05Z33

iTrader: (11)

This is so true. The dyno is really only a tunning tool. A week before getting tuned on this same dyno; I was at a dynojet and made 400whp. On that same tune we did a base line pull on the mustang and made 322whp(this is more than 10% difference). Bottom line is after tunning my car made somewhere between345-350whp and my cog belt got stripped. I know Jack had fun finding cog teeth for days all over the place. Anyways I gained close to 25whp on the new tune, and that is the number that counts more than anything else.

I wish my car would have been ready for this day. I would have housed all you putas.

















Then Gus would have put his car on, and he would make mince meat out of all of us.

TheOtherRob

iTrader: (14)

Ok I understand know. I never heard about adding 10% to my numbers when I was there. I thought the numbers everyone was posting where true mustang dyno numbers. It all makes sense now. Thanks for the clarification Gus.

westpak

iTrader: (19)

LOL I wouldn't do that

And I think Jack is still finding pieces of your belt even though we moved to the new location LOL

Well with yours we were simply comparing your numbers on the same dyno, people at dyno day were asking about what it would be on a dynojet

And my bad also, having been around this dyno for almost 4 years I assume everyone knows about it.

CrillZ

i'm so upset i couldn't go....

jruocco

iTrader: (7)

really, i heard you made 145 whp? should have had the interlagos wing for more HP!

CrillZ

lol...na man...ive been sick as a dog. i woke up at 2pm that saturday. with the meds i didnt hear the phone, john called me in the morning. ive been out of touch with everything the whole weekend.

TheOtherRob

iTrader: (14)

Yeah, I didnt realize that everyone was posting dynojet equivalent numbers.

Tuned2JZ

Hey Gus, I found out what the dyno mode settings for my car were supposed to be set to...And plus it was supposed to be dynoed on 5th gear, not 4th...

I should have done research on this before taking it to the dyno. But being busy with work, etc...so on and so forth, I just let this go by, and went to dyno day, just cuz it was dyno day...Plus I simply thought you guys knew how to dyno my car...But it's a first for everything, and it's not a biggie...I guess next time we'll know what to do.

Yes I understand that a dyno is simply a tuning tool...But being that we were in this whole topic about dyno machines and the difference between a dynojet and a mustang dyno is because from what I've seen throughout a bunch of forums that claim that a dynojet is more accurate than a mustang dyno and that a mustang dyno reads 10-13% less than from a dynojet.

I'm not a dyno expert!!!

All mustang and dynojet machines aren't the same. Some will read different numbers than others...I was told about this from a friend of mines today that I just found out works for Mak Performance in Hialeah, and that they too have a Mustang dyno...I also went online and saw a few C63's doing around 375-383 to the wheels stock on a mustang dyno...So go figure...

Now for mines to read only 335whp on the mustang dyno this past Sat at HP, simply blew my mind and I knew for a fact that that wasn't right and that the settings on the car weren't set correctley...Well now I know...From the car being 451hp at the crank, to then have it dynoed at only 335whp at HP Logic? That's a 116hp difference

But there's no hard feelings here with you Gus, Jack, and Roger...The car just wasn't set correctly on dyno mode. And don't get me wrong, I still had a blast and a half on dyno day and can't wait to do it again next time...Everything was well organized and the pizza and drinks were great!!!

Now since I know what the correct settings for my car needs to be set to and to be runned at 5th gear instead of 4th during dyno, having my stock wheels put on, and having my hood opened up instead of being closed which was the case this past Sat (which was something I should have remembered to do when I got out of the car after parking it on the rollers), to have lots of air being blown into the intakes and at the same time letting out all of the hot vapor coming from the extremely hot V8 motor during the runs...then we should see different and higher numbers next time...As a matter of fact I'll be passing by Mak Performance this Sat just to see what my car does this time around.

Sorry for this long post, but that's just me...I'm very detailed

Oh and btw for Amy to make 257whp with only intakes, test pipes, and Nismo exhaust...only 5hp off and compared to the Z that has made 262whp with not only exhaust, intakes, and HFC's, but with a TUNE on top of that...Well that's my girl!!! I can only imagine with a tune how much more Amy would have made. I know it would have been well over 262whp...

westpak

iTrader: (19)

Milton I am not sure what the big issue is with your numbers, your own numbers prove the theory that your horsepower was right on the money for the Mustang dyno, not sure what you were expecting.

451 at the crank would result in about 360 at the rear wheels when taking out 20% for drivetrain loss in the transmission. then take into account the 10% difference between a dynojet and mustang dyno and you would get to about 324 RWHP. So where is the beef?? I say almost in all of this because there are many variables that go into this, from engine tolerances, to condition of moving parts to ECU.

you will also find that 4th to 5th gear wont make too much of a difference at those power levels, you may see 5 hp more.

