Dyno Readings

[farmtruc]

So, lately my dyno has been reading a little low, lower than Superflows actually read, so I contacted SF tech dept and asked them what they thought.

After many times back and forth on why my dyno was reading low, the variables were brought up on why, and now I need to address it. So, I think I'm gonna have it fixed.

But, during the time I was going back and forth with this engineer, he kept saying "all dyno's are going to read differentely" and "your superflow dyno will never read the same as the next dyno".
Of course I understood this, my question was "why is my dyno reading lower than it normally read in the past"

He sent me an article, but one page was very interesting. It had to do with DynoJets and why they spit out bogus and inflated numbers. Yes, DynoJets are always the target and this document I'm about to share explains why. It also attacks any dyno that falls under the same technology as a DynoJet.
We all know, or have heard of DJ's showing higher numbers than say a Superflow, Mustang, or Land and Sea dyno, but you really didn't know why. I really didn't know why either, but I knew if someone went from my dyno to a dynojet, they we're gonna get higher numbers from the DJ.
One reason I always assumed was the DJ doesn't have a strain gauge / torque cell. I'm no mathematician, but from the calculations required to show users charts, you have to have it.

Ok, so enough of my opinion. And before this gets out of hand, it's not attacking anyone on here, this is just a proven fact from a document I just read (actually had it for years but never read it). I own a Superflow dyno and I'm always being attacked by the DynoJet users and how their numbers are higher, or at least their ego.

Read below:

[farmtruc]

Taken from a document written by:
Bret Williamson of Superflow Technologies

Below is a quote from the inventor of DynoJet


The “Zen of Inertia” by Mark Dobeck
In 1985, the Dynojet dynamometer became a product for anyone to purchase. Dynojet founder
Mark Dobeck decided everyone could benefit by having a chassis dynamometer, so he set out to
build and sell them. Much like Mr. Watt, he had other motives: he needed a way to prove his jet
kits worked so he could sell more of them. Mr. Dobeck succeeded in producing and selling a
chassis dynamometer and has long ago sold off his interests in the company. He gave an interview
to Sports Car International that was published in March 2006. The most revealing part of that
interview is extracted here for your entertainment and understanding:
“One of the biggest headaches of Dynojet's go-it-alone chassis dyno
project was figuring out how to assign meaningful power numbers in
the face of unknown inertia from the moving parts of hundreds or
thousands of engine, drivetrain and tire combinations.
Wrestling to fully understand inertia and powertrain losses, Dobeck
and his team quickly realized that the standard physics formula of
weight, time and distance for converting acceleration into
horsepower simply didn't work right. Even after eliminating all
drivetrain losses and attempting to account for all heat loss in the
vehicle and dyno systems, the derived number was always lower
than accepted numbers.
The Dynojet team poured on resources and burned up time and
money investigating the Mystery of the Missing Power. But no matter
what it did, the mathematics never added up.
Dynojet's final number fudge—which would eventually be applied to
every vehicle strapped to a Dynojet chassis dyno—was arbitrarily
based on a number from the most powerful road-going motorcycle of
the time, a 1985 1200-cc Yamaha VMax. The VMax had 145 advertised
factory horsepower, which was far above the raw 90 horsepower
number spit out by the formula. Meanwhile, existing aftermarket
torque-cell engine dynamometers delivered numbers that clustered
around 120.
Always a pragmatist, Dobeck finally ordered his chief engineer to
doctor the math so that the Dynojet 100 measured 120 horsepower for
a stock VMax. And that was that: for once and forever, the power of
everything else in the world would be relative to a 1985 Yamaha
VMax and a fudged imaginary number that was close to the
'agreement reality' of the average of some other imaginary numbers.
Dobeck's engineering staff was dismayed by the decision. But the
Dynojet 100 measured surplus power available to accelerate the
vehicle' mass—no more, no less—and that was true even if the power
modification was a low-inertia flywheel or lightweight wheels. As
long as the inertial dyno's numbers were repeatable, the critical
question of whether a particular mode make the engine accelerate
faster or slower would be answered correctly.”
Dobeck then began selling the new “bogus meter” to dealers all across the USA. But whether the
numbers were right or not didn't matter, because at that time, his was the only game in town, and
no one knew differently. Again, if the dyno was used to provide a baseline and then evaluate how
a change to the vehicle impacted that baseline, it worked great!

[T-Stark]

very interesting, good find man


btw did you get my p.m.? sorry for the thread jack

[Crazy Blu]

Hmmm interesting... Always wondered same thing..

[Trick1]

So he built a tool to help gauge what your mods did for your vehicle from start to finish. Then tweeked it so he could sale the units to public.
Said it for years, dynos are tuning tools not the end all... Nice read....

[farmtruc]

Superflow dyno's give realworld hp numbers and are capable of producing DJHP numbers, and are good tools for tuning fuel injected engines, recording steady state hp values, as well as acceleration hp numbers. Something an inertia only dyno CANNOT do.
DynoJets are not good tuning tools, they are good for spitting out a bogus number that is calculated from made up numbers.

Superflow dyno, is a tuning tool.

[Trick1]

Still an interesting read.

[farmtruc]

Still an interesting read.

I'll post up more, there's a lot of useful data on this document. I found the entire doc very interesting and stayed up way past my bedtime reading it, lol.

[DBRODS]

Awesome!!!!

[2boosted]

I'll post up more, there's a lot of useful data on this document. I found the entire doc very interesting and stayed up way past my bedtime reading it, lol.

beg u all night to turn off that light.....now I'm tired too.

Hope this dead horse beating ends today.

I wanna get a good night sleep !