If the "driveline loss" figure (I am assuming you would use a %) that is added on is the same for both runs would those graphs be showing an actual % increase or not?

 

Isn't that exactly what he said??? :smile:

 

I don't know anything from first hand experience, but I believe I could summarize most of the comments posted on this site over the last year or two by saying it's not very good. I don't think anyone dynoed their AmD and found it to make more than a couple horses.

 

Who knows what was used as a fudge factor on those dynos. The idea of "measuring" drivetrain loss with a chassis dyno is ridiculous and anyone selling parts or running a dyno should know that. In any case, I have seen exactly one real dyno of a customer comparing his Unichip -vs- stock and the results were less than stellar, to say the least.

 

GIAC is $325 for 15%, same for 19% (+$350 or so for injectors). i think this constitutes the best bang for the buck if you ask me because it still comes in under the Unichip (19% just barely), and if you go to an authorized GIAC dealer they can tune it on their dyno to match any new mods you may have made (don't they?-i think they do). i myself am waiting for the GIAC with Smartcable to come out so i can switch back and forth when i go to the dealer or even valet mode, this option on other applications is around $100 more still bringing the GIAC 15% to around $425.

 

I THINK what Andy is saying (and it's a BIG I think) is that a chassis dyno is not the proper tool to assess hp. IF that's what he is saying, then it doesn't matter what the readings or the driveline loss figures or corrective factors are - the numbers are worthless.

Say for example you have a scale and you want to measure your change in weight. If the scale is accurate then even if it reads high or low (as most scales do), you will still be able to measure the CHANGE in weight even though the exact numbers aren't important.

HOWEVER, if the scale is beat up say, and it can no longer properly measure weight (as Andy is saying that a chassis dyno cannot properly measure hp - right Andy?) then the change in weight is worthless b/c the weight readings you got weren't accurate in the first place.

Here's another example:
Bodyfat measurements. They're similar to dyno testing. Really.
You can take someone's bodyfat using skin calipers. You pinch the skin at a particular spot and measure it with the calipers. Do this at several sites on the body and use a formula to get your bodyfat %. The formulas (like dyno correction factors) are controversial. So it's not the "corrected" number that matters. Any one bodyfat test (or dyno) doesn't really show anything. HOWEVER, if you just take the individual bodyfat measurements and take them a month later and compare (without using formulas or using the SAME formula), you'll get an accurate comparison provided you used a person skilled in caliper bodyfat testing (or a skilled dyno operator). Skinfold caliper bodyfat measurements have been shown to be VERY accurate when taken by a skilled person.

NOW...say you use a bioimpedance body fat scale - these scales that you step on and they give you your bodyfat percentage. It works by sending a small electrical signal through your body from one foot to the other. Muscle and fat conduct electricity differently so depending on the resistance, it gives you a measurement. Well these scales have proven to be VERY VERY inaccurate for measuring bodyfat percentage. If you're warm or cold or recently taken a shower or just worked out or have a full bladder or drank too much water (or anything else) or are dehydrated, your readings will be off. There are just way too many variables which makes ANY bodyfat reading taken on one of these scales worthless. So if one measurement is worthless, then taking another worthless one and comparing them will not give you an accurate before and after picture. (Can anyone tell I'm involved in the fitness industry?)

This is what Andy is trying to say (right Andy?). He is saying that the Dastek doesn't properly measure hp. And if that's the case (and I wouldn't know) then comparing two measurements from a tool that's not the right tool to measure them in the first place will not give an accurate change in hp.

 

This is, of course, not necessarily a reflection of the product, but rather a sign of an innefective tune. The features of this unit are really lost on someone who is only looking for a standard off-the-shelf map.

 

Ah okay thats what I was trying to ask. I guess was pretty much whats wrong with that type of dyno.

Hopefully Andy can come in and say if thats what he meant or not.

BTW nice comparisons.

 

For me, personally, I'm not looking for lots more power from the ECU reprogram. I'll save that for the pulley (and to a lesser extent CAI). I want an ECU upgrade tht gives smoother throttle response and better fuel economy from the mods that I'm adding. Until there is a time when somebody can run controlled tests under (near) identical conditions for all of these programs, any HP claims must be taken with a huge grain of salt.

