Mustang dyno vs. others
Mustang dyno vs. others I got my car tuned today on a Mustang dyno. With mods in sig it made the numbers in the sig. Honestly, after what I've read I was expecting about 340ish. He told me (before I even said anything) that the Mustang dyno is more of a true reading than other dynos. He said other dynos make claims that are roughly 10% higher than the 'true' numbers. Can anyone confirm this with some sort of actual evidence and not just an opinion. My numbers don't really bother me. Honestly, I just wanted it tuned and to get some sensors turned off. I just wanna know if what the guy told me was true.
Thanks!
Thanks!
mustang dynos put a load on the car as if it were actually driving on the road, hence why the numbers are lower then dynojets which dont put a load on the motor and offer less resistance.
The fact that a Mustang dyno loads the vehicle is NOT why the measured number is usally lower. DynoJet numbers are calculated from acceleration rate of a know inertia and supposedly have a "adder" factor built in the software.
Mustang (or other load cell dyno) MEASURES the force (or torque) with a load cell. Generally the more load you apply to the vehicle being tested the HIGHER the measured number will be. This is from the fact you are reducing the acceleration rate of the test vehicle which will give you a higher test number.
Same as going from a 500 rpm/sec sweep to a 300 or 150 rpm/sec sweep or a step test on any common engine dynamometer.
Mustang (or other load cell dyno) MEASURES the force (or torque) with a load cell. Generally the more load you apply to the vehicle being tested the HIGHER the measured number will be. This is from the fact you are reducing the acceleration rate of the test vehicle which will give you a higher test number.
Same as going from a 500 rpm/sec sweep to a 300 or 150 rpm/sec sweep or a step test on any common engine dynamometer.
Mustang dynos are loaded dynos, meaning load is applied to the rolls to provide resistance to the tires. An eddy current absorber measures torque and hp is calculated. Loaded dynos actually measure torque, dyno jets do not. Dyno jets are inertia dynos that are basically glorified accelerometers, and can be affected by things like tire and wheel sizes. Supposedly dyno jet numbers are inflated anywhere from 5-15%. They have a correction factor, and when a car is dyno'd on a dynojet they should give you the corrected numbers.
Personally, I dont like inertia dynos because they dont measure torque, and are susceptible to variables. I dont trust numbers off a dyno jet, but I do off any other loaded dyno (like a mustang or a superflow).
Personally, I dont like inertia dynos because they dont measure torque, and are susceptible to variables. I dont trust numbers off a dyno jet, but I do off any other loaded dyno (like a mustang or a superflow).
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I'm no pro, but I've always heard that the numbers a dyno jet gives you are more accurate. If you do the calculation for the track time and ET a car runs to get horsepower, it ussually comes out to what a dyno jet gives you, and not a load dyno. I have NO clue what that calculation is but I've heard it from more than one person. Plus, too many things to F*** up when using a load type dyno. I've seen 500 whp dyno jet cars make like 410 on a mustang dyno because the operator messed something up in the set up. IDK, I just havn't had very good experiences with mustang dynos, where as everytime I've been to a dyno jet, the numbers have always been the same or very close. Just my .02 cents.
You just have to figure, if you make x horsepower on a load type dyno, add something like 8-10% to get the dyno jet number.
You just have to figure, if you make x horsepower on a load type dyno, add something like 8-10% to get the dyno jet number.
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Staging Lane
Joined: Sep 2009
Posts: 97
Likes: 0
From: Pittsburgh
I work in a shop where we use a mustang dyno, everyone is usually heart broken when they get on the rollers. They do read lower, exact figures I cannot tell you. When people are scared they wont make the numbers they want they make sure they skip us and go to the local dynojet dyno 
From my experience, the final number doesn't matter. What matters is that you use the same dyno going forward so that any mods you make can be compared to prior runs. This is very important. My last dyno run was down 4.5% across the RPM range, after a little head scratching we believe it was the winter fuel blend that was put in the car just before the dyno session. Winter blend has less BTU/gallon then summer blend. So be careful what you read, dyno numbers sell parts and provide bragging rights. I would love to have huge numbers, but a good safe tune is a lot more important and the Mustang dyno has an advantage there in my opinion because the tuner can load the car during the tuning session.
