found these..attached files, i can't add more files in the same post.

this dynosheet, is the same car, 3th gear and 4th gear, you can see almost identical whp readings, less than 2whp difference in some ares only. you can notice more drivetraing losses in one pull than other one, thats normal. i will upload the other dynosheet for HP crank readings.

here is HP crank readings, different gears, same car.

SO it will be imposible to know engine power accurate? as you told, i will need to calculate moi for every car???

@walter

i dont understand, why whp is same but no crank hp, losses should to be the same, and % of friction losses must to be same on 3th than on 4th.

for to know really HP crank, you have to use an engine dyno, anyway you can get very close Hp readings in a roller/hub dyno. ive tested many cars getting exacts HP that car is supposed to make. also all cars havent the same power that manufacturer says, and people think if a car is supposed to make 225hp for example, many of these doesnt make that power, maybe for years, conditions of engine, or just because these cars never made 225 really. many people dont understand about it.

About MOI, yes, it should be calculate per each car but i think about MOi calcuation , what you calculate too is MOI of your dyno, i thought this conclusion when i calculate MOI, when you are calculating MOi, you measure MOI of the car/dyno in accelerating, you still measure MOI of your car/dyno in steady for seconds, and finally you measure moi of car/dyno going down, ok, when you after that measure, and you have yo adjust, i think you are adjusting the MOI of the dyno, because MOi of the car is a constant value, dyno value doesnt, then that's why you have to adjust it until you get it. maybe with other car could be different? maybe, i never calculated with other car, maybe forwared just for information. maybe im wrong, but im very happy with results on my dyno and after +2years, when first 6 months i was comparing with other dynos like dynojet, dynodinamics, mustand dyno, because you want to have a dyno with good readings as everyone ,all of these dynos has slight different readings but mine reads very close to all of these , and after to tested many cars, looking the results and comparing , i think your dyno is Ok, anyway all dynos are another tuning tool, it worths more to test before and after tune.

another question is, it's the same friction of a gearbox acceleration than accelerating? what happen when you use engine brake? you get the same engine brake in 5 gear than 2 gear at the same speed? it's like when some people use a dyno roller in one way, the load cell is located in compression, what happens when they use in the other way? load cell is working in extension, it will measure same load? 

HI to all!

Lot of new info about my fla!

First of all thanks so so much to all for help and support, especially thanks to walter, i have learned so much talking with you and of course to Jostein, helping me remotely calibrating my dyno and finding problem.

I had problems with wheels slip, my room is under construction yet  and floor has lot of dust, so with dirty tyres no good grip...

Jostein advise my to use wd40 for solving slip problem, i was a bit skeptical about it but it works, and trust me it works very very good.

With good grip MOI could be calculated properly, which as tuttur advise me is 11.5.

On the other  hand pid setting was set to kp: 1 ki: 0,5 and kd: 0.050.

Power sweep now works like  charm.

it's great your dyno is working good already! 

@ivanro_jo

I'll give that setting a try aswell, for now with the 1.6/0.7 it works fine, but could be better.

Only thing I seem to struggle with is the moment the stabilisation is over, and it goes into the sweep, it releases the brake to get the rpm rise going, but then has to cut back in to maintain the speed. Maybe this would've been better with lower inertia rollers, I don't know.

@admin 

I seem to remember there has been an update on this?

@tutuur, i use 6 seconds for sweep stabilization just works very well normally i have start rpm arround 1200 for turbodiesel engines and 1500 for fuel engines, works quite ok.

ON the other hand i am having some troubles with slipping with high torque cars, could you guys advise me some kind of grip paint for rollers?

BR

Hi ivanro_jo , what sort of vehicles rear wheel drive or front wheel drive ? Solid axle differential or IRS diferential rear wheel drive vehicles? 

What method to you employ to secure the vehicles down to the chassis dyno rollers ?

ivanro_jo

ON the other hand i am having some troubles with slipping with high torque cars, could you guys advise me some kind of grip paint for rollers?

BR

All kind of them, i have  run front and rear wheel drive, and solid differential and not.

Now i can just strap cars on the rear, no place for strap it on front ( i am working on it), so maybe problem could be there, on the other hand i make run on a diesel bmw with 600 nm, and i had to strap it a lot sit people inside the car, and spraying  adhesive to rollers, only possible to make runs without slips on no brake mode.

 i have no paint on wheel path on my roller, maybe with good grip painting will be better, but no idea how much time will stay the paint on it.

Posted by: @ivanro_jo

and i had to strap it a lot sit people inside the car, and spraying  adhesive to rollers, only possible to make runs without slips on no brake mode

I've had three rolling roads over the years, the first one a water cooled HP Anderson 30+ years ago, and the problem you always run into with the 'standard' small twin roller European type designs is that eventually traction becomes a problem

Depending on the vehicle weighting, higher powered rwd cars are the worst in this respect, traction problems can onset surprisingly early

Coatings will eventually come off, even the factory applied ones, and the various knurls & grooves can help, but aren't usually cost effective to do on an already installed roller set

Rolling roads are convenient, but with that convenience comes compromise, as you've found out ...... I'm not saying they can't be made to work, especially if you split the load between both rollers, or maybe go to the large drum designs, but most people don't have that as an option and have to work with what they have

Hence my decision some time back to build a hub dyno ...... with it's own particular set of compromises ...... although there are tentative plans to maybe build a twin brake roller set sometime going forward

Good luck with your project

Good resource for understanding the issues :

https://www.dynomitedynamometer.com/dyno-tech-talk/roll_diameter.htm

There are many ways of strapping and tying down vehicles with big RWHp/torque.

i just copied DD's system for solid axle differential and have no issue holding  700BHp+ cars running 9 seconds quarter mile. 

Without slippage. As most of my vehicles are rear wheel solid differential happy to share information if you require it. 

Have also a good system for front wheel drive cars too.

Thanks

Posted by: @mach_1

i just copied DD's system for solid axle differential and have no issue holding  700BHp+

 Steady state ?

Sweep is a whole different ballgame ....... and doesn't cover everyone's needs ......

It's not uncommon for RWD cars to light the rollers up at 300lbs ft against the brake, even strapped down and with a handful of people in the hatch

It's torque that breaks the traction, not bhp per se

Be careful about pulling the vehicle down with too much strap, and running for any length of time

These are my direct observations, and the long post above is a reasonable synopsis ...... your results may vary