Y2KZX12R
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posted August 21, 2009 08:25 AM
Fuel Injector Sizing...
In case any of you guys are wondering about your injectors being ok for your application, here's a link to a work sheet at friend of mines shop, Marren Fuel Injection.
Remember to use crankshaft HP numbers not rear wheel hp numbers. On an inertia dyno (dynojet dyno in inertia mode) the zx12r is about 16 HP loss to the rear wheel from the countershaft and about 20 from the crankshaft. If you have an aftermarket light weight wheel it would be less of a loss. And ramair on a zx12r is claimed to add 8-10 hp at high speeds (200 mph).
http://www.injector.com/injectorselection.php
They will make an injector for your application if they don't have one that is s direct replacement in the flow you need.
Tim made me a custom set of 430 cc/min injectors for my zx12r that I used with this 1427 build at Loring.
He makes custom Busa injectors as well.
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DR JOE
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posted August 21, 2009 09:14 AM
Thanks for the info.
Doc.
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entropy
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posted August 21, 2009 09:33 AM
Jim,
WAY cool worksheet!
did you log duty cycle at Loring?
430cc seems pretty big compared with my puny 370's and it would be interesting to compare duty cycle logs
I do log duty cycle, but really didn't pay attention to it on my loring logs.
It would seem that the Factory Pro hp would be a direct input to the worksheet???
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Y2KZX12R
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posted August 21, 2009 09:53 AM
No I didn't log Duty Cycle.
Your rc370's if they are in fact 370cc/min @ 42 psi, would have a duty cycle of about .91 and the bosh 430's would be about .8.
230 rwhp = 250 crank + 10 ramair hp = approx 260 hp
Pump that 260hp into the worksheet.
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Y2KZX12R
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posted August 21, 2009 09:57 AM
 Edited By: Y2KZX12R on 21 Aug 2009 17:57
Hey Karl, what time is it there? Shouldn't you be working? 
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entropy
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posted August 21, 2009 09:57 AM
if i am getting 195 FactPro hp, how much engine hp does that translate to??
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Y2KZX12R
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posted August 21, 2009 10:34 AM
Dunno, The stock zx12r was supposed to be 178 hp at the crank according to the manual.
Mine dynoed 100% stock at 162 rwhp on a dj 150. So that's how I come up with the 16 hp loss.
But you don't have a baseline 100% stock on that dyno do you?
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entropy
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posted August 21, 2009 11:12 AM
260 & my 370cc injectors doesn't seem to work.
but it gave me an idea... i gotta look at duty cycle on the dyno and at Loring and compare for same AF (if possible)
Jim could you please send me the fuel map you ran at Loring; just 100% 8-12000rpm
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mrsantafe
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posted August 21, 2009 11:47 AM
260 crank hp is too much for 370cc injectors?
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9.78@155.13 mph 1.71 60 ft @ a near mile high dragstrip
2006 ZX14 gone
2006 ZX10r (Wifes street bike)
2004 zx10r (her race bike)
2002 ZX12 (still kicking a--)
2007 gsxr 1k (race bike)
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entropy
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posted August 21, 2009 08:32 PM
Edited By: entropy on 22 Aug 2009 04:43
quote:
260 crank hp is too much for 370cc injectors?
It seems my 370's are not too small for my motor.
On Doug's 222mph pass, thru traps at 12,280rpm & AF = 12.0-12.1, the duty cycle was 83%
from what i understand, 83% is a good # for RC370 injectors.
when I put 83% and 234hp (whatever kind of hp that is???) into the worksheet, i get 370cc (my injector size)
i am completely confused as to what type of "hp" is being used in that worksheet.
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tcchin
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posted August 21, 2009 09:06 PM
Brochure Horsepower.
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entropy
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posted August 21, 2009 09:17 PM
quote:
Your rc370's if they are in fact 370cc/min @ 42 psi, would have a duty cycle of about .91 and the bosh 430's would be about .8.
my "370's" were cleaned/tested by RC in mid 2008 at 370cc/min at 43psi
Marren cleaned/tested the same injectors jan 2009 and his data sheet showed 130cc/min @43psi
something seems wrong or i don't understand Tim's data sheet.
I have too much data
this stuff makes my head hurt
In any event, when I get the Bosch 430's i will test on the dyno after the Texas Mile.
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Y2KZX12R
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posted August 22, 2009 04:05 AM
Karl, I'll have to get the map off my laptop and I'll post my values for 100%. I'll post them here. I'd like to see yours as well.
How did you calculate your duty cycle?
According to Tim's chart which is based of of basic formulas using 260 hp and .5 as BSFC we both need 426cc/min injectors to be at 80% duty cycle.
