Are 911's scared of dynoes?
04-25-2011, 12:34 AM
#1
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Are 911's scared of dynoes?
This sounds funny, and kind of like I am being a smart ***, but i am not.
My car will be back in 36 hours, and i want to break it in, then do some exhuast and a cold air. car already has a APR tune.
I see dozens of posts about this cold air, or that, but i have not seen ONE actual thread with mods done and a dyno vid or sheet to go with it.
I Have a corvette i drag race, and i can say, i know how everything i do to it effects the car either by effecting the E.T or using a dyno if track time is not available at the time.
I realize, the 911 is not a drag car. I did not buy it for that or expect to se any guys using them for that on here, but for as much as you guys spend, and soon me included, you would think i would see actual dyno time being used to judge parts..
My car will be back in 36 hours, and i want to break it in, then do some exhuast and a cold air. car already has a APR tune.
I see dozens of posts about this cold air, or that, but i have not seen ONE actual thread with mods done and a dyno vid or sheet to go with it.
I Have a corvette i drag race, and i can say, i know how everything i do to it effects the car either by effecting the E.T or using a dyno if track time is not available at the time.
I realize, the 911 is not a drag car. I did not buy it for that or expect to se any guys using them for that on here, but for as much as you guys spend, and soon me included, you would think i would see actual dyno time being used to judge parts..
04-25-2011, 02:34 AM
#2
Race Director
Porsche 911's aren't scared of dynos, but maybe the people who spend big bucks trying to improve on the factory are afraid to find out that their money didn't buy them anywhere near as much as they thought it would or the claims of aftermarket performance parts would have them believe. 
You mention adding a "cold air" system to your 911 for example; you realize, of course that the 911 already has an exceptionally effective cold air system as standard equipment and the ability to improve on it is debateable.
You also mention the comparison to the Corvette. The standard LS3 engine develops 430HP from 6.2 liters. By comparison the Carrera S makes 385HP from only 3.8 liters or over 100hp per liter from a normally aspirated engine compared to about 70hp per liter from the Corvette. The point is that Porsche is squeezing a heck of a lot of horsepower from a relatively small displacement unlike the much bigger engined Corvette which has more room for development. To get the additional 23 HP in the GTS, or the added 50 HP in the GT3 requires significant (and very pricey) modifications. When someone thinks they can accomplish the same type of gains with just a change of exhaust or a different air cleaner they are fooling themselves, IMO. All things considered, if it was that easy to make extra power the factory would be doing it that way. And maybe that's why people aren't doing dyno tests and publishing the results of their mods; ignorance is bliss!
Just my own biased $.02.
You mention adding a "cold air" system to your 911 for example; you realize, of course that the 911 already has an exceptionally effective cold air system as standard equipment and the ability to improve on it is debateable.You also mention the comparison to the Corvette. The standard LS3 engine develops 430HP from 6.2 liters. By comparison the Carrera S makes 385HP from only 3.8 liters or over 100hp per liter from a normally aspirated engine compared to about 70hp per liter from the Corvette. The point is that Porsche is squeezing a heck of a lot of horsepower from a relatively small displacement unlike the much bigger engined Corvette which has more room for development. To get the additional 23 HP in the GTS, or the added 50 HP in the GT3 requires significant (and very pricey) modifications. When someone thinks they can accomplish the same type of gains with just a change of exhaust or a different air cleaner they are fooling themselves, IMO. All things considered, if it was that easy to make extra power the factory would be doing it that way. And maybe that's why people aren't doing dyno tests and publishing the results of their mods; ignorance is bliss!
Just my own biased $.02.
04-25-2011, 04:24 AM
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I am not comparing. although i think the 3.8 is amazing. I just wish I could find real data. i also have a somewhat knowledgeable automotive background. There is more to things like aftermarket exhuast and intakes than Porsche "leaving hp on the table" like i keep reading the purists keep saying. There are In cabin noise and at speed and passing noise levels Porsche HAS TO ABIDE BY on street dwelling autos. Aftermarket items do not have such worries and most of the time, this is what holds the factory parts back in comparison to the aftermarket peices.
