[verbs]

I always wondered this. Most other car forums I visit use SAE method of converting dyno numbers, which is more conservative, and is supposed to more closely reflect real world driving conditions.

None of the American car owners/forums I know of dyno in STD. STD was always used by tuners or performance shops as a dyno trick to make their tunes or mods look like they make more power, since STD always dynos 3-4% higher than SAE.

I've owned, modified and dynoed everything from Camaros to CTS-Vs to 335i's and now own an M5. It's just strange to me to see such a lack of consistency across car brand's owners.

So I guess my quesiton for all the 335i owners and shop sponsors here....why STD?

[335e92tx]

Im not sure why 12hp makes a difference one way or another- especially when its easly corrected.

[verbs]

Originally Posted by 335e92tx

Im not sure why 12hp makes a difference one way or another- especially when its easly corrected.

It's misleading if you're shopping for say a tune, and you compare dyno graphs of one shop who uses SAE and another who uses STD.

At the end of the day dynos are best used to compare one's own mods, so theoretically it should be a moot point, however people very frequently compare.

[themyst]

It's a good question actually. The tuners and whoever else uses STD because the numbers are higher, period. Since the tuners set this precedent for our platform, most people continue using STD as their correction method.

But seriously, not a huge deal to guesstimate an SAE output. Just reduce whp by 3-4% like someone before me said.

[Mr. 5]

Originally Posted by verbs

It's misleading if you're shopping for say a tune, and you compare dyno graphs of one shop who uses SAE and another who uses STD.

At the end of the day dynos are best used to compare one's own mods, so theoretically it should be a moot point, however people very frequently compare.

You really answered your own question. It's to show more power.
Nothing is dyno'd in STD. It's just dyno'd and then STD is chosen afterwards to show the correction.
SAE could be chosen just as easily before one posts the chart but since STD has paved the way then people seem to go with the same thing for comparison.

There are so many people around here that love to measure their own P**** by the dynos so if anyone posts SAE then a lot of the people will overlook that and start talking trash on how bad the tune is bla bla...

[335e92tx]

I would not recommend 'shopping' for a tune based which one has + 3-4percent max output. Too many things (not all documented or as easily determined as std/sae) can influence that.

[supahdave]

I wouldnt really say numbers are inflated. Its more what temp the numbers are corrected to. Std is corrected to 60 degrees, 29.92 in/hg, while sae is 77 deg, 29.4 iirc. As long as one method is used consistently on the same car it doesnt really matter imo. Std is more common due to higher numbers. Dyno calibration is more of a concern vs correction factor. 2 of my local dynos read ~30whp different from eachother. So realistically, dynos are useless to compare #'s unless its all done on same dyno.

[supahdave]

Fwiw, i dynoed 400.6 sae, 413 std.

[R1000K3]

Originally Posted by TrackRat

Don't believe any of the dyno data you see posted because it's rarely ever accurate or repeatable or under controlled conditions, thus it's worthless. Many people who operate dynos have no clue how to conduct a proper SAE dyno tests. The way that most chassis dynos are operated is about as accurate as pulling a HP number outta your arse.

Even if the data is corrected to SAE stds. it does not make the data accurate if the test is not conducted properly, which it rarely is unless it's done by a car maker or engineering dyno test lab that must certify their results. The saying is you can fool most of the people most of the time... and it's true.

+1

[forza1976]

Uncorrected FTW...

[biz77]

A dyno is a tuning tool, not a measuring stick. Are you really shopping performance parts based on what a single dyno sheet says?

[BrianMN]

I think correction factors are good and worth it to make up for overly bad or overly ideal conditions.

[verbs]

Originally Posted by biz77

A dyno is a tuning tool, not a measuring stick. Are you really shopping performance parts based on what a single dyno sheet says?

I don't, but a ton of people do. I've been in the game long enough to know better. I feel it's those people being taken advantage of.