laverda1200
Parking Attendant
Posts: 23
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posted June 30, 2010 12:02 PM
Performance tuning WITH stock exhaust?
Hi all
to run in the "Production" class at BUB Speed Trials on the Bonneville salt requires a "stock unmodified" exhaust system.
After talking with a tech inspector/scrutineer, it appears likely that an added O2 bung may be acceptable, but that is it. No gutting of silencers, no removing catalytic convertors, etc. Even ceramic coating is not permitted, apparently.
so, I have yesterday put a stock unmodified complete exhaust system back on the bike (with an O2 bung ahead of the catalytic convertor in the 08 exhaust header in the location used on the Euro ZX 14's), and temporarily gone back to a "Zero" map in the PC 5. I also temporarily hooked back up the stock "fresh air" system to inject fresh air into the exhaust ahead of the cats, which unfortuatley skews the reading from the wide band O2 sensor.
First question: to get an accurate reading of the actual air/fuel ratio, I need to plug the fresh air sytem. How long will the cats in the header and the silencers survive with the fresh air system plugged? Minutes/hours/days/weeks etc? I am not clear on how badly the cats need the fresh air system, but I at least need the cats to survive say 2 to 3 hours on the dyno while I try and optimize mid range and top end fueling for absolute best top end power at 100 per cent throttle. Does anyone know for sure one way or the other? I would hate to have the cats plug up during tuning and restrict the exhaust flow.
Second question: for best top end I don't see pulling the secondaries (flies) or a TRE as being a whole lot of help. What else can anyone suggest for top end performance enhancement for a bike forced to run a stock unmodified exhaust system? I have already done the Speedo Healer/ ceramic wheel bearings/ smaller rear sprocket selection/ non O ring chain/ PC 5 with Autotuner and accelerator pump feature enabled.
I actually cut a spare stock silencer apart on a bandsaw to see what I was dealing with, and in fairness to Kawasaki the silencers actually look pretty decent for exhaust volume. Similarily I sectioned an 08 header, removed the cat, welded it back together and ran the gutted header on the bike with no noticeable increase in power (but a noticeable decrease in heat).
So, stuck with the perceived restriction of a full stock 08 ZX 14 exhaust system and its three catalytic convertors, what would be the best tuning route to go for best top end wide open throttle tuning for a run on the salt at Bonneville?
Paul
ps I have already heard all the advice to creatively interpret the rules by modifying the stock exhaust as unobtrusively as possible, and I am not going down that road. I would hate to be fortunate enough to succesfully achieve a record speed then lose the record at tech tear down after a protest.........
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laverda1200
  
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RACNRAY
Expert Class
FAST OLD GUY
Posts: 178
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posted June 30, 2010 12:17 PM
Runnin the skoot with or without the fresh air system has no affect on the cats. The job of the fresh air is to clean up emmisions, it does that by simply allowing the inherent vacuum present in the exhaust ports to pull air in, but the key is the oxygen in that air combining with any unburnt fuel to reduce emmissions. It is the oxygen that is the important part of the end result of a pair system's operation. I imagine that exhaust temps may be higher with an active functioning pair system as there will be some combustion of the unburnt fuel in the exhaust.
Unplug the pair system, there will be no harm to the cats.
HOPE THIS HELPS
RACNRAY
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no chicken strips on this south florida boy's skoots!!
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smokinZX14
Needs a life
Posts: 10197
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posted June 30, 2010 12:45 PM
It's a fact the zx14 stock runs real real rich in the upper RPMs .. Some 08 and 09 have been mid 11s on the A/F stock .. Now add the altitude of Bonneville and you have one fat running motorcycle ...You are going to have to do your tunning at altitude in Bonneville .. I don't race LSR so i can't tell what A/F would be the best but i do drag race and find 12.8 to 12.9 to work very well .. That 12.8 to 12.9 i use is on the dyno without ram air , with ram air that would be closer to 13.2 i would think ..If you can get the A/F to read inbetween 12.8 to 13.2 going down the race track i think you would be pretty damn close ..
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Smokin Performance Cycles..
Tampa Bay , FL .. Brocks Performance Dealer ..
Gen 2 ZX14R Best ET 8.43 , Best MPH 164.95
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laverda1200
Parking Attendant
Posts: 23
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posted June 30, 2010 01:03 PM
thanks, guys.
I already found out that my 08 ZX 14 runs ridiculously rich in the upper rpms at big throttle openings, guess Kawasaki wants to keep warranty claims down by making sure the engine won't go lean and melt even if someone sticks an open exhaust system on it without re-mapping......
I thought the Pair fresh air system was to help the cats out by further cleaning up emissions before the exhaust hit the first cat in the header, but if the cats can survive w/out the Pair fresh air sytem as RACNRAY tells me, I will plug the sucker back up. My target AFR is around 13:1 from about 75% throttle as set up in my autotuner for the PV 5, and I am starting with a zero map. I am at around 3,200 feet where I live, and I know Boneviille effective density altitude can range from 4,000 - 7,000 feet, but I'll build a base map here where I live with the autotuner, then trim further once I get to Utah late August.
problem with dyno tuning is the lack of ram air, but I like Smokin's suggestion to go a little bit richer on the dyno to compensate. I'll give it a try, as trying to autotune full throttle mapping on the street is a realy dangerous thing to try and do.........
Paul
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laverda1200
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Ozonkiller
Expert Class
Posts: 350
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posted June 30, 2010 07:16 PM
Add an Innovate data logger and you can down load all the info you'll need under real world conditions. Smokin is right, 12.8, or so is a good target for a best power A/F number.
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RACNRAY
Expert Class
FAST OLD GUY
Posts: 178
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posted July 01, 2010 05:22 AM
quote:
thanks, guys.
I thought the Pair fresh air system was to help the cats out by further cleaning up emissions before the exhaust hit the first cat in the header, but if the cats can survive w/out the Pair fresh air sytem as RACNRAY tells me, I will plug the sucker back up.
Paul
You are right, the pair system does clean up the exhaust thus reducing emmissions. Kawasaki was the first m/c company to use the pair system in 1979. I remember 1979 as being the year of alot of changes in Kawi's skoots, and we were sent technical detail sheets on the 1979 models. The big things with the skoots were the introduction of electronic ignitions, automatic cam chain tensioners, liquid cooling and a drive shaft on the
KZ1300, and the pair system. Kawi claimed that the carburetion did not have to be leaned out too much to meet the new and stricter emmission standards, thus they claimed improved performance. All the manufacturors have been using pair systems for years on non-catylizer skoots, but with ever stricter emmission regs cats have become a necessity.
Also, i wonder if pair systems are still in use on any cages and trucks these days. My 2007 truck does not have a pair system and has 4 cats, so there is no need for a fresh air system with cats unless the pair system is needed to get past emmission standards.
RACNRAY
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no chicken strips on this south florida boy's skoots!!
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