I went to a place up here that has a mustang dyno and numbers were even lower then what even what mustang dyno's sometimes show.

The question I have is that I read the wrong vehicle weight and told the guy 4500 pounds when the gto is 3775.

How much will this hose up the results a mustang dyno will show?

 

More entered weight will slow the rpm per second acceleration rate thus giving a higher tq number, since less force is being used to accelerate. If you run the dyno inertia only with the load shut off, usually you will see a greater difference in torque down low than you will in hp numbers, but there is no magic conversion number that you can use. You can with the Mustang Dyno software, run it in controlled accel. rate also. If everyone uses the same accel. rate, it could help tighten up alot of the varying numbers between same dynos in different shops.

 

I agree with DynoDR, the more weight you enter the higher your HP/TQ numbers will be, but how much I could'nt tell you. Picking up on DynoDR's running a dyno in a controlled accel rate, if we had more dynos capable of doing this, I agree, we could then set up a uniform standard for testing thus allowing more direct #s comparisons from dyno to dyno. Example, if we all used a standard of allowing the engine to accelerate at a 300 RPM/second sweep rate for HP/TQ #s only, this would eliminate much of the differences we see when a different transmission gear is selected or different rearend ratios. A 3000 to 6000 RPM pull would take exactly ten seconds. This same engine put in a different car would test much closer with the same test. But this would require controlable, measureable load chassis dynos only, so, unfortunately, it wont happen soon.

EJ

 

this is why we bought a car scale to weigh every car as it sits.

 

i dynod with a mustang dyno and the less weight we entered the more power and tq was produced on the machine. i was under the assumption that it put less of a load on the chassis causing to to read higher numbers. i may be wrong though

 

Thats just one of the problems with Mustang's software and controllers. The weight entered should have ZERO effect on the measured rwhp. Mustang, like alot of the older dyno-saur manufacturers have not spent the time or money to intergrate feed back into their controllers, load cells and inertial compensation. In other words, when you are entering the weight, you are really just choosing from a predetermined acceleration rate (200 RPM's per second...for example). A modern system like Land and Sea simulates true road load conditions depending on the power the dyno is observing/measuring real time for the weight and drag of the vehicle. (I think Superflow is similar)

Think about it....if your engine was in a dump truck, would it make less HP????????

The sad part is, the old technology dyno's like mustang, Clayton, Sun are still miles ahead of dyno-jet (pronounced dyno-joke) Believe me, once you use a high-end machine, you will never waste your money on some of the junk out there again.

 

waSStock, concerning the Mustang brand dynos, you have your facts wrong. You do not choose a predetermined acceleration rate when you enter the weight (and body air drag factor). It has feedback and it is so accurate that the drag race simulation is amazeingly accurate if you get these factors correct. The feed back is so accurate that if you do program it for an acceleration rate of 200 RPM per second...for example, it is truly a strait line. Measured HP/TQ does change with load because an engine/drivetrain that accelerates quickly under light load has to overcome its own internal/external enertia. An extreme example of this is a reverse sweep method of HP/TQ testing, yes some advertise their engine HP using this method. With a deceleration rate of XXX RPM/second, an engine will measure much higher HP/TQ because now this engine/drivetrain enertia is working for you. The Superflow also has this measureable load/feedback capability, exellant chassis dyno. Don't get me wrong, I am not pro any specific brand dyno, but here is where we possibly agree, I am very pro measureable load bearing chassis dynos with feedback control, I can not imagine tuning on anything less. Please get your facts strait before bashing specific brands.

EJ

 

I didnt look close at the land-sea but they should have got a better marketing team.. It was hard enough to buy a dyno that says Mustang, but Dyno-O-Mite was just over the edge.

 

waSStock,

You need to go back and do some research. Dynocar is correct... the Mustang dyno is the only dyno that you listed that will accurately simulate road load.

 

sorry I haven't replied...been busy

paynful....you are painfully wrong. You missed 2.

