Y2KZX12R
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posted January 31, 2002 02:41 PM
 Edited By: Y2KZX12R on 4 Feb 2002 10:17
oops zx12r head flow rates
I was going off memory (lack of) and quoted some wrong numbers for zx12r head flow rates in some other thread.
The intake at 10" was not 128 cfm but 121.7 @ .310" lift.
And the exhaust was 106.5 cfm @10" test pressure and .294" lift.
128 cfm was another set of heads I have.
fuelie 1.94 heads. oops sorry
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Y2KZX12R
CompetitionCNC.com
   
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johns
Expert Class
Posts: 205
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posted February 03, 2002 07:54 PM
Edited By: johns on 3 Feb 2002 19:56
zx-12 flow numbers
I had my zx-12 head ported and the following is data taken off the flow chart.
stock head at 10 inches, lift in thousanths.
.150 lift=77 cfm,.200 lift=98 cfm,.250 lift=112 cfm,
.300 lift=120.4,.350 lift=126 cfm,.400 lift=131.6 cfm
ported head with stock size valves, inlets reshaped with epoxy and port volume reduced 10cc.
.150 lift=89.6cfm,.200 lift=110.6cfm,.250 lift=126cfm
.300 lift=136.9cfm, .350 lift=143.2cfm, .400 lift=146cfm
the exhausts were ported to 85% of inlet flow. very difficult to get high exhaust flow numbers on this head.
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2006 ZX-14 (sold)
2012 ZX-14R (Brock's Perf. project bike Louisville Slugger)
2013 Honda VFR1200F
2003 124 C.I. H.D. Super glide
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krexken
Zone Head
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posted February 03, 2002 08:41 PM
Nice gains. Be cool to see the hp gained by porting only.
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Y2KZX12R
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posted February 04, 2002 10:00 AM
john, thanks for the info.
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Y2KZX12R
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ra12r
Zone Head
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posted February 04, 2002 09:12 PM
Reducing CFM?!
Previously i read the article about porting that said reducing the size of the intake would increase velocity. Is that why you reduced the intake and the flow numbers increased?!
So basically you are saying that your intakes are now smaller than when they were stock?!
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ra12r
Zone Head
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posted February 04, 2002 09:13 PM
What are the cam lift numbers In and Ex?!
What is the duration for In and Ex?!
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Y2KZX12R
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posted February 05, 2002 03:03 AM
Intake max lift is .310" exhaust is .295"
Intake duration from IVO to IVC is 300 degrees
Exhaust duration from EVO to EVC is 294 degrees.
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Y2KZX12R
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posted February 05, 2002 08:39 AM
airflow
I read on a thread on labusas about the stacks and a few misstated things about airflow.
When the air has to squeeze by a restriction its velocity increases and its pressure DROPS. After the restriction the velocity drops and the pressure will rise again.
As a general rule the faster moving air has a lower pressure than slower moving air.
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Y2KZX12R
CompetitionCNC.com
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EastBayDave
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posted February 05, 2002 07:51 PM
Interesting thread guys, thanks!
I know this has been dealth with before, but didn't see the results of the thread. Has anyone noticed the exhaust "D" shape exiting the head? While installing my Akra, I found myself wondering if anyone changed the "D" shape to a "O" shape to match the pipe? If so, or if not, why???
Thanks!
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Enjoy the ride!
02' ZRX1200
00' ZX12R sold
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johns
Expert Class
Posts: 205
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posted February 05, 2002 08:03 PM
H/P increase from porting work
KREXKEN thats and interesting question and I dont have a precise answer as to how much the ported head helped my ZX-12 because I made several modifications at the same time.
Doug Meyer told me to expect 3 to 5 H/P. All my testing was done on the same dynojet 250 and all the readings were corrected. All runs were made with pump gas. You may be able to infer from the following figures how much the head work helps if you can get comparible corrected data on a 1270 from someone without headwork.
My ZX-12 made 158.5 H/P and 89.7 ft/lbs torque when it had 3000 miles and was compleatly stock (about average i think).
The bike made 176.6 H/P and 97.8 ft/lbs torque (again about average) with the following modifications. Muzzy ti pipe, power commander,timing set +5 degrees, Muzzy block off plates, K&N filters, fitch fuel catalysers, 89 octane standard oil gas, dyno time to optimize the P/C. No internal mods including cam timing made at this stage.
The engine was torn down and the following mods were made.
1270 Muzzy pistons, fully ported head with stock valves, cams degreed to 105/100 C.L.'s, Inlet stacks opened to match throttle bodies (suggested by Doug Meyer), milled flats on the throttle body butterfly shafts (flats on both sides) for less turbulent flow at WOT, Installed the standard Muzzy map in the P/C, set timing at +5 degrees, wrapped the header with insulation tape, 93 octane standard oil gas, dyno time to optimize the P/C. The last dyno run on October 3rd was 196.4 H/P and 104.7 ft/lbs torque. The max H/P was at the rev limiter and was still slowly increasing which indicates to me the head is breathing pretty well. I haven't tried to change the timing from the Muzzy reccomended +5 degrees but I might get a few more H/P by backing off a couple of degrees. Plan on trying this the next dyno session this spring.
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2006 ZX-14 (sold)
2012 ZX-14R (Brock's Perf. project bike Louisville Slugger)
2013 Honda VFR1200F
2003 124 C.I. H.D. Super glide
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