Custom Dyno tune

[12:1]

Originally Posted by Andreasy

I have this slip on which is large enough. Sound without the slip on was acceptable when installing it so it's not that db killer that concerns me. My concern is the result of I removed that, the bread box and the cat. Yes the bigger slip on will help but i don't know how much

I was in the same boat with my RS. Akrapovic header (weight saving alone is worth the admission price, not to mention build quality and aesthetics)
Neighbours said they could hear me from over a kilometer away with the free flowing stock can. I bought a used akra slip on and even that was too loud (made a $100 on the resell)  I ended up with a full size yoshi R77s. Matches the 40mm akro at the beginning but 75% in it ramps down to 35mm. I can now cruise away from home without any negative feedback and it seems perfect at high revs. Take your SC DB killer down to an exhaust shop and get them to modify it to a 35mm outlet. No point though if you don't go full headers. You gain 10bhp with free flowing exhaust and a dyno tune. Don't skimp on exhaust gaskets either, they are a one time use crush gasket. Buy 2 sets.

[notsoaverageguy]

On the exhaust gaskets, you can reuse them ,(I have several times) just take a flame (propane butane ext..) get them glowing red and immediately throw them in cold water. It Re aneals  ( expands them) ready for Reuse.

[12:1]

Originally Posted by notsoaverageguy

On the exhaust gaskets, you can reuse them ,(I have several times) just take a flame (propane butane ext..) get them glowing red and immediately throw them in cold water. It Re aneals  ( expands them) ready for Reuse.

Just gave it a go on oem gaskets. Gave one 90 sec with map/pro benrzomatic torch hanging from a coat-hanger wire, it was hard to get a uniform red, then straight into cold water. Thickeness measured 2.10 mm before and 2.10mm after, none of the header pipe high/low indentations changed on the gasket.
I just buy 3 sets of K factory gaskets from webike any time I put an order in if needed. I did try to reuse the OEM once (without the above) and had to chase down a ticking noise that ended up being the flange gasket. Each one to there own. Maybe might work with an oxy but not for me.
Z900 not listed but just used a set on the z900 motor, same/same.
https://japan.webike.net/products/24983285.html

[Andreasy]

So to finalise the end result, i have finally removed the cat and silencer from the sc slip on, kept the bread box to keep volume down and installed bnc filter.

End result: i got the powerful tone i was looking for, loud enough to be heard by nearby cars, soft and deep bassy tone but not too loud to disturb neighbours at night. Dyno made the engine running much smoother, gave more power, i feel the engine breathes easier and runs better.

I know i could get a much better performance result by removing the breadbox but with this solution i get the best from both worlds. I haven't regret it so far.



https://cdn.img.z900forum.com/Screenshot_20230921_061854_Facebook.jpg

[RainbowJo1]

 

Originally Posted by Andreasy

I'm about to go next level with custom tune (Z900SE 2023). Currently have SC project slip-on.
Talking with my mechanic we said that the only real benefit will start firstly by removing the slip-on db killer which I though was not removable on Euro5 slipons. He said that it can be done with a small modification which will make it to easily take on and off on demand. Next important is the cat, although the best is taking everything out, including the breadbox and also installing an aftermarket metal filter. That is said to not provide any benefit alone but he insisted that the custom tuning will take benefit of all these.

Being afraid that doin so will end up with extremely loud exhaust, I see myself doin what he said but leaving the breadbox on. His opinion is that could be acceptable as long as we remove the slip on db killer because leaving that on would block all the benefit we gain from unblocking the airflow before that and that would void all benefit gained. I understand this because indeed, opening all airflow from manifold and blocking it at the exit point would indeed restrict the airflow and cause high temperatures at the slipon.

Unfortunately, listening to youtube sounds doesn't really help and I'm really skeptic for the loudness as high rpm.

Has anyone done a custom dyno with this setup (removing everything except breadbox) and could provide any feedback? Also, anyone skeptic like me before who removed everything and either regret the loud noise or liking it?

I just need some ideas to decide what to take off and what to leave on. Sadly, once you cut off cat or breadbox, you can't just play by reinstalling it back just to test so what we do is mostly permanent.

Hi there, i have a 2017 performance model z900 and wanted the bike to sound louder without being deafening. I test rode another bike, same year and model, which had been de catted with the same Akrapovic end can as mine and it sounded a lot better than mine without being too loud~the Akrapovic end can has a db killer in which can’t be unscrewed, (can be drilled out though and unscrewed~vids on you tube) so I got a decatted exhaust, put the end can back on with the db killer in, and had the bike ecu remapped and a custom Dyno tune; the bike sounds great without being too loud, runs smooth and has gained an extra 10 horse power and 5 Ft/lb torque. I was asked if I wanted flames and popping coming out~I said no~this bike does pop a lot once tuned! I may at some point get someone to drill a hole in the end can and remove the baffle as long as it can be put back again just in case it is too loud. I paid
£450 for the tune, and £273 for the decatted exhaust with the gaskets (apparently, it’s only the end can which makes the sound, so I didn’t feel I needed to buy expensive pipes.