Uncorrected dyno numbers

[Islandcat]

Guys,

Yesterday i got my car dyno tuned and the dyno guy gave me the uncorrected numbers. I didn't think it was a big deal because i just figured i would get on the internet and find a conversion calculator to figure out the sae ratings. Well i could only find one conversion calculator, and i couldn't figure out how to convert my barometric pressure and vapor pressure to the units it was asking for. Then i found a bunch of information on STD vs. SAE numbers and uncorrected numbers, but my head is now spinning and i still haven't figured out how to convert.

Does anyone know how to covert uncorrected numbers, or could just point me to a website that would be easy to understand and use.

 

[CuZzO99L]

Who tuned it? Any tuner should be able to read both numbers out to you just as easily by a click of the mouse while on the dyno... from my experience at least.

 

[Spawn]

DITTO i get all the run files from my tuner and put them on a thumb drive on my key ring. I can then print out any field and correction factor I want. Most of the shops I use use Dyno jet so you can download winpep for free and print out those files.

 

[Islandcat]

Stanghi. Like i said, he showed it to me on the computer and printed out a copy. I didn't say nothing because he was talking up the big gains and i thought to myself no big deal i will just figure out how to convert when i get home. Well it hasn't been that easy unfortunately. I guess i should have spoke up and told him to give me the sae numbers.

 

[Ray Lucca]

So Cat what did you put down, HP and Tq, Mods???

 

[Robert M]

Guys,

Yesterday i got my car dyno tuned and the dyno guy gave me the uncorrected numbers. I didn't think it was a big deal because i just figured i would get on the internet and find a conversion calculator to figure out the sae ratings. Well i could only find one conversion calculator, and i couldn't figure out how to convert my barometric pressure and vapor pressure to the units it was asking for. Then i found a bunch of information on STD vs. SAE numbers and uncorrected numbers, but my head is now spinning and i still haven't figured out how to convert.

Does anyone know how to covert uncorrected numbers, or could just point me to a website that would be easy to understand and use.

I have had a question about this for a long time, but have not had the opportunity to ask............Doesn't the computer make all of the changes needed to keep an engine running the same at sea level or at higher elevations? I thought that was one of the benefits of computer controlled cars, the engine (fuel/air etc.) would be adjusted so that the car would respond reletively the same while driving on Daytona Beach as it would if you were to take the car up into the mountains.

I know that pre-computer cars needed tweaking depending upon altitude (and there were cars build and sold specifically for higher elevations), and even a difference in humidity could cause a non-computer engine to either run great, or not so great, but doesn't the computer make the changes now? and the calculations/formulas required on the pre-computer cars are now performed seamlessly by the ECM?

What is to be corrected? I thought the computer corrects........

The only thing I remember about STD (or maybe it was "NET") vs. SAE is that in 1970 (1971 for Ford and Chrysler) the auto industry changed the way they rated h.p. on their vehicles. Pre-1970 the manufacturers rated the engine at the flywheel without accessories (STD/NET), and after 1970 (1971 for Ford and Chrysler) all engines were rated at the flywheel, but with accessories installed, p/s pump, alt., a/c compressor, etc. (SAE). This later 1970/1971 and newer SAE was more realistic for the real world, and the lower h.p. numbers (with accessories) were reflected in this SAE testing.

R

 

[Islandcat]

My horsepower was 583, torque was 578, but these were uncorrected number in 50 degree weather with about 20 percent humidity. My mods were just a 2.6 pully and tune. I figured with just those mods i should be 520 to 545 sae horsepower, but i cant figure out how to convert my numbers lol.

 

[zporta]

Damn those #'s seem high.

 

[CuZzO99L]

:nonono:

 

[IronTerp]

Approximate conversion factor from STD to SAE is about 2.2%. Thus 583/578 STD would equate to roughly 570/565 SAE.

Now that's not to say that by stating that the above numbers were "uncorrected", that they were measured in STD. STD is actually a conversion factor just like SAE. Just a different one which takes into account a different measure of dry air density.

It does not appear that the numbers you were given were STD, but were indeed truly uncorrected.

 

[DavidHasselhoff]

My horsepower was 583, torque was 578, but these were uncorrected number in 50 degree weather with about 20 percent humidity. My mods were just a 2.6 pully and tune. I figured with just those mods i should be 520 to 545 sae horsepower, but i cant figure out how to convert my numbers lol.

You should go get dynoed somewhere else and see how "great" his tunes are. That's all I'll say.

 

[DavidHasselhoff]

My horsepower was 583, torque was 578, but these were uncorrected number in 50 degree weather with about 20 percent humidity. My mods were just a 2.6 pully and tune. I figured with just those mods i should be 520 to 545 sae horsepower, but i cant figure out how to convert my numbers lol.

I made 560rwhp on his dyno with those mods, but it was cold when you dynoed and it was 98 degree when mine was dynoed with the same mods so you should of dynoed a bit higher than me, but not that much more.

 

[Robert M]

Approximate conversion factor from STD to SAE is about 2.2%. Thus 583/578 STD would equate to roughly 570/565 SAE.

