GMP - Matthew

I think the two forums are completely different but at the same time I think any kind of software debate will stur up both beasts lol

dustinr

Yeah, I got crucified and my post frozen the last time I mentioned APR on this board. I have a 996 Turbo X50 and I love APR's product but they don't currently have a tune for the X50. So I contacted APR and they said that if they could use my car they would give me the hardware and tune for free; problem is, I live half way across the US from their facility. So I posted on this board trying to let anybody with a X50 car nearby to APR know that they could go to APR and get a free tune. I was amazed at the amount of flack I got. I was accused of working for APR and trying to market their product and therefore any information that I provided was biased. Plus I got the "there are so many other tried and tested tuners out there like GIAC, why would anyone let them "Practice" on their car."
I'm not sure why there's such resistance to APR on this board but there is... could be they don't sponsor this board so this board attempts to discredit them. But conspiracy theory asside; I asked in one of my posts if anybody could name me another tuner that has a tune in which you can change maps on the fly without having to plug something in to the OBDII and nobody could give me another option, so I'm still a fan of APR.

TB993tt

On Rennlist they are discrediting themselves by saying they can get 700ft/lbs out of standard VTG turbos.....

I already posted the reason, the machine they are using for measuring the torque is not suitable for measuring this load of torque and gives silly numbers - another example is below, an EVO700 measuring a whopping 750ftlbs (out of modified VTGs) which if measured like Porsche do it would be more like 580ftlbs....

GMP - Matthew

TB993TT, this is merely an informative thread about APR's performance software. If you don't believe APR's numbers to be true that is fine, your entitled to your opinion, but please reframe from posting that thei numbers are false unless you are a previous customer of APR and have tried their programming on your 997 Turbo or you are employed by APR. I encourage anyone to either purchase a 6 hr trial or purchase the software complete with a 30 day money back.

This thread is note supposed to be a software flame war so lets just keep this professional and strictly about APR and no one else.

Dustin, I'm sorry your not able to get your tune through APR, How long ago was this post? Are you still in need of software? I would like to help if I can. I can see why moderators would think you were trying to post for the company, maybe I can create a post for you.

TB993tt

Rennlist is a "technical" forum we have always questioned spurious claims.... The torque which is being claimed from stock VTGs is not possible, the measuring tool is wrong, this is not opinion. I have posted a dyno sheet above as an example of how these low loading dynos give spurious numbers.

If you really believe the stock VTGs can give 700lb/ft 952NM then prove it in another way:
Maha LPS chassis dyno or some data logged runs 60-130 would be a start, if 952NM hits the tarmac (or whatever that ends up on the tarmac) it will be pulling mega Gs in third gear - lets see it

I won't refrain from tech talk on Rennlist, being doing it since before 2000

GMP - Matthew

TB993,

APR uses a Dynapack Dyno, Are you familiar with this particular one?

cannga

So for someone new to this, which dyno number should I trust? Is there a particular dyno machine or method that stands out as being more accurate for the Turbo?

Looking at this example by this EVO example, even professionals seem to be tricked??

AAHTT

Can, the only numbers you can trust are acceleration numbers from a GPS based device like PBOX or similar and even those are not 100% accurate, let alone a chassis dyno. the best way would be a test on a sanctioned track.

TT Gasman

I think an engine dyno, as used by the factory, Ruf, RS Tuning is the only way. Chassis dynos numbers are almost worthless IMO.

TB993tt

As TT says a proper turbo specific engine dyno set up is the only way and it has to be set up in a way which controls the intake air temperature to mimic what happens on the road. Ruf and RS use water cooled intercoolers and their own formulae for correction, it is a bit of an art but their numbers are as close to Porsche's as I've seen...

As far as chassis dynos, the Maha LPS seems to do a decent job with the right cooling set up.
Here is my 7 GT2 with 200cell cats and headers. Note how the torque is produced at ~2900 right where Porsche say it should be. Now go back and look at EVERY other tuner's graphs and you will see the torque peaking at much higher revs, maybe 4500rpm - this is incorrect and is because these other dynos are not loading the engine enough to make the torque - this is why these other dynos cannot be taken seriously IMO... simple to see by comparing charts.
If you read the top right of the printout below you will see the Maha has a setting for Otto Mottor, Turbocharged, Air cooled - it is a specific setting to work with the charactaristics of our cars....