Other things guys dont seem to get it power % gained.. not total numbers.. and ALSO, peak power is NOT what i am interested in. I would never buy a exhuast that offered me 15 peak hp but lost 5-6 hp in the 3-5 k range. these are the things i would like to see in real world dyno comparisons.
Other things guys dont seem to get it power % gained.. not total numbers.. and ALSO, peak power is NOT what i am interested in. I would never buy a exhuast that offered me 15 peak hp but lost 5-6 hp in the 3-5 k range. these are the things i would like to see in real world dyno comparisons.
04-25-2011, 10:23 AM
#5
Rennlist Member
This sounds funny, and kind of like I am being a smart ***, but i am not.
My car will be back in 36 hours, and i want to break it in, then do some exhuast and a cold air. car already has a APR tune.
I see dozens of posts about this cold air, or that, but i have not seen ONE actual thread with mods done and a dyno vid or sheet to go with it.
I Have a corvette i drag race, and i can say, i know how everything i do to it effects the car either by effecting the E.T or using a dyno if track time is not available at the time.
I realize, the 911 is not a drag car. I did not buy it for that or expect to se any guys using them for that on here, but for as much as you guys spend, and soon me included, you would think i would see actual dyno time being used to judge parts..
My car will be back in 36 hours, and i want to break it in, then do some exhuast and a cold air. car already has a APR tune.
I see dozens of posts about this cold air, or that, but i have not seen ONE actual thread with mods done and a dyno vid or sheet to go with it.
I Have a corvette i drag race, and i can say, i know how everything i do to it effects the car either by effecting the E.T or using a dyno if track time is not available at the time.
I realize, the 911 is not a drag car. I did not buy it for that or expect to se any guys using them for that on here, but for as much as you guys spend, and soon me included, you would think i would see actual dyno time being used to judge parts..
04-25-2011, 10:30 AM
#7
Race Director
[QUOTE=RedBarron2007;8499086] I would never buy a exhuast that offered me 15 peak hp but lost 5-6 hp in the 3-5 k range. QUOTE]
+1000. very good point. So many overlook this.
+1000. very good point. So many overlook this.
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04-25-2011, 03:34 PM
#8
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Putting a car on a dyno and getting numbers that make real sense is not that simple. You have many other significant variables that can completely invalidate your findings, e.g, air temperature, humidity, etc.).
Most aftermarket tuners are not disciplined enough to go through the process of doing a baseline dyno and then follow up with a post-mod dyno.
I have a friend who has a dyno and uses it a lot to fine tune his various race cars. But you have to know what you are doing and document everything in a disciplined protocol.
Most aftermarket tuners are not disciplined enough to go through the process of doing a baseline dyno and then follow up with a post-mod dyno.
I have a friend who has a dyno and uses it a lot to fine tune his various race cars. But you have to know what you are doing and document everything in a disciplined protocol.
04-25-2011, 04:02 PM
#10
Rennlist Member
Putting a car on a dyno and getting numbers that make real sense is not that simple. You have many other significant variables that can completely invalidate your findings, e.g, air temperature, humidity, etc.).
Most aftermarket tuners are not disciplined enough to go through the process of doing a baseline dyno and then follow up with a post-mod dyno.
I have a friend who has a dyno and uses it a lot to fine tune his various race cars. But you have to know what you are doing and document everything in a disciplined protocol.
Most aftermarket tuners are not disciplined enough to go through the process of doing a baseline dyno and then follow up with a post-mod dyno.
I have a friend who has a dyno and uses it a lot to fine tune his various race cars. But you have to know what you are doing and document everything in a disciplined protocol.
I think Dynos are actually benefitial and they definitely can show how a component or program can affect engine performance, however, it HAS TO BE DONE right, with as much control environment as possible and with a good discipline and documentation... otherwise the X variables are so great that might cancel out the effect of a component.