Most mustang dynos are around 8% less than dynojets from what I've seen on here but every one could be different. 323.7rwhp x 1.08 = 349.6rwhp which seems correct for those mods and m6.
You can have a different reading between two dyno jets. my first set up was dynoed on speed inc's dyno. It read 423hp 407tq. the same set up was on hard core's dyno and got 395hp 380tq. I always thought speed inc's dyno was high due to another jet reading lower. I then went to a mustang dyno and got 370hp 358tq. I'm not saying all or most will read this different,but i was shocked when i got the numbers from a stang dyno. I know one guy who saw only 3hp differents between a jet and stang dyno.
Last edited by mike c.; May 10, 2010 at 06:11 PM.
As Vettenut's said -the best thing is to use the same dyno when adding mods to see the difference. I use to run a Dynojet and it worked well BUT you could easilly run too much timing which could make more hp but it would detenate on the street. For tuning I like the Mustang alot more.With the load you won't over advance the timing due to the load the dyno put's out.
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dynojets numbers vary from one to another. I can tell you i have had my car dynoed 4 different times on 4 different dynos and none make sense compared to the other numbers.
TECH Apprentice
Joined: Nov 2004
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I am not referencing these earlier posts / threads to add any controversy to this thread, but there is some very interesting info in them.
https://ls1tech.com/forums/dynamomet...-dyno-jet.html
https://ls1tech.com/forums/dynamomet...mbers-low.html
https://ls1tech.com/forums/dynamomet...-dyno-jet.html
https://ls1tech.com/forums/dynamomet...mbers-low.html
Last edited by Gary Wells; May 11, 2010 at 10:40 AM.
You made good power for your mods. Just remember the rules:
Rule #1: Every dyno is different. Some are old, some are new. Some shops have weather stations, some don't. Some apply a manually-entered correction factor, some don't.
Rule #2: An inertial dyno (like a DynoJet) is just a heavy spinning drum. Typically, these are 3000 lb drums, because a 3000 lb car will spin a 3000 lb drum as if it was driving on a flat road. Cars that weigh less than 3000 lbs will dyno as if they are driving ever so slightly uphill (less power than actual). Cars that weigh more than 3000 lbs will dyno as if they are driving ever so slightly downhill (more power than actual).
Rule #3: A load bearing dyno (like a Mustang) applies a variable electronic resistance to the drums to simulate street load. The load is calibrated when the operator enters your vehicle's weight. Typically this results in a more accurate and consistent reading
Rule #1: Every dyno is different. Some are old, some are new. Some shops have weather stations, some don't. Some apply a manually-entered correction factor, some don't.
Rule #2: An inertial dyno (like a DynoJet) is just a heavy spinning drum. Typically, these are 3000 lb drums, because a 3000 lb car will spin a 3000 lb drum as if it was driving on a flat road. Cars that weigh less than 3000 lbs will dyno as if they are driving ever so slightly uphill (less power than actual). Cars that weigh more than 3000 lbs will dyno as if they are driving ever so slightly downhill (more power than actual).
Rule #3: A load bearing dyno (like a Mustang) applies a variable electronic resistance to the drums to simulate street load. The load is calibrated when the operator enters your vehicle's weight. Typically this results in a more accurate and consistent reading
That being said, there are also some very good dyno operators out there. Just stick with the same dyno before and after mods and you'll be good. Also stick with a place that doesn't mind if you're there when the car is dynoed and you can ask questions, etc.
Not sticking around for the actual dyno process has, in the past, produced dyno sheets printed out in STD correction or uncorrected and even shops trying to pass off other people's dyno sheets as my brother's when we went to pick up the cars.
Last edited by ScreaminRedZ; May 19, 2010 at 02:48 PM.
