Load Vs. Unload Tuning

[Lextreme II]

I have a question for the experts. Would an engine dyno tuning be the same as the rwhp dyno tune? Meaning if I take my spare motor and get it running on a stand and tune it properly to the power and psi i wanted. Would this engine stand tune be the same as the motor install into the car? Now are talking about load tune vs unload tune....

 

[Toysrme]

It's never the same as in the real world. That's why you can make a dyno queen supra @ 1000hp, but you try to make that power toting around 4,000lbs of heavyness instead of spinning a relatively un-stressful few hundred pounds of a drum.
Pop goes the weasle.
Always make any static tuning conservative. By a good margin.


There wouldn't be much differance in a static engine dyno, and an installed dyno. Minus whatever would be caused by mild heat differances (including an A/T transmission fluid cooler on the radiator if equipped).

 

[JustenGT8]

Hmmm you can't tune 'unloaded' at all. A dyno, be it and engine dyno or rolling road still 'loads' the engine. As Toysrme says though this can still be different to on road. Best to do both...or even all three. An initial engine dyno is great for running and engine in and getting the basic tune sorted. Chassis dyno for the bulk of the work as it's real world drivetrain and then a final road tune to sort out light load and driveability tweeking. I've never had the opportunity to use and engine dyno but find i get a good result tuning for power on the chassis dyno, not a POS dynojet but a real dyno like a dynodynamics where you can hold load points etc....and then a road tune to make sure it drives right to suit me.

I think the results from the Celica speak for themselves

 

[steveo]

Dyno tuning comes in a few flavors...
You can use steady state dynos to get the basic mapping for all sorts of engine parameters sorted out, but to get closer to the "real world" tuning you would need tun ethe transients on a more sophisticated (more money) dyno. That is the main reason that there will always be some sort of tuning based on road feel. The transients of driving on real roads and all the variations that you come up against are hard to pre-program for transient dyno runs.
Eddy-current dyno can adjust the load on the engine very quickly and are used to tune the transisents with great succes. They can also hold constant load like the majority of dynos out there (steady-state), so that particular points in the mapping/tables can be adjusted for optimum.

Having dealt with both chassis and engine dynos in the past, I would say that no matter how much time is spent on the dyno, you will always have some tuning to do once the driver gets in the car. The driver can pick up on things that dont' 'FEEL' right better than trying to sort it out by looking at data.

Steve-o