Z900

Please login or register.

News: A big welcome to all new members !

Scorpion EXhausts

Author [ES] [MY] [PL] [PT] [IT] [DE] [FR] [NL] [DK] [NO] [GR] [TR] Topic: Z900 Bread Box dissected.  (Read 3895 times)

0 Members and 1 Guest are viewing this topic.

Offline ras

  • Z900 God
  • *****
  • Posts: 2242
  • Is What It Is
  • Bike: 2017 Z900 ABS
  • Town / City: Central Vermont
  • Country: us
Re: Z900 Bread Box dissected.
« Reply #40 on: November 09, 2018, 09:19:28 PM »
*Originally Posted by zed9 [+]
No point going half way with the full exhaust, especially if it's an expensive system. In for a dime, in for a dollar.

 :0461:

Offline bmartinZ900

  • Z900 Pro
  • ***
  • Posts: 170
  • Town / City: Denver CO
  • Country: us
Re: Z900 Bread Box dissected.
« Reply #41 on: November 09, 2018, 09:42:12 PM »
*Originally Posted by zed9 [+]
There is little point to a free flowing exhaust unless you free up the air moving into the engine. Adding also a low restriction air filter the bike will run lean.

The Z900 certainly does not run lean even with a filter and a full system. In fact, tuners are having to pull fuel to make power throughout the rev range. Stock AF is around 12.1-12.5 WOT and with a full system + filter with the stock fueling AFR is hovering around 12.8-12.9. Tuned fuel maps are targeting 13.2 AFR for peak power. So we know that no matter what bolt ons you add, the motor is running on the conservative/slightly rich side. This is why we haven't seen huge gains from full systems + filter, because the stock fueling is pretty close.

Offline zed9

  • Z900 God
  • *****
  • Posts: 2208
  • Bike: 2017 z900
  • Country: us
Re: Z900 Bread Box dissected.
« Reply #42 on: November 09, 2018, 10:58:02 PM »
*Originally Posted by bmartinZ900 [+]
The Z900 certainly does not run lean even with a filter and a full system. In fact, tuners are having to pull fuel to make power throughout the rev range. Stock AF is around 12.1-12.5 WOT and with a full system + filter with the stock fueling AFR is hovering around 12.8-12.9. Tuned fuel maps are targeting 13.2 AFR for peak power. So we know that no matter what bolt ons you add, the motor is running on the conservative/slightly rich side. This is why we haven't seen huge gains from full systems + filter, because the stock fueling is pretty close.
Seriously, I did not know this about the z900 nor have I ever heard of such a thing on any other bike. I believe you but historically any bike with performance mods including full exhaust and filter requires tuning, at least to get gains from your investment.  Carbs or FI.

Offline bmartinZ900

  • Z900 Pro
  • ***
  • Posts: 170
  • Town / City: Denver CO
  • Country: us
Re: Z900 Bread Box dissected.
« Reply #43 on: November 09, 2018, 11:25:14 PM »
*Originally Posted by zed9 [+]
Seriously, I did not know this about the z900 nor have I ever heard of such a thing on any other bike. I believe you but historically any bike with performance mods including full exhaust and filter requires tuning, at least to get gains from your investment.  Carbs or FI.

And that is exactly why Power Commander sells out the ass. People just assume they need one because full exhaust = blown motor or burnt valves.

I'm not saying the Z900 doesn't need tuning. I'm saying that tuning is not mandatory for the motor to run at a safe AFR. Tuning is absolutely the best thing you can do after mods and will yield a bit of power gain. But, we haven't seen the big jump in power from full systems because Kawasaki #1 underrated the stock power #s and #2 those numbers are underrated because the stock fuel map is  close (ish) to optimal AF. I suspect the breadbox reduced emissions enough to allow for a more aggressive fuel map from the factory. Tuning then becomes more of moving those power curves lower in the rpm range and hold through redline. All the graphs I've seen on here on tuned bikes show around 70ftlbs of tq from 4k holding through 9k. On a stock bike it's more like 60ftlbs @7k. Not much difference in power, but where the power is made. That is what the goal of tuning should always be.

