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Hey all...

This may be a really stupid question, and I'm pretty sure she was wrong, but here goes..... (figured I'd ask the "experts") :)


I was checking out a custom shop (they do a lot of work with Harleys from what I've heard) and the lady behind the counter (part owner maybe???) told me she was told that the '03 EFI was redesigned and it adjusts itself to changes. now she said it wouldn't work for any major changes, but if I changed the air cleaner and pipes it would adjust itself. I know cars can do this to some extent, but I thought the H-D EFI didn't do that. Who is right?

Thanks in advance for the info.
 

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The Delphi EFI will compensate for MINOR changes. Results vary some from bike to bike, but in most cases it is likely to compensate for reasonable slip on's and possibly the SE intake kit.

What it means in plain english is that you may get away with it.
By no means are we talking optimized setup here as even a stock bike can benefit from changes to the ignition and fuel maps.
 

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I think she's saying that she wants to sell you some things but knows she doesn't have the skills in the shop to fix your EFI calibration so she is hoping that you won't notice a small change.
When you change equipment like pipes or cams, or intake you affect the VE ( volumetric efficiency of the cylinders) i.e., you allow them to flow air more efficiently (sometimes less efficiently). For the rocket scientists an 88 CI moter has a theoretical flow at 5600RPM of (88/2*5600/12/12/12) or 142.6 cubic inches per minute. Now the precison of the EFI is .005 or one half of one percent .
So lets say your change allows a flow of 145.5. That is a two percent change so your EFI needs remapping.
So what I am saying is if you touch anything then theoretically you need an EFI recalibration.
However Hippo is quite right the EFI does compensate a bit. It does this using knock retard ion sensing across your spark plugs. And guess what - the factory EPA friendly EFI calibration has knock retard going on all over - from 1-10 percent ignition retard. So when you make an equipment change the EFI compensation is that you get more (bad) or less (good) knock retard because of the change.
However, all knock retard is bad (performance is not optimized) so if you had previously tuned all of it out, then you make a change in equipment, you will definitely need to tune again.
It cannot compensate for fuel as these are tables tied directly to MAP, Throttle Position and RPM.
Remeber .005 is small. And she's right you probably won't notice it .
I did put a post showing factory EFI graphs before and after tuning under Factory Calibration
 

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While you are correct I have a feeling the Delphi also does compensate for fuel to a minor extent. While the maps are fixed by making the system very heavily MAP signal dependent the compensation happens indirectly in the sense that changing restriction some at the intake and exhaust it will change MAP signal under a given load.

On the older MM system this was absolutely not the case because the predominant input was TP which obviously can not change in response to pipes or air filters.
 

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The thing about the EFI MAP table is that it moves in increments of 10kPa so you basically set Air Fuel by 10s from 20 -100 MAP for each RPM break. So if an equipment change bumps the MAP read 2kPa higher across the boards then from say 49-51 it would affect fuel. If the operating MAP is affected 53-55, 61-63, 65-67 etc. (i.e., not crossing that 10kPa line there would be no change. So you would get some compensation when the operating MAP crosses a setting increment.
The real effect on an equipment change is VE and VE calibration is tied to Throttle Position so no help there.
We oughta do some classes on this stuff!!
But then I'm sure the sales lady knew what she was doing - bolt on that SE intake and pipes and maybe it won't knock as bad - so in essence it does compensate as far as she knows.
 

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So I guess the next step for tuning our EFI bikes will be to buy some software and a laptop to start tuning it ourselves. Sounds to me like it will be like tuning a late model Mustang or Camaro after adding Superchargers or NOS. This could be fun but I really only bought my Bike to ride not race, well except for the occasional thrash when leaving a corner or stoplight! Gotta let people here that thunderheader sometimes!
:cool:
 

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If a "snot nosed" 19 year old with a laptop can make a Ford Focus SVT faster in the 1/8th than most any car costing under $100k without touching a wrench, then it seems a 50 year old "snot nose" grabbing the wrench AND the "mouse"should be able to do the same with HD. And better.
 
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