Air flow past the throttle plate

[Dqracer]

We are running the Honda RR motors,04-07, I'm using Yamaha R6 carbs on them,which seems to work better than alcohol F/I for being faster on the track,we have had many discussions as to which is better,carbs or F/I , but when you look at the results each week , the top 5 cars all have carbs. I believe the carbs work better because the huge amount of alcohol enters the port further away from the valve ,than with the injectors, offering more time to atomize.
A buddy of mine, Charlie Toy, use's the ole' KZ 1000 (turbo'd) in his Bonneville bike. 234.438 mph on gas, is his record several years ago. Running the amount of boost he does (up to 40lbs) on ERC fuel, a few of them have melted to the ground...LOL
Honda in 07 , redesigned the ports in the RR, very small , as compared to the 03-06 RR,they also took out some 3 lbs of rotating weight , in stock form it runs as hard as the built Yamaha's.
From looking at the ports, the exhaust side needs the most attention, the short side radius has what looks like a reversion dam built into it right where the header tube meets the port., it is also the biggest obstruction,other than overall port size. I'm looking forward to getting a bench up and running soon, cause this is drive'n me nuts,not being able to move forward the correct way..LOL , tried to post a pic, but the server had issues. I'll try it again..

[larrycavan]

That's some boost!

IMO, injector location & spray pattern both can be used as tuning tools. How much fuel pressure are the injected engines running for fuel?

Are the stepping up the injectors or using fuel pressure and ECU to richen the mixture for alcohol?

[Dqracer]

The inj. are stepped up for alcohol, 55 to 60 psi F/P, with fully programmable map. 20 laps on a 3/8 mile track = 7.5 miles. I use almost 2 gallons of alcohol = 3.75 mpg... with carbs.
Mpg for Inj. is about the same. thats alot of fuel to pour thru 600 cc. Even with a perfect map dialed into it. Carbs still pull the best on the big end, which leads back to the throttle plate,woes,, the inj's are located on the portside, with the carbs dumping fuel on the top side of the plate.

[larrycavan]

Photo shows ZX14 injecting.....gasoline....

Notice the dual throttle plates. One for the rider...one for the ECU...yank the rear plate for more bottom end...



Edited By larrycavan on 1211070412