So what were you expecting on a Mustang dyno?

Nismospeed4life

iTrader: (21)

Mustang VS. Dynojet


I didnt author this. It is a copy-paste done w/o prior consent or approval (from another's copy-paste efforts i found online)

this should help us all understand the difference b/w the two major dynos, and as to why there are considerable differences in their output readings.....


"It's been said that a man with a watch always knows the correct time, but a man with two watches is never really sure. Unfortunately, there are no proverbs about a man with two knowing how much power his car really makes. In this article, we'll examine two popular chassis dynamometers and explain why each will give us a different rear-wheel horsepower for the same engine. We test both the Dynojet model 248 chassis dyno located at Strope's Speed Shop in Washington, Pennsylvania and the MD-250 Mustang chassis dyno located at Speed Nation in McDonald, Pennsylvania. We also performed testing at Keystone Raceway in New Alexandria, Pennsylvania, using a dyno system
from West Automotive Performance Engineering.


Dynojet
The Dynojet chassis dyno is referred to as an inertia-type dynamometer, because large drums provide an inertial load to the drivetrain instead of a friction brake. The working end of the Dynojet includes two 48-inch diameter drums that are mostly below the surface and driven by the vehicle's drive wheels. In the photos of the Dynojet, notice how the rear wheels are centered on the drums and there is one drum per wheel. This will become important later.
The vehicle is typically run in the transmission gear closest to 1:1 (Forth gear for manuals and Third gear for automatics) to or a variable load that maintains a preset engine rpm or vehicle speed. This feature is ideal for forcing the vehicle to operate at certain loads for tuning. The Dynojet can also measure air/fuel ratio while testing.


Mustang
The Mustang chassis dyno uses an Inertia load as well as an eddycurrent brake load to simulate the "actual" load (combined aerodynamic plus rolling frictional load) that the vehicle would experience when in motion. Notice in the photos how the rear wheels sit between two smaller 10.7-inch diameter rollers. There has been some discussion about the tires getting "pinched" between the rollers and creating more rolling friction, but no substantial evidence of this could be found. However, Mustang has a dyno (MD-1750) with a single 50-inch diameter roller per wheel that alleviates the wheel-pinch concerns. The internals of the Mustang dyno are composed of an eddy current brake to provide a variable load and an inertial disc to provide a fixed load. Mustang claims because its dyno loads the vehicle as it would be on the road, you can perform 0-60 mph, 0-100 mph, and quarter-mile measurements on its chassis dyno. Speed Nation has obtained quarter mile times within 0.1 second of actual runs at the track. We're not sure how the launch dynamics are simulated on the Mustang dyno, which
includes weight transfer, acceleration, jerk (the derivative of acceleration - how fast the acceleration occurs) and some other variables. The Mustang dyno can also measure the air/fuel ratio while testing.


CorrectIon Factors
Correction factors are used by both dynos to account for varying atmospheric conditions such as temperature, pressure, and humidity. The measured horsepower and torque are multiplied by the correction factor to obtain the corrected values. This is similar to the corrected times and speeds provided by some quarter mile tracks. Theoretically, you can dyno on a hot day in the high altitude of Denver and on some other cool day at sea level and produce the same corrected horsepower even though the observed horsepower you are producing at each location is different. Both dynos calculate a correction factor based on a Society of Automotive Engineering document (SAE-J1349). When testing was performed on the Dynojet, the correction factor was 1.10, which means the observed numbers were multiplied by 1.10 (adding 10 percent) to get the corrected values. The correction factor for the day when testing was performed on the Mustang dyno was 0.9595 (removing 4.05 percent). The correction factor when road-testing at
Keystone Raceway was 0.962, a correction reduction of 3.8 percent.

Nismospeed4life

iTrader: (21)

