Bigger injectors=new tune?

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Sep 23, 2016 | 05:07 PM

#11

hd_rolling

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From: Grays Creek, NC

Quote:

Originally Posted by qtrracer

Whom ever wrote that 5.3's were only good for 120hp was incorrect for whatever reason.

It's from the Harley screaming eagle parts catalog.

5.3 23% more than Original equipment injectors. Recommended for use with engine configurations making more than 100 rear wheel horsepower.

6.2 grams/second, 59% more than the Original equipment injectors. Recommended for use with engine configurations making more than 120 rear wheel horsepower.

Sep 23, 2016 | 05:26 PM

#12

hd_rolling

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From: Grays Creek, NC

Thanks for all the advice.

Last edited by hd_rolling; Sep 23, 2016 at 05:31 PM.

Sep 24, 2016 | 12:27 AM

#13

Next In Line

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Quote:

Originally Posted by hd_rolling

Parts catalogs are meant to sell products, not give accurate information.

Sep 24, 2016 | 07:57 AM

#14

hd_rolling

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From: Grays Creek, NC

Quote:

Originally Posted by Next In Line

Parts catalogs are meant to sell products, not give accurate information.

I agree, but many of the big name builders use this chart as a guide, and to try to stay under 80% duty cycle

3.91 are good for about 50 Hp per injector
4.35 are good for about 55 Hp per injector
4.9 are good for about 62 Hp per injector
5.32 are good for about 67 Hp per injector
6.2 are good for about 79 Hp per injector
6.7 are good for about 85 Hp per injector

Sep 24, 2016 | 09:23 AM

#15

Next In Line

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Quote:

Originally Posted by hd_rolling

I have a 124" with a 55/58 throttle body and 5.3g injectors. I bounce off the rev-limiter on a regular basis and don't see a need upgrading to a bigger throttle body and/or injectors. I will hit the speed limit long before I hit the 80% duty cycle. If I get close to the 80% duty cycle, then I shift gears.

If I do hit the 80% duty cycle in 6th gear, I would be more worried about the police chasing me and the motorcycle not falling a part than saying to myself "Gee, I guess I should have upgraded the throttle body & injectors".