[Devious2xs]

The problem is that the short tuned length of the Zard silencer wants less fuel at low rpm. We are finding that the tunes that work fine with systems using longer midpipes, need to be leaned down under 4600 rpm to improve performance and starting with the Zard silencer.

There have been several discussions about the issue on this site.

Let us know the outcome of the "dyno war", and post any graphs if possible.

 

[Devious2xs]

If you host the tif on another site like Photobucket, you can post it here.

Or you can convert it into a bit map, jpeg, etc.

 

[Devious2xs]

That is the FIRST independent dyno for a Zard silencer I have seen - THANK YOU.

What were some of the other bikes putting out in comparison? Just trying to see how this dyno compares to others - it looks a bit lower than I would expect, but that can easily be dyno variations.

 

[Devious2xs]

The numbers for the Yosh piped 07 GSXR 1000 sound about right - depending on tuning. But the 750 sound low - very low. The dyno could just read a bit lower than average.

Why are the runs done in 6th gear? Did the dyno operator do this?
I generally use 5th (closest to 1:1 gearing) and the engine is loaded better. Notice that on your graph, the smoothing is at 5, and the engine is erratic at higher revs. Runs in 5th gear would be less erratic, even using the smoothing set on 2. You would only have a very slight loss due to gearing between 5th and 6th.

Thanks again for the chart. ;D

 

[Devious2xs]

Was the whistling sound coming from the exhaust - like a flow restriction? That could be part of the erratic reading on the top end.

Does your Zard have a preforated cone baffle between the silencer and the oxygen sensor?

 

[Devious2xs]

Don't drill the airbox. You have more flow than you need. My bike made 108 hp stock, and 135 hp the last trip to the dyno with the stock airbox.

Drilling holes just adds noise - I really wish those who keep telling others to do this would test what they recommend and quit spreading old wive's tales.

Check the seal on the airbox to the throttle body. You likely have a gap somewhere.

 

[Devious2xs]

Start by checking the seal on throttle number 3 - right side. This one tends to give problems.

Also, make sure the crankcase breather line is conected well.

 

[Devious2xs]

EWwwwwwwwwwwww.

Not a good sound.

 

[Devious2xs]

It is so difficult to diagnose a sound related problem based on an internet video file. It could be anything from metal on metal, to a bearing, to an intake air leak.

Either way, it needs to be fixed - the sound would drive me nuts!

 

[Devious2xs]

The problem is that the short tuned length of the Zard silencer wants less fuel at low rpm. We are finding that the tunes that work fine with systems using longer midpipes, need to be leaned down under 4600 rpm to improve performance and starting with the Zard silencer.

There have been several discussions about the issue on this site.

Let us know the outcome of the "dyno war", and post any graphs if possible.

Is this why I notice the bike sputtering in first under 4000 rpm....I just noticed that it is beggining to do this more often.....anything higher than 4000 rpm and the bike screams.....Still thinking of that power commander...

More than likely.