What are some mistakes people make when engine dynoing and track dynoing that cause false reading? That will cause you to go down a path that you shouldn't have gone. I'm guessing the V-Max 800 made 135-140 hp to the track.
I wouldn't know much about the track dyno because I've only spent a couple of days on them. Honestly, the track dyno never taught me anything other than I already had a prefect setup on the V-Max, which I knew already from the timers, but a grass dragger wanted to see if their clutch setup would be better, and it was a great winning grass racer that wanted to see if his theory's would be better. His setup would probably be great on the grass, but on ice not so much, my setup couldn't be improved upon on my V-Max 800 Pro-Stocker on the track dyno. I was able to gain knowledge on some different carburetor's & carb setups I had been working on. On the track dyno I was able to help confirm how the different carbs worked and reacted in the field. I spent 2 years making a set of new carbs work better than another set and making refinements to them before switching to them for racing. Like building my own clutch weight profiles too. Takes years to evolve things to make improvements on known setups. Track dyno can sure speed things up when testing things though vs running on the timers. It's a tool like many things are, but not the be all end all. Nothing is better than field testing, it just takes longer to do that.
I've have spent major time on engine dynos, many many days and dyno pulls on the engine dyno when developing parts and pieces, pipes ect. You can't fool an engine dyno unless you are off on the calibration or don't know what you are doing with it. Engine dyno however can fool you if you don't know what you are after or doing with it. A dyno operator can do any number of things to fool the public, but when the operator knows what they are doing and is honest with themselves, you cant mess it up.
The thing with a engine dyno is you tune the engine for the conditions of the day. In other words, you can build a warm weather engine calibration or a cold weather engine calibration, (high or low altitude same thing). You don't want to build an engine for ice racing and try and run it in the hot summer air and visa versa, at least a race engine anyway. Thats one way a guy could get fooled if you dont know what you are doing, or if running at high altitude or something like that. You can think you gained power in the warm poor summer air showing high
corrected HP, but take that engine back into good winter air and the power will be down. Typically engines dynoed at high altitude or hot summer air days will show
higher corrected HP as the SAE calibration is showing more
corrected power because you tuned for the poor conditions. One needs to look at
actual observed HP, because that is what you are really dealing with and showing the clutches and track,
observed HP is the REAL HP for that day. For instance, say you have an average engine making
150 HP observed in the cold air at say 20F, take that same engine to 100F air, and
observed will say be down to 140 HP, but
corrected will still show 150HP, now you can correct for the poor less dense air and put bigger carbs on, maybe change the porting to move more air, a little more compression and timing and that engine will now show
160HP Corrected in that 100F air, but it
now really makes 150HP observed instead of the previous 140HP observed. All you did was tune to the poor air conditions, but the corrected shows higher HP.....
If it's an engine builder selling engines, he now wants to sell that 160HP engine to the public as a real 160HP because thats the
corrected HP right. Now take that that same
160 Corrected HP engine back to a 20F ice race and its a absolute turd, its setup for that 100F air. Put it on the dyno again at 20F and the
observed power is down to say 135 HP because you tuned it for bad air previously, corrected HP is also way way down. Observed HP is what really matters ultimately. Corrected HP is not relevant to the machine its in. You can't race corrected HP figures. You need to tune the edge for the conditions of the day to make it the most efficient it can be. People get all caught up on corrected HP, and corrected HP does not win races, only actual observed HP wins races.
There are also certain conditions where you will make super HP like when theres a fog in the air right around 32F also. The engine likes the conditions and you can tune for that cold moisture and see an extra 10 HP. Above or below that temp and the power drops that 10 back to normal. Its almost like having meth injection at that freezing point, and you can lean things out or increase timing to get that power increase. Thats the best I can explain that phenomena anyway.
Also, on a two stroke you could say run hot pipes and a cold engine or something too, that will give good power readings. It important to dyno and test in similar conditions you are going to be competing in to bae able to optimize the tune up and design the edge for those conditions. When I dynoed, I made similar runs on the den the way we'd race them in the field, any other way and you are not getting good direct results.
Example of tuning for conditions: Many years ago when I was coming off John Noard's Anoka-Ramsey Sports Center dyno on that foggy 32F morning, Rick Ward was going on with his Pro-Stock bike to finalize calibrations and try and pick up some added power on his Pro-Stock bike engine. I asked him why in the world he'd be doing that in December's cold MN air. Well, they were heading to Florida to run a race down there and wanted to "really dial things in for the race". I mentioned to him that whatever he learned there in that cold winter dyno room would be irrelevant. Keep in mind I'm talking to Rick Ward, a guy I consider an absolute genius. He was "the man", he built the Pro-Stock motorcycle engines previously for Vance & Hines, a guy that then started his own performance shop of Ward Performance, a guy who cast and built the heads all the Pro-Stock bike guys were using at that time. He was a world beater in the Pro-Stock bike world. Here I was, a lowly two-stroke snowmobile engine builder telling a guy I consider a true four stroke Pro-Stock bike genius, he was making a mistake in doing this on that cold MN day, go figure. I must have have some balls doing that or have no filter, all right I have no filter.... maybe even on the spectrum a bit.....
I met with Rick a couple years later about building 4-stroke RX-1's for an asphalt drag race program Yamaha was thinking about doing at that time, he said to me, "you remember you told me I was crazy for tuning the bike in that cold weather". I said yes I remember. He says "you were absolutely right, we lost that race and it was because I tuned it on the dyno for those cold conditions, and it hurt me in the warmer Florida conditions". He said he'd learned his lesson and would never again dyno a race engine that was not in its element and the general conditions and parameters in which it was going to run in. I knew this because I had done just that with the two-strokes, I built different engines for summer and winter racing, and had already made these mistakes in taking them into the different environments than they were going to run in. I pushed one of my engine designed so hard on the dyno in the environment it wasn't built for, and ended up blowing it up pushing these boundaries and learning the lesson the hard way. It seems I alway have to learn stuff the hard way like that. I call it the school of hard knocks.....