04-25-2011, 05:20 PM
#11
Rennlist Member
This sounds funny, and kind of like I am being a smart ***, but i am not.
My car will be back in 36 hours, and i want to break it in, then do some exhuast and a cold air. car already has a APR tune.
I see dozens of posts about this cold air, or that, but i have not seen ONE actual thread with mods done and a dyno vid or sheet to go with it.
I Have a corvette i drag race, and i can say, i know how everything i do to it effects the car either by effecting the E.T or using a dyno if track time is not available at the time.
I realize, the 911 is not a drag car. I did not buy it for that or expect to se any guys using them for that on here, but for as much as you guys spend, and soon me included, you would think i would see actual dyno time being used to judge parts..
My car will be back in 36 hours, and i want to break it in, then do some exhuast and a cold air. car already has a APR tune.
I see dozens of posts about this cold air, or that, but i have not seen ONE actual thread with mods done and a dyno vid or sheet to go with it.
I Have a corvette i drag race, and i can say, i know how everything i do to it effects the car either by effecting the E.T or using a dyno if track time is not available at the time.
I realize, the 911 is not a drag car. I did not buy it for that or expect to se any guys using them for that on here, but for as much as you guys spend, and soon me included, you would think i would see actual dyno time being used to judge parts..
http://www.6speedonline.com/forums/a...pictureid=8782
if I ever install a supercharger I will do dyno runs again. it is just imperative to understand that one got to use same dyno and preferably same operator so car would be strapped in same exact way, fans would be placed in same way, plus ultimately all those 'numbers' you get on a chart are relevant mostly within this same dyno only.
04-25-2011, 06:17 PM
#12
Rennlist Member
I did dynos prior and post my mods. as little sense as it offers it still shows what got changed.
http://www.6speedonline.com/forums/a...pictureid=8782
if I ever install a supercharger I will do dyno runs again. it is just imperative to understand that one got to use same dyno and preferably same operator so car would be strapped in same exact way, fans would be placed in same way, plus ultimately all those 'numbers' you get on a chart are relevant mostly within this same dyno only.
http://www.6speedonline.com/forums/a...pictureid=8782
if I ever install a supercharger I will do dyno runs again. it is just imperative to understand that one got to use same dyno and preferably same operator so car would be strapped in same exact way, fans would be placed in same way, plus ultimately all those 'numbers' you get on a chart are relevant mostly within this same dyno only.
04-25-2011, 06:22 PM
#13
Rennlist Member
04-25-2011, 07:30 PM
#14
Rennlist Member
04-25-2011, 07:35 PM
#15
Rennlist Member
i do not think it works this way, really. all you see in 'post' section is a total result effect of intake/exhaust mods allowing extra air to pass through, ECU flash allows proper usage of that surplus air. if you got no surplas air - ECU flash will not add much, if you got air but no flash - same result.
only 'movable' part was ipd plenum of which I honestly still do not know if it added anything or not and prefer just not to think much about it.
and again - when you look at those dyno charts, do not look much at how numbers changed, look at how curves shape changed as this shape defines how equally your car pulls. you need that pull to be as uniform as possible without 'gaps' in certain RPMs, it should start pulling after 4-4.5K rpms and continue to pull until 7K. stock m96/m97 ars have very annoying 'drop' in about of 5.5K or so, newer DFI cars IMHO are way better in that regard.
only 'movable' part was ipd plenum of which I honestly still do not know if it added anything or not and prefer just not to think much about it.
and again - when you look at those dyno charts, do not look much at how numbers changed, look at how curves shape changed as this shape defines how equally your car pulls. you need that pull to be as uniform as possible without 'gaps' in certain RPMs, it should start pulling after 4-4.5K rpms and continue to pull until 7K. stock m96/m97 ars have very annoying 'drop' in about of 5.5K or so, newer DFI cars IMHO are way better in that regard.