Info CBR250RR MC22 TSR full exhaust system 4 into 2 into 1

I missed this, I want it so much but the price is outrageous.

 

ah for what it is its still 50% cheaper than a new one. surprising what a difference a full system can make....money well spent if your going racing.

 

http://global.rakuten.com/en/store/auto-w/item/201543006/?s-id=borderless_recommend_item_en
The above is brand new and better and 100au cheaper, admittedly it took me months to find but still a better option than the TSR.

 

200$ without muffler you say. that actually might be a really good deal, whats the material?

 

To tell the truth every calculator/formula/math I have run says that all these exhausts are wrong.
The best and cheapest "performance" mod you could do with the exhaust is cut the stock headers down to 15" attach a 4-1 collector and connect a straight through drilled and packed muffler directly to the collector.
better to aim for weight savings and center of gravity vs trying to squeeze out power that isn't there.
With the collector being closer to the correct length on the primary's there will be slight gains from scavenging and being that the inner diameter of the primaries is to big the 4-1 is a better suit. Everything points to the top end with the mc22 and I mean everything, its better off to cop the loss of the low end and mid range and focus everything at the top instead of trying to make the bike something its not and hurting its strong point.

 

Show us your math Damus I'm curious what analysis you're doing

 

Okay to go through it,
CC's ÷ number of cylinders: in this case 249 ÷ 4 = a cylinder volume "CV" of 62.25
CV x RPM ÷ 88,200: in this case 62.25 X 12000 ÷ 88,200 = C/s area 8.4693

8.4693 = primary pipe c/s area
88,200 = mathematical constant
RPM = RPM at torque peak

square root of 8.4693 = 2.9102
x reciprocal constant 0.7854 = 2.2856cm
which is essentially 0.9inches inner diameter
all in all the the pipe size OD should be 1" if we are aiming for the nearest pipe size

unless somehow I went horribly wrong being that I am no math expert and just using
pre existing formulas to come to this conclusion

annnny who length is another long winded story I cant be bothered to type out but seriously in a 4-1 situation and the nature of our small displacement engine it pretty much boils down to place the collector as close as possible which is really where the pipes reach under the engine logically, like a cheap little turbo charger haha, anyway 3.5" is the rough size the collector needs to be.

And with the tail pipe length needing to be about hmm 8 inches or so if you just use a 20" drilled and packed muffler that will actually give a better result then "just" an 8" pipe. Based on a video explaining that when the exhaust velocity slows down enough to vibrate in the tube the holes allow that vibration to escape leaving the inner flow of the exhaust un-harmed to flow freely out the end of the pipe.

I have also used many web site calculators again it comes down to 1inch pipe, collector as close as possible in a 4-1 config and using a muffler as the tail pipe based on above paragraph.

 

time to get spending so

 

Would be great if you let me know some sites where finding calculators. I'm trying to know all I can to build a vf400f full exhaust, but all the software I could find cost many money.