Dyno'd the bike today.

Traumahawk said:

Well dyno'd the bike this last saturday. I swapped to a kerker 4-1, and went from 104 to 107. I then took the Y off of the airbox, and went to 109.6.

You can see the last 2 runs on the first pic. also the air/fuel ratio.

The last pic is all 3 runs, and you can see how they compare with the first.

Well looks like a muscle jet kit in my future.

Click to expand...

The HP curve with the Y seems to be more consistent.
THE AF ratio is lower without the Y! Did you change the 147.5 mains??

Itgoes said:

Looking at that first graph, your baseline, it really looks to me like the operator got off the throttle early, or hit a rev limiter. You can see how quickly the power falls off, that is not normal from my experience.

Click to expand...

The point I was eluding to was that you only see that power falling off the table on the first baseline run, and it happens earlier than 9500 rpm. More like 8500. I doesn't look like the engine was run to the limiter on that particular pull.

...

...

My bike made 87hp on the dyno. Ran something like 11.45 with 1.76 60ft first time at the track. You can throw all the bolt on stuff you want at them and they're still slow. Still gets alot of attention at bike night but will never live up to the V-Max legend in performance unless you want to totally molest it.

coolmax said:

My bike made 87hp on the dyno. Ran something like 11.45 with 1.76 60ft first time at the track. You can throw all the bolt on stuff you want at them and they're still slow. Still gets alot of attention at bike night but will never live up to the V-Max legend in performance unless you want to totally molest it.

Click to expand...

I wonder what was wrong that it only made 87 hp....was it a restricted version?

Sent from my PB99400 using Tapatalk 2

Traumahawk said:

I wonder what was wrong that it only made 87 hp....was it a restricted version?

Sent from my PB99400 using Tapatalk 2

Click to expand...

Yeah something was a matter with the bike or the dyno one !

Traumahawk said:

It was....but you can only see it because that is where the line for the graph stops.

Apparently power on a Vmax with stock exhaust starts falling off around 8500. It was the same on a dyno run in Topeka. Here is the pic from that run. Now differnt dyno, so slightly different numbers, but everything was exactly like the first run this year at Wind River.

Click to expand...

I got ya. I never ran any of my "Stock" Gen 1's on a dyno. They all had at least a pipe, jets and an air box mod.

That fall off in power on a stock bike is quite severe.......it should be short shifted when racing IMO. No need rev the piss out of it, it would only slow you down.

It's no wonder the HP seems low - it was done on a Hardly Davidson dyno....they probably aren't calibrated for such high figures!

MaxMidnight said:

It's no wonder the HP seems low - it was done on a Hardly Davidson dyno....they probably aren't calibrated for such high figures!

Click to expand...

Thats funny....you talk with the dyno operators...and they are getting decent hp numbers like these....out of the 113 cubic inch harleys.....but thats still a WAY heavy bike.

Sent from my PB99400 using Tapatalk 2

Itgoes said:

I got ya. I never ran any of my "Stock" Gen 1's on a dyno. They all had at least a pipe, jets and an air box mod.

That fall off in power on a stock bike is quite severe.......it should be short shifted when racing IMO. No need rev the piss out of it, it would only slow you down.

Click to expand...

I totally disagree. The rpm drops in each gear shift are NOT optimal by short shifting. You fall out of the rpm range where power starts. Is it harder on valve springs? Not really since your not really revving it beyond a safe point. But yes it would be harder on valve springs as compared to shifting at 8500 rpm.

If you talk to Dale Walker and other guys of that era, you will find out most of them revved beyond the power range too, and that's how they pulled better numbers than most people.

I ran mine quite a few passes and found the sweet spot for it. 4000-4500 rpm was the perfect launch point and shifts on the tach of 10,200 ( which is probably an honest 9600-9800 at the motor ) made the best et's and mph for me. If I shifted lower my et's grew. I tried shifting all over the place and that 10,200 mark on the factory tach ( again optimistic factory part ) made the best runs time and time again.

I have strings of time slips with 10-15 runs in a row that fluctuated by hundredths if I did my part correctly.

