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Can we all agree that dyno numbers can be deceiving?

I am sure all of you have seen or had a bike that is a real performer on the dyno, and just a regular performer on the track. A dyno "simulates the best "seat-of-your-pants" road testing right on the shop".

As we know, "a dynometer is a tool to help us understand, track and compare engine performance under a controlled enviroment". That being said, as I mentioned earlier, sometimes a bike with a great dyno chart does not perform well on the track.

In your opinion, which is best, track testing where you'll receive a slip of paper with your 60-foot time, e.t., and top end mph? Or do you think that after getting your bike dyno tested, the "seat-or-your-pants" feel is more accurate?

Suggested reading: Dyno operators can fix results...

Exaggerated dyno gains are rampant but generally harmless, unless the dyno operator is purposely inflating (or shrinking) figures and using them to take cash from customers. Artificial numbers can hinder your progression in the sense that the claimed 10 HP increase you received from a “tune” might only be worth 2 HP had the dyno not been manipulated.

Artificially deflated numbers can also be the pits, as an operator can take a bike that’s actually making 105 HP and tweak the dyno to read 100 HP (or less) for the baseline. After the customer forks over some cash, the operator pretends to tweak the map for more power when in reality all he did was adjust the dyno. With the dyno back in calibration (and without a single change to the bike) you’ll see a power increase back to the original mark of 105 HP.

Disclaimer: I am NOT in any way shape or form implying that YOUR dyno test has been manipulated.

Talk amongst yourselves....

Kofla

2010 ZX-14 MotoVlog

Kofla,
Thank you for bringing this conversation to a new thread. As I posted on the Romans Flash thread, dyno charts reveal how our engine is performing under certain conditions and that's it! Has nothing to do with going fast. Infact it is not just calibration that affects dyno results. Results may be affected by things like ceramic bearings, light wheels, fresh spark plugs, old or new tires etc!!! SAE and Standard Smooth also affect results given situations. Aging dynos are an issue and cross comparing one bike to another on a different dyno will shake reliable results. Suffice to say, if you are interested in the health of your engine and want to collect data on your engine go get one!!!

Now the street is where I shine, an operator, with the right set up (mods, flash, airflow) or as Romans says (3L's) Lighten, Lengthen and Lower) equipped with these tools, the right pilot can make use of these features to GO VERY VERY fast. The human element (skill) when matched with set up (bike) produce that track number. When skill levels are aggressively matched, everyone knows certain bikes with certain mods = better finish times.

Me personally, I like a dyno sheet, I like to know what the engine is theoretically making and then I like to seat of pants ride it on the street! This year I like to do launches at a track!

My friend Beast had his bike dyno tuned with a map that produced a higher hp number. He rode home on it and restored the previous map (lower hp number) as he felt (I agree with him) the bike went faster or produced power more aggressively with the previous map.

The bike has a certain top hp number 200 PLUS some have exploited above 210 (wow!). It's not that number so much as how we get there. Got to say though a 210 plus number is WAY COOL! I know one cat that can do that and his flash is on its way to my house!!!

In the end I am not an expert racer or tuner, but I love to shred tires and ride hard until my legs shake and my heart beats. I like to hold the bike wide open until I crest the 5th or 6th gear top end or at least until the helmet buffets beyond the point where I can read the gauges. Thus far my only concern is that the bike feels "normal" as I have adjusted to its power.

Sorry for the long response!

Gentlemen start your engines.

* Last updated by: Wolfman on 11/28/2013 @ 9:13 AM *

The bike has to be run in the real world to determine the level of performance. The underlaying question is, "what is THE real world?" Racing, Sport riding or Bike Shows?

In Racing competatively, test by racing. Use a dyno to get in the zone but datalog and tune at the track to go fast.

Sport riding, test by seat of the pants. I have a friend who loves his old ZX-10 more than the new ground breaking Gen4 he bought. The reason he prefers the slower Gen3 is that it is more exciting.

Bike night, bragging rights are what matters. Tune it in on the dyno and hope you don't ever find yourself up against a stingy dyno.

Like I always say make it run right and just ride it, its yours so your the only one who has to like it, enjoy the freaking ride, your ride!!

I dragged raced a 68 Firebird for 5 years. I tuned it from 13.4 at 104 mph to 11.6 at 116 mph without major engine changes. 461 CI with heads ported, 3.25 gear with a 400TH - 3,580 lbs. Tire change got it to 13.0's. Accelerator pump correction 12.9's. Carb changes 12.5's. Launch technique changes 12.3's on a perfect day. Switched cam, carb, torque converter, and added Cal-tracs (leaf springs) and ran 11.9's out of the box the next season. Kept falling flat on it's face at the top of 1st. Put an 18 lb spring in the fuel pump and it ran 11.60's in good air and 11.7's in poor air.

What I have found is the butt dyno is ususally wrong with small changes. What typically happened is I hurt my 60' time but would feel the rush more because because I hurt the bottom end torque which made me think I was faster..... Go to the track....60' down = slower ET/MPH. The butt dyno is completely worthless for small changes. When I swapped carbs (750 vacuum secondaries to a 650 Double Pumper) I picked up .5 and 5 MPH. It was insane; felt like I added nitrous. Secondaries on the 750 were not functioning property....the butt dyno was dead on. But tuning a .1 here and there, butt dyno is worthless.

Dyno. You can do a lot of tuning on a dyno; but, if you have fuel deliver issues (like I had) or traction issues it won't help much. You may get more MPH; but, won't go quicker if you can't hook. I parked Mustangs, Vipers and Corvettes all day long that made 550+ HP on a dyno because they couldn't hook. What HP did I make? No idea, but, I ran 11.6's all day long at 116 MPH in good air in a 3,580 lb (with me) car.

One buddy had a Corvette that was "supposed" to be faster than what I was running at the track with his "mods"...according to the magazines. Pulled up next to him doing 45 MPH...dropped a gear and smoke'em for 100 yrds....he never spoke that nonsense again. Another buddy said the same crap about his Z28...I told him I would pay his Test and Tune fee. I would get 3 runs and he could have as many runs as he wanted and if he posted a time slip within 1 second of my fastest one, I would give him $100...and if he lost he owed me $0. He declined and shut up after that.....

I have a ZZR 600 and put a ingnition advancer in and shimmed the carbs. I could ride while cruising in one gear higher than normal. Was it faster? The changes eliminated the lean surge down low. The front tire would come up without effort in first vs. before it wouldn't. Butt dyno says yes; but, I don't have time slips to prove it....

Just my opinion on butt dynos.

* Last updated by: gnorv on 12/4/2013 @ 1:21 PM *

Thank you to those of you who responded. Happy Holidays!

Kofla

2010 ZX-14 MotoVlog

Gnorv,
Cool write up thanks for posting. I like your style!