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kpr's kp60


kpr

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Top fail..  Results from stepped extractors, bottom of last page. 

 

Pink line is the 38.1mm extractors.  Good gains from 6000rpm to rev cut with the stepped 38.1/44.5 extractors . Pretty impressive for 120mm length of smaller diameter tube.  Before i  stepped the 44.5mm extractors  they basically matched the smaller 38mm extractors from 6000rpm onwards.   Both versions of the 44's have the same massive hole between 4000 & 5500.  Obviously getting reversion. Hopefully should be able to fix that with a different collector.

 

44-5-extractors-stepped-vs-38-1.png

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  • 2 weeks later...

put the 38mm extractors back on 

 

below is comparing the big and small extractors,  both runs done on the same tune.  looking at afr (pink line 38mm.  blue line 44mm stepped)   massive lean spot and no reversion with the 38mm.   then from about 6500 onwards the big extractors make a little more power.     but interesting thing is the gain isn't from the bigger tube. its the 38mm stepped section that has made the gains over the 38mm extractors. 

 

 

Also  before i swapped back to the small extractors.  I adjusted the cam timing to reduce overlap, hoping it would tame some of the reversion and gain some top end.  but no deal, just made it slower..

 

small-extractors-big-extractor-tune-27-1

 

 

for reference these are the 38mm's, the merge is nothing fancy,  same 2.5" collector.    dont really have any idea, other than the 44mm tube being to big thats causing the reversion  ??

 

 

dsc05224s.jpg

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Dug this out of the shed after 6 months,   got a fresh wof  and reg,   then proceeded  to some    @Roman Dave science  

ali express wideband bungs

img_20171117_152041s.jpg

pretty weak science.  i only have 1 wideband  so these are all different  runs . some on different bits of road.     bit of variance between cylinders.  but  nothing to be worried about or really any power to be gained by trimming cylinders.     and yeh my tune is a bit screwed up.  i think before i put it into hibernation for 6 months, i swapped back to the small extractors and didnt reload the right tune..   i'll fix that..

prob need to click to see full size:

afr-kp1.png

 

 

 

 

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Aluminum muffler fell apart. so made another one from junk had laying around and bits of the old muffler .   isn't the prettiest thing ever but  seems to work ok. and is a bit stronger

20180609_125759d.jpg

20180609_130802d.jpg

its got some other fiberglass stuff/ bit of everything between the steel wool and the outside bit below

20180609_133029d.jpg

it looks the same as the old one from outside..

 

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