Will I need BB or SB CPI's?

[banshee_blue_03]

Not new to banshee's, but new to the cubs.......kind of a dumb question.......I just bought a 65mm stock stroke cub top end. Will I need big bore or small bore CPI's?

[FireHead]

Not new to banshee's, but new to the cubs.......kind of a dumb question.......I just bought a 65mm stock stroke cub top end. Will I need big bore or small bore CPI's?

Small bore. :thumbsup:

[dajogejr]

Yep...what he said.

 

68mm bore and 7m stroke and up like the big bore pipes.

[theshee]

Small bores. Even if you had a bigger bore your altitude can decide what pipes to use. I have heard that big bore pipes dont work well at our high altitude so small bores are what everybody here runs.

[FireHead]

Small bores. Even if you had a bigger bore your altitude can decide what pipes to use. I have heard that big bore pipes dont work well at our high altitude so small bores are what everybody here runs.

 

Pipe diameter is purely a function of exhaust gas volume multiplied by flow rate. Altitude obviously has some effect as it effects the density of the exhaust gas, but that's it. You may want to verbaly abuse whom ever it was that told you that big bore pipes don't work well at high altitude. :thumbsup:

[theshee]

I dont really know if it does or doesnt run better, but I have heard from several people in Colorado and Wyoming that the big bore pipes dont make as much power. One fella acutally switched pipes on the dyno and made less power with the big bores. Im clueless on the issue though, my shearers work good enough for me so im happy. :thumbsup:

[majicmike]

Pipe diameter is purely a function of exhaust gas volume multiplied by flow rate. Altitude obviously has some effect as it effects the density of the exhaust gas, but that's it. You may want to verbaly abuse whom ever it was that told you that big bore pipes don't work well at high altitude. :thumbsup:

 

One of those people is me the big bore can work on the flats rather well but on the hill they have a bog for some resone :shrug: This was not only found by me but buy kim @ k&t and lynn at L.C. where we all run over 4500 ft. Also the air desity is afected here at 5280 we lose .7 points of compresion and 1.2-1.3 points where we race at 8500 ft so yes a big bore pipe does affect Things. One guy had a .104 methanol jet with the power jets 2 turns in, in his 10mm cub try that at sea level and watch what happens