[bubba297]

BB Shearer's made a best of 103 hp (with Lectrons) @ 9000 rpm, with no overrev whatsoever. SBs made 103 (with Lectrons)@9600 rpms with good overrev. BBs had a little better power at lower RPMS, not a good broad curve that I thought the BBs produced.



We ended up getting 109 hp out of the SBs with some different carbs, but never tried the BBs with them.



So, is it better (in 300ft) to have a motor that makes 103hp @9000 or 9700? Or does it even matter as long as its geared accordingly? The motor should (and did) make peak power quicker (i.e. reach 9000 rpms quicker) with the BBs for sure, as the SBs had to rev out to 9600 rpms.



I plan on getting more HP out of this motor, but for now I have to run it for what it is.

HP is HP, more is good. Personally I have always liked more rpms. The low end on the BB is similar to the SB pipes, so why wouldnt you want to run the pipes that make more power? As long as you gear and clutch it correctly, it will run faster. Your never going to launch a Banshee at anything less than full throttle anyways, so low end isnt as much of an issue. Also remember that a pipe with more overrev will be a little more forgiving if you miss the shift on the high side a bit. The 10mil will have enough ooommmpphhh to pull it out. Just my .02

 

[bubba297]

The problem is not enough people use them...and there are only two distributors for them in the whole country.



If more people carried them and sold them, think of the actual advances that could be made.

I keep some building secrets to myself, but my squish is WAYYYYY less than .050

 

[bubba297]

I fell That .36 is way to tight I would not suggest anything lower then .42 but what do I know

The only thing I am going to say.......and I dont mean anything bad by this so please dont take it the wrong way.

If you dont know what your MSV is or how it affects combustion (maybe you do), how do you know that .036 is too tight? Squish band width and angle play a part in MSV, so they have to be factored in as well.

 

[bubba297]

lol...we dont now nothing...

Well, obviously you know how to still have a nice picture by your name LOL

 

[bubba297]

I wanted to throw this in as well. I usually run the shearer SB out of frames on my 4mil cub. I had the chance to try a set of big bore CPIs. Now the CPI big bores are done differently than how Matt does his big bores. Think of them more like a small bore pipe with a big stinger. I know it's not exactly that but we'll just say that for easy thinking on it lol.



I was running them on the 1/8th mile asphalt. In the 330ft scenario, the big bores run practically identical to the small bores. The 60ft and 330 mark all showed about the same, and that was taking into account weather, track conditions, and making a lot of passes. We run there alot and I know the track well. Where the small bores started to shine was after the 330 mark. The pull out much better for my motor after the 330, when in 5th gear and sustaining more upper RPM over a longer time. I have a lot of exhaust area and wanted to see how the big bores would perform, but obviously the motor CC size is still limiting me to staying with a small bore pipe. Good info none the less.......

The small bores at the 1/8th mile mark are worth about 3mph for me, and they still perform well down low with a lot of gear, providing clutch setup is right. Hope that might help.

 

[bubba297]

I hear ya dajogejr. If we all had dynos to use we could be faster. Keeping the same combo for awhile and using the track times will get you some answers. I also use an air density gauge and keep track of everything. It just takes a lot longer to get them fine tuned like that. Matt made me a set of small bores one out each side, and I had him do the ends with a turn out. Man the people at the dragstrip hate that I think. Talk about loud when they point right at you LOL. I love those pipes though. They wont be going anywhere.......