BlownV8

No. HP = tq * rpm/5252 Wheel hp is wheel hp and crank hp is crank hp. Unless you have the car on an actual engine dyno it isn't really accurate to convert it from the wheels to the crank. Measure it on an engine dyno or report RWHP. Maybe you can share the correction factor that you are using from the wheels to calculate your crank numbers?

E552006

But RWHP is RWHP
Less a lot of variables.

Cory @ Kleemann

All inertia dyno's measure what? How fast a fixed weight can be accelerated- this is the measurement of torque. Using the formula you posted, it then calculates HP, but also uses correction factors for ambient pressure, temp, humidity, etc. So, our Dyno not only measures the acceleration of that fixed weight, it also measures the deceleration (in neutral) as well. Then using another formula, it will give you a number that is the drivetrain loss, add that drivetrain loss to the torque measurement it took during the acceleration run, and you've got a very close estimate of what crankshaft HP/TQ will be. The dyno does not use a percentage loss, nor does it use a correction factor for drivetrain loss- it measures the rate of deceleration, just like any other dyno measures the rate acceleration. If you're telling me that measuring the rate of deceleration is somehow inaccurate, then you are also saying measuring the rate of acceleration is not accurate.

rflow306

This is a good article explaining how a dynojet works pasted below.

Now, for those of you who really want to understand how that Dynojet Dyno works, here's your chance!


You know the stuff you were supposed to remember from high school physics class about Force? No, not John Force. Newton's Second law of motion. On an inertia dyno, the computer calculates the acceleration of the dyno drums by continuous measurements of their speed and the time. If the surface of the drums spin from a speed of zero to a speed of 10 feet per second in one second, then their surface acceleration is 10 feet per second per second, or 10 ft/s2. Sound familiar?

Force = Mass x Acceleration

That's Newton's 2nd Law of Motion. Force is one of the things that we're looking for. Force in the automotive world is called - you're supposed to shout it out..... torque. Torque is rotational force, and its most common unit for us is foot-pounds. Plain and simple, if you have a 12-inch wrench and you lean on the very end of the handle with 10 pounds, you're applying a force of 10 ft-lb. to the nut you're trying to turn.

The mass in our case gets a bit complicated. Mass in most cases is easy - how much does the object weigh that you're accelerating. In the case of the dyno drums, however, it's not that simple because we are not "moving" the drum, we're spinning it. We are not creating a "translational" motion on the drum, we are creating a "rotational" motion.

To understand the difference, think of the actual dyno drums. Say each one weighs 2700 pounds. It would take a pretty impressive force to push a 2700 lb. object across the floor. Now imagine just spinning those drums. The shaft going through the center of the drums rests on two hugely expensive bearings. The drums spin with the slightest touch. To calculate away this difference, physicists came up with the "mass equivalent" of a rotating body, which is very similar to the "moment of inertia."

We haven't measured the actual numbers (the computer program knows them), but let's just pretend the mass equivalent of the dyno drum is 50 pounds. That means that spinning the 2700 lb. drum is like pushing a 50 lb. weight across the floor (yes, there's friction, but lets not go there for this demonstration, ok?)

Some people say that this is not the correct way for calculating horsepower, but in this case - it is. Many of you are familiar with the hp = rpm x torque / 5252 formula. In many situations, that formula is the way horsepower is calculated. In the case of the Dynojet dynamometer, it is not. The Dynojet calculates horsepower even if there is no torque reading, and it does this in the manner shown. Those of you that have had your vehicles tested at a shop and have watched the computer screen closely have seen that the computer plots out only the horsepower after each run. It does this because sometimes there is no torque reading, or the torque reading is faulty. This can happen because inductive and optical rpm pickups may not be perfect, and/or your ignition system may make things go a little haywire. If the rpm readings are not perfect, and the computer used the rpm x torque / 5252 formula, the hp reading would be inaccurate.

Work = Force x Distance

Now we get to the good stuff. Calculating the work is pretty simple for the computer. It just figured out the force, and it can easily figure out the distance because it knows the circumference of the drum and how many times it has rotated.

Power = Work / Time

We have an answer. Somewhere the computer factored in the bearing drag, and it throws some constants into those formulas to get the numbers to come out into the right units, but you get the idea.



In the real world -

What's the difference between horsepower and torque?

Basically, Horsepower is the ability to do work in a given amount of time, and Torque is strength.

