SAE vs STD???

jjtgiants · 07-24-2006, 07:37 PM

I was under the impression that SAE numbers were more accurate dyno numbers because they are corrected, however I see some people with dyno sheets that say STD. Why would a dyno tuner use STD numbers instead of SAE numbers?

From what I've seen STD numbers register about 4-5% higher vs SAE numbers. So if that's the case then my mach is putting down 319rwhp and 346rwtq?? not a chance.

*03gtmustang* · 07-24-2006, 09:14 PM

SAE #'s are the ones you're supposed to use. I guess some tuners use STD #'s to make it look better? Maybe the customer doesnt know the difference?

Saleen S330 · 07-25-2006, 08:05 AM

My dyno was STD but when i asked what would my numbers be if SAE and he said add about 10HP or less to the numbers i have. So then i would be about 300HP to the wheels, which i know i dont have. My 289 sounds more accurate.

jjtgiants · 07-25-2006, 09:03 AM

Quote:

Originally Posted by 03gtmustang

SAE #'s are the ones you're supposed to use. I guess some tuners use STD #'s to make it look better? Maybe the customer doesnt know the difference?

I think you might be right.

Saleen S330: That's what I was thinking to....If I used STD numbers my numbers would be WAY high and not accurate from what I can tell......... So SAE FTW!!!!

r3dn3ck · 07-25-2006, 09:23 AM

There are at least 4 major standards but they're all pretty equal. The difference is in the average temp and barometric pressure that's applied to the correction factor. All in all as long as it's corrected to factors you're likely to encounter day to day there's no major difference. Readings will be higher or lower by very small margins.

On the upside, I've seen cars pull 10hp differences day to day. Dyno racing is therefore interesting but not accurate. Only tires on the pavement will tell you how much usable power you have.

From my research STD and SAE are so close that you can interchange them. Differences are negligable.

Saleen S330 · 07-25-2006, 10:24 AM

Quote:

Originally Posted by r3dn3ck

There are at least 4 major standards but they're all pretty equal. The difference is in the average temp and barometric pressure that's applied to the correction factor. All in all as long as it's corrected to factors you're likely to encounter day to day there's no major difference. Readings will be higher or lower by very small margins.

On the upside, I've seen cars pull 10hp differences day to day. Dyno racing is therefore interesting but not accurate. Only tires on the pavement will tell you how much usable power you have.

From my research STD and SAE are so close that you can interchange them. Differences are negligable.

That's true, i've seen a car dyno one day and a month later the numbers are almost a 10 hp difference, and there were no mod changes. I also just heard recently that they are pretty dang close to each other.

JayC · 07-25-2006, 03:27 PM

Quote:

Originally Posted by r3dn3ck

From my research STD and SAE are so close that you can interchange them. Differences are negligable.

If you go to the Dyno-Jet website and download the Runviewer program (FREE BTW) you can easily change corretions from SAE to STD as well as couple of others. For instance, one of my early pulls was 239rwhp SAE and 250rwhp STD. With this program you can clearly see that the STD is always higher on the same pull.

Jay

r3dn3ck · 07-26-2006, 04:42 PM

depends on what your starting real temperature and pressure are. They're correction factors from whatever the weather is today to a standardized temp and pressure base. It's intended to normalize the readings within a standard. Comparing the two is bench racing and we all know where that gets us.

I use SAE correction exclusively. It's appropriate to the average weather in my location.

jjtgiants · 07-26-2006, 05:03 PM

[quote=r3dn3ck] It's intended to normalize the readings within a standard. Comparing the two is bench racing and we all know where that gets us. QUOTE]

Good point. I was trying to figure out which numbers are more accurate cause I see people with STD numbers that look higher than they should.... just curious

07-24-2006, 07:37 PM	#1 (permalink)
jjtgiants jjtgiants Join Date: Jan 2005 Location: Dublin, CA Posts: 3,762	SAE vs STD??? I was under the impression that SAE numbers were more accurate dyno numbers because they are corrected, however I see some people with dyno sheets that say STD. Why would a dyno tuner use STD numbers instead of SAE numbers? From what I've seen STD numbers register about 4-5% higher vs SAE numbers. So if that's the case then my mach is putting down 319rwhp and 346rwtq?? not a chance.

07-24-2006, 09:14 PM	#2 (permalink)
03gtmustang Super Moderator Join Date: Jan 2005 Location: Northern Va Posts: 3,245	SAE #'s are the ones you're supposed to use. I guess some tuners use STD #'s to make it look better? Maybe the customer doesnt know the difference? __________________ D&D Auto Detailing -Dan

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07-25-2006, 08:05 AM	#3 (permalink)
Saleen S330 Banned Join Date: Jan 2006 Location: Sumter, SC Posts: 900	My dyno was STD but when i asked what would my numbers be if SAE and he said add about 10HP or less to the numbers i have. So then i would be about 300HP to the wheels, which i know i dont have. My 289 sounds more accurate.

07-25-2006, 09:23 AM	#5 (permalink)
r3dn3ck Wowbagger hates me too! Join Date: Nov 2005 Location: Magrathea/California Posts: 7,015	There are at least 4 major standards but they're all pretty equal. The difference is in the average temp and barometric pressure that's applied to the correction factor. All in all as long as it's corrected to factors you're likely to encounter day to day there's no major difference. Readings will be higher or lower by very small margins. On the upside, I've seen cars pull 10hp differences day to day. Dyno racing is therefore interesting but not accurate. Only tires on the pavement will tell you how much usable power you have. From my research STD and SAE are so close that you can interchange them. Differences are negligable.

07-26-2006, 04:42 PM	#8 (permalink)
r3dn3ck Wowbagger hates me too! Join Date: Nov 2005 Location: Magrathea/California Posts: 7,015	depends on what your starting real temperature and pressure are. They're correction factors from whatever the weather is today to a standardized temp and pressure base. It's intended to normalize the readings within a standard. Comparing the two is bench racing and we all know where that gets us. I use SAE correction exclusively. It's appropriate to the average weather in my location.

07-26-2006, 05:03 PM	#9 (permalink)
jjtgiants jjtgiants Join Date: Jan 2005 Location: Dublin, CA Posts: 3,762	[quote=r3dn3ck] It's intended to normalize the readings within a standard. Comparing the two is bench racing and we all know where that gets us. QUOTE] Good point. I was trying to figure out which numbers are more accurate cause I see people with STD numbers that look higher than they should.... just curious