Dynocar...I am assuming you are talking about engine dynos with a reverse sweep test. I remember when that was the only way to test the peakier two strokes! The trick was not "jerk" the absorber and see the spikes you are talking about, but to a reverse step test and let the engine, absorber and load cell stabilize. On the other hand, if your dynamometer software has enterable inertial compensation for each component of a drivetrain...problem solved.

Just as important is inertial compensation for a dyno's components(rollers, drive, belts and absorber) This will also help in the cure for the variances in power the guys are talking about. Just out of curiosity...how much change in entered weight (or the length of the pull) to change how much power.

To see the actual change in power/torque, just graph measured(load cell) torque/power versus inertial torque power....

 

I have not seen the vehicle weight effect the output on a Mustang dyno unless something else was not set-up properly. I have run test in different gears and have seen little differences.

I read the info on Land and Sea and it looks as though they went away from water brake systems and copied the Mustang dyno's eddy current set-up. It is almost blatant. Mustang dyno is releasing new software that will be as good or better than anything out there. Superflow will not accurately simulate road load. If you go to www.mustangdyne.com and look at the article that compares the a dynejet and a Mustang to a 5-wheel style dyno (The most accurate road load dyno) you will see that the Mustang is right in line with what the car sees on the road. We have also proven this through the dynos 1/4 mile simulation. Most of the cars we have run have been within .1 sec and 1mph of what they run at the track.

Mustang dyno's compensate for all of the parasitic losses associated with belts, bearings, ect. to exclude it from the power output.

Almost all of the variations in output are usually due to lack of proper set-up.

 

Are you trying to get a job for mustang or what ....land & sea has had dry gap and liquid cooled eddy currents and better yet A/C dynamometers for years. They also use a water torroid. Copying Mustang???!!! Ever hear of Froude? One of the other problems with Mustang is that they are assemblers, not manufacturers. Go to the Mustang factory and try to figure out how much of their dyno is made in-house....you will be shocked.

I don't know anything about their "soon to be released software"...but it is a little late. Although it is great to see them dropping that DOS based stuff for good...again, they didn't write it...its Lab View! Oh yeah...using your judgement...they must have copied some one else.

To make a long story short, there is no way in the world you will convince me that a Mustang is in the same ball park as a Superflow or a Land & Sea dynamometer.

However...good to see another person realizing the value of a loading, torque measuring dynamometer.

 

you are right about them being assemblers, Superflow also doesnt make their software, they use WinPEP Like dyno Jet. Plus anyone can buy anyones software they want. You sound like a Dynomite salesman too.. What is it exactly that makes it better?? I couldnt tell from their website.

 

Haha...now that I am reading this whole thing...I should be on the pay roll!! Anyhow, I'm not sure how much dynamometer owning/operating you have, but the most important things in a dyno is this=customer service and support, software, and data aquisition. I look at it this way...a frame is a frame...the rolls are round, but they better not be knurled, they must be grooved (or you'll have a polished surface in no time!) The absorber and load cell are completely dependant on the "software and data aquisition"...and the company teaches us how to use the software and data aq.

When I spend 30 to 50k for a machine...I better be able to talk with the people who engineered it...not assembled it.

As far as data aquisition...How many channels? Of these, how many are customizable/0-5 volt? How many samples per second? Can the software be customized to read 3rd party sensors?? As updates are released, does the data aquisition, firmware or software have to be replaced, or just updated through the internet? Get specific about the tech support process? Price of hands on training? (worth every single penny!)

A couple of the questions to ask and compare of any dynamometer co. being considered.

