GT500 Dyno
08-06-2010, 11:22 PM
#12
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After I thought about it for a while I suspect the dyno and/or the op.
Allot of factors.... It's hot... Does the dyno guy know how to dyno a gt500 (believe me you'd be surprised how many don't) is the dyno guy got something to gain (ie is he trying to sell you a tune or mods etc) your hp and torque lines don't look smooth at all? Is there spark blow out.. How hot was the car on First run...I've seen a stock low of 418 and avg around 425-430 with higher stock numbers 435-450... Mine came in at 443 prior to mods...so yes numbers are low but I'd be more concerned on your shaky lines.... Don't think anything is wrong but it looks like the runs were not as smooth as they should have been... Find another dyno guy IMO...
Thanks for the replies everyone!
08-06-2010, 11:25 PM
#13
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08-07-2010, 11:56 AM
#14
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Yeah, I was thinking those numbers were low, too, until I looked at the temp on the dyno chart. It was a fairly warm day. But I'd still expect to see at least 425HP. And I agree with the wheel slip. You gotta make sure they cinch it down to where it's still real world road force on the tires.
08-07-2010, 12:53 PM
#15
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definitely could be...again that goes with does the dyno guy HAVE experience doing dyno runs for the gt500... its just like I said the lines look really choppy and just not as smooth as they should....FYI...here is my older Dyno sheet by justin (one of the best knowledged tuners in the US for our cars...) the first numbers were after the ford CAI and Ford tune which gave me about 40rwhp off of stock number of 443. you can see the smoothness of the lines and how the run went...the 2nd and 3rd numbers were with justins tune then the 2.6 pulley...
obviously before my other mods L&M throttle body, high flow racing cats etc....which has me at my numbers now...anyways..put it here for your info to see lines, curves etc
obviously before my other mods L&M throttle body, high flow racing cats etc....which has me at my numbers now...anyways..put it here for your info to see lines, curves etc
08-07-2010, 12:57 PM
#16
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Also have to factor in the air intake temps. Ask him for a dyno chart showing actual boost during the runs. As an example, my pulley is designed for 12-13lbs of boost, but due to heat was only seeing 10 lbs.
08-07-2010, 01:18 PM
#17
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+1 absolutely....heat, humidity, altitude all HUGE factors....but I still say by looking at his numbers and dyno chart...this guy was probably not as experienced at putting a gt500 on a dyno....heck he let off it before it even hit 6k rpm..
08-07-2010, 01:27 PM
#18
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I would definitely be concerned on the shakiness of your lines still too...STD is usually HIGHER than SAE smoothing...and STD 5 as yours was printed in should have shown a MUCH smoother line.... mine shows some quivering but its at the roughest setting of SAE 0 neither changes your HP but it smooths out the graph charts the way I understand it...little info on SAE vs STD below
SAE -- The SAE standard applied is a modified version of the SAE J1349 standard of June 1990. Power is corrected to reference conditions of 29.23 InHg (99 kPa) of dry air and 77 F (25°C). This SAE standard requires a correction for friction torque. Friction torque can be determined by measurements on special motoring dynamometers (which is only practical in research environments) or can be estimated. When estimates must be used, the SAE standard uses a default Mechanical Efficiency (ME) value of 85%. This is approximately correct at peak torque but not at other engine operating speeds. Some dynamometer systems use the SAE correction factor for atmospheric conditions but do not take mechanical efficiency into consideration at all (i.e. they assume a ME of 100%). SuperFlow uses a more sophisticated algorithm for calculating friction torque, based on a summary of thousands of friction power tests performed by the automotive industry. This proprietary algorithm estimates friction torque as a function of piston speed and engine displacement.
STD -- The STD (also called STP) standard is another power correction standard determined by the SAE. This standard has been stable for a long time and is widely used in the performance industry. Power is corrected to reference conditions of 29.92 InHg (103.3 kPa) of dry air and 60 F (15.5°C). Because the reference conditions include higher pressure and cooler air than the SAE standard, these corrected power numbers will always be about 4 % higher than the SAE power numbers. Friction torque is handled in the same way as in the SAE standard. Once again, this means the STP corrected power displayed by your SuperFlow test system will be more accurate than power numbers obtained using a default Mechanical Efficiency of 100% or 85%.
SAE -- The SAE standard applied is a modified version of the SAE J1349 standard of June 1990. Power is corrected to reference conditions of 29.23 InHg (99 kPa) of dry air and 77 F (25°C). This SAE standard requires a correction for friction torque. Friction torque can be determined by measurements on special motoring dynamometers (which is only practical in research environments) or can be estimated. When estimates must be used, the SAE standard uses a default Mechanical Efficiency (ME) value of 85%. This is approximately correct at peak torque but not at other engine operating speeds. Some dynamometer systems use the SAE correction factor for atmospheric conditions but do not take mechanical efficiency into consideration at all (i.e. they assume a ME of 100%). SuperFlow uses a more sophisticated algorithm for calculating friction torque, based on a summary of thousands of friction power tests performed by the automotive industry. This proprietary algorithm estimates friction torque as a function of piston speed and engine displacement.
STD -- The STD (also called STP) standard is another power correction standard determined by the SAE. This standard has been stable for a long time and is widely used in the performance industry. Power is corrected to reference conditions of 29.92 InHg (103.3 kPa) of dry air and 60 F (15.5°C). Because the reference conditions include higher pressure and cooler air than the SAE standard, these corrected power numbers will always be about 4 % higher than the SAE power numbers. Friction torque is handled in the same way as in the SAE standard. Once again, this means the STP corrected power displayed by your SuperFlow test system will be more accurate than power numbers obtained using a default Mechanical Efficiency of 100% or 85%.
08-07-2010, 04:35 PM
#20
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