Jussi

Nice to hear that you can also do maths. I have been playing with these numbers since 2000 when I started to mod my cars more seriously.
And 2004 I published something which also contained these dyno calculations but that is another story..
But why do you still "estimate" your power to 620-640hp because you have more.. If you would have 4WD (using 17% transmission lost) those numbers would mean over 700hps but when using 2WD lost is about 12% and that makes almost devil's power
So you have nice truly +650hp engine anyway

I have checked my OBD speed to GPS and it was +-1 accuracy in 100km/h.
Yes, you were right that if I really zoomed that one and only test where engine was hot, time is exact 6.70s but gear changes were lazy as I said, 0.5s and 0.4s, so they can easily cutted for 0.3s so that would make 6.7-0.3 = 6.4s
And remember that if OBD speed is little late, some milliseconds, it is late from beginning to end, so that little error compensated quite good

So then you also know what means my 666Nm at 7150rpm

biiig-hp

No problem.
Bob is one of the tuners that claim REAL numbers. I don't now how people decide to claim more. I know that I had one of Bob's motors and it put out more power to the wheels on a dyno jet than it did on his fly wheel dyno. Maybe thats where the problem comes.

pole position

Let me just guess, you got your drivetrain loss estimates from a chassis dyno.......lol

Also, you hardly provide facts, there is always a lot of "would" "estimate" " lazy" "error compensation" etc etc in your posts.

Jean

js-911

So I take it you are an engineer or similar, yet you seem to lack a lot of precision in what you say.

It really is not about my engine, I will be happy to say I have 400HP if that it how they feel when driving it, dyno is dyno , and real life is real life. It has 620-640HP true HP to do a 100-200 in 5.6seconds. My runs were done in very hot weather and with less octane than my 705HP ENGINE dyno test, there could be some difference there, but irrespectively, I have a pressure sensing setup, not MAF.

When I extrapolated TB993TT's acceleration data on my model and converted it to Flywheel HP and torque, it was spot on with his dyno sheet, his tuner uses a 3/4 million dollar engine dyno that 99.9% of others cannot afford. So what they see is what they really are extracting from those engines, and the limits they talk about, are also the real limits of hardware and software. I obviously have no agenda in saying this, I am simply being 100% transparent and true.

Since you asked me for data and you say it is simple to calculate, do you mind showing the calculation here and we can then see how much HP is really there in that data that I gave you above ? You answered on a tangent before. I will then tell you how to get the correct drivetrain losses and all.

Your OBD readings pick up the speed from the speed sensor and is as inaccurate as the speedo readings.

For someone who does so much testing and truly believes that 700HP with MAF is "simple" with a pair of Garretts, RS cams and little more, nothing better than an inexpensive GPS logger to test and tune your car, you will have it in 24 hours from the UK, just a suggestion.

Jussi

Jean: yes, I can calculate your data and produce hp/Nm curve to here.
btw.Did you know that OBD speed sensor output is different and more accurate than that analogue or digital speed gauge. I rechecked that today with GPS and OBD 140km/h was 139km/h in GPS.. I haven't checked that at 200km/h or higher because it is a bit risk in public 100km/h limited road. Maybe you can check that at higher speed? but remember, 255($FF) is OBD's max value

Here is my flowtesting from stock 993TT MAF and that Ford Lghtning MAF.
I installed them one after another and made few test runs on road.
You can see how easily stock MAF exceeds its max. value 4.98V if car has a lot power..
I got max value 5.7V and that Ford MAF gave 4.99V and I think it never goes over that - so it has better/safer electrical desing for Motronic.
MAF comparison
So if somebody has running problem with stock MAF and you have more than 550hp, check that MAF Voltage if it exceeds, it might be a reason for that..
And remember that it might occur only in road testing, not in dyno because road test loads car much more (because of wind resistant)

Jussi

Jean: sorry but I just have to correct this statement..
The OBD speed value is pretty accurate. It comes from ABS's speed sensors which updates about 40 times per round..
And it has nothing to do with speedo readings..
See comparison with 5Hz racing GPS and OBD. Speed values
So, when doing horsepower, acceleration or any performance tests with OBD based system, the results must be taken seriously.
My opinion is that, it would be very good way to produce comparability power tests between our cars, instead of speaking and fighting which dyno is best and what these readings are "in true Porsche or RS or etc scales"..

