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 "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

No cat problems will occur you remove the PAIR for tuning. The heat of the honeycomb is the chemical reaction to the emissions burning clean.
You noticed no gain gutting the cat because the pipe is huge compared to the non-cat header. So, no loss everyone thought you'd lose hp with a cat? Kawi fooled you!

If I were to setup with no mods made class:

1. Run the complete ram system.
2. Staple gun a few pleats to open the air flow. I know the aftermarkets lose hp so I am OEM you hear me say different.
3. I have my brakes retracted both front and rear. I am going for it and my confidence says I only need to pump the brakes a few times at about 30 mph to stop for the return truck or ride back and not touch them till I get to my pit.
4. Super sycn the throttle body using all 5 screws and all 4 cylinders.
5. Soak the drive chain in hot grease or gear oil before the run.
6. If rules say you need a brake and not the stock system fore and aft, I'd remove the front calipers, master and discs. Use the rear only to comply to a brake needed.
7. I would not code the bike like run a tre. I want to be bone stock. I'd speed heel toe another way without the aftermarket tre deal there too.
8. I'd run 0w engine oil.
9. I'd run race fuel.
10. I would remove as much as I could with weight, be it the tool kit and box, the rubber boot for the ECU and relay box. Padding, brackets, etc. Every little thing not needed for I bend no rules I waste all that time not reading what the class demands and follow that to the letter and cheat from there.

WOT I miss?

A. Blueprinted engine?
B. That as it may, I rather set the valves tight and go for top end.
C. That temp on the salt I tune in a cool room?
D. Is for dynojet that shit up that day is a waste you ballpark that tune close on the sniffer and roller room.
E. nd of the day, you need to tune for that day or you are behind me for seconds at the cash window.

And since I would hand build the engine from the ground up, it came to mind that you can do one of two things. Remove the carbon off the complete intake chamber system and clean all the valves. On the '06, I had a water route down the intake ports to steam off the chamber. Get the water to break off the carbon behind the intake side, or the port side, you do not need to tear down the engine.

Blown head gaskets with water jackets like old GL1000 heads, would clean the intake as if that piston was brand new out of a box. Head was clean. That was the concept so as not to be robbed of fuel being stuck in the carbon deposits.

When Dublin Kawasaki set the record for the class above the one you are shooting for in 1991 with a zx11, laverda, they did a lot of what Hub is suggesting. Cut weight everywhere the rule book didn't say it had to be there. They took the front rotors and calipers off and replaced it with a tiny little two-puck unit. Apparently rules said it had to have a front brake?

The big thing for them, though, was blueprinting the engine. The act of setting all the tolerances absolutely correct, and balancing the rotating components, and lightening where possible made a whole lot of horsepower.