Testing
Testing was performed on each dyno using a '00 six-speed Z28 Camaro. We measured the horsepower and torque versus engine rpm in Second, Third, and Fourth gear. The test data also included how fast the engine accelerated in Second and Third gear (in rpm versus time) to be compared with actual road tests to assess each dyno's loading of the drivetrain. After each individual test we let the engine coolant temperature as displayed by our AutoTap OBD-II scanner to read between 200 and 205 degrees F for consistency. Dynojet sent out a representative to Strope's Speed Shop to verify calibration and witness testing. Calibration for the Dynojet is just a matter of verifying that the computer's configure file has the proper load-roller inertia factor. There are no manual calibrations for the Dynojet.
The road tests were pertorrned at Keystone Raceway to provide a level surface to measure the vehicle's rpm versus time in Second and Third gear using AutoTap. Chad Fellabaum of C&C Racing in Pennsylvania weighed the car so the exact weight could be used for the Mustang dyno loading to be compared with the road tests.
The dyno curve charts show horsepower and torque versus rpm in Third gears for both chassis dynos. You can also see that the Dynojet dyno measures a higher rear-wheel horsepower than the Mustang dyno.
The Dynojet measured 5.1 percent higher horsepower in Fourth gear, 7 percent higher horsepower in Third gear, and 8.2 percent higher horsepower in Second gear. We will try and explain this difference a little later.
Graphs 8 and 9 show the engine rpm versus time when the vehicle was loaded by the Dynojet dyno, Mustang dyno, and the actual road loading at Keystone Raceway in Third gear. You can see that the Mustang dyno loaded the car much closer to the actual loading in Second and Third gears.
Why Is loading the Vehicle Important?
The answer to this Question is twofold. First, the engine produces horsepower at the flywheel (brake horsepower) that is reported by the automobile manufacturers. Engine power is coupled to the rear wheels by a transmission and a rearend. But this is no free ride - there are losses in both the trans and the rearend. Therefore, the power to the rear wheels is equal to the flywheel horsepower minus the drivetrain power loss. The drivetrain losses are
mainly composed of three loss areas: friction loss, inertia loss, and viscous loss. The friction loss is largely due to the surfaces of the gear teeth rubbing against each other. Gear friction is related to the torque being transmitted through the drivetrain. The gear power loss is related to the speed at which the torque is being transmitted. This is why it is recommended to have a transmission cooler for towing. The transmission must couple more torque to pull the boat resulting in more frictional power loss, which shows up as more heat in the transmission to be taken away by the transmission cooler.
Inertial loss is related to the rotational acceleration (i.e., angular acceleration) of the drivetrain components. The inertial loss does not result in a power loss (i.e., heat) but absorbs energy that can be coupled to the rear wheels. This energy actually gets stored in the drivetrain components. The stored inertial energy in the flywheel keeps the revs up while the clutch is pressed in during shifts. The inertia loss is more pronounced in lower gears (i.e., First or Second) when the acceleration is highest. The viscous loss is basically the pumping of lubrication fluid in the transmission and the rearend. This is one reason why you get better e.t's when the
drivetrain is warm, because the oil is thinner and provides less "pumping loss." Therefore, to measure the actual rear-wheel horsepower, the drivetrain must be properly loaded to obtain the correct drivetrain loss. If the dyno provides a lower drivetrain load, then the drivetrain losses will be lower and the resulting rear-wheel horsepower will be higher.
The second reason why vehicle loading is important is that the newer computer-controlled vehicles use engine load as a control parameter. For example, ignition timing is a function of engine load. You will see higher timing advance when revving the engine in Neutral than you will when the vehicle is fully loaded at wide-open throttle in Third gear. This engine loading factor (and airflow dynamics, which is beyond the scope of this article) can help explain why some people have dyno'd identical to a friend's engine on a Dynojet dyno but got different results on a Mustang dyno.
Which Dyno Measures the Actual Rear-Wheel Horsepower?
West Automotive Performance Engineering has developed a proprietary device that independently measures a vehicle's actual speed and acceleration. This device is similar in operation to a fifth wheel but doesn't use accelerometers that can be influenced by the vehicle's body tilt. Using the vehicle's speed, acceleration, and weight (mass) and the application of simple physics equations, the exact horsepower and torque can be calculated. The horsepower and torque measured by West Automotive Performance Engineering's dyno is actually the horsepower made-good, or the horsepower left over to accelerate the vehicle after all the aerodynamic and rolling-friction losses have been overcome. These losses were accounted for and included West Automotive Performance Engineering's dyno so that a comparison with a chassis dynamometer can be made. The Mustang dyno includes the aerodynamic load that it places on the drivetrain as part of its reported rear-wheel horsepower and torque. Stated another way, the Mustang dyno does not measure the horsepower made-good.
Graphs 7 and 10 show the horsepower and torque versus rpm in Second and Third gear, respectively, for the Dynojet dyno, the Mustang dyno, and from road testing with the dyno from West Automotive Performance Engineering. You can see that the horsepower and the torque, as measured on the road, are closer to the Mustang dyno measurements. Also from the acceleration tests you can see how the Mustang dyno loads the vehicle very closely to how it will be actually loaded on the road. Based on our test data, the Mustang dyno loaded our test vehicle and measured the rearwheel horsepower closer to what the vehicle experiences on the road.