 

waSSTOCK wrote, "Dynocar...I am assuming you are talking about engine dynos with a reverse sweep test. I remember when that was the only way to test the peakier two strokes! The trick was not "jerk" the absorber and see the spikes you are talking about, but to a reverse step test and let the engine, absorber and load cell stabilize. On the other hand, if your dynamometer software has enterable inertial compensation for each component of a drivetrain...problem solved."

waSSTOCK, I did not state, "reverse step test", I stated "reverse sweep test", the results from a reverse sweep is totally different, readings much higher, mostly due to the engines enertia (flywheel affect) on an engine or chassis dyno. Again, a dyno's measured HP/TQ should and will change with different ecceleration/decelleration rates of an engine. A good example of this is to look at the measured HP/TQ in each gear on a "drag race simulation test". The higher the gear the more HP measured, mostly due to engine enertia losses. Our dyno's roller, etc enertia has already been compensated for in our enertia calibration setup. We have found that some cars will produce the same or more HP in 3rd gear then 4th gear. Some possible reasons for this is that there is not as much of an engine ecceleration/enertia change in these two gears and more power is lost at higher speeds due to more friction heat being generated by rotating bearings, tires, etc.

Also, I'm sorry to state this, but you lost a lot of dyno knowledge credability with me due to your unnessesary, inaccurate attack on the Mustang brand of chassis dynos. We have been using a Mustang Model MD 1750 measurable load bearing, feedback chassis dyno for 5 yrs and we, like many, are very satisfied with its operation, reliability and capabilities, more then we'll ever use. It has plenty (16) available input channels with ample sampling rates of 10, possibly more, times per second. We have installed many aftermarket lab level sensors to monitor such things as vacuum/boost in psi, kpa, or hg, fuel pressure, MAF signal and A/F ratio with the Mustang supplied Horiba (the best) wide band system, plus extra alligator clips to monitor other items, such as temps, with the extra channels. These 0-5V channels are very easily and quickly configurable. After 5 yrs of testing hundreds of cars, our roller knurling is still very good on the huge 50" rollers. We can measure up to 1750 wheel HP to 225 MPH, great to have for the powerful drag cars we test. When I went shopping, back in '99", to replace our old chassis dyno, the Mustang MD 1750 dyno stood out, was the best on the market and still possibly is, way ahead of its time in my opinion, I looked at all of them. Then, Land and Sea quoted me a dual roller water brake chassis dyno, totally obsolete, hell, this is what I was replacing, so who is leading who in the chassis dyno market place? Later, the Superflo chassis dyno entered the market and I may have gone with it, very impressive, I've got to have big, single rollers. I don't care if the software, rollers, PAU etc are made by someone else, no one company can be the best at everything, even IBM farms out much of their manufactureing and essembly and software. Even though I've had some issues with Mustang, bottom line, if I had to purchase one today, it would probably be this one again because it will do everything that we need to do now and for the forseeable future. Maybe it's like my Harley Ultra Glide, there may be better bikes made, but it's dam good. Just wish Mustang had a different name and gave higher numbers then DynoJet.

EJ

 

hey dynocar...don't take a reply to "just another thread" questioning hp results using Mustang dyno's personal...

But the fact remains that dynamometer technology is going forward at a very rapid rate. 16 channels and 10 samples per second is unacceptable for the money these machines cost and useless for any type of real life transient testing. To put that into 2004 perspective, 22 channels and 800 samples per second (USB) is closer to the minimum. Maybe I am quick to point out my dislikes with Mustang, but I have my reasons. I once defended them myself.

As far as dyno knowledge, I'll give you this freebie....water absorbers have a purpose and will never be obsolete...Water absorbers are one of the only reasonable means of doing any type of steady state testing without a dramatic loss in absorption capacity due to heat soak. As far as an affordable low inertia absorber that has tremendous capacity that can maintain the hp absorption level for as long as it has water, nothing better. In fact, one of the best chassis dyno's I ever worked with was a water absorber coupled to an a/c motor...motoring capability opens up a whole new world of tests. But I think this is where you an I differ. I am not brand loyal...I am always seeking the best bang for the buck. I wouldn't care if it said "Unknowledgable and Uncreditable Peoples Dyno" on the side of the machine....if it has the latest and greatest equipment backed by excellent customer service....they get my vote. Your last reply also explained to me a lot of our different opinions...we use dynos for different purposes.

Don't be sorry about your opinions of people...

 

Opinions are like ********, everyones has one.

What I don't like is Arrogant ********.

Obviously you love your Land and Sea dyno and we are all happy for you.