That's true but I think that's only part of it. You, me, and everybody else knows you can put the same car on 5 different dynos and you'll be lucky if they're within 20whp of eachother, and that would be using the same type of dyno. Start throwing Mustang vs. Dynojet numbers in there and well... you know how that turns out.

One thing I've noticed in my own experience is the change of Afr in the tune of Dyno vs road. This may only be in my case but I tuned my other vehicle via Dyno at 11.5 Afr but in real time down the road in similar conditions its consistently 11.1-.2 along with a few froeda vehicles on a dyno showing similar results again this may be my specific tune but my log road tune in the Evo is dead on Afr since it was tuned or real time road conditions. I agree a Dyno is a more controlled environment for consistent numbers and can be a great way tp dial in a car with repetitive conditions but I've never been a huge number guy I just like the track results

Friends*

What type of dyno were you on?

I'm with you petey. When operator actually knows how to set it up and use all the functions of powerdyne software. Mostly all road conditions can be met and very easy sweep the entire mapping anywhere as you know sir

It was a mustang Dyno. It was my lightning truck I've never dynoed my Evo. But it seemed to be a consistent thing from my friends who have tuned there. Idl what the deal is to be honest

a datalog acquired on a dyno will not correctly generate a representative whp/tq curve for two reasons: 1) the effective mass of the rollers is typically not set to the mass of the vehicle. 2) there is no wind resistance on the dyno. wind resistance is non-trivial for a 3rd gear pull. off the top of my head, i think it takes about 25 whp at 80 mph. all the road dyno programs estimate the additional power needed to cut through the air.

with that said, i've caclulated whp/tq curves from my dyno datalogs at English Racing and found pretty good concurrence. its purely coincidental though.

I have to disagree.
1. The effective mass of the rollers (inertia) Can no doubt match the vehicle, having it setup correctly I cannot speak for.
2. Wind resistance IS in fact compensated for in mustang powerdyne software by EPA default values and 3rd party measurements or frontal areas included in the vehicle PDF sheet which is available for aditional cost. You can also do the measurements yourself and calculate the values, I have a nifty spreadsheet for just that.

The problem with the original posters Dyno comparison, is that the place where the Dyno is located did not get the proper training, because they bought the machine from slow boy racing before they went out of business and missed a critical part of learning how to set it up properly from MD. Outside of that, I've seen their Dyno, and their ventilation sucks extremely bad where both third and fourth gear pulls will easily overheat a car. Last time I saw the place, they didn't have any proper dyno fans and they're aerodynamic figures and vehicle weight was not being inputted correctly

ok, i didn't put "typically" enough times in my post. yes, its possible to set up an md to simulate road condtions, but how many dyno operators do it as a matter of course?

This thread is a huge waste of time for all parties involved. Just my 2 cents.

Wait Slowboy Racing went out of business?

Here's a video:
http://www.youtube.com/watch?v=ha2QqxVBAL0

I like the idea of a car being tuned in the exact environment of which it will be ran in. Street cars on the street, and dyno queens on the dyno.

I do believe a MD can be setup to simulate road conditions. One of the problems is that the fans used on the dyno will never produce the volume of air the front of your car sees going down the road.

I disagree with most of peteyturbo's posts, no point to argue though, in this thread... I think all tunes should be touched up on the street or track if first dyno tuned. Saying for one you can replicate airflow on the street on the dyno is just not possible and it's more about tuning the cells u enter on the street, vs numbers you can influence by a bunch of dyno settings(like wind resistance). That is just missing the point mr pturbo.

Dyno's have their place, but to think a dyno can replicate every condition is....just wrong. It's also ludacris to think people at these shops have time to play with the dyno for every car, please..

What a pleasant surprise of awesome! Everything I said was wrong and you are correct!