Stock Z06 Dyno Tuned
06-23-2013, 09:33 PM
#1
Cruising
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Stock Z06 Dyno Tuned
Went on a trip to Philly this weekend and got convinced to put the car on the Dyno (Dynojet). Car is completely stock; not even an intake. Not much peak horsepower gain (from 321 - 325), but the mid range is higher and there was an excellent torque gain (from 265 - 304). Pulls were done in 3rd.
06-24-2013, 03:25 PM
#3
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What derp derp dyno did you take it to? Dyno should be done in 4th, not 3rd (closest gear to 1:1 always). This is why your graph reads low. All else equal, higher gears (numerically) means higher horsepower numbers on your graph.
Last edited by hamhead; 06-24-2013 at 03:28 PM.
06-24-2013, 05:31 PM
#4
Race Director
06-24-2013, 06:13 PM
#5
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Yes, power pulls should be in 4th. This car is completely stock and it was only on the Dyno for fun and to tweak the tune a little; numbers didn't matter. I only stated that the pulls were in 3rd to explain the lower numbers, and clarify that there isn't a serious flaw in the 65,000 mile engine in it
Anyways, I was sharing the graph, because I was curious if it was common to find 40 ft. Lbs. of torque with a tune.
Anyways, I was sharing the graph, because I was curious if it was common to find 40 ft. Lbs. of torque with a tune.
Last edited by Z06_YOLO; 06-24-2013 at 06:17 PM.
06-28-2013, 11:01 AM
#7
Tech Contributor
Seems low for a 405HP LS6.
Most dyno 350-360 rwhp
Here is mine bone stock in 2004.
2004 Z06 - 500 miles - Dyno Jet
Most dyno 350-360 rwhp
Here is mine bone stock in 2004.
2004 Z06 - 500 miles - Dyno Jet
06-28-2013, 11:39 AM
#8
Drifting
Jesus, that is scary that a guy tuning an LSX car doesn't know the car needs to be run in 4th.
I would get that thing retuned ASAP. If you're still in the Philly area, take it over to CSP @ westchester.
I would get that thing retuned ASAP. If you're still in the Philly area, take it over to CSP @ westchester.
06-29-2013, 10:44 AM
#9
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07-07-2013, 02:34 AM
#10
Le Mans Master
Seems the dyno operator isnt very knowledgeable. 3rd gear pull is wrong. STD with smoothing on 0 will be the highest reading numbers in the summer.
The trq being so low is either clutch or tire spin etc. Something just isnt right. I would get it checked out.
The trq being so low is either clutch or tire spin etc. Something just isnt right. I would get it checked out.
07-11-2013, 02:25 PM
#11
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I wanted to clarify a common misconception about how to use a chassis dyno in regards to what gear is used to make the pull. Lets start with the basics.
HP= (TQxRPM)/5252 in this case we will use wheel rpm
Let's say that we use 4th 1:1 ratio and the torque is 300ftlb at 5252 RPM. This comes out to be 300HP.
Now let's use 3rd gear with a 1.25:1 ratio. this gives us 375ftlb (300x1.25 gear ratio). at the same time the torque is increased the wheel rpm is decreased due to the numerically higher gear ratio to 4201.6 RPM now lets plug these numbers back into the formula.
HP=(375x4201.6)/5252 The horsepower is still 300hp at the same engine rpm but slower tire speed. From these calculations we can see that it does not matter what gear the car is in it will still make the same horsepower in 3rd as it does in 4th.
There is a very good reason why everyone uses the 1:1 ratio when doing dyno pulls. The slower the engine speed climbs, the easier it is to make a smooth graph. Using overdrive would smooth the graph out even more however now the dyno is spinning at a much higher rate of speed. Using the overdrive gear of a corvette for instance would have the car traveling above 250mph at 6000 rpm but would only be going 140mph at 1:1.
HP= (TQxRPM)/5252 in this case we will use wheel rpm
Let's say that we use 4th 1:1 ratio and the torque is 300ftlb at 5252 RPM. This comes out to be 300HP.
Now let's use 3rd gear with a 1.25:1 ratio. this gives us 375ftlb (300x1.25 gear ratio). at the same time the torque is increased the wheel rpm is decreased due to the numerically higher gear ratio to 4201.6 RPM now lets plug these numbers back into the formula.
HP=(375x4201.6)/5252 The horsepower is still 300hp at the same engine rpm but slower tire speed. From these calculations we can see that it does not matter what gear the car is in it will still make the same horsepower in 3rd as it does in 4th.
There is a very good reason why everyone uses the 1:1 ratio when doing dyno pulls. The slower the engine speed climbs, the easier it is to make a smooth graph. Using overdrive would smooth the graph out even more however now the dyno is spinning at a much higher rate of speed. Using the overdrive gear of a corvette for instance would have the car traveling above 250mph at 6000 rpm but would only be going 140mph at 1:1.
