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This conversation is civil compared to my "Latest Z400 photos" post which morphed into an ecu battle and photographic critique. Thanks for all the fact information. On a non technical note, when I removed my stock pipe and Coffman the exhaust color was black and sooty. I always thought lean would be a light grey or tan. With the Musarri full system the exhaust color is still blackish. If the fuel mixture was to lean out, wouldn't the color be lighter?
 

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Discussion Starter · #22 ·
MWR race air filter and exhaust, Running FTECU. It is a race bike, sits at 4 bars unless ambient is over 105F and then it'll go to 5 at race pace. Usually measures around 104Db on the meter.
Yes! Very focused. :)

Still remarkable that you got a 14% power increase with just the exhaust, filter, and FTECU tune.

Jim G
 

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This conversation is civil compared to my "Latest Z400 photos" post which morphed into an ecu battle and photographic critique. Thanks for all the fact information. On a non technical note, when I removed my stock pipe and Coffman the exhaust color was black and sooty. I always thought lean would be a light grey or tan. With the Musarri full system the exhaust color is still blackish. If the fuel mixture was to lean out, wouldn't the color be lighter?
Not always. Tail pipe color and your temp gauge are not very good indicators of fuel mixture. :)

12.8:1 here.
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Yes! Very focused. :)

Still remarkable that you got a 14% power increase with just the exhaust, filter, and FTECU tune.

Jim G
I'm wondering if the conditions between the first run (stock) and the next one (with upgrades) were different. I know dynos vary but 41 hp sounds very low for a bone stock bike. Most seem to be around 43-45 depending on the dyno. 47-48 sounds very reasonable for his upgrades, but the stock readout is less than expected, so I'm wondering if there was some other factors present during the first run that caused the dyno to read lower numbers.
 

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Discussion Starter · #25 ·
I'm wondering if the conditions between the first run (stock) and the next one (with upgrades) were different. I know dynos vary but 41 hp sounds very low for a bone stock bike. Most seem to be around 43-45 depending on the dyno. 47-48 sounds very reasonable for his upgrades, but the stock readout is less than expected, so I'm wondering if there was some other factors present during the first run that caused the dyno to read lower numbers.
I MIGHT have figured it out. IF the "before" dyno run was done before the tune but AFTER the new exhaust hardware had been installed, I can understand the big gain. The "before"run would then be running the new hardware but the OEM tune - a bad combination that might indeed drop the OEM power by 2 or 3 rwhp. This would also explain why the "before" AFR was so bad (18): a really freeflowing (LOUD!!) exhaust that needs more fuel to match the higher airflow, but the OEM tune could not deliver that amount of fuel. Hence the crappy "before" power.

Jim G
 

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I MIGHT have figured it out. IF the "before" dyno run was done before the tune but AFTER the new exhaust hardware had been installed, I can understand the big gain. The "before"run would then be running the new hardware but the OEM tune - a bad combination that might indeed drop the OEM power by 2 or 3 rwhp. This would also explain why the "before" AFR was so bad (18): a really freeflowing (LOUD!!) exhaust that needs more fuel to match the higher airflow, but the OEM tune could not deliver that amount of fuel. Hence the crappy "before" power.

Jim G
That's exactly it. All mods were installed and then the first run was on the OEM tune.
 

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That's exactly it. All mods were installed and then the first run was on the OEM tune.
Ohhhh....that explains it. So the "before" run was actually worse than bone stock most likely. First you made the bike perform worse, and then the tune unlocked its potential. Now it makes sense :)
 

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Discussion Starter · #28 ·
The interesting thing I'm seeing when I look at all the available data here and elsewhere is that simply replacing the ultra restrictive OEM exhaust system with any decent quality full exhaust system seems to uncork the 400 particularly well and easily, and its OEM tune seems remarkably able to handle the uncorked airflow without going super lean.

A man who spent 19 years working at Kawasaki in a variety of roles (sales, parts desk, service writer, tech, and shows) told me recently that the OEMs have come a long way in the last few years in the capabilities of their ECUs, and I guess the 400 is evidence of that. Getting a custom tune, or even a mail order tune from a reputable tuner is still certainly superior, but when I see 5 to 7% more power being added by simply installing a full exhaust on an otherwise stock bike, without triggering big ECU tune issues, I am impressed.

Jim G
 

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If you maintain the stock O2 system it will pretty much try to tune the bike to the same af ratio no matter what exhaust you run. That’s within its operating range which is smaller throttle openings and below 5-6k revs. This is the range where all the environmental regs apply. Above that the manufactures are free to set the fueling however they want which is normally much richer than down low and are tuned for good power.

Airbox changes have a much larger effect on fueling than exhausts normally do. Start making big changes there and you had better have a good tuners help. And I don’t mean just changing to a K&N filter which usually does nothing. I mean when you start cutting holes, changing stacks, etc.
 

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Discussion Starter · #30 ·
If you maintain the stock O2 system it will pretty much try to tune the bike to the same af ratio no matter what exhaust you run. That’s within its operating range which is smaller throttle openings and below 5-6k revs. This is the range where all the environmental regs apply. Above that the manufactures are free to set the fueling however they want which is normally much richer than down low and are tuned for good power.

Airbox changes have a much larger effect on fueling than exhausts normally do. Start making big changes there and you had better have a good tuners help. And I don’t mean just changing to a K&N filter which usually does nothing. I mean when you start cutting holes, changing stacks, etc.
Yes, I agree about the effect that intake mods can have. I see that in the effects of the velocity stack and drilled airbox kits that Jesse Norton sells. They are very effective. Just look at his dyno charts which show that.

But I knew that a couple of years back, when I was doing my Yamaha R3 project. Graves sold me a pre-release kit that included a modified airbox & stacks and a new ECU tune and new exhaust to match, and it had a huge effect on the R3s power. In fact, the effect was large enough that many on the R3 forum disputed my report on it, saying that it was unlikely that the kit could produce results that good. However, the subsequent applications of the same basic techniques by Jesse Norton and others to the Ninja 400 have shown that the Graves claims were legitimate.

The Ninja / Z 400 platform is proving to be a much more satisfying platform for me to do mods on than the R3 was. The R3 was simply just a bit too small in displacement, whereas the 400 is just large enough, and still light enough, to be able to hit really satisfying acceleration while still getting the smallest insurance premium demanded by our Government-run, monopolized insurance here in British Columbia, Canada. :)

Any time an "entry-level", relatively inexpensive motorcycle can easily be modded to out-accelerate some very quick performance cars, that's a winning product.

Jim G
 
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