I had a 10.90 in there somewhere in the bike ( 11.02's and quite a few of them at that ), I didn't own it long enough to coax it out. 1.68 60 ft time and 124 mph out of a bike with a pipe only and no other tuning proves that the bikes are capable IF you can do the magic number. I am not a light weight either 235-240 lbs dressed.

I never dyno'ed my bike either. I never ran a tune on it, I just rode it and took it to the track. I guess my point is, that if your going to drag race, it takes alot of effort to try different things to see what works. If your only going to beat on the street with it, then just short shift, as that extra .2 tenths you pick up at the track means shit on the street most of the time.

So if you do go to the track, don't just look at the dyno sheet and pick your shift points, test other points, heck super short shifting might make it faster, you just never know. But a dyno is NOT the tool to use to determine shift points, its only a baseline to give you a start. Gearing , tire size etc, can change all that, as it does with the Vmax.

Todd

I totally disagree.

Click to expand...

Well of course you do....I would expect nothing less. :biglaugh:

There are a multitude of different factors that determine the optimal shift points, launch rpm etc. You've touched on most of them. A dyno graph can only tell you so much.

That being said a quick look a the graph shows that the bike has lost about 20 HP from 8,000 rpm to 9,500. Shifting at say 10,000 rpm is most likely (can't be sure without knowing the ratios of all the gears) going bring you back to somewhere in the curve where the HP is diminishing.....well past the peak. That is definitely not what you want. I'm only using this bone stock bike and it's dyno graph as an example, it would not apply to a Vmax that has a pipe and has been jetted.

There are calculators for this stuff that work pretty well......but like you said it's often just trial and error to get the most out of your bike at the track.

One thing to keep in mind, and I myself didn't even realize it until I started watching videos where you can see the gauges.......is that the rpm does not drop off much at all when going WOT after a shift. On my Gen 2 it's only about 1,000 rpm or so after each shift. Of course gearing spreads are different from bike to bike, but not dramatically so.

https://www.youtube.com/watch?v=Qg2DXVrIAaI

Itgoes said:

https://www.youtube.com/watch?v=Qg2DXVrIAaI

Click to expand...

Your video says private?

Todd

https://www.youtube.com/watch?v=tUAyaSgiIuI

Your absolutely correct on the gearing spread.

I can't really say for 1st to 2nd and 2nd to 3rd, because I wasn't on it 100% throttle opening. But from 3rd to 4th I was and it looks like roughly 11,600 range ( limiter kicks on ) and drops down to just under 10,000. I had to pause it a few times and there is glare so I couldnt get an exact look. But close enough. So without seeing your video, I can't say about a Gen 2 Vmax. But Looking at the ZX14 it drops roughly 1600-1700 rpm from 3rd to 4th gear.

And I ll be honest I didnt look at Trauma's dyno sheet but a quick glance. I just looked at the last one and shifting at peak power ( say 8500 rpm ) puts him just under the power curve if you were to say it dropped to 7500 rpm. Worse if it dropped 1500 rpm he would be further away from peak power. But shifting at say 9200 would bring him in close to peak power on the next gear change.

The thing about the Vmax's and even the ZX, is that they have an abudance of torque, so short shifting many times will feel faster. Just as reving the piss out of it makes you feel like you might be going faster.

My Pontiac heavy street car ran 10.80's and I would shift that around 5500 rpm. But it sure felt like it was making power at 6500 rpm. I ran in the 11's and kept dropping my shift points and kept going faster and faster lol.

On the other hand my GSXR 750 I shifter damn near 14,000 rpm and it ran 10.80's also. It was screaming. On the street there was no reason to shift that high. But it didnt really start making power till 8000-9000 rpm. I dont even remember what that dynoed at, I want to say almost 100 hp or something.

Anyways, my point and your point I think is well understood.

Todd

Fixed the video....I had sent a link to my daughters concert to my parents, I didn't want them seeing my VMax videos (the ones on the street) so I locked them all.

Even at 54 I'm hiding stuff.....LOL! It's not worth the grief I'd get, my mom would kick my ass. :rofl_200:

...

great findings either way

went to a vintage bike show that had a dyno and most people had to walk up and look at the entry paperwork to see what it is. then when I went on the dyno peoples faces where priceless. pulled 153hp and 104 torque

Those are some WAY impressive numbers.