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Injector size change. Help me math

 
Old 03-25-2019, 06:27 PM
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Default Injector size change. Help me math

Old injector at old fuel pressure: 1265cc
New injectors at new fuel pressure: 2255cc

78.5% increase in injector flow

Base fuel table only-
My tuner says to multiply my current base fuel table by 0.569

I think I need to multiply it by 0.215

Whos right? Or neither?
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Old 03-25-2019, 06:33 PM
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1265/2255 = 0.561/1
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Old 03-25-2019, 06:37 PM
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Originally Posted by concealer404 View Post
1265/2255 = 0.561/1
Thats reducing the values by 44%

Thats what I dont understand
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Old 03-25-2019, 06:41 PM
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Why not? 1265 is approximately 56% of 2255, so 44% less, though i don't believe that's correct terminology.
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Old 03-25-2019, 06:49 PM
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Originally Posted by concealer404 View Post
Why not? 1265 is approximately 56% of 2255, so 44% less, though i don't believe that's correct terminology.
I cant wrap my head around why I would only reduce PW by 44% when the injector is flowing 78% more. Seems like it would be super rich then
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Old 03-25-2019, 06:52 PM
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Math, mostly.

2255 x 0.215 = 484.825.

Is that what you're after? No.

You want the number that when multiplied with 2255 gives you your original number.

So.... 0.561
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Old 03-25-2019, 07:04 PM
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Originally Posted by LownSlow616 View Post
I cant wrap my head around why I would only reduce PW by 44% when the injector is flowing 78% more. Seems like it would be super rich then
If you increased the injector flow by 100%, would you reduce PW by 100%?





Your new injectors flow 78% more than your old one. IOW, you take your old injectors and multiply by 1.78 to get the flow of your new injectors. Thus, you need to divide your fuel map by the same 1.78 to keep the same flow. Or, you can multiply it by ~0.561. Same thing.
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Originally Posted by codrus View Post
Basically I've come over to the camp of "If something is a reliability problem on the track, just ask Andrew and do what he says".
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Old 03-25-2019, 07:14 PM
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Originally Posted by Savington View Post
If you increased the injector flow by 100%, would you reduce PW by 100%?
had a good laugh when I read that to myself slowly. I understand now.
Thank you both for the explanations
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Old 03-25-2019, 07:30 PM
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Why would you change your fuel table rather than Req Fuel? What kind of ECU?
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Old 03-25-2019, 07:36 PM
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Originally Posted by DNMakinson View Post
Why would you change your fuel table rather than Req Fuel? What kind of ECU?
fcking hydra
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Old 03-26-2019, 12:18 AM
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Originally Posted by LownSlow616 View Post
fcking hydra
No way, hydra doesn't use VE?
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Old 03-26-2019, 01:20 AM
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AEM Gen1 does not either, they both use raw pulsewidth. Granted, the AEM also has a tool which allows you to quickly rescale the fuel map for injector and/or pressure changes. I forget if Hydra has something similar.
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Originally Posted by codrus View Post
Basically I've come over to the camp of "If something is a reliability problem on the track, just ask Andrew and do what he says".
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Old 03-26-2019, 11:09 AM
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Originally Posted by Ted75zcar View Post
No way, hydra doesn't use VE?
You can chose pw or ve. I use pw
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Old 03-26-2019, 11:13 AM
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Originally Posted by LownSlow616 View Post
You can chose pw or ve. I use pw
Why?
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Old 03-28-2019, 05:26 PM
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Originally Posted by Ted75zcar View Post
Why?
Life's no fun if you make it easy for yourself
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Old 03-28-2019, 05:34 PM
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The first basemap that FM sent to me was set up as PW so thats just what I've always used. Its the first and only ecu I've ever played around in. I make fuel adjustments and its always worked out so if its not broke I don't fix it
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