Now that's not to say that by stating that the above numbers were "uncorrected", that they were measured in STD. STD is actually a conversion factor just like SAE. Just a different one which takes into account a different measure of dry air density.

It does not appear that the numbers you were given were STD, but were indeed truly uncorrected.

What is the difference in dyno results when someone says "SAE vs. STD" or "incorrect"? Is it the way that the specific dyno is set up to measure hp and tq? some are set for SAE and some are set for STD? or how would what is "real" at the rear wheels change with an equation/calculator. If a car dyno's xxx at the rear wheels, how is that considered incorrect given the location that the car was dyno'ed? unless that specific dyno is known to be incorrect when compared to other dynos locally on the same day, same temp., same car, etc.?

This is new to me, so I am interested in learning........

R

 

[03 KB Sonic Blue]

You should go get dynoed somewhere else and see how "great" his tunes are. That's all I'll say.

What is that suppose to mean? Im running a custom tune from him now. Is there something his customers should know?

 

[CuZzO99L]

What is that suppose to mean? Im running a custom tune from him now. Is there something his customers should know?

Cuz this may not be "entirely" accurate....

 

[Nathan'sTsi]

I have had a question about this for a long time, but have not had the opportunity to ask............Doesn't the computer make all of the changes needed to keep an engine running the same at sea level or at higher elevations? I thought that was one of the benefits of computer controlled cars, the engine (fuel/air etc.) would be adjusted so that the car would respond reletively the same while driving on Daytona Beach as it would if you were to take the car up into the mountains.

I know that pre-computer cars needed tweaking depending upon altitude (and there were cars build and sold specifically for higher elevations), and even a difference in humidity could cause a non-computer engine to either run great, or not so great, but doesn't the computer make the changes now? and the calculations/formulas required on the pre-computer cars are now performed seamlessly by the ECM?

What is to be corrected? I thought the computer corrects........

The only thing I remember about STD (or maybe it was "NET") vs. SAE is that in 1970 (1971 for Ford and Chrysler) the auto industry changed the way they rated h.p. on their vehicles. Pre-1970 the manufacturers rated the engine at the flywheel without accessories (STD/NET), and after 1970 (1971 for Ford and Chrysler) all engines were rated at the flywheel, but with accessories installed, p/s pump, alt., a/c compressor, etc. (SAE). This later 1970/1971 and newer SAE was more realistic for the real world, and the lower h.p. numbers (with accessories) were reflected in this SAE testing.

R

The car compensates becasue it is metering the air that is coming into the engine and that reading and load level is applied to a fuel and spark tables in the ECU.
The "correction factors" are an attempt to equalize differences that would be caused by dynoing on the same dyno, in different weather conditions. For example, if you dyno during the summer, and it's 100 deg out and 50% humidity, your numbers uncorrected numbers would be much lower than if you hit the rollers on a cool, dry day. It also makes comparing different dynos i different areas easier, but that can get pretty sketchy since no two are exactly the same.
The correction fastors equalize the temperature and humidity to "ideal" conditions, as well as converting the numbers to seal level numbers. That being said, corrected numbers are not worth piss at high altitudes for forced induction cars as it always over inflates them.

 

[Islandcat]

well,

Who do ya'll suggest i go to in louisiana to get put back on the dyno and get everything checked out. At the track this past saturday, i was told there is a guy in layfayette and a guy in prairieville that are pretty good. The only problem was i had already set up my appointment for monday and i wasn't gonna back out of it that late.That is why i didn't check out the other two guys. It was too late.

 

[DavidHasselhoff]

What is that suppose to mean? Im running a custom tune from him now. Is there something his customers should know?

You shouldn't be losing to stock Z06's from a roll though with 600 rwhp. Shoot me a pm if you want to know.

 

[DavidHasselhoff]

Cuz this may not be "entirely" accurate....

Actually the "custom" tune isn't entirely accurate either...lol

 

[CuZzO99L]

Haven't heard of the laff.tuner but Wes @ TPS Performance. In prairieville is a very good tuner however he is not there anymore an can be no longer "hands On" I believe lanny chouest hired him and moved him to New orleans to be his personal tuner for all his exotics and is building wes a new facility at the road course they are developing on the westbank. So now he basically does remote tuning, which is fine...but Im less then fond of the guy running the shop at tps now. So really without any of that having to be said a little over 3 hours away from me (houma) you have johnson motorsports that I have been more then impressed with, heck The Tuner's first cousin is chris Johnson from what I've been told co wrote and developed SCT software back in the late 90s. Regardless off all the mumbo jumbo I've been more then impressed with my tunes from him, my numbers are great and more importantly my drivabilty is good also, if you just wanna run over there to check out the facility an stap ur car on to check the numbers you can, then obviously if you want him to crack another 10 -15 out of it you can pay to do so. Ur setup is very basic, so it was probably just a matter of loading in a base tune from sct without any need for fine adjustment, so any one who can operate a computer can click a stored file... it only the highly modified stuff i've seen Baton Rouge have issues with where you actually have to start adj fuel tables an such....so to clear my name you probably have a very solid tune from a Very Nice Tuning Shop!!!