So I knew this car ran strong and I know our dyno reads low, and I can only hope this comparison will shed some light onto how much different these two totally different types of dynos can spit numbers out. We all know the dynojet is the automotive performance industry's standard of measuring HP at the wheels, but when it comes time to actually tune the car they leave alot to be desired compared to the eddy current counterparts. What better idea then to tune on the MD and stroll over to a DJ to get some REAL numbers..

Dyno's aside, this car is just running it's *** off with a very moderate list of mods, or lack therof. Main points of intrest are stock cams and GT30 (3065) series turbo..

Keep in mind these graphs were not done on the same day, however nothing was changed in the tune or the car. We were utilizing ECU controlled direct psi based boost control via Tephra V7 and an omni 4bar so needless to say the boost profile is very repeatable and consistant under most any condition. Max boost is between 33 and 34 psi with an emphasis on top end to reduce TQ. and gain HP to keep the completely stock longblock happy. Turbo kit is a standard Buschur Cast manifold 3065 kit which I had ported and was sent to Swain Tech for their white lightning coating.

Mustang numbers: 493HP
Dynojet numbers: 578HP
Difference: 85HP peak

Onto the Graphs:

 

Good stuff. Eddy loaded dyno's are my standard. I don't care what the "industry" uses. Real world simulation tops it over any DynoJet IMO.

 

Wow that is more than expected. I would think around 10% but that is closer to 18.

 

yeah it is 18 %, i can't believe it

 

+1. I thought it was closer to 10%. Interesting how many posts from other tuners there are floating around basically saying " its about a 10% difference" lol

 

Very good information.

 

WoW I'm shocked 18%. Of course my car is tuned on a dyno dynamics... I wonder how that compares to a DJ/Mustang hmmmm?

Tuner used a 1.2 correction factor on the dyno dynamics to give (dynojet) numbers.

 

Normally its 13-15% on a properly setup Mustang (which it appears KHC has) but weather correction can play a larger factor as well. If the Mustang numbers were with differing humidity and they were uncorrected vs the Dynojet corrected there is the percentage difference.

Looking at vs speed the car didnt really make 578...it spiked right at the end when they chopped it. It would be interesting to see vs rpm and what the power was at right as it was dropping off around 84mph in that graph.

aaron

 

I was wondering what that was all about as well. But from what I understand a dynojet just takes roller speed and time to determine hp so I was under the assumption it didnt matter what engine rpm was. How can a dynojet spike upwards if there isnt a roller acceleration for the instance? I am sure you are more familliar with it then I am. My first thoughts were it may have been a boost error correction or lack therof but like I said you may know better then me.

 

i have also seen a thread like this where the mustang read higher than the dynojet.

 

Nice work Petey.

 

We have a local md and it is setup and calibrated to read identically to a local dynojet.

 

You have a spike in your Dynojet plot...

The DJ should make 557-567whp which it looks to be spot on if you don't account for the spike at the end of the run.

In my experience using an old school Mustang versus all the local Dynojets... its 13-15%. In more recent history it seems to lean closer to 13%.

If you wanted to do a fair comparison... you might take comparisons at each given RPM. that might be a better indicator rather than taking a peak number.

check the torque on your cam gear bolts too.

 

I tune on both dynos every week as i work out of 2 shops with dynos one with a DJ one with MD... And honestly i prefer the Dyno Jet and i know quite a few very well known tuners in this industry that share this opinion with me. And it is just that, its my opinion and what i personally prefer.

My reasons for DJ over MD are many but for 1 you don't have to worry about the #s being questioned as its not easily manipulated such as a MD can be very easily as well as a lot of the others dynos on the market. I'm much more familiar with the #s Dyno Jets spit out and there much more accurate from DJ to DJ for comparison. With a DJ you don't have to worry about going to another shop in another state and wondering if the calibration has been changed from the one you tune on in your home town for example. Also if you know what u are doing "which you damn well better if your dyno tuning someones car!" it will tune just as good as any dyno IMHO. Take AWD Motorsports for example they set VERY IMPRESSIVE records coming right off the DJ to the track. That speaks well for a DJ for those that say u cant tune as good on them as u can other dynos... And that's one thing i get tired of hearing is you can't tune as well on a DJ and that other dynos simulate the road etc... No matter what you do you will never simulate the street or the track exactly no matter what dyno your on. And for those that want eddy current DJ offers it as an option. I also like the way a DJ graphs better and the way the software works. A lot of this can be personal preference and a DJ is my personal preference for MANY reasons.

 

I hear you, but don't mind me if I disagree somewhat.

This has more or less to do with a hp figure, for tuning a car I feel the point is moot so long as it is repeatable in relation to baseline. This has more to do with shops playing the number game, and sounds more like political reasoning rather then physical dyno operation.

I know it is a fact that inertia dynos cannot apply load conditions to an evo as accurately an eddy current dyno can. It does not mean you cannot tune a car sucessfully on a dynojet, it just means it is not good at supporting the conditions for it, and that is the bottom line. It does not mean it cannot be done with great success.



I can justify your personal preference here, but looking at the graphs I posted and hearing complaints of spiking (what can cause this?) I cant see how anyone would prefer the plotting from the dj as apposed to the MD figures posted. Mabye operator error had something to do with it