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Sticky I was going to write a long response to you comments and then thought better of it.
At the end of the day there are many causes of (in)accuracy and (im)precision. Unfortunately a lot of the data I see out of the US is neither accurate or precise. This is compounded by many tuners willingness to knowingly run happy dynos.
I will leave it at this, for Porsche sports cars, particularly those with PDK - the MAHA AWD dynos are the bench mark (independent electric driven speed matched rollers). They are the only dyno that (routinely) you see WHP and run down losses which combined define crank HP and torque. The run down losses (or towing HP) are critical to this assessment.
Unfortunately most tuners queer their own patch by not providing before and after runs done under the same conditions. Many can't even provide adequate air flow etc.
As it currently stands, I am comfortable that X51 equipped S makes around 450HP and 550Nm at the crank. Keeping in mind a Porsche reaches peak HP at between 10,000km and 40,000km. Clearly running one at 5k is going to yield a different result to one run at 20k and 80k.
Sticky I was going to write a long response to you comments and then thought better of it.
At the end of the day there are many causes of (in)accuracy and (im)precision. Unfortunately a lot of the data I see out of the US is neither accurate or precise. This is compounded by many tuners willingness to knowingly run happy dynos.
I will leave it at this, for Porsche sports cars, particularly those with PDK - the MAHA AWD dynos are the bench mark (independent electric driven speed matched rollers). They are the only dyno that (routinely) you see WHP and run down losses which combined define crank HP and torque. The run down losses (or towing HP) are critical to this assessment.
Unfortunately most tuners queer their own patch by not providing before and after runs done under the same conditions. Many can't even provide adequate air flow etc.
As it currently stands, I am comfortable that X51 equipped S makes around 450HP and 550Nm at the crank. Keeping in mind a Porsche reaches peak HP at between 10,000km and 40,000km. Clearly running one at 5k is going to yield a different result to one run at 20k and 80k.
Write whatever you feel I'm more than happy to discuss the topic with you.
I just don't think you have much dyno experience based on our discussion. Instead of speculating you could go get a baseline and then have a point of reference for upgrades like your X51 kit. That way you know exactly what is changing and how.
What data are you referring to as unprecise? Specifically, what data? What is your argument?
I'm sure a MAHA is a great tool and as stated it is popular in Europe. I don't live in Europe.
I'm sure you can just logically deduce a modern 911 does not have 19% drivetrain losses. That by itself should tell you a 368 whp reading is conservative.
The MAHA does not invalidate all other dynamometers in the world. I have my baseline runs and low and behold another base 991.2 made almost the same baseline figures on another Mustang. Very accurate point of reference when comparing using that dyno type.
You keep mentioning losses. How is a chassis dyno calculating them? It's just an equation. Regardless, once again, ask yourself if 19% losses make sense.
I have no doubt your X51 is delivering as advertised and is likely underrated. We'll know better as we get more data out there to reference from various dynos. You had a golden opportunity to test this on your own. I'm sure Australians are just as capable of producing a dyno just as accurate if not more so than a MAHA. Actually, they do. It's called a Dyno Dynamics. I've used this dynamometer and it's fantastic.
I just don't really understand what point you are trying to make. So a MAHA reads low, so what? You need to pay attention to the delta on the same machine to get valid reference points. Considering the volume of Dynojet and Mustsng runs to reference you have a huge data pool available that is more useful than a MAHA at least for me.
P.S.
Regarding your 'happy dyno' comment I can send you a link if you like that explains why dynos read differently and how to interpret the graphs. Dynojets are well known for reading high but the Mustang is well known in tuning circles for being conservative.
Write whatever you feel I'm more than happy to discuss the topic with you.
I just don't think you have much dyno experience based on our discussion. Instead of speculating you could go get a baseline and then have a point of reference for upgrades like your X51 kit. That way you know exactly what is changing and how.
What data are you referring to as unprecise? Specifically, what data? What is your argument?
I'm sure a MAHA is a great tool and as stated it is popular in Europe. I don't live in Europe.
I'm sure you can just logically deduce a modern 911 does not have 19% drivetrain losses. That by itself should tell you a 368 whp reading is conservative.
The MAHA does not invalidate all other dynamometers in the world. I have my baseline runs and low and behold another base 991.2 made almost the same baseline figures on another Mustang. Very accurate point of reference when comparing using that dyno type.
You keep mentioning losses. How is a chassis dyno calculating them? It's just an equation. Regardless, once again, ask yourself if 19% losses make sense.
I have no doubt your X51 is delivering as advertised and is likely underrated. We'll know better as we get more data out there to reference from various dynos. You had a golden opportunity to test this on your own. I'm sure Australians are just as capable of producing a dyno just as accurate if not more so than a MAHA. Actually, they do. It's called a Dyno Dynamics. I've used this dynamometer and it's fantastic.
I just don't really understand what point you are trying to make. So a MAHA reads low, so what? You need to pay attention to the delta on the same machine to get valid reference points. Considering the volume of Dynojet and Mustsng runs to reference you have a huge data pool available that is more useful than a MAHA at least for me.
P.S.
Regarding your 'happy dyno' comment I can send you a link if you like that explains why dynos read differently and how to interpret the graphs. Dynojets are well known for reading high but the Mustang is well known in tuning circles for being conservative.
Sticky, I have been involved in many STI/EVO builds and still have a Cosworth long block in a STI which makes over 500HP without restrictors .
Thus, I know enough about dynos (thats why I understand that top end MAHA dynos electronically control front and rear wheel speeds to match and thus not trip the car electronics e.g. Porsche PDK) and thus (over here) I would only uses MAHA (MSR500/1000/1050) or hub dynos (Dynapack) if I wanted consistent results. This is no longer relevant to me as I'm no longer involved in that form of "hobby".
