JHM Dyno sheet.

General Discussion
#21

Thanks for the info everyone, esp CV, very good read.

The medical analogy is something that we see a lot. For example, say I come up with with a new drug aimed at reducing stomach acid with the goal of preventing ulcers. We’ll call it bangomanozole. It increases pH in the stomach by 25% (less acidic) more than another drug, lansoprazole. It must be MOAR BETTER right?! Even if it costs 20% more!

Well, reducing acid by 25% is the answer to the wrong question being asked. We should be asking other questions too:

  • does it actually reduce the incidence of ulcers?
  • 25% of what?

The vast majority of this site’s membership would be most concerned about the rate of reduction of ulcers.

The bottom line question is how do we go faster, not how do we make more hp.

#22

^ bangoman - is there a better job in the world than pharma sales & marketing? You don’t create anything or cure anything… yet you get to be the middleman for the people that do both.

#23

I dunno it seems to be a pretty shitty job these days. Gone are the days of all expenses paid golf trips, cruises etc… When I first came to Canada in 2010, the drug reps used to buy us textbooks. Now, they can’t. I think much of their job is dealing with frustrating administrators.

#24

I can think of a few

#25

My comment was not meant to be taken seriously. Next time I’ll be sure to include the “roll eyes” emoticon. :slight_smile:

Indeed. :smiley:

#26

Here’s a great example of the dyno being an issue

Guy dynos B8 S4 stock 280 whp

Guy then dynos GIAC stage 2 - 337 whp

Guy is disappointed and says something is wrong.

B8 forum agrees ‘somethings wrong’…’ seems really low’.

Guy says he is going to buy the GIAC DSG tune to see if it helps.

This is dyno marketing 101. If you’ll recall GIAC put out a completely bogus 402 whp dyno sheet in their marketing material 2 years ago. You may also remember APR put out stock numbers of around 320 whp on their hub dyno (which reads nothing like a typical mustang dyno like this guy went on).

As a result of results like those, the general population’s reference points for a B8 S4 get reestablished. Now the guy and the forum for the most part, thinks he is down 30-50 whp and needs to buy more stuff to see it.

The guy gained 57 whp. That’s 20%. That’s massive delta. That’s what Apr gained. That’s wheat everyone gains. The peak ‘after’ number is so low because he is testing on a tough reading mustang dyno. All that matters is delta, and his delta is excellent.

He also complains about the shape of his curve being too flat so he must be losing hp. Or… The multiplying effect of a calculated hp number when you scale down the numbers also scales down the slope of the curve. When you scale it up, the slope steepens.

Had he been on a happy dyno for before after, he and the forum would think his numbers were fine. Had he been on a happy dyno, he and the forum would think the slope of his curve is fine.

But he wasn’t so now he feels the need to buy a transmission tune in order to get more delta…which is frigging impossible since you don’t change gear on the dyno last time I checked.

All around a great reason for this JHM thread to exist, showing why the dyno was never meant to be used for this stuff and is dangerous in the hands of people who don’t understand it.

#27

And here’s a good video by AMS on the perils of the dyno for comparisons or before after testing to prove the validity of a modification. As we know they are another shop who track tests everything to show standardised performance test gains.

http://www.youtube.com/watch?v=sDwjfZvmPHg

#28

That video was funny

#29

Great writeup!