The analogy that most people seem to understand is that of a human weightlifter to an automobile engine. An engine in a typical 4 cylinder commuter car might have 100 hp and 100 ft-lb. of torque. How about the weightlifter? Let's hook him up to a handwheel that has a 1 ft. radius. A big strong guy should be able to push and pull on that wheel with 100 lb. of force, therefore generating 100 ft-lb. of torque, easily equaling the engine. When it comes to horsepower however, our guy is going to fall short. One horsepower is defined as lifting 550 lb. up one foot in one second. Two horsepower could be 1100 lb. up one foot in one second, or 550 lb. up two feet in one second or 550 lb. up one foot in half a second, (you get the idea.) Let's attach a rope to the handwheel and tie that to a 550 lb. weight. How is our weightlifter going to do now? You can imagine - not very well. Attach the handwheel to a gearbox and then to a wheel with the rope and he might be able to perform some work. Unfortunately, he'll be lucky to generate a few horsepower before petering out. Bottom line - both the engine and the weightlifter can be strong, but the engine can perform a lot more work.

Which one do I want for my vehicle?

Torque is what gets you started. Torque breaks your wheels loose when you launch, and torque allows trucks to tow heavy loads. Torque accelerates your vehicle. Combine some measure of torque with speed and time, and the result is horsepower. Horsepower is what gets you through the quarter-mile. As far as which one is best, the answer is - it's best to have both. High torque numbers allow you to leave the gate quickly and power out of turns. High horsepower numbers keep the vehicle accelerating and give it a higher top end. Just as important as the peak numbers, though, is what your curves look like, and where those peaks are. An engine might have a high horsepower peak at a high rpm, and a graph that looks like one side of a steep mountain. This means that in order to take advantage of the high horsepower, the rider must keep the engine at that high rpm. This requires more shifting, which can result in lost time. Flat curves mean that the rider can take advantage of the engine's power without as much shifting, but in order to obtain a flatter curve, an engine tuner must sacrifice some power.

To determine the type of curve that will work best for you, take into consideration the following:

Riding Style
Reliability (peaky engines which require lots of clutch work and sustained high rpm don't last as long)
Skill (smoother power makes beginning and intermediate riders faster, while experts can benefit from a peakier curve)
Type of riding - Especially if you ride widely varying terrain. Say you race MX once a year, but ride tight trails every weekend. You'd be tempted to build an engine that would rip on the MX track, but would that be the best option for the majority of your saddle time?
The engine's original design and intended use. Yes, you can make a Banshee into a Tractor Pull contender, or race a Grizzly on the local TT track, but completely changing an engine's power curve is expensive and normally not very effective.




newtonslaw







Newton's Law of Universal Gravity was and perhaps still is one of the greatest discoveries in the science of physics (yup, even greater than the Pastrana rule of 360). Sir Isaac Newton came up with this theory by comparing the acceleration of the Moon with the acceleration of objects on the Earth. The law of universal gravity depends on the amount of matter in the objects being attracted to each other, and the distance between the objects being attracted to each other.

Isaac Newton formulated the general principles of motion into the Three Laws of Motion.

First Law of Motion: An object at rest tends to stay at rest and an object in motion tends to stay in motion in the same direction and with the same speed unless acted upon by an unbalanced force. There are two parts to this law, one which predicts the behavior of stationary objects, and the other which predicts the behavior of moving objects. The behavior of all objects can be described by saying that objects tend to ‘keep on doing what they're doing', unless acted upon by an unbalanced force.

Second Law of Motion: Acceleration or increase in speed of an object is directly proportional to the magnitude of the force, the same direction as the force, and inversely proportional to the mass of the object. Inversely proportional means if one value goes up, the other value will go down, assuming everything else stays the same.

Forces result from interactions.

Third Law of Motion: For every action, there is an equal and opposite reaction. For every action force, there is an equal in size and opposite in direction, a reaction force. Forces always come in pairs, known as "action-reaction force pairs". Identifying and describing action-reaction force pairs is a simple matter of determining the two interacting objects and making two statements describing ‘who is pushing or pulling on whom', and in what direction

Evolution Marine

CoryU - Nice explanation on the Enertia Dyno.

rflow306 - Good article on "Force", "Work", and "Power". - Bob

BlownV8

Yes, however, you can add or remove the correction factors and change the factors to manipulate hp and tq output.


Yes, but that, IMHO, is not very accurate and as you said that it is an "estimate." That's why I'm not a big fan of trying to convert it back to an "estimated" crank hp figure. Just report the RWHP, correction factors if any, and you don't have to do an "estimate" when you get your power output.

