gear it's in, nothing.

ok I'll send you a log.
Registered 40 to 100 mph today + simulates the launch of the Dyno in 5?..
It seems that I see everything well.
A doubt. Is the torque indicated by the log real? I mean, does it have some type of torque meter in the gearbox or engine?
Or is it an estimate that may be false?
Because that would belie the little torque that the Dyno showed.



Keep in mind that the torque that appears on the dyno graph is in NM. which would be 431 lb
On the other hand, the log that I attach shows 680NM

40 to 100 mph and more.hpl

[edcmat-l1]

The 680 torque you see is a command, not a calculation. The calculated torque is much closer to your dyno sheet @ 480ish max.

[kprog]

The 680 torque you see is a command, not a calculation. The calculated torque is much closer to your dyno sheet @ 480ish max.

I am not able to see the value of 480 torque calculated in the log.
where does it say that value?
And what do you think of the log?

[edcmat-l1]

Log doesn't look bad at all. TM kicked in on the 1-2 shift. Other than that the blade stays open and there's not much knock retard. 23 degrees is about as much timing as you want to run in one of these. At least that's my experience.

delivered engine torque.jpg

engine torque.jpg

[kprog]

Log doesn't look bad at all. TM kicked in on the 1-2 shift. Other than that the blade stays open and there's not much knock retard. 23 degrees is about as much timing as you want to run in one of these. At least that's my experience.

delivered engine torque.jpg

engine torque.jpg

Thank you if I saw this value. I think the traction control acted in 2nd gear.
I was referring to later in the log. I accelerate in 5th gear all the time. simulating the launch on the dyno.
I see that this value goes up to 680Nm.
Is it reliable?
If so, this refutes the response on the dyno, since under the same conditions it did not exceed 585Nm.
I think some configuration is more on that dyno.

[04silverado6.0]

I had a 14 auto c7 make 37x bone stock(converter locked) on a md se500xl. I figure this one was low, i guessed 380-390.

[CYN_CRVR]

317 to the wheels with 442 calculated at the engine is a 28% drivetrain loss. That seems too high, even for a torque converter.

I suspect something is up with the dyno reading. Don't these things need to know your trans gear ratio, final drive ratio, and tire rolling diameter in order to measure properly? Is it possible one of these values was read incorrectly?

[kprog]

317 to the wheels with 442 calculated at the engine is a 28% drivetrain loss. That seems too high, even for a torque converter.

I suspect something is up with the dyno reading. Don't these things need to know your trans gear ratio, final drive ratio, and tire rolling diameter in order to measure properly? Is it possible one of these values was read incorrectly?

Yes, I also think that the bank is the problem. He didn't do any configuration. He said it wasn't necessary...
Also, I have a friend with a grand sport. 2017. manual transmission. and when we race, my car always beats him. so I don't think it lacks power.

[kprog]

According to what he says, a 40 to 100 of less than 6 seconds is great for a stock C7... which would only be achieved on its best days.??
Mine always does 5.6 to 5.7
another indication that it does not lack power.


40 to 100 mph r.jpg

[1scls1z]

Dynos are a tool for tuning. Without a baseline number before mods it's kind of useless. The fact that you beat a stock C7 indicates you are making more power. Cat delete and CAI isn't going to gain a ton on a stock car. Newer cars are much more optimized from the factory. If you want to gain some good power, put a flex fuel sensor on it and run E85.

[kprog]

It confirms that the problem was with the Dyno.
I don't set the rotating mass of my car because it doesn't know how many kilos it is.
Does anyone know the weight of the rotating mass?

[Ben Charles]

Tune is fine, don?t chase dyno numbers

[kprog]

Tune is fine, don?t chase dyno numbers

I know... I know you did a good job!
I bought a Dragy. I will send you the time records.

[kprog]

This is my test. I lost some time on the way out. It is on a street road, using the launch control.
I know that you can make better starts without traction controls, having good touch..
But I was more interested in knowing the 60 to 130...
What do you think ?

D16DD8C1-DFF4-45EF-B75F-0C10F84015A9.jpg

[kprog]

Tune is fine, don?t chase dyno numbers

What do you think of these results?

[RobZL1]

Looks about right to me. You could maybe expect to take some off for a glory run, but for a mostly stock C7 60-130 in the 10's is on the money in my opinion.