Chassis dyno ramp upload rate vs actual on road

[BLACKCAT]

Never really fully understood how different engine setups are tuned at various ramp rates.

Example: real world (on road) figures-
car A accelerates from 100-130km/h in 4 seconds in 4th gear (1:1)
car B accelerates from 100-130km/h in 6 seconds in 4th gear (1:1)

car A has a large displacement engine with lots of mid range torque
car B has a small forced induction engine & is laggy in the mid range

From what I have seen most tuners use 8, 10, 12 or 15kmh/sec upload ramps.

Now if the above cars are tuned, at different ramp rates, and they both produce the same horsepower output is that accurate & what ramp rate would be closest to real word (on road) as not many people drive their cars on chassis dynos?

I have driven cars that supposedly had a great tune on the dyno but once driven on the road performed a lot different.

 

[NashMan]

not every thing is a shitty dyno jet


but yes verying load dyno is the best to run but it's good to do street tune after s words to work out the small bugs

 

[bloodasp90]

so what would be the best type of dyno then to maybe be tuned on then? say in our cases that is.. 1js/2js or 7m's, or would that also have to depend on what the motor is being built for?

 

[Nick M]

so what would be the best type of dyno then to maybe be tuned on then? say in our cases that is.. 1js/2js or 7m's, or would that also have to depend on what the motor is being built for?

The dynamometer sold as a brand name Mustang Dyno is a loaded unit, and should be used for tuning. The brand name DynoJet is for bragging rates and is an acceleration run.

 

[Devin LeBlanc]

There are Load based Dyno jets as well.

We use a Dynocom eddy brake load dyno. It can apply enough load it will stop the engine.

 

[speedfreak426]

Need to use a dyno like this like I use
Good luck getting access to one!

 

[NashMan]

^ water break dyno I see



but ya dyno jet's are just junk in stock forum, you can upgrade them with a loading drum but really there just not as good in the end any ways

 

[speedfreak426]

It's actually not a water brake dyno, it's all electric. $5000+ dollars a day to operate in electricity alone!
(But free for me! )