I've heard good things about AmD's improved throttle response. And the One-Click has ease-of-use advantages over both the Shark and GIAC. AmD doesn't require a battery charger like the Shark does, and as of right now, the GIAC hardware for at-home-use is not available. I don't want to have to visit a shop to reset programs prior to visiting my dealer - that's just way too inconvenient.

Knowing that no "stock" set of ECU remappings are going to be perfectly tuned to my car, I will settle for a program that is better than factory stock, and easily updated.

 

Actually, I think a chassis dyno is a very effective tool for measuring POWER AT THE WHEELS, and is an even more effective tool (when used correctly) to compare POWER AT THE WHEELS between different mods on the same car. What it is not good at, and cannot do, is measure POWER AT THE CRANK. Only an engine dyno can do that. I do not trust any "dyno" figures that purport to show crank hp unless they are from an engine dyno (where the engine is removed from the car and bolted directly to a specialized dyno).

 

Ah...so I guess my explanations were for naught. But Andy didn't you say (in a different thread I believe) that a dyno that meausres coastdown power (which is what the Dastek does, no?) can't accurately measure what mods make when accelerating???

 

randy's claims from the early days have been that you see more gains from the Uni on a near stock rig compared to a more modified (pullied) car. the charts he posted show that there is a factor of two. multiply that factor by whatever you want.


I agree about the need for full customer tuning. apparantly the Apexi offers inigiton tuning for their non-export version, or did, but had too many over zealous "tuners" in the US and deleted the feature.

 

What was that the measured coastdown power is different from the driveline loss powe that is absorbed during acceleration. As long as the physics behind the Dastek dyno are good and it's in a good state of tune, it should be able to accurate measure whp. What is can never do is measure the crank horsepower, nor can it measure the difference between wheel horsepower and crank horsepower.

Cliff notes:

Chassis dynos that measure whp are good.
Engine dynos that measure bhp are good.
Chassis dynos that purport to measure bhp are big fat stinkin' liars.

 

The Dastek dyno's measure WHP via acceleration if it's not being used as a loading dyno (AKA Dynojet mode), if the PAU's are in use they measure wheel torque via load cells and calculate WHP. On the coast down phase it measures parasitic losses and applies that to the measured WHP or WTQ to [font=Verdana]estimate[/font] BHP. Is it 100% accurate on BHP figures? No, but it's really close. Most stock cars are within 2-3HP of their claimed BHP. What's important anyway is the delta from run to run. If you don't believe in the dyno's ability to accurately [font=Verdana]estimate[/font] BHP at least believe that it is consistent and the delta is real! Every single dyno is different and will read differently. I’ve used many Dynojets and seen a lot of different results on the same car…. Coolant temp, air temp and air quality are the most overlooked factors I see on dyno's. Most people look at the gauge and say "It's in the middle so we're fine." When in reality you need to monitor the temps to the degree, if you're not doing that the dyno runs aren't valid anyway.

Quote:

Originally Posted by andy@ross-tech.com

What was that the measured coastdown power is different from the driveline loss powe that is absorbed during acceleration. As long as the physics behind the Dastek dyno are good and it's in a good state of tune, it should be able to accurate measure whp. What is can never do is measure the crank horsepower, nor can it measure the difference between wheel horsepower and crank horsepower.

[font=Times New Roman][size=3] [/size][/font]

 

I feel the exact same way. Does the AmD ECU eliminate the top speed govorner and slightly raise the rev-limiter like most of the others do? I'm not going to spend all that money on an ECU that doesn't even remove the top speed govorner. Can you give me a link to an AmD dealer website that deals in USD? Auto-amd.com isn't in the US dollar and it doesn't really tell in much detail about the One-click unit on that site. I also can't find a way to order off that site either.

 

But if you take away the hp added by thier "driveloss figure" you would get the cars whp, right.

And since they have 2 runs one with and one without, you can still calculate the gain (% not actual number) from the modification.

I see no reason to doubt that the car got a 11% increase in power, unless you think the test was rigged or faked.

 

I get what you are saying, but how do you know what was added to each run? Was it the same percentage? Was it a percentage at all? If one run had a "driveline loss" of 20 hp and another run had a "driveline loss" of 30 hp, which do you believe?

