HP and TQ going haywire

[arnold1]

I finally got my speed working on TS and MLV so I thought I might as well try to see if I can log HP and TQ. Well, it only worked right once as far as I see it. My engine should have about 580--620 crank HP and 550 ft/lb TQ. My first try was 559.3 HP @ 6560 rpm and 534.7 ft/lb TQ @ 5150 rpm. This really showed me MLV wasn’t all that far off and the rpm range was right on. I realized I forgot to add my own weight in the calculation and so I thought I might gain about 25 HP or so when correcting the values.
Next day I drove the same road in both directions logging in 3rd, 4th and 5th gear. After checking my msl I saw I logged a lot of garbage. I now had 601 Hp / 592 TQ both @ 5309 rpm. Depending on which gear I was in max Hp varied between 445 and 601, the same with TQ.

Grateful for any help
Arnold

[arnold1]

Just wanted to add, I'm using the latest Firmware and of course the newest update.
Isn't there anybody that can tell me why HP and TQ are not working properly??

[LT401Vette]

What type of garbage are you referring to?

Or are you more concerned with the power difference in each gear?

It is normal to have less power in lower gears as with the addition torque multiplication there is significantly greater loss. Also the delta RPM is higher so more power goes into accelerating the engine.

[arnold1]

Phil, thanks for chiming in.
I attached a new log where you can see I drove twice in 4. gear and once in 5. gear going all the way up to 162.4 mph. If I would live in the US I would never find out how much HP I have because I couldn't even drive 2. gear up to 6900 rpm which would exceed every speed limit in the states!! This would also mean that MLV would show about 250 HP at most. Sorry but this is no way of showing the correct HP/TQ…

In 6. gear I would even have more HP, is this correct?? I can't drive 6. gear because the ratio is way too long, therefore I would never reach 6900 rpm.
For those of you which can't open my msl log; notice the discrepency in the RPM and HP/TQ range
5. gear 583.8 HP @ 6533 rpm and 553 ft/lb TQ @ 5302 rpm
4. gear 477 HP @ 6750 rpm and 400 ft/lb TQ @ 5250 rpm first run
4. gear 460 HP @ 5750 rpm and 460 ft/lb TQ @ 5750 rpm second run

2014-04-25_11_modified.msl

[LT401Vette]

Generally speaking you will get the best power to the wheels in a 1:1 gear, that will usually yield the lowest losses. Once you get to overdrives, you will have greater losses again.

Another factor to consider here is that the faster you are going, the less of the calculated HP is coming from acceleration and more of it is from the aerodynamic drag calculations. so accuracy of frontal area and drag coefficient begin to count for much more at higher speeds.

[arnold1]

Phil, thanks for coming back and trying your best to explain it to me. Theory and practice are often two pair of shoes.
My 4. gear ratio is 1.0 but doesn’t work at all. You probably looked at my modified log and you can see there is no resemblance between the two 4. gear runs, not in power, torque or rpm. I have others to compare also and have not had one that even looks a little bit alike in 4th gear.
My 5. gear ratio is 0.75 and this comes pretty close at least some times.
Made 3 runs in 5th gear:
559 hp @ 6560 rpm // 535 ft/lb @ 5160 rpm without driver weight
601 hp @ 5300 rpm // 592 ft/lb @ 5300 rpm HP rpm way to low,
584 hp @ 6500 rpm // 553 ft/lb @ 5300 rpm best up to now

TQ should be about 550 ft/lb @ 5350-5550 rpm
HP should be about 600 hp @ 6350-6500 rpm

I also noticed something like a sine curve when looking at the logs. Power and torque on the 5. gear run for example, going up and down like 120 hp.

[LT401Vette]

Are all these runs on the same road, same direction?

any up or down will make a significant difference.

[arnold1]

It's always the same road and the two 4. gear runs are in different directions. The road is top flat and on that day hardly any wind. Look at the first log I posted of the 5. gear run with 601 HP. No way do I have 601 hp @ 5300 rpm, especially 592 ft/lb at the same rpm.

[LT401Vette]

It's just math based on acceleration rate, so where ever you see a swing in power that looks suspect, you will find a less pronounced, but there change in delta speed that will correspond to the power.

[arnold1]

Yes, everything is just math and how the software deals with it, but in my case it doesn't seem to work. There must be something wrong. Not one of the many runs is similar and the only thing left for me is to go to a dyno and see how much HP/TQ I really have. The last run with 583.8 HP looked very promising but I can't go driving 162 mph on a frequented road just to see if I can top that.

Question is, what do the other fellows do, shouldn't work for them either.
Doesn't the swing or sine curve come from the delta speed not being calculated fast enough either through the software or my laptop??

[LT401Vette]

Without looking at the input data for each I really can't say. What I can say is that there is a change to your delta VSS1 to produce a change in hp.

I would make a custom field for deltaVSS1 or probably better a smoothed deltaVSS1. Then you can compare the inputs.

Also you can have it log the components in the power, aerodynamic drag, road, etc. Then you can see how much of the total power calc is based on acceleration vs over coming drag.

In the end for tuning, to get repeatable results, you need repeatable conditions. inclines, wind, temp, etc. That is of course much easier to manage on a dyno than on an open road.