Dyno test and tune

[fekbmax]

How hard is multiple pulls on a dyno for the purpose of testing and tuning the ignition, mechanical, timing, and fuel systems on an engine. ?  What's the pro's and cons of tuning on the engine dyno verses a chassis dyno. ? Should both be used ? Use the engine  dyno to get timing and fuel curves closely ball parked then do fine tuning on the chassis dyno to optimize rear wheel HP ?
Just intrested in the opinions of you guys that have these resources readily available.
Would my dyno time be best spent on the engine dyno or chassis dyno?

[blykins]

My vote would be engine dyno, then track.   We have put 20-30 pulls on one engine, trying to get the tune right, trying different things, etc.  IMO, a dyno is harder on an engine than a race track, as there is no slippage anywhere and you can absolutely pull the guts out of one.  However, I think you gain more data and knowledge there than on a chassis dyno. 

[jayb]

I would agree that while both are useful, an engine dyno is the way to go for most folks.  Often overlooked as advantages of an engine dyno is the ability to change parts easily, with the engine exposed, plus identify minor problems like oil leaks that may be difficult to diagnose in the car. 

[Posi67]

I agree with Brent.. If you've ever been at a Dyno session it's nerve wracking even if they aren't trying to kill YOUR motor. Just the way the engine is loaded then let run sounds hard on parts however if something isn't right, it will show up in a hurry on the Dyno. Chassis Dyno IMO would be better for drivability issues. Going down the track (or road) will be the best test.

[cjshaker]

Plus one on the engine dyno. Nothing is worse than having to pull an engine because of an issue that could have been caught on an open stand. If it was just a mild street engine or stocker, I probably wouldn't mess with it, but from now on I'll dyno every engine that is performance oriented.

And I agree with Dale, it definitely makes you grit your teeth. The pulls seem painfully slow, like a long 4th gear pull. I'd be a constant nervous wreck if I were one of the engine builders who did this on a weekly basis. You guys must have nerves of steel, or a big liquor cabinet.

[fryedaddy]

i can rev my engine in park for just a second or two and it seems scary,that really seems nerve racking to rev one up for 10-20 seconds on a dyno.there is no dyno machines in my area. i just go for a short drive several times till im happy with how it performs

[Posi67]

Try putting your foot to the floor at the tree and hoping your 2-step rev limiter is going to catch the engine before it runs away. I don't leave very high but it took quite awhile before I got comfortable with that. Can't imagine the guys leaving at 7000+

Here's a fun Dyno session with a shift simulator. Pro Stock stuff.

https://youtu.be/7py-d7arEnM

[Barry_R]

A well built engine can go through an extended engine dyno session without suffering.  Its hard on stuff, but you learn so much that its worth every bit of stress.  Imagine a standing start pull through high gear from 3000 through highest RPM.  ON one of the EMC entries I reached somewhere in the range of 189 recorded pulls chasing little stuff.  Thought I was on the verge of crazy.  Got to the show & discovered that Kaase had made around 400 pulls and freshened the engine...