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Post by 90GTVert on Oct 13, 2015 20:22:03 GMT -5
Malossi MHR Big Bore II Piston face to flange 38mm Flange 6mm thick 27x28mm Length Diameter 1: 33/39 32 2: 22/31 36/37 3: 18/32 37.5/39 4: 20/32 40/40 5: 19/32 42/42 6: 18/32 43/44 7: 16/33 44/46 8: 17/33 46/47 -------------------- 1: 50/53 47/52 2: 101/107 52/77 3: 92/108 77/102 Belly: 70 102 1: 175/20 180 Ubend: 230 OD 21od/19.5 ID Silencer: 9 3/4 x 24mm id The pipe has a very nice contour to it and that's the reason for the numbers the way they are. The length is the inside and outside measurements, the length is the beginning and end of each section. |
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Post by 90GTVert on Apr 10, 2016 6:20:30 GMT -5
I soo hate to see pipes with telescoping headpipes,header pipe,next is a larger pipe slid over the head pipe and so on,,PG,Leo vince,Technigas,etc. like this method cause its cheap,,works fine when the exhaust gas is going out,but what about the reflected returning mixture charge before the exhaust port closes?Kinda like a down hill skier on a stair well!Tapered head pipes are where its at,gotta have that smooth flow(in both directions) to have a decent pipe..A quiet pipe would be ideal for this ride,the Penton/KTM dirt bikes had the most simple set up kinda like this;  Ive used this baffle setup on many pipes and love it,doesnt hurt the power at all,but makes it nice and quiet.. |
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Post by 90GTVert on May 31, 2016 11:52:00 GMT -5
I hope I did it more or less correct. Please don't take those numbers as 100% correct it was kinda hard to measure it. Here some info: Flange: ( ? ) *not sure what you call that. (End part of section 4)ID 27.7mm OD 35mm Stinger Tip: (Section 1)Length: 36mm ID 22.6mm OD 25.1mm Stinger: (Section 2)Length: 150mm OD 22.2mm Silencer: Length: 270mm OD 60mm inner hole ID 19.8mm tip length: 75mm / ID / 22.2 / OD 24.8 Section 4 is made out of 9 smaller cones.  Well done tsimi!!Looks like a nice pipe!Headpipe is 1.1 degrees,2 stage diffuser,1st stage 36.1-178-68=5.3 degrees,2nd stage 68-128-100.2=7.3 degrees..2 stage baffle,1st stage 100.2-70-87.5=6.7 degrees,2nd stage 87.5-140-24.5=12.7 degrees..total length 790,headpipe is 28% total length (30-32% ideal),headpipe+diffuser is 66.5% total length (64-68% ideal).. From the belly back is the same as the C16,the fwd sections were redesigned for a slightly lower max rpm,but smoother delivery..As usual Yasuni has built a pipe that others will copy(maybe even me!!),it should run verrry well!!! |
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Post by 90GTVert on Jun 8, 2016 6:28:13 GMT -5
Here are the pipe measurements. Some of the pieces are oblong so I got the average of the diameter. My smart phone isn't smart enough for me to write over a picture of the pipe but you should get the idea. Arrow for Elite/Dio Flange 6.5mm thick, 27mm opening Length -- Diameter 67 -- 29 Slip fit 144 -- 28/34 185 -- 34/47 54 -- 51/60 142 -- 62/90 Belly 75 -- 90 84 -- 90/63 129 -- 63/22 Stinger 142 -- 19.5 Silencer 210 -- 22  From the dimensions,we have a 211mm long headpipe at 1 degree then a 3 stage diffuser of 185mm at 2 degree,54mm at 6.9 degree and 142mm at 6 degree Baffle cone is 213mm at 9.1 degree.. Total length of 880mm Headpipe is 24% of total length (ideal is 30-32%) Headpipe+diffuser is 67% of total length(ideal is 64-68%) This is a quite simple pipe with a few strange dimensions,the 880 TL gives an estimated 9800RPM peak power,,styling and sex sells!!  |
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Post by 90GTVert on Aug 1, 2016 19:01:26 GMT -5
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Post by 190mech on Aug 6, 2016 18:44:39 GMT -5
More pipe tech;How to measure a pipe,carefully examine the pipe and determine where the angles change(headpipe to 1st stage diffuser,1st stage to 2nd stage diffuser,and so on,,Measure the OD(outside diameter)of both ends,record measurements,,next use a piece of soft wire(coat hanger,copper,or aluminum)and place it on the SIDE of the bend,exactly in the center,mark the length and straighten the wire for measurement,continue to the next cone,etc;        Hope all this makes sense!! |
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Post by 90GTVert on Mar 7, 2017 7:17:10 GMT -5
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Post by 90GTVert on Mar 21, 2017 20:28:40 GMT -5
13,500 peak power.   Had to average some of the dimensions due to the number of segments,but here is the results; Has up to date dimensions,tuned for around 11,250RPM,should be a strong pipe with the right cylinder porting! |
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Post by 90GTVert on Jul 22, 2018 7:05:15 GMT -5
Design Testing Idea from friday1So here I was in my fab shop with a pipe cut in half so I built a pipe, saving the header, with pieces of exhaust tubing-no science or ruler was used. I tack welded it all together and gave it a good rubdown with brake cleaner and applied HVAC silver tape to the non welded joints just to ride it around the block a few times and see what it would do. The HVAC tape withstood a few miles of heat and I removed the tape with a heat gun and razor blade then finished it off with brazing rod, filling all the gaps. The HVAC tape let me do any mods first without doing the final welding. |
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Post by 90GTVert on Nov 5, 2018 5:10:18 GMT -5
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Post by 190mech on May 15, 2019 19:31:24 GMT -5
Building tapered headpipes 'Of the third kind' We covered the sectioned headpipes,and hydroformed headpipes,here is another method that yields a decent part. A mandrel bent exhaust tube is selected for size using the big end of the headpipe,a center line is drawn on top and bottom of the pipe,then the small end circumference is calculated(say 30X3.1416=92.248,then divide in half = 47.124),that # is transfered to a paper strip and laid on the side of the pipe between the 2 center lines,then we have the 'pie slice lines'for cutting..   The elbow can be cut in shorter sections for easier pie slicing,here they are cut and pie sliced;  They are far from round then,so channel lock pliers are used to get them close before welding them;  Here is the final part,its far from a 5 minute fab,but does work well;   |
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Post by 90GTVert on Mar 10, 2020 21:51:39 GMT -5
Malossi MHR Big Bore 77-86cc Exhaust : Part Number 3215198 Click to enlarge.
 Ran the Malossi Big Bore pipe on the calculator,looks like a 12.000 RPM unit,all of the % #'s are close to Frits Overmars ideal percentages..Appears to be a well designed pipe for that size engine...  |
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