@Neo961Being a So Called "Tuner" you should know what the importance of a Dyno is in Tuning business and Why is it necessary? If you do not know, then let me tell you. There are two ways to measure engine power. 1st is the engine dynamometer (used by engine manufacturers and certain engine tuners and the measuring unit is known as Bhp or Brake Horse power) which is used prior to the engine being placed in the vehicle, very easy and simple but once the engine is bolted down in the vehicle this engine dynamometer becomes a long and tedious process. So to simplify things a rolling Dynamometer also known as chassis dynamometers, these are used to measure power at the driving wheels. This avoids the inconvenience of having to remove the engine to test it if a tuning modification has been made. However, it means that the power figures obtained will be lower than the flywheel power because of the frictional losses in the drive train and tires.
What is a drive train loss? Well all mechanical systems suffer from friction and a proportion of the power fed into a system will get dissipated by friction and turn into heat and noise. Note the key phrase there - "power fed into a system". For there to be a loss there must be an input - simple and obvious yes but we'll see the relevance in a minute. When your car is parked overnight with the engine switched off, the transmission losses are obviously zero. When the car is running then some proportion of the flywheel power will be lost in the gearbox, final drive, drive shaft bearings, wheel bearings and tires. For a given mechanical system these losses will usually stay close to a particular fixed %. For example if the loss percentage was 10% (just picking a nice round number for ease of explanation) and the car cruising on a level road was developing 20 bhp at the crankshaft then 2 bhp would get absorbed as friction. Under full power, say 100 bhp, then 10 bhp would get absorbed.
Now it is true that not every component in a transmission system absorbs a fixed % of the input power. Some components like oil seals and non driven meshed gears (as in a normal car multi speed gearbox) have frictional losses which are not affected by the input torque. These losses do increase with speed of course but at a given rpm can be taken to remain constant even if the engine is tuned to give more power. We'll look at real world transmission loss percentages later. Finally, the biggest source of loss in the entire transmission system of a car is in the tires - they account for half or more of the total losses between the flywheel and the rollers. Each set of driven gears, i.e. the final drive gear or the particular gearbox ratio that you happen to be testing the car in, only absorbs about 1% to 2% of the engine's power.
The average front wheel drive road car with between 100 and 200 bhp loses about 15% of the engine bhp as transmission losses.
The average rear wheel drive road car with between 100 and 200 bhp loses about 17% of the engine bhp as transmission losses.
The 2% increase in losses over front wheel drive is because the differential has to turn the drive through 90 degrees at the back axle which soaks up a bit more of the engine's power.
So back to the point being, how would you know what modification is actually increasing or decreasing the given horsepower of a particular car? The Dynamometer is the Answer! That is the reason Tuners swear by a Dynamometer. You not having dyno in your shop, and modifying cars will be Like Shooting Arrows in The Dark! This process is not only followed by us but the whole industry in the whole world, no matter where you are. Hope you get the point.
“dyno figures change with change in wheel sizes so its stupid to consider that a dyno can tell exactly how fast a baby will go. but it can give a good idea on power at crank to cacluate performance power use real world conditions that is what the pros do they setup a car and they test it on track and”
Yes dyno figures change with the wheel size and it’s the same in real conditions too and by the same amount. Sorry Dynos do not tell you how fast your car will go but how much of torque and whp your car is churning out and it is not measured at the crank it is measured at the wheels on the Chassis Dyno. There is a big difference between the wheels and the crank. Its at the wheels where it matters most coz that is what your first contact is to the surface of the road. Yes to calculate Time and speed pros test their cars on a track and on the street to save money (using the track facilities costs money and a deserted street does not) and so does everyone else including me and FLi or anyone out there. Hope I have cleared some of you misconceptions bro!
I will try but he only knows how to work the switch under the acceleration pedal. I just could not find it, lol! Must be going blind and stupid, lol!