FWIW Cargraphic claim 560PS/700NM for the components I have on the car so the torque number looks high, maybe it is not accurate but from my experience it does feel about the right number on the road. Don't know what happened to the other 17.5PS - they seem to have escaped somewhere !

cannga

First, Matthew, please don't get too upset at my slightly OT questions. One, I am a potential customer, two I am sure these posts are bringing more publicity to your thread , and three, the questions are relevant to some degree.

Anthony/Doug,
Thanks. I see what you are getting at. Better to measure closer to the source which is the engine dyno, for less number of "other" variables,and to look at real life evidence -- how the car does. The true bottom line I would think.

cannga

Your post is interesting & helpful and caused me to look up Mustang Dyno and GIAC web site. I am playing a bit of a devil's advocate here only to learn; no bad intention.

1. From both APR curve here and the GIAC curve, are you saying if a dyno shows peak torque to be at somewhere other than 2900, then it is not correct? The GIAC curve shows peak torque at 3700 or so?

2. How could such big names (GIAC, Mustang, APR, etc.) be wrong?

3. Is the Mustang Dyno not a good one compared to Maha?
http://www.mustangdyne.com/performancetuning.htm

dustinr

My original post was back in Dec.

https://rennlist.com/forums/996-turb...free-tune.html

and yes I'm patiently waiting for an X50 tune from APR.

TB993tt

That is what I am saying yes...
So many "tuners" can talk the talk so well (I just read APRs notes on why they are THE best at programming Motornic - impressive words) that is so hard to really get to the truth of the matter. Surely simply if Porsche say that the 997tt engine produces its peak torque at ~3000rpm then that is something we should take as fact (over and above what the tuners tell us) ?

Armed with this fact and knowing that the tuners swear by their dynos why don't their dynos show the peak torque at the correct revs ? It is a serious error IMO it surely negates the rest of the power curve because simply the rollers are not loading up the engine enough for it to give its peak torque - these dynos do not seem suitable for our cars with their specific turbocharged charactaristics - like I said the Maha has the special setting and from my research does seem to be the only chassis dyno to be able to measure accurate Porsche turbo numbers.

The one below has to be the worst one I've seen. I think it is some sort of Mustang dyno, an EVO700 kit on a 997tt, this machine seems to think the peak torque is at 4400rpm and the way the tuned engine delivers its torque (one big surge I would guess) it also measures it at 750ft lbs which is wayyyy to much, in reality it probably has under 600 ft lbs

I just don't think these other brands are set up for measuring the huge torque surge which a Porsche turbo can deliver...... I would love to have a proper explanation from a dyno manufacturer..

Todd/A.W.E.

Toby,

Any load type dyno, whether Mustang, Maha, Dyno-Dynamics, or Dynapak, can be calibrated to show whatever you want them to show. The shape of the curve is linked to the load which is adjustable on all these dynos. The scale is linked to the software correction factors, which is adjustable on almost all these dynos. Therefore, there is not one "right" dyno as they are all at the mercy of their software parameter set-up.

HOWEVER, as long as the software parameters that are used for the baseline are ALSO used for the modification test, the results are valid, REGARDLESS OF SHAPE OR SCALE. Sorry for shouting, but this is an essential concept to understand. The "delta" or difference between the curves is all that matters as long as the load being supplied to the car is not unrealistic.

For example, we could have loaded up the 997 GT2 lower in the curve to produce more boost in that area which in turn would make the low end look more powerful. HOWEVER, such a load caused clutch slippage, which immediately told us we were loading the vehicle in an unrealistic manner. On an engine dyno, there is no clutch to worry about. But there is a clutch to worry about on the street and track, which is where the power is being used in the real world. Thus, clutch spec is an important factor to consider when looking at chassis dyno results.

The only major dyno that does not have variable load control is the Dynojet. Instead, they rely on a rather unconventional mathematical calculation of power as a function of how fast their known roller mass can be accelerated to a given speed. Without a variable load control, realistic adjustment to the vehicle is not possible, resulting in rather "isolated from reality" results, in my opinion and others.