07-11-2013, 04:16 PM
#12
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I wanted to clarify a common misconception about how to use a chassis dyno in regards to what gear is used to make the pull. Lets start with the basics.
HP= (TQxRPM)/5252 in this case we will use wheel rpm
Let's say that we use 4th 1:1 ratio and the torque is 300ftlb at 5252 RPM. This comes out to be 300HP.
Now let's use 3rd gear with a 1.25:1 ratio. this gives us 375ftlb (300x1.25 gear ratio). at the same time the torque is increased the wheel rpm is decreased due to the numerically higher gear ratio to 4201.6 RPM now lets plug these numbers back into the formula.
HP=(375x4201.6)/5252 The horsepower is still 300hp at the same engine rpm but slower tire speed. From these calculations we can see that it does not matter what gear the car is in it will still make the same horsepower in 3rd as it does in 4th.
There is a very good reason why everyone uses the 1:1 ratio when doing dyno pulls. The slower the engine speed climbs, the easier it is to make a smooth graph. Using overdrive would smooth the graph out even more however now the dyno is spinning at a much higher rate of speed. Using the overdrive gear of a corvette for instance would have the car traveling above 250mph at 6000 rpm but would only be going 140mph at 1:1.
HP= (TQxRPM)/5252 in this case we will use wheel rpm
Let's say that we use 4th 1:1 ratio and the torque is 300ftlb at 5252 RPM. This comes out to be 300HP.
Now let's use 3rd gear with a 1.25:1 ratio. this gives us 375ftlb (300x1.25 gear ratio). at the same time the torque is increased the wheel rpm is decreased due to the numerically higher gear ratio to 4201.6 RPM now lets plug these numbers back into the formula.
HP=(375x4201.6)/5252 The horsepower is still 300hp at the same engine rpm but slower tire speed. From these calculations we can see that it does not matter what gear the car is in it will still make the same horsepower in 3rd as it does in 4th.
There is a very good reason why everyone uses the 1:1 ratio when doing dyno pulls. The slower the engine speed climbs, the easier it is to make a smooth graph. Using overdrive would smooth the graph out even more however now the dyno is spinning at a much higher rate of speed. Using the overdrive gear of a corvette for instance would have the car traveling above 250mph at 6000 rpm but would only be going 140mph at 1:1.
Source.
However, there's another, often overlooked, factor in the brew: rpm and torque are inversely related to calculating horsepower, so changing the rear axle ratio or testing in other than a 1:1 transmission gear seemingly shouldn't change the horsepower numbers. But this doesn't take into consideration the fact that changing gear ratios changes the engine's rate of acceleration. For example: We know that on an engine dyno, if you change a sweep test's acceleration rate from, say, 300 rpm/second to 600 rpm/second, the flywheel power number (bhp) drops due to the faster rate of acceleration. As an engine accelerates at a higher rate, the power required to accelerate the engine increases, and a greater portion is consumed before it gets to the flywheel. Going to numerically higher gear ratios-whether in the trans (testing in a lower gear) or in the rearend-is like increasing the rate of acceleration in a sweep test. Whether this actually changes a given chassis dyno's reported results depends on how the specific dyno manufacturer does its math. For the most consistent results, always test in the same trans gear (generally 1:1) and rebaseline the vehicle after a rear-axle ratio change.
You can see this on any car you do a full quarter mile pull on a dyno with. I'm speaking to Dynojets as they are by far the most common, but the case is similar on any other dyno I've been on.
Last edited by hamhead; 07-11-2013 at 04:24 PM.
07-14-2013, 07:13 PM
#13
Pro
Yes, power pulls should be in 4th. This car is completely stock and it was only on the Dyno for fun and to tweak the tune a little; numbers didn't matter. I only stated that the pulls were in 3rd to explain the lower numbers, and clarify that there isn't a serious flaw in the 65,000 mile engine in it
Anyways, I was sharing the graph, because I was curious if it was common to find 40 ft. Lbs. of torque with a tune.
Anyways, I was sharing the graph, because I was curious if it was common to find 40 ft. Lbs. of torque with a tune.
07-14-2013, 11:11 PM
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There is a lot of criticism being offered up here. The car was not put on the Dyno to see how much power it could make. It is stock for crying out loud. The fuel and timing were just getting tweaked a little. Unless i have this wrong the smoothing value was set at 0 and it looks like a very smooth line to me; relative to some of the other charts i have seen (with a smoothing value of 5, which should be better). Also, (I am going to screw this up) the torque slip was getting adjusted to not limit it. Perhaps despite it being stock the first run the torque slip reduced the power and that is why it picked up 40 ft lbs. from the other stock Dyno charts I have looked at the hp-tq relationship is closer to the final run, so I don't think there is anything to raise concern over. Also, as hamhead's camaro Dyno run shows (approx. 15 hp difference from 3rd to 4th) accounts for the lower hp numbers.
04-12-2017, 08:15 PM
#16
Melting Slicks
This thread is 4 years old
