How good are dyno charts and peak HP claims?

**roogazza** · 28th October 2006, 10:40

With so many variables, common sense tells you that you use just the one dyno ! Temps, humidity,how you hold your old fella, all effect readings. So if you start with a stock bike on a high reading dyno you can at least show improvement.
I've done a bit to my Bandit and although it pumps out noticibly more its actually very little faster over my usual fanging roads. The power is 2000 higher and now I have to cope with traction and the front lifting.
But then again a bit of animal in a bike, is fun !!!!!! Gaz.

**Lou Girardin** · 28th October 2006, 16:54

Originally Posted by Crasherfromwayback

Dynojet Dyno's read low. .

They can be made to read high, but what's the point?
Dynos are for measuring the effect of changes to the bike, starting from a base line. Whether dyno A reads higher/lower than dyno B is of use only in pissing contests.

**Crasherfromwayback** · 28th October 2006, 17:09

Originally Posted by Lou Girardin

They can be made to read high, but what's the point?
Dynos are for measuring the effect of changes to the bike, starting from a base line. Whether dyno A reads higher/lower than dyno B is of use only in pissing contests.

Yeah I'm quite aware of that mate. But if you care to go back to what I was getting at there.....it was to the chappie that was saying MOST manufacturers bullshit about HP claims. He was referring to his experience using DYNOJET dynos, and I stated that infact they tend to read a bit low.

Seeing as he was obviously interested in that type of work/tuning, I stated he'd like ours, as it's state of the art. I don't really see that it was a pissing competetion. He took it that way a bit too. I gather from some of your posts that you perhaps work at AMPS?...if so, and if you've been there for a while, you may well remember that Brett Richmond used to race an 883 for them in TwinSport. I was racing one at the same time for WMCC, and Brett and I got on well. He used to jibe me about having a 'cheaters' bike, as mine was quite a bit quicker than his. After many Steinie fuelled sessions, I finally convinced him to bring his bike down to us (sorry if I'm about to drop you in it Brett!).

After a day on our dyno we sent him away with 4-5 HP and quite a bit more torque than mine had.....he never accused me of cheating again! As far as I know....he paid for it himself. THIS was my point. Dynojet Dynos are 100 times better than no dyno....but we've spent the money and taken them to another level. I was simply thinking that the starter of this thread would be interested. My cock's still in my pants. Facts have little in common with urine, unless of course it's urine we're taliking about.

**Crasherfromwayback** · 28th October 2006, 17:25

[QUOTE=idleidolidyll;803519].
Firstly, it doesn't matter much which dyno a rdier uses to develop their bike as long as they use the same dyno after each modification. That virtually eliminates the differences between dynos and the software they run and leaves things like barometric readings for the computer to equate.
Secondly; Of course your dyno reads higher BHP numbers. Taking out the back wheel and presumably the chain reduces that 10-20kg of rotating mass to zero kg. Comparing dyno numbers between dynos is a silly pastime but comparing a dyno that is attached directly to the output shaft to a dyno that reads how much power is transmitted at the footprint of the tyre is lunacy.
/QUOTE]

I think you may have misunderstood what I was trying to say, and maybe I wasn't quite clear enough in saying it. All good mate....but...if you take your bike off a Dynojet dyno ten times, I bet you'll get ten different readings. There's no way you can accurately duplicate readings when tyre slippage is at work. Don't get me wrong....DynoJet dynos are so much better than no dyno. But when you remove variables like tyre slippage, you're a whole lot closer to the truth. F1 car teams use pretty much what we have, and Yoshimura Japan came over and spent a day with us and purchased the same item after seeing it in use. That is a fact. I'm not rubbishing other dynos, but I thought seeing as you're into that side of work/tuning, you may have been interested in ours.

