I have a question about Data Log Lab and how it would compare to a Dyno Jet. The best I have pulled on DLL is 387WHP and the best a few months ago I pulled on a dyno jet was 370WHP... Now my question is since DLL is calculating HP with load (Road Tuning) as a factor what would a car pull on a Dyno Jet where there is no load? Basically if a dyno jet could simulate driving on the road and the numbers were 387WHP what might that figure be if I were on a none load DJ? I know DLL isn't accurate but it has been pretty damn close in all of my pulls to the dyno jet numbers but then again I have turned up the boost slightly to get some more HP out of the car. If load were not a factor in DLL what would my numbers look like? Is there any equation to take load out of the final numbers?

Thanks

 

Well, I don't understand where you're going with all this "load" talk...

The difference between a Dyno Jet and DLL is:

DLL uses your ability to rev the engine based on wheel/tire size, gear ratio, weight, and drag coefficient. The downside to this is factors such as wind & road angle... so if you're on a flat road with little to no wind, and your car definition including weight is spot on, then DLL is very close to accurate.

DynoJet uses your ability to accelerate a drum of known mass. Less variables, so less chance of screwing up the calculation.

Dyno Dynamics uses your ability to accelerate an electronically controlled drum with precise resistance. It makes it the most accurate method of measuring torque at the wheels.

In any event, I'd say weight & environmental conditions are the biggest downside to using DLL. If you can get those to be accurate, and use SAE correction, you will have a reliable number that should be comparable to a dyno

 

MY exact point.. DJ = no load on the engine allowing it to rev faster meaning higher numbers. I am just looking to see if there is a formula to calculate DLL numbers minus load on the engine caused by going zoom zoom on a road vs zoom zoom on a drum that has no resistance. LOL If a DJ would simulate road conditions and I were to make 387WHP what would that figure be without that resistance?
DLL = Road Resistance on Wheels
DJ = NO Road Resistance on Wheels

 

bumb cuz i want to know too

 

This is an incorrect assumption. Yes, the load is different between a dyno and an on-road pull, but that doesn't mean your on-road pull is showing less power.

It boils down to what each method uses to calculate HP and TQ. The Dyno uses a more reliable method, because the variables are few (just weather). There is no driving angle or surface friction VARIABLE... those things exist, but they are unchanging, meaning the calculation is more exact.

This is also an incorrect assumption. A dyno has a drum load for which the wheels must overcome, just like the road is a surface for which the wheels must overcome the friction of.

The only thing DLL doesn't have is compensation for driving angle or surface friction CHANGES (different tire, different surface). It simply assumes zero angle and typical tarmac friction when making it's calculations. So there is no way to say "Well if I make ABC amount on DLL, I'll make XYZ amount on a dyno"... the only thing you can say is a dyno is more repeatable, and you have less chance of screwing up the calculation. You cannot interpolate one to the other with precision. You can only use DLL as a rough estimate. For this reason, many people suggest using the same spot of the same road on the same tires in similar weather when doing on-road pulls

 

I would not say that there is no load on a dynojet. The one that Brotherz Racing has, in Tampa, has 2 rolls that are 3500 pounds each.

 

I've just started logging my car within the last 2 weeks and was unaware that the DLL was so accurate. I was just using it only as a tuning reference. So far my best dynojet numbers have been 345 whp and after tweaking my Xede maps, my DLL readings are 367 whp. I'm curious what my dyno jet numbers are now.

 

i have a question if in my case iam at 3300'feet of altitude and my car according to DLL on the same road that i always use for logging it always hits 300whp,i also check the SAE space to it,so my question is if i go to sea level will my whp increase or it wont increase of the SAE correction it makes and i will always hit the same 300whp?
thanks
interesting thread maybe someone here has used DLL while being on a dyno...

 

ok your dynojet numbers you say where 345whp but what where they before you tweaked your xede?

 

345 whp was my untweaked numbers.

 

wow so it gave you the same whp that your dynojet run gave you?
so damm it must be very accurate good to know thanks

 

Lol, I just have been logging and tweaking my maps for the past 2 weeks. My 345 whp dynojet numbers were done back in June with a 100 octane and 91 octane mix. I've been tweaking my Xede maps using 91 octane and water/alcohol injection. According to the DLL my new numbers are 367 whp on 91 octane with W/A injection. My car definitely feels stronger. To be honest with you, I'm not a dyno numbers guy. I'm just using the DLL numbers just as a tuning reference. I'll be hitting the drag strip soon to see what my trap speeds look like.

 

My dll numbers have been fairly accurate also. I have always heard that a DJ is not so great for tuning as there is no "load" on the car like other brands of (load baering) dynos, and it does not simulate a real world driving situation. Would it be false to assume that spinning a rolling object (dyno) would create less load on the engine then driving over a stationary object (road)?

 

Just as a foot note for DLL to dyno comparisons, the last dyno run I made with my car took over twice as long to climb through 4th gear as the car does on a level road. That meant I was seeing intake temps of ambient +40 'C on the dyno when I'd see less than ambient +20 'C on the road, and the ECU was having to pull timing due to heat related knock. I don't believe the dyno result under those kind of circumstances would be an accurate indication of the real-world power of the car on the road.

Food for thought...

Glenn
Data Log Lab Support

 

Hey Glenn,

Awesome product, I did not know you were on the boards here.

I had a suggestion that I wanted to make to you. It would be great if you could make it so you could click and drag to highlight or select a portion of the graph and then it will take that selection and zoom in. I find it kinda annoying to have to click the enlarge button and then the plus or minus keys to get the window just right. It would be cool if you could simply highlight the area of the graph you want to see take up the full window.