Offline zed9

  • Z900 God
  • *****
  • Posts: 2208
  • Bike: 2017 z900
  • Country: us
Re: Z900 Bread Box dissected.
« Reply #44 on: November 10, 2018, 12:53:17 AM »
*Originally Posted by bmartinZ900 [+]
And that is exactly why Power Commander sells out the ass. People just assume they need one because full exhaust = blown motor or burnt valves.

I'm not saying the Z900 doesn't need tuning. I'm saying that tuning is not mandatory for the motor to run at a safe AFR. Tuning is absolutely the best thing you can do after mods and will yield a bit of power gain. But, we haven't seen the big jump in power from full systems because Kawasaki #1 underrated the stock power #s and #2 those numbers are underrated because the stock fuel map is  close (ish) to optimal AF. I suspect the breadbox reduced emissions enough to allow for a more aggressive fuel map from the factory. Tuning then becomes more of moving those power curves lower in the rpm range and hold through redline. All the graphs I've seen on here on tuned bikes show around 70ftlbs of tq from 4k holding through 9k. On a stock bike it's more like 60ftlbs @7k. Not much difference in power, but where the power is made. That is what the goal of tuning should always be.
The breadbox won't reduce emissions, only sound. It's a modern tune so who knows what they are looking for?  I'm in the catagory of "If you want a faster bike, become a better rider" type of guy. The z9 has all the power any street rider could ever need.
There are dyno runs that show stock vs modified. The gains aren't all that much. Kwai did a good job with this motor.

Offline ZROD

  • Z900 Member
  • **
  • Posts: 15
  • Bike: CBR250/GT650/Z900
  • Town / City: Bangalore
  • Country: in
Re: Z900 Bread Box dissected.
« Reply #45 on: December 06, 2018, 02:02:57 PM »
*Originally Posted by bmartinZ900 [+]
And that is exactly why Power Commander sells out the ass. People just assume they need one because full exhaust = blown motor or burnt valves.

I'm not saying the Z900 doesn't need tuning. I'm saying that tuning is not mandatory for the motor to run at a safe AFR. Tuning is absolutely the best thing you can do after mods and will yield a bit of power gain. But, we haven't seen the big jump in power from full systems because Kawasaki #1 underrated the stock power #s and #2 those numbers are underrated because the stock fuel map is  close (ish) to optimal AF. I suspect the breadbox reduced emissions enough to allow for a more aggressive fuel map from the factory. Tuning then becomes more of moving those power curves lower in the rpm range and hold through redline. All the graphs I've seen on here on tuned bikes show around 70ftlbs of tq from 4k holding through 9k. On a stock bike it's more like 60ftlbs @7k. Not much difference in power, but where the power is made. That is what the goal of tuning should always be.

Should have read this post before i bought my PCV  :138:

Online Greyhairhoon

  • Z900 Pro
  • ***
  • Posts: 349
  • Town / City: Launceston, Tas
  • Country: au
Re: Z900 Bread Box dissected.
« Reply #46 on: December 06, 2018, 07:38:30 PM »
*Originally Posted by ZROD [+]
Should have read this post before i bought my PCV  :138:

Yeah that's right. I downloaded and looked at the PC5 map for the Z900 a while back and posted it on here somewhere, but in the map they are removing fuel from nearly every area, so the bike definitely does not run lean from the factory, just about all exhaust manufacturers for the Z say "no tune needed" for this bike.
By all means if a person wants to tune the bike, then do it, but it does not need it and the gains just are not worth it IMO as the bike has more power than 99% of riders will ever use on the road. I have not gone any further than the $8 exhaust mod as that's all I need for noise, I spend my money on good tyres, getting the suspension and geometry right, I gain more speed from doing that than any other mods.