Conclusions

The Test Results table summarizes the testing that we performed. Keep in mind that the peak numbers are influenced by the amount of smoothing or averaging done to the final data. For comparing dyno plots to determine losses or gains, don't focus on the peak values but take a visual average by comparing the before and after curves on the same graph. If you can't see a marked improvement on the dyno, you probably won't see a performance improvement on the street. Also, realize that both the Dynojet and Mustang chassis dynamometers are useful tools that have excellent repeatability. Both dynos measure the correct horsepower and torque for the load that they apply. Both dynos will show losses or gains from modifications. It is recommended that you pick a dyno for your baseline testing and stick with that dyno type and dyno location (and dyno operator) for subsequent testing. Always start at the same engine coolant temperatures before each run. Also, use an OBD-II diagnostic scanner like AutoTap (from B&B Electronics) to monitor your engine's operating parameters. This will provide the best indication of power improvements or losses. We like to monitor the engine-coolant temperature, timing advance, knock retard, pre-cat O2 voltage, and rpm. Monitoring the engine-coolant temperature lets you make sure your engine is at the same temperature before each run to produce the most consistent results. The timing advance and knock retard indicate if any detonation is occurring that results in reduced timing and lower horsepower. After doing some research, the pre-cat O2 voltage can provide a correlation to the air/fuel ratio even though the O2 sensors are not too reliable in this air/fuel ratio region.

The bottom line:

dyno numbers are for show, and track times are for the dough!

-author unknown

westpak

iTrader: (19)

Unfortunately not all load based dyno owners keep their dynos as they should and because people complain about their numbers being low compared to what they have heard on forums they go ahead and adjust the settings so they read similar to dynojets and then people would be happy.

We refuse to do that and keep the settings as they should be, because some times we get customers that are knowledgeable and are not surprised by the low numbers in fact they expect them and what they are looking for is a gain in the tuning or realize they will get higher numbers on a dynojet so it would be embarrassing and dishonest if our numbers were the same or more than dynojet.

myladyz33

iTrader: (2)

i thought the 331 that the c63 put down was spot on for a mustang changing the gears, wheels, and opening the hood wont change the fact very much dynojets just make people happy because of the higher numbers mustangs are optimum for tuning

350z spd

iTrader: (10)

Yes exactly. First off your car was spot on for a mustang dyno for the numbers it put down. Now for having your hood open and different wheels wouldnt make a noticeable difference in power. why not have your car dynoed the way you drive it on a daily basis. That way you know how your car is with what you have on it. Each car varries from factory. I think that there is always an issue with dynos trying to make their customers seem like there car is putting down bigger numbers then they really are. I think that everyone who dynoed their car at the dyno day made good power for the dyno that they were on(Mustang Dyno). Im sure there are a few people in need for a good tune. I know when I put my car on the dyno on my first motor (rev-up Oil Consumption) I was really rich for being N/A. I know for the mods I have on my car, I am now in the range where I should be before a good tune. I am happy where I am at and hoepfully soon My Numbers will go up Dramatically with something special I have up my sleeve. Just my

Tuned2JZ

Like I've said already I'm not a dyno expert here...I raised my numbers Gus by 10% like you told me to on Sat, because like I told you on Sat, 331-335whp could not have been correct for the car, especially from all the C63's that I've seen, rather it be on youtube, or on the Benz forums doing stock between 370-380+whp. After bringing up my numbers by 10% like you told me to, my numbers were about correct of what my car should really have down on whp more or less.

And I brought up the whole issue with the comparison between a mustang dyno and a dynojet from tons of people and experts throughout other forums stating that mustang dyno's tend to read 10-13% less than a dynojet...

I'm not trying to pick a fight here...

All I was trying in my case here was that I found out what the correct dyno mode settings for my car should have been set to, and that could have made a difference in numbers on the dyno...But you know what? Who knows...And at this point I really don't care anymore...

I have no beef up in here!!!!

This thread shouldn't have been blown up to this...

The more throughout the day I've been looking into this, the more I realized that all dyno machine readings aren't the same. It's more of a tuning tool I guess...If I ever put more mods into the car and do an ECU upgrade to it, I'll simply use the dyno as a tuning tool and not bother about all of this that has been said today and misunderstood about...

350z spd

iTrader: (10)

Hey there is no fight hear, Im Just trying to give you information and background info about my experience and knowledge of this dyno. Trying to be the most informative to help someone out. No worries here man

05Z33

iTrader: (11)

We need to put all this dyno stuff aside and have a track day at PBIR. 1320 times are the best numbers to tell you what you need to know about your car and driving skills. So who's up for that?

350z spd

iTrader: (10)

Pierre, Lol maybe you should go back to a Z. I dont think you know how to handle your audi tt. I mean you didnt even know how to turn off you TCS

Tuned2JZ

Nah that's cool and you said it very well...And I thank you for that...

But seriously when Gus said where is the beef? THERE IS NO BEEF!!!I HAVE NO BEEF!!!

I'm just stating my opinions and point of views that I've been reading about from other forums and about finding the correct dyno mode settings for the car and that it could have done a difference...THAT'S ALL!!! Would it have done a difference? Who knows!!! Sooner or later I'll find out...

Nismospeed4life

iTrader: (21)

Bring it!