Jean

js-911

The ABS speed sensor measures rotation of the wheel (hub) through a pick up point and calculates the speed, the speed measured will never be as accurate as a GPS based device due to a few uknowns, just exactly the same as a speedometer error which takes it readings from that same sensor (the error is not in the speedo, it is in the data routed to it). Different tire sizes or tire expansion, tire pressure, etc will all be fooling your readings.

Why don't you just post GPS datalogger data and get done with it.

Jussi

What!?, Did you watch that picture I linked?
I have also a speed test where OBD and GPS readings follow each other till 200km/h what was max value of that test..
Speedometer shows much more in these speeds and is not comparable..
So, If I make acceleration test with OBD speed it gives same value than that 5Hz racing GPS based test.
btw.Did you know that GPS's accuracy is in dozens meters?
And, of course, when using bigger diameter tires than standard, that causes error to speed value but I have standard tires

Jean

js-911

Whatever buddy I am not going to repeat it yet a third time , enjoy your OBD2 custom software, as far as I am concerned, it is pretty meaningless to me. Once you get a GPS datalogger, I will be happy to spend more time on this.

Jussi

OK Jean, maybe we are not in same frequency but for other people: I tested and verified those readings with 5Hz GPS datalogger and they are same
And I highly suggest that, for example TB would do his torque/horsepower test with that kind of device. Then we all know what he has and what means "RS tuning dyno reading" in reality

TB993tt

And here is the crux of the matter which we have endlessly debated on here for years
"if" your software works as well as a GPS logger then an "hp test" should give the same curves as the ones I have on my engine dyno printout sheets, I guess it is using data like drag, weight, speed, time over a run say 60-130mph to extrapolate the hp/torque curves, just like a chassis dyno run but done on the road so with real load for that run.
What your software cannot reproduce is that the 550hp my engine has at 5250rpm will still be 550hp (or rather 748NM) if the engine is braked at those revs under load for 30 seconds.....
A meaningless excercise for a multitude of "tuners" but one which produces race winning "real hp" engines.

Jussi

Yes, accuracy is comparable to GPS measurements. We have done many test and in three different cars, car's OBD speed value was same than with 5Hz racing GPS within +- 2 km/h marginal. GPS looks to retard little when accelerating hard and when braking hard its value is little delayed - so I would even say that OBD speed is more accurate, but it is just my opinion and based to my road test datalogging..
And yes, you are right, it uses parameter you listed.
If I simplify that situation, it is like this forum's very popular "60-130 thread testing" but it also observes car's weight and its aerodynamics, in other words it moves all cars to same scale and thus performance comparisions are more sportsmanlike


But If you test car with 6th gear from 2000 rpm to 7300 rpm, that tells very well how good motor's tuning has been done because at those speeds, wind resistanse is tremendous and it loads car enough/much and this test also takes over 30 seconds.
And if you believe that you car remains all its power when engine is cold/normal temperature and after many hours race tracking - you can just make simple dyno test and certify that.
That test separate properly tuned cars like by Porsches or RS Tuning from "not-so-educated-ones" who just add bigger turbos and retune ECU - they might be heat soaked and gives a lot lower hp/Nm reading when hot - but it is not my point, my point is that you can test it.

TB993tt

Your objectives are praise worthy and I see you do appear understand the different "brands" of hp, however........

YOU stated at the begining that you had an unequivocal 500KW/680hp measured using your software, and now you say that your software can uncover the truth as to just how much "real" hp you have- so are you now a little more enlightened that your 680hp may not quite be what Porsche would sign off on their engine dyno ?

You even try and argue with Jean (who seems an experienced realist in this subject) that he must have more hp than he claims based on your own hp findings from your software.

The fact is most people really only want to know that they have the largest hp figure which the tuner can possibly tell them (Brad- quiet at the back ) and will carry on believing it in blissful ignorance until they try and race a "real" hp similar car, then they will get confused or make excuses.....
I do not think people want to test their road cars in the full "heat soak" method, in reality there is little point for a road car, so people will continue to make claims and others (with more knowledge on that specific subject) will continue to dispute them - this is how its always been