Discussion and questions related to the course Practical Dyno Tuning
Hi, in regards to the technique of braking in order to maintain the same RPM and creating load.
While I've learned that this can be done at 2500rpm +-, What range of RPMs would also make sense trying to tune using the same technique? Can we simulate load with changing to a higher gear, let's say 4'th or 5'th, or perhaps trying to a steep hill in a high gear?
Basically, I've got 500+ whp, 7800 max rpm , turbo spooling at 4500'ish. What would be the steps of tuning in this case?
Loading the engine down on a public road with the vehicle brakes can get dangerous and heat up the brakes. I would be very careful doing it. You can maintain the same rpm by popping it into the highest gear (typically 6th on a modern car, 5th on an older one, or even higher than that if it's a modern automatic that gives you enough control) but again you're on public roads so you have to be careful. You might have to go 200 kilometers per hour to get the rpm you want.
You actually should be able to get pretty good results road tuning the low rpm areas of the map on this sort of setup. It sounds counter intuitive but large turbos that are a little lazy to spool actually make road tuning and left foot braking easier because you're not going to end up making much boost/power in the low rpm areas so it's easier to hold the car on the brake. I'd be concentrating my efforts in the 1500-4500 rpm region. Remember that you don't need to be doing this necessarily at WOT as you can tune these areas using ramp runs.
Thanks Andre, makes sense indeed.