I have a pretty good understanding of this stuff - the fundamental problem with dynos is without the supporting information, corrections, smoothing through to engine hours, tire condition or even airflow measurements the numbers produced are often at best a good approximation.
Comparisons between results from different dynos, in different locations under different conditions at different times is fraught with misinterpretation (as you know). According to just about every forum, all Porsche cars are massively under rated - they are not, you only have to look at the paperwork that comes with crate replacement engines - they have the rated HP and torque stamped on the box for that specific engine.
Hence my question to you - was there a correction applied to your run with your 991.2 and directed you to the very good article by Sport Auto - on the effect of double dipping (I think it was released Jan 2016). In a nutshell, they concluded that with current generation turbocharged cars its a mistake to apply certain corrections. The result being an over estimation of 40 to 47HP (with respect to the TTS they tested).
Also, this run was completed when it wasn't optimal turbo weather out
Now that it's getting cooler at night here in FL, I'll be heading to the track again and will see what time/trap speed is possible
Very interesting!!
Is there anything similar for Torque?
And have any tuners found what is "safe" for this motor to push the boost up to?
Thank you Arter for the graph.
Im not expert in turbos but heres some fact....Our base turbos making more than my n54 power and i have been daily drive the n54 at 20psi for 40k miles now, no issue so far. I think thats positive news if one wants to raise close to 20 but i wouldnt do it more than 21 on 991.2 base.with supporting mods.
Im not expert in turbos but heres some fact....Our base turbos making more than my n54 power and i have been daily drive the n54 at 20psi for 40k miles now, no issue so far. I think thats positive news if one wants to raise close to 20 but i wouldnt do it more than 21 on 991.2 base.with supporting mods.
The GTS model uses larger turbos to achieve 18 psi without having to spin the smaller base and S model turbos as fast. How much that effects long term reliability and turbo bearing heat build-up is unknown ( by me).
I expect the 992 GTS model to use this same engine and run at 19 psi for 475hp, probably with the same GTS turbos. So Porsche design tolerance at 18 psi should be good for the rest of the engine components up to 20 psi or more ( ingoring long term heat buildup).
Drag racing could tolerate much higher boost psi than track use as there is little time for heat to build up. As I am a track user, probably will not add boost on my GTS until I understand the heat capacity of the car.
The GTS model uses larger turbos to achieve 18 psi without having to spin the smaller base and S model turbos as fast. How much that effects long term reliability and turbo bearing heat build-up is unknown ( by me).
I expect the 992 GTS model to use this same engine and run at 19 psi for 475hp, probably with the same GTS turbos. So Porsche design tolerance at 18 psi should be good for the rest of the engine components up to 20 psi or more ( ingoring long term heat buildup).
Drag racing could tolerate much higher boost psi than track use as there is little time for heat to build up. As I am a track user, probably will not add boost on my GTS until I understand the heat capacity of the car.
I got your point. Im neither drag or track user but certainly wont mind making more power in a safe manner for few fun canyon runs. Techart has piggy back for the base which promises at least 60 hp gain. With smaller turbos in the base, that must be more than 18 psi. They also provide warranty that matches w factory so I guess that gives some comfort. Time will tell.
I got your point. Im neither drag or track user but certainly wont mind making more power in a safe manner for few fun canyon runs. Techart has piggy back for the base which promises at least 60 hp gain. With smaller turbos in the base, that must be more than 18 psi. They also provide warranty that matches w factory so I guess that gives some comfort. Time will tell.
Boost level is what gives the Hp. Smaller turbos just have to spin faster to make 16 psi than does a larger turbo.
base running roughly 16.5 psi should make 430 Hp ( base plus 60 hp)...... just like the S makes 420 at 16 psi.
Sticky I was going to write a long response to you comments and then thought better of it.
At the end of the day there are many causes of (in)accuracy and (im)precision. Unfortunately a lot of the data I see out of the US is neither accurate or precise. This is compounded by many tuners willingness to knowingly run happy dynos.
I will leave it at this, for Porsche sports cars, particularly those with PDK - the MAHA AWD dynos are the bench mark (independent electric driven speed matched rollers). They are the only dyno that (routinely) you see WHP and run down losses which combined define crank HP and torque. The run down losses (or towing HP) are critical to this assessment.
Unfortunately most tuners queer their own patch by not providing before and after runs done under the same conditions. Many can't even provide adequate air flow etc.
As it currently stands, I am comfortable that X51 equipped S makes around 450HP and 550Nm at the crank. Keeping in mind a Porsche reaches peak HP at between 10,000km and 40,000km. Clearly running one at 5k is going to yield a different result to one run at 20k and 80k.
Team - Dyno's are pretty worthless to compare different cars - on different dynos (even if they are the same make/model) on different days in different environments.
For example - a highly boosted engine can have a spread of 100hp over a similarly specced HP NA engine if you go to high altitudes.
Dynos are tools to measure and benchmark on the same car to determine before/after changes and to get a baseline tune.
Comparing cars' dyno results is dumb. Any internet warrior can get the shop to manipulate the corrections to show whatever number they want... I know on here we're all above that but it is a sticky situation we can get ourselves in. Everyone believes their shop knows what they are doing... many tuners learn as they go and many don't know how to do corrections properly on boosted cars. Again - surely anyone that any individual uses would surely be a wizard and know everything but just be open to this not being the case. At the end of the day it doesn't matter. When people have to go here it's because they don't love their cars enough and need to make it something they are not.
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10-28-2017, 10:41 PM
