newby oil cooled question

[johnr]

ok, im pretty new to the world of oilcooled motors, and their many variants and interchangabilities is a tad confusing, so, for thee moment, theoretically. ive a kat with a gsxr1100 slingshot motor in it, iirc its an 1100k motor. and my queery is, would a set of bandit 1200 barrels go onto the cases as a cheap big bore kit, or will it feck up the compression? im only asking cos i may have a set of bandit 12 barrels and pistons coming up and i was just wondering if at some time in the future, this might be a useful home for them.?

[Nik]

Going from 1127 to 1157 cc is not worth the effort. Save your efforts 'til you can do a proper upgrade. 

Edited April 7, 2018 by Nik

[johnr]

ah, i never realised that the 1200 wasnt actually a 1200, told you i was a newby to this oilcooled mullarkey stuff.

 

[canamant]

Compression will be a lot lower as the 1127 pistons have a 1mm or so flat topped raise on them compared to the bandit piston which has a true flat top.  I've just this week measured the CR of a bandit 12 cylinder and piston on a 1127 bottom end and head.  I came out at about 8.5 to 1.  Head volume was 33cc, squish vol 6.1cc, swept volume 289cc gives a CR of 8.4:1 which is poor.  You would need to check valve to piston clearances to see how much you could skim off the head then recalculate.  Might be easie r just to stick to 1127 ?

 

[Nik]

Great info, Canamant! Thnx. 

Edited April 7, 2018 by Nik

[Nik]

43 minutes ago, johnr said:

ah, i never realised that the 1200 wasnt actually a 1200, told you i was a newby to this oilcooled mullarkey stuff.

 

Welcome, and stay curious! :-)

Edited April 8, 2018 by Nik

[johnr]

fair enough, i was only asking as ive got the 1100 motor in it at the moment, and theres various bits of bandit about the place and curiosity just got the better of me. for the faffing about its pretty much zero gain, i suppose i should wait till iv got all the bits for a turbo build together then!

[canamant]

If I remember correctly that low compression would be better for a turbocharged engine. 

[Gixer1460]

^^^ Is generally true - subject to what boost you want to use! The OP question isn't so daft - true, it won't hike the capacity but that's what the turbo is for! It will however produce a lower CR which allows more boost. BUT, the caution is that std. cast pistons won't last long under increased turbo boost (that doesn't = 6 to 8 psi!) - the rings are too close to the piston top, it overheats which crushes / traps the rings and best scenario = lots of smoke, worst = scored bores. If its real budget build, the Bandit barrels + early Busa pistons =1216cc and will withstand 1 bar of boost if prepped right and they are forged. If the budget allows and you want more boost, only bore to 80mm and use proper dished Wiseco / JE turbo pistons that will cope with pretty much anything.

[canamant]

I omotted to say "someone who knows about turbocharging will be along shortly" :-)

 

[johnr]

well i have the bandit motor, the busa gen 1 pistons and  rods, i was just perusing the gsxr engine in the other kat frame, and wondering about the bandit pistons, tbh i wont be touching th gsxr engine, but i was just musing on the variables with different versions of the same engine.