It shows that a 370cc/min injector would be about 92% duty cycle.
I had Tim clean and test a set of stock injectors for me also. They flow 355 cc/min @ 3 bar (43.5psi)
According to Tim's worksheet the stock injectors will support 216hp with an 80% duty cycle. So that's right about 200 RWHP on a dynojet dyno.
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aliveagain
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posted August 22, 2009 05:20 AM
Marren cleaned my injectors also and the #'s were around what Karl got .It confused me too.Would bigger injectors have a different spray pattern and not atomize as efficiently?
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Y2KZX12R
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posted August 22, 2009 05:45 AM
Pete,
The cone angle does vary with different injectors but its not due to the size of the injector.
According to Tim, when an injector gets over 80% duty cycle its out of response time. The response time of an injector depends on the mass of the moving parts. Some of the disc type injectors have low mass and fast response time but very poor atomization.
The only draw back of a big injector can be its ability to spray tiny amounts of fuel at an idle.
But the Bosch injectors are good at idle. My bike idles as good as the stock injectors did.
Tim isn't a fan of removing the diffuser disc to gain flow which is what he claims RC (Russ Collins) does on many of his injectors. You gain flow at the cost of atomization control.
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entropy
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posted August 22, 2009 06:07 AM
quote:
Marren cleaned my injectors also and the #'s were around what Karl got .It confused me too.Would bigger injectors have a different spray pattern and not atomize as efficiently?
i wish i knew what Marren's numbers meant? i called him back when i got the sheet and he was busy or something.
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entropy
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posted August 22, 2009 06:12 AM
quote:
Karl, I'll have to get the map off my laptop and I'll post my values for 100%. I'll post them here. I'd like to see yours as well.
How did you calculate your duty cycle?
According to Tim's chart which is based of of basic formulas using 260 hp and .5 as BSFC we both need 426cc/min injectors to be at 80% duty cycle.
It shows that a 370cc/min injector would be about 92% duty cycle.
I had Tim clean and test a set of stock injectors for me also. They flow 355 cc/min @ 3 bar (43.5psi)
According to Tim's worksheet the stock injectors will support 216hp with an 80% duty cycle. So that's right about 200 RWHP on a dynojet dyno.
hey Jim,
i don't calculate duty cycle, i log it directly.
I also have had stock injectors tested, once at RC and also at a place in Houston. 325-330 both times.
hmmmmm....
different than Marren's numbers.
wonder what's up?
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rgeorge
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posted August 22, 2009 08:10 AM
Marren tests the injectors with a 6 ms pulse. Not 100% duty cycle like other people use. The flow at 6 ms is trivial, but is good for comparison and matching. If an injector is slow opening or closing, it will be apparent with the pulse test, but not the 100% test.
I recently bought some Bosch 440s from Marren. I'll post the test data this afternoon.
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rgeorge
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posted August 22, 2009 10:24 AM
quote:
i am completely confused as to what type of "hp" is being used in that worksheet.
Karl, adjust the BSFC number until you get a flow rate that matches what you expect from your other data. Since you run a fairly rich AFR, your BSFC may be a bit higher than usual.
Someone should start a new thread to discuss BSFC numbers.
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entropy
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posted August 22, 2009 10:24 AM
quote:
Marren tests the injectors with a 6 ms pulse. Not 100% duty cycle like other people use. The flow at 6 ms is trivial, but is good for comparison and matching. If an injector is slow opening or closing, it will be apparent with the pulse test, but not the 100% test.
I recently bought some Bosch 440s from Marren. I'll post the test data this afternoon.
thanks, Rob!
clears up a mystery.
he oughta do both.
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Y2KZX12R
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posted August 22, 2009 10:42 AM
Karl, on the bottom of the sheet, wasn't there a max flow number?
Mine says 355cc/min @ 3 bar.
But it may have been a comment, I'll have to dig it up.
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rgeorge
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posted August 22, 2009 11:56 AM
My new injectors tested from 133.6 to 135.0. All within 1%. Marren charged an extra $10 per injector for testing and matching a new set.
Tim was very helpful in selecting an injector for my application. I intended to get injectors about 570cc, but the biggest Bosch style (best spray pattern) is 440cc. I decided to go with the 440s and feed them fuel at 70psi.
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dougmeyer
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posted August 23, 2009 12:40 PM
AH HA! This is the trail to the BSFC I was hoping we could create........
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2000redrocket
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posted August 23, 2009 07:09 PM
so jim your 12 dynoed what mine did stock after 4500mi of mostly easy riding. i think it was a 250 though. i guess i may have to get larger injectors or more fuel pressure.
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2000redrocket
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posted August 23, 2009 07:10 PM
anyone got the good bosch handmedowns?
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