Thank you for the information. I will be using the Bullet cams and the valve lifter will be taken out. Heard I may experience wet sumping problems. I think the avl conrod is 163cm or there abouts am hoping it will be a high reving engine. What are your thoughts on its characteristics, compression should be 13 to 14 to 1 will be running on methanol with a 38mm carbie.
Okay, well that's a fairly short question which requires a very big answer!
I can't give you all the answers on that yet, because I don't know everything about your build intentions.
One thing is that you won't be doing it with that piston. You need to end up with about 35cc chamber volume to get 14:1, and that piston can't get there, no matter how high you try to set it. Also, that piston is about a quarter of a pound too heavy to be under any consideration for "high revving".
Secondly, the "high revving" with any cams available for the Bullet, unless you do our roller rocker hi-lift mods, can't really peak the hp any higher than around the 7200 rpm area. So, that's the limit with any cam lift on the Bullet. We have seen this with other racing Bullets. They are flow limited because they are lift limited. You can have rpm extension that retains pretty decent amount of peak hp going higher than 7200 rpm, but it won't be gaining any higher hp at those rpms. If you want to make more hp at higher rpms than 7200 rpm, you need our lift kit.
Regarding the 38mm port, again there are limiting issues. The 38mm port technically can serve up to 8250 rpm before hitting port speed issues that would start to choke it off. So, that's a lot higher than 7200 rpm. The result is that the port is too big for the 7200 rpm package, and we could produce a Bullet port of probably 34-35mm that would be able to supply the ~225 cfm necessary to get to 7200 rpm, and be a much faster responding and lively engine in the moderate rpm range, like coming out of corners. But if you want the 38mm port with the 8250 rpm potential, then you need to get the valves lifted enough to flow about 285 cfm, and for that you will need our porting and our roller rocker hi-lift kit.
So basically, if you look around the world at the Bullet racing scene, they all are peaking hp in the area of 7200 rpm, although they may be winding it higher than that for revving over the hp peak on some track sections where it might be necessary. The only previous racer who seemed to be able to go higher, but kept his secrets, was Steve Linsdell. Now, we have managed to bring this kind higher revving and higher power package out for other racers, and Bullet Whisperer is going to be the first to field this on the actual race track. We shall see how it does when the get the engine complete, and on the dyno, and on the track. We are very hopeful(and expecting?) a record breaking engine here.
So, to sum up, we now have the engineered design, and the experience, to take your racing Bullet up to the next level, which was not available before. But we need to consult closely on the effort and application of our products, because there are other technical aspects to getting there than just the head work and valve train. The cams, piston, wave-tuning, etc, are all vital to the final result.
BW has the right piston for the job, and it is designed to work with our combustion chamber mods which we did in his head. I don't know if he plans to sell those pistons, but if he will, we can CNC your chamber to be correct fit for those pistons, and set your desired static compression ratio for methanol that way.
We will need to discuss cams, and also ports and flows and lifts, to suit what your desired rev range will be. We can set it up for any rpm you select.
Topic: AVL bullet (Read 6895 times)