I was a mechanic by trade before I got into the bike industry, and while I've forgotten more than I was ever taught, I still have a grasp of the basic principles. I was a non believer in all the dyno black magic....untill I stayed behind after work with Bruce (our man that runs it) trying to find HP and torque outta my 883 race bike. Things I thought were urban myths like asbestos header rap....the dyno is so sensitive it showed us not only the 2HP gain....but how we could move the torque up and down the rev range by varying the length we used. And because the tyre ain't slipping, if we put the bike back on it a week later, we'd be back to 'ground zero'.

Hope that all (kinda) makes sense!

Pete

**AllanB** · 28th October 2006, 20:17

My bikes a better rider than I am - I'm just there so it does not look silly riding along on its own..........

**TonyB** · 28th October 2006, 20:50

Originally Posted by TonyB

Surely the "Torque v Road speed in one gear under top" is heavily dependant on the gearing of the bike. Doesn't this graph just say "the GSX1400 has lower gearing"??

Ooops, HIGHER gearing. Anyway, all these graphs demonstrate is differences in gearing

**scumdog** · 28th October 2006, 21:24

I guess you can't really test ram-air theories on a dyno - or conversely how high engine temperatures cause lower hp due to ingesting warm air into the intake?

**Crasherfromwayback** · 28th October 2006, 22:44

Originally Posted by scumdog

I guess you can't really test ram-air theories on a dyno - or conversely how high engine temperatures cause lower hp due to ingesting warm air into the intake?

We can't ram air down the bikes throat like it's going 185mph....but we do blow a fair amount of cool air at them.

**imdying** · 29th October 2006, 21:03

Originally Posted by scumdog

I guess you can't really test ram-air theories on a dyno - or conversely how high engine temperatures cause lower hp due to ingesting warm air into the intake?

A well setup dyno room goes a long way towards compensating for a lack of airflow (heat build up). Bugger all that can be about ram air at this stage though :/

Crasher, does your dyno plug into a Power Commander 3 to make tuning faster and more effective like the dynojet ones do? Sure sounds like a bloody good trick to have

I'm guessing you guys have something similar?

On a similar subject... when you guys are doing Suzukis (you're a Suzuki dealership right?), how do you adjust the ECU. When the Suzuki dealership down here did mine, apparently they used something akin to a 'yoshi' or 'teka' box, except the Suzuki version? And what about other brands? Can you reprogram the average ecu, or is a PC3 pretty much mandatory?

/edit: No hurry for an answer, feel free to ask your dyno operator tomorrow, just keen to know how bikes are usually remapped. PM me if you like

**FleshDevice** · 25th October 2010, 18:28

Get a Bit Sick of me m8,s Bangin on about there 120hp fxr Harley they Had Dyno on yo machine

Originally Posted by Crasherfromwayback

You'd love our Dyno mate....it ain't no Dynojet jobbie!
The software alone cost more than a Dynojet Dyno. It was built for us by International Dynometers with some input from the DSIR, and it's gospel.
We take the back wheel out and drive a hydraulic pump, so it's not simply a free running spool, and obviously we get notyre slippage. If you're ever in town, call in for a demo!

**Stylo** · 25th October 2010, 19:22

Originally Posted by FleshDevice

Get a Bit Sick of me m8,s Bangin on about there 120hp fxr Harley they Had Dyno on yo machine

Ummmmm...not so sure Fleshdevice .. (.wtf ? )

If you wanna see some real numbers on the HP Dyno, the answers pretty clearcut ...as always..

VFR1200 ? ....nah , Honda don't do Hp any more and 28k ?

Wheel in the old favorites, ZX14 and the 'Busa .....enough said

**wayne** · 19th November 2010, 20:41

at least bmw on there sports bike are accurate to claims

**pritch** · 20th November 2010, 09:54

Originally Posted by wayne

at least bmw on there sports bike are accurate to claims

BIKE reported that the new BMW sprot bike was the first bike they ever tested that produced more horsepower than claimed. The inference I drew being that BMW didn't want to upset the Eurocrats.

**schrodingers cat** · 20th November 2010, 11:15

I was told that a dyno sheet was worth about as much as the paper it was printed on so I got mine done on some really expensive gold embossed stuff and now my bike has more horsenpowers...