The fact is, the dyno MEASURED whp, yet they chose to add some ficticious driveline loss to each one. Why wouldn't they just show the actual wheel horsepower?

 

I think its safe to assume the lyin' dynos are at least lyin' consistently. just don't compare one to the other or try to make an absolute claim

 

To answer a couple of questions:


I don't care what the numbers are per se, I want the deltas. I've said that ad naseum.
The Dastek measures in WHP and uses coast down to determine BHP - something almost all dynos manufactured outside of the States do. That's just the way it works! It always ends up being the same driveline loss on the same car, so it is accurate for a delta.

As far as tuning the Unichip goes - I have developed 15 different maps. If you buy a map for your current mods, then do something else to the car, just call me and let me know what you have done, and I can simply update the map on the Unichip module. It only costs you shipping.

If you want to do a custom tune from the beginning, the cost of the unit is less - $635 v. $735, and most tuners will charge around $200 for a custom map. That brings you to $835 for a fully custom map for your car.

Hope that helps!

Randy

 

The information quoted below was taken from an article by Dastek. The author is trying to explain dyno's in laymen's terms. If you want the complete version use this link. http://www.dptmex.com/english/dyno.htm

Note that a chassis dyno is best used to tune for performance and not for claiming a given power output from an engine. I also liked the use of the term "Tractive Effort" rather than "Torque" when measuring using a chassis dyno. When I was designing frontend loaders we used the torque values from an engine dyno along with drivetrain factors to predict vehicle performance (speed on grade and in different gears as well as digging performance) by calculating tractive effort. Rolling resistance also must be taken into account along with drivetrain losses. Use a dyno for tuning but not for hp wars.

 

Just a correction Andy, a chassis dyno MEASURES torque and speed. You then use those numbers to CALCULATE HP. Even on engine dyno's, correction factors are used for barometric pressure and temps to standardize the results. It's too easy to tweak the results of a chassis dyno to use them to compare hp between runs.

 

A correction to a correction. :smile:

A load-type chassis dyno (like a Mustang) measures torque. There is a large water brake or electrical brake that applies a force to cancel out the force applied by the drive wheels of the car.

An inertia-type chassis dyno (like a Dynojet) measures horsepower. The drive wheels spin a drum of known mass and the acceleration of the drum determines the horsepower.

 

Amen brother

 

Picking nits. Nobody wants to believe BHP measured from crank by engine dynos. So they do chassis dynos with driveline losss, now that isn't good enough.
You beleive they use different driveline loss %? It would be unethical, and possibly illegal if you could prove it.

It good to know the diff between whp and driveline loss etc. But you seem to be taking this way too far. They show ther differences. SInce manufacturers show their cars with BHP and not WHP it seems counterintuitive to someone selling something to try to use WHP and then try to explain themselves to the consumer why their product claiming an improvement is really an improvement because its WHP and not BHP . Instead since everyone is locke on a numbert they try to simulate BHP without the hassle of an engine dyno.

The data may not be what you want but its better than anything else here posted. Unless I missed some part of this thread.

Paul

 

I understand why manufacturers use BHP numbers - even though I don't agree with the choice.

The fact is, however, that as soon as you take delivery of your car there is no practical way to ever get a BHP number again. If you visit a dyno you will always be receiving a WHP number. The transition to WHP in the aftermarket is an accepted practice and one that consumers shouldn't have a hard time accepting.

This is the ONLY car community I have ever visited where both the members and the vendors insist on mixing the two standards. It may be because vendors are hoping higher numbers to improve their marketing hype, but more likely, it's because on average, mini owners seem to be less technical than those of other makes. Between all the BHP numbers being thrown around, the need for a quick fix tuning solution, and the apparently lack of desire to do any "real" tuning (read: on a dyno) frustrates me. Then again, maybe it's just that the overall number of mini owners is low, consequently the total number of technical owners is low, even though the percentage is the same.

I honestly don't intend any offense by my comments. In my short time here I have run across quite a few people pushing the envelope with these cars.

I would rather see no numbers than BHP numbers. Honestly though, manufacturer claims are often-times worthless and not to be believed until confirmed by independent dyno tests.