Q&A Forum
Hp is a function of torque they both affect traction. I can hold it in stready state and ramp rate mode redardless no traction issues.
Hp is a function of torque they both affect traction.
Thanks for the clarification, I'll make a note of that
I can hold it in st(r)eady state and ramp rate mode re(g)(d)ardless no traction issues.
Well, maybe then you need to educate the OP on how to hold 700hp, steady state ...... by extrapolation he's struggling holding a lot less, unless his 'diesel BMW' is pulling 8308 rpm ..... strapped down, full of people !
[442.5 lbs ft (~600nm) x rpm :- 5252]
And with that, I'm out ...... 🤪
PMSFL ..... why does everything have to turn into a pissing contest ?
Think about it people in the back seat equals downward force of what " the sum of the peoples weight" im sure if you put 100 people in the back seat you won't get tyre slippage ! " I'm being sarcastic here!" i see so many people tie vehicles incorrectly on chassis dynos!
if i say i can believe me i can hold it on my DD650max chassis dyno. Don't know what your dyno is ? Maybe you can shed some information on you unit you use ?
Setting mixtures on carburetors on WOT on 700Bhp engines on steady state mode for the last 30 years is a no biggy.
If i shifted gears down the quarter mile drag_strip at my engines maximum torque_rpm ? I would be losing all my races! LOL !
I'm not into dyno competition's I'm into drag_racing !
What do you think will be the correct way of strap cars on dyno? it is something i wonder a lot.
What do you think will be the correct way of strap cars on dyno? it is something i wonder a lot.
Ok , you tell me what chassis dyno you're using. Full roller dyno length , two rollers, one roller , four rollers coupled front and rear rollers , independent front and rear rollers un_coupled..... then i will go into what works on my DD650max chassis dyno.
Tell me how you tire your solid rear axle vehicle down. Then i will tell you my system " as i stated already copied DD's system' " no secret!
Ok , chassis dyno design will influence how you tire the vehicle down but you will get the idea.
This is the method i use on my DD650max chassis dyno.
It's very self explanatory view DD's utube link
How to use the Dyno Dynamics HP Traction Control!
https://m.youtube.com/watch?v=Z_k9mu3Q_1I&t=183s
This works for me! And my style of chassis dyno!
This system allows you to apply as much downward force you need as per application , no need to seat 100 people in the back seat of the vehicle being dyno tested !
Some chassis dynos might need some form of alterations/fabrication engineering work to adapt DD's strapping system to work on another chassis dyno style.
that setup will be good if you use ramps and dyno is not in the ground.
Lol my chassis dyno is in the ground ....... and have mounting points for different wheel base lengths for front wheels also in the concrete..... where there is a will there is a way!
cool then! post some pictures, may help to someone with similar dynos and slippage problems!
A bosch fla 203 is similar to a DD650max ? How so ? The utube clip is worth a 1000 pictures.
HI again guys, i wonder if some of you have the same problem than me.
I calculated the moi and i think now is almost perfect or very close, it is set to 11.5 like tutuur i calculated it with diferents cars and 11.5 looks the best number.
But i have a problem with power numbers, if i make a run with this configuration with a tdi car numbers looks ok same power as it should but on other cars like na engines or turbo from renault or honda, numbers looks a bit low like 10% i noticed when i start to runs high power cars.
If i applied a % of power corrections tdi engines give too much power and futhermore torque.
Someone of you have similar problem, is like i had to use different calibration for each kind of engine which i think have no sense.
@tutuur do you apply any % power correction on your dyno?
I start to think that maybe my load cell is the problem and thinking to upgrade it to a new one, it has arround 30 years maybe it is no so accurate as new models...
Hi,
Your MOI might be slightly too high. So you reduce it a little and add some power correction.
If your engine numbers are "correct" with Power correction at 0 then likely your MOI is too high. The reason is that there is definitely some power loss in the transmission at full power, so you should need to correct for it.
Another thing to note is that engine power calculation is always an estimation. You never know the exact losses, we are trying to estimate them. You might need different power correction factors for different cars. Even the MOI changes somewhat from car to car due to wheel weights/size and transmission MOI.
My problem is that i can´t find correct number for all cars, and if i change configuration for each kind of car ir will not be possible to have a real reference.
Problem looks to be just with tdi cars, if i applied 10% on power correction power and futhermore torque is crazy high, but on the other hand if i use this numbers on a na petrol engine or turbo petrol power looks ok.
Moi have been calculate it lots of times and looks very accurate, the only think i think could be problem is o a bad calibration of my load cell (i did it more than 10 times) or on a load cell not much accurate.
hehe i am getting crazy
One thing to think about is to do the gear ratio calculation while applying load to the brake. This options ensures the tires are loaded when setting the gear ratio.