I'm not saying that you guys are overrating the improvements but I think you lose some accuracy trying to convert it back to a "crank" number without an engine dyno. Your way of measureing hp is good to see the gain or loss in hp with the improvements, as any dyno is good for, but it is not good for an independent party to see what the output is at the wheels or when comparing the power of other cars the utilize a DynoJet or Mustang dyno.

Grumpy666

The chassis dyno was never intended to be an absolute measure of engine torque. There are just too many loss mechanisms and variables to get an accurate measurement of crank output. It's best used to determine changes in torque caused from a modification. Even then you have to be careful that the variables haven't contributed to the measurement.

The dual-roller, inertia dyno that measures deceleration will actually under-estimate crank output as engine torque is increased. The fritional losses of a drivetrain coasting to a stop in neutral will be constant. But the fritional losses of a drivetrain will increase as engine torque increases. This increased loss cannot be measured during deceleration. But it will be measured during acceleration and will result in reduced output.

BTW - Keemann uses a DynoMet dyno, not a DynoJet.

rflow306

Cory question? After the pull you put the trans in neutral and then it calculates drive-train losses. The reason I ask is in neutral there is no line pressure in the transmission therefore you are only turning the converter, fluid pump, input shaft, planetaries and the output shaft. How does it take into account the drag from the clutch pack, fluid friction and the rest of the hard parts like the sunpac which just freewheels in neutral.

BTW: I'm referring to an E55 tranny please explain if I'm incorrect.

04E55 AMG

Take it from me...Your car will ROCK, ROCk

vraa

Dang straight.
There'a a reason why everyone suggests Kleemann for almost all their Mercedes related tuning needs!

Rock

Spero,

If I trap at over 120mph I will be more than happy. Thank you again for all of your help.

Dave

DerekFSU

Rock, congrats on the mods. Kleemann is definitely the way to go, imo. Let me know when you wanna run what ya brung.

As for numbers, my last dyno was with a 65 shot- 550rwhp and 625 torque. I've since doubled the shot but no new dyno yet.

Rock

DAY THREE!!!

The headers were completed today. Cory sent me a few pictures and I did not realize the difference in size between stock and Kleemann. Also, I was informed that even though they run a different ECU program for K2 they initially install the K1, ECU program.


From Cory:

Hello Dave-

As promised, attached are a few pictures of the KLEEMANN headers VS.
the stock manifolds. As you can see, it's quite a large difference.
I've also attached a few pics of the headers installed on the car,
the car sitting on the rack, and a couple of quick shots of the
cylinder heads with no manifolds attached. It should be no problem
getting the headers done tomorrow, and possibly the LSD as well.
I'll definitely keep you updated as things progress!

JamE55

Ah yes those pics look very familiar! Any more recent Dynos Dave? Keep us posted with the creation!

Rock

A couple more pictures.

Also, a few pictures of Pikes Peak (near Kleemann) in Colorado Springs.
I was out there last week and was able to take the 19 mile trip to the top.
I felt like I was going to drive off the mountain a few times. It is hard to believe people race cars to the top and live.

JamE55

Last 2 pics were just simply beautiful and amazing! I can see how you can lose 2lbs of boost. Thanks again for the pics Dave!

lowphat

When you get your car back this is what you'll look like in everyone else's rear view mirror....

Rock

More dynos on Tuesday.

Tony007

Any guesses on what you think you'll see?

medici78

Thanks for sharing those pics!!!
Did you have your headers Jet-Hot coated?

Rock

Tony007: I'm not sure at what point the next dyno is completed. I will post it as soon as I get any additional information.

medici78: Unless Cory really likes me, I think I just get the standard Kleemann headers.

vixapphire

gee whiz, those headers are unbelievable!!! your car's gonna be rolling unbridled violence when they get through with it. if you don't mind my asking, what's the ballpark price on all these mods (k1, k2, k3)? by the description and the anticipated end-improvement, i wanna guess something in the 25k+ range. or am i overstating things?

does kleemann stop producing the kits for any particular model after awhile; say in 2009 i wanted to get into an upgrade like this for my '05 e55 - would that be possible, or would i be stuck with having to buy a newer (07?) e63 to have it worked on? i always wonder about this w/ regard to new-model eurotuner products. thanks for your indulgence of my ignorance and curiosity about the hyper-tuner world of benz. ...and here i was, figuring that having an e55 wagon that c&d says can turn a 4.1 second qtr mile was plenty fast and furious enough!

silly me...

Yellow R1

A 4.1 quarter mile? Can you say typo? :p

04E55 AMG

Great pics Dave! Stock headers are just crap

Tony007

That's what it looks like at first but looking more closely it appears to be the flash from the camera.