What are the pros and cons of the Dynojet vs the Mustang Dyno?

 

people like dynojets cause they show more accurate HP numbers.

the mustang dyno(basing on the experience we had it at the dyno day) seems to show more accurate a/f mix numbers and other tuning stats. the hp numbers are low, but if you use a 30-35% adjustment, you can be pretty close.

basically, one is good for bragging rights and the other is good for tuning.

 

The DynoJet usually gives slighly higher numbers, and is best for comparing two different cars in two different parts of the country. Since you are rotating a known mass, there are no calibration settings other than ambient and baro...etc. But is a more apples to apples comparison when trying to compare to cars. You can tune on them, but its more challenging to hit the part throttle points, becuase there is no load on that dyno.

The Mustang Dyno, Dyno Dynamics, DynaPac, etc...are all inertial based eddie current dynos. They use a electical current on the drum, to simulate load. This allows you to hold the load at a specific RPM or throttle point, for better and more precise tuning. However, due to the myriad of calibration settings, it is not very accurate when comparing two cars on different dynos. Also, it is much easier to fudge the numbers to crease higher dyno charts..not that anyone would do that....of course.

My personal opinion is that the load based dyons are much better for tuning, and the dynojets are better for getting comparable HP numbers to compare different cars with one another.

 

It all depends on what you want to use the dyno for. To make a long story short, Dynojet is good for running baselines and getting accurate comparison between diffrent cars.

The other dynos are better for tuning purposes. I personally like the DynoDynamics setup, they have many good features that make tuning a little easier, I plan on getting one in the very near future.

 

Thanks Guys. Great information!

 

Bingo!!!!!!!

 

DynaPacks do not use eddie current (electric generators) as means of loading. It uses hydraulic (water) brakes to generate the load that is variable. The same water is also used to cool the system for added precision. It's similar in concept to the hydraulic based engine dynos (vs. chassi dynos) used in the racing industry.

Sharif (gq_626) did bring up a good point with respect to different calibration point. Load based dyno does have one more variable to deal with when compared to roller based dyno. However, the load is fairly precisely monitored and controlled (at least by the DynaPack) and shouldn't pose as any issue between dynos. It is still the the *global* calibration point for ALL types of dyno that will skew the comparibility from one to the next. Having said that, different makes of dyno have their own interpretation of conversion factor from roller or axle to horsepower at the 'rear wheel' or at the 'crank' ... this is where a direct comparison between DynoJet vs. DynaPack vs. Mustang, etc. is not readily possible. The absolute numbers will always be debated till the end of the world. Look no further than delta numbers and you'd sleep a lot better.

I like ALL load-based dynos, but especially favor the DynaPack because tire alignment and slippage is an impossibility. RPM is also spot on because it is calculated from axle speed using the exact drive ratio. RPM signal pick up could be tricky business for transisitor driven direct ignition system. Lastly, it is extremely safe to operate on. No tie downs needed and no fear of car accidentally launching off the test rig. It's especially welcoming for high power cars. Daisy chainable to support 4WDs too (STi and EVO heaven).

DynoJets ... if setup and the test conducted correctly is perfectly fine for measuring wide-open-throttle power.

 

There's also a good read of the two types of dyno in one of the links at the bottom of the page, where it has the "similar threads."

 

Yeah, you'd think that these newbie’s would do a search before asking questions that have been answered 100 times before.

(And before anyone gets their panties in a bunch, Tony is a good buddy of mine and I'm just busting her *****). Gotta love those androgynous names.

 

The problem with any dyno is that test don't simulate real world.........in direct gear [1:1] the dyno simulate what would be 80-140 mph] unfortunately the drum mass nor the eddy brakes hold the engines BACK.........the engine accelerates [changes rpm much faster than a road load with wind resistance].

Oem designs software [in each gear] for real road not a dyno load, so REprogramming on a dyno usually creates less optimum results........tests fine on dyno but pings on the highway under same speed conditions.

The tires are the greatest single friction drive train loss segment in the calculation.

 

for some of us (g35x) we can only go with mustang dyno. other types don't support awd autos.