QwkTrip

Did 3 dyno runs on a Mustang MD500. No forced air cooling and hood closed, no cool down period, and trans locked in 4th gear.

a) Why is there a torque spike in Run 1 but not in Run 2? Operator said the torque converter flashed during Run 1. I am assuming the torque converter was locked up during Run 2. Does this seem like a reasonable explanation?

b) Am I short on power considering the mods, or does a Mustang dyno just make everybody feel bad about the results? The horsepower was nothing to brag about and seems low for what I've done.

c) Should I just not worry about these numbers and get it on the 1/4 mile track to see where I really stand?


winter fuel blend (it is January!)
LET 91 tune
Solo downpipes
Wagner intercooler
170F thermostat

QwkTrip

Oh, I see the shop screwed up and printed run 2 twice. Well, there were 3 runs but I didn't get the 3rd print out.

QwkTrip

I'm starting to get a little better understanding how a Mustang dyno works and feeling better about my results. And it looks like I was falling into a common trap by comparing my numbers to other people.

First, I think the dyno setup was wrong and caused my Horsepower numbers to be low. Apparently those dynos attempt to simulate driving on-road and the vehicle weight is one of the factors that goes into how much resistance is applied to the wheels by the eddy current load cell, thereby effecting the rate of acceleration and reported Torque and Horsepower figures. I remember the technician used the generic F150 Ecoboost from the drop-down list which happened to be a SuperCab. My truck is quite a bit heavier than that -- a whopping 900 pounds heavier. I don't know how much that effects results but it would only make my numbers better had they used the correct weight.

Now I wouldn't be concerned at all if I didn't already know the "big numbers" reported by other truck owners and tuners. I guess I need to put that out of my mind too because I am learning comparing my dyno numbers to somebody else is pretty much pointless. Reason why is there is huge variation between dynos, and even settings used on the same dyno. I need to focus on my own improvement since my last baseline (which I don't have), using the same dyno and same settings. The dyno is a tuning tool, nothing more. If I really want to know how much good my mods did then I have to return my truck to stock and measure the improvement. And if I want to know how I compare to other people then I need to run down the 1/4 mile.

Never ran a dyno before so I never had to think about what the numbers meant, outside of being able to read torque vs speed. Looks like it is more complex than just reading a torque curve.

redcelica

why'd they start the run at 2520 rpm and not idle??? Good looking numbers though. Would like to see how much is lost on an 87 oct tune.

QwkTrip

The run did begin at a lower speed but the data wasn't captured for some reason until 2500 rpm.... which happens to be the same speed that the operator calibrated the rollers to the tachometer. Coincidence?

This stuff isn't free you know! LOL!
The only 87 tune I have is the SCT tune from the box.

I have thought about going back with a stock tune so I can get a better idea of relative improvements. But at the end of the day this is just my slow truck and not a hot rod. Not sure how much more effort I'm putting in this. It drives well, runs well, and it didn't break down yet so I might just call this good enough.

TJPlatinumEB

Mustang dyno will always read 10-15% lower than a standard DynoJet dyno. It is how it is done and calibrated and how it can put load on the wheels that the DynoJet can not.

Speaking of which, what kind of load was being simulated? The operator could literally put a heavy enough load that your wheels wouldn't even turn the drums. All of that, plus the correction factors applied, will play into how you can compare or use the information they gave you.

Mustang is notoriously used for actual driving simulation and real life loads that the truck/car will see on a daily basis. Once it is tuned, you are good to go. Most that have been tuned on a DynoJet, will then go out and run the car and see how it runs in the "real world" and make adjustments accordingly. It is unfortunately not load based so it can't simulate the real driving situations and circumstances like a Mustang Dyno can.

redcelica

I might have missed it, but what year is your truck?

QwkTrip

I don't know. Only information I have is on that piece of paper.

2012

TJPlatinumEB

Sounds to me you need to go back to shop and find out what parameters were used. Granted, you shouldn't be comparing someone else's results to yours anyway as there are too many variables, but something isn't adding up with those numbers anyway. Even though it is a Mustang dyno, unless they are putting some crazy load on the rollers, I would personally think those numbers are still low.

QwkTrip

Thanks for the input. I thought the HP was low too but needed to hear somebody else say it.

I guess I could put my old (very old) G-Tech on the truck and see what it runs in 1/4 mile. If I can break into the 13's then that pretty much solidifies that these numbers are skewed low.