instantaneous piston speed?
01-05-2006, 08:46 AM
#21
swmn,
The piston loads at 5500rpm with a 3.622" arm aren't enough to worry about the rod strength. The OEM parts can more than handle that so don't over think that like the rest of this.
If you want a simple way to figure out header lengths go to www.maxracesoftware.com and get PipeMax. Very good program for giving you header diameters and lengths for whatever header design you need.
Bret
The piston loads at 5500rpm with a 3.622" arm aren't enough to worry about the rod strength. The OEM parts can more than handle that so don't over think that like the rest of this.
If you want a simple way to figure out header lengths go to www.maxracesoftware.com and get PipeMax. Very good program for giving you header diameters and lengths for whatever header design you need.
Bret
01-12-2006, 08:47 PM
#22
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OK, I got a couple trigonometry books and got a handle on this. Then I picked up the Engine Masters Racing annual as suggested elsewhere in this section. Thumbing through that I saw they had it 'solved' , so I went ahead and chunked it my way, to better understand the EM article of course.
The "Law of Cosines"I got (again) from Andreescu, T. and Zuming, F. (2005) _103 Trigonometry Problems_, Birkhauser, Boston. pages 34-35.
For any triangle with Vertices A, B and C, with corresponding sides a, b and c, the length of side b, expressed |b| is expressed thusly:
b^2= c^2 + a^2 - 2ca cosB
ABC does not have to be a right triangle, it works with any triangle.
So I renamed the triangle CRP as explained earlier in this thread, and then labeled the sides of my triangle crp to match. So side p is the crankshaft throw, or half the stroke, in this case |p|=2.000 inches. Side c, opposite the centerline of the crank is the connecting rod length, in this case |c|=6.000 inches. Side r, opposite the big end of the con rod is the distance between the little end of the con rod and the centerline of the crank.
Logically at TDC |r| = 8.000 inches, R=180° and C=0°. Also, at BDC, |r|=4.000 inches, R= 0° and C=180°, q.v.
I also solved the isoceles triangle. The one with two sides = 6.000 inches and a base of 2.000. That one has equal angles somewhere between 80° and 81°, leading to angle P being something like 18-20°.
Gotta go. I plugged and chugged some, got the length of leg r nailed down just fine, realtive to crank/con rod angle. Don't have piston location relative to crank rotation yet, but I am still teasing on it.
The "Law of Cosines"I got (again) from Andreescu, T. and Zuming, F. (2005) _103 Trigonometry Problems_, Birkhauser, Boston. pages 34-35.
For any triangle with Vertices A, B and C, with corresponding sides a, b and c, the length of side b, expressed |b| is expressed thusly:
b^2= c^2 + a^2 - 2ca cosB
ABC does not have to be a right triangle, it works with any triangle.
So I renamed the triangle CRP as explained earlier in this thread, and then labeled the sides of my triangle crp to match. So side p is the crankshaft throw, or half the stroke, in this case |p|=2.000 inches. Side c, opposite the centerline of the crank is the connecting rod length, in this case |c|=6.000 inches. Side r, opposite the big end of the con rod is the distance between the little end of the con rod and the centerline of the crank.
Logically at TDC |r| = 8.000 inches, R=180° and C=0°. Also, at BDC, |r|=4.000 inches, R= 0° and C=180°, q.v.
I also solved the isoceles triangle. The one with two sides = 6.000 inches and a base of 2.000. That one has equal angles somewhere between 80° and 81°, leading to angle P being something like 18-20°.
Gotta go. I plugged and chugged some, got the length of leg r nailed down just fine, realtive to crank/con rod angle. Don't have piston location relative to crank rotation yet, but I am still teasing on it.
01-12-2006, 09:05 PM
#23
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Originally Posted by SStrokerAce
swmn,
If you want a simple way to figure out header lengths go to www.maxracesoftware.com and get PipeMax.
Bret
If you want a simple way to figure out header lengths go to www.maxracesoftware.com and get PipeMax.
Bret
01-12-2006, 09:18 PM
#24
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Also, if anyone wants to host an excel file i made a tool that calculates instantaneous piston speed @ a given position and maximum piston speed.
This is for you SWMN.
Hope this saves you some time.
This is for you SWMN.
Hope this saves you some time.
01-12-2006, 10:01 PM
#25
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Ok, here is the calculator. Open it with Winzip, Winrar, or the Windows archiver that comes in Windows XP, then use Excel to open the file contained in the zip file.
You just need rod length, stroke, and rpm. The program does the rest.
</puts his spoon up>
You just need rod length, stroke, and rpm. The program does the rest.
</puts his spoon up>
01-13-2006, 09:06 PM
#26
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Ok, one more post on this and i'm done...
Max piston speed of a stock lt1 @ 7000rpm: 110 ft/s
Max piston speed of a 2004 gsxr 600 @ 14500rpm: 109 ft/s
It's amazing how stroke can affect piston speed that much...
Max piston speed of a stock lt1 @ 7000rpm: 110 ft/s
Max piston speed of a 2004 gsxr 600 @ 14500rpm: 109 ft/s
It's amazing how stroke can affect piston speed that much...
