Rolling Road Test - essential or not necessary?

[vRS Carl]

Im not professing to be an expert (far from it) and both Nick & Dave you will know a lot more than me. So im after a bit of education.

However,

Downforce & Aerodynamic lift are apparently not important. So your telling me that a car travelling at say 120 mph, on a track, that the effect of the weight being put on the car by the wind has no bearing on what the engine is doing. Despite the fact it will be having to work harder to keep the car at that speed to push through the wind resistance?

I understand that a RR is a fantastic tool when used properly, by a competent tuner, and that you can do things on a RR you can't do on Tarmac in the UK (unless you have your own track) like the situations you have previously mentioned.

But if a Dyno was THE best way then how come all the professional motorsport teams & tuners like REVO & APR do real world testing (i know it's not just to do with the engine for motorsport)? Surely they would just stick their vehicle on a Dyno with a big feck off fan in front of it, set it up perfect and then give it the driver??

As i said im not professing to be an expert and i am just curious

[R-tech-Nick]

Im not professing to be an expert (far from it) and both Nick & Dave you will know a lot more than me. So im after a bit of education.

However,

Downforce & Aerodynamic lift are apparently not important. So your telling me that a car travelling at say 120 mph, on a track, that the effect of the weight being put on the car by the wind has no bearing on what the engine is doing. Despite the fact it will be having to work harder to keep the car at that speed to push through the wind resistance?

I understand that a RR is a fantastic tool when used properly, by a competent tuner, and that you can do things on a RR you can't do on Tarmac in the UK (unless you have your own track) like the situations you have previously mentioned.

But if a Dyno was THE best way then how come all the professional motorsport teams & tuners like REVO & APR do real world testing (i know it's not just to do with the engine for motorsport)? Surely they would just stick their vehicle on a Dyno with a big feck off fan in front of it, set it up perfect and then give it the driver??

As i said im not professing to be an expert and i am just curious

The main thing is load not drag coefficient, a rolling road can replicate the most extream road going conditions out there by adding load to the engine the same as a downforce & drag at 120+mph.  I know Revo will make changes to there maps on there own car and test them on the road on the way to work and back, then they will book a rolling road session to do the final testing this way they save money and dyno time, not because its a better way to tunning.

The best place to start is by reading about MAP manifold absolute pressure and engine load, this will give you an insight on how an engine loads up, then you will understand where was are comming from.

On our maps when we make major changes to our own cars we test them on the way to work and back with an eobd2 logger, if the car feels ok on the road we will then make some time to get the car on the rolling road to test and log the map changes to the extream.  The only way tuners work this wa is to save time and money.

The only thing you cannot get from a rolling road is the feel of the car from load pick up, turbo spooling, peak boost cut ect..

Nick