Degree'd injectors

[Quick_2s]

Where does the degree-ing of the injector spray pattern come more into play on bottom end or top? I'm thinking bottom is probably more critical due to making every stroke count more to make the bottom end torque. Just looking for some brain food on the matter.

[uglyDougly]

  I think it's about emissions not power or torque.
  You can get the power with a wide variation of emissions depending on how much is vapourized on the inlet valve head. Face it, the MoCo has to worry about passing emissions in order to sell their product. They may need to change the spray pattern to get the drivabiliy they need to satisfy the customer and still meet emissions standards.

  I will say this again; the drivability differences between the two different spray pattern injectors says more about the variables in the system (fuel pressure, actual injector flow rate variation) than it does about spray patterns.
  That is what makes 'no two bikes are the same' a true statement.
   A good tuner can make either injector behave from a drivability standpoint, but the emissions may vary and may be too much to comply.

   Something I have never recieved an answer on is; when the injectors are changed does it require a different calibration?

   Doug

[fuzznut5197]

I understand Doug's post about running dissimilar spray pattern injectors, but it that what you mean by "degreed injectors"?

[FLTRI]

Doug,
"Something I have never recieved an answer on is; when the injectors are changed does it require a different calibration?"
If what you are asking is are the 8deg injectors the same output quanity as the 25deg injectors, I have found the 25deg injector to put out more fuel requiring the EFi to be recalibrated.
So the answer s/b: yes
Bob

[Quick_2s]

Mainly was wondering if the injectors I have which are not harley would be out performed by a multi degree injector of a comparable size. Mine are Marren 6.19gps

[FLTRI]

If you are 120ci or less those injectors can be replaced with smaller ones that will increase low end throttle resonse and make the bike feel more snap all round.

However, you may need those over 124ci.

[Quick_2s]

114" Motor, but I went as large as I could on valve, intake runner, manifold and TB size so I was hoping I'd need that much injector.

[ToBeFrank]

Something I have never recieved an answer on is; when the injectors are changed does it require a different calibration?

After doing your injector variation testing (I think that was your site I read it on), wouldn't you have to answer yes here? Even replacing injectors with the same model injector, due to the variation it would require a retune.

[uglyDougly]

  > After doing your injector variation testing (I think that was your site I read it on), wouldn't you have to answer yes here? <

  There are two answers to that.
  First, that is why the MoCo has gone to dual O2 sensors. They don't do something like that because they like spending more money on producing motorcycles, they do it because of the variations and how they affect the emissions.

   Second, yes, but I feel that everything needs to be tuned, or at least can be improved by tuning. When I say that there are folks who will state or imply that, because I'm a tuner, I must think that way (to a guy with a hammer, everything looks like a nail.)
  Rather, I think that way because I have looked at all of the bikes that have ever come to me for tuning (using the tools that allow you to 'look') and that is what I've observed.
  I won't 'hard sell' anyone on tuning, but they all need it. Some riders just have lower expectations than others.

   Doug

[FLTRI]

Doug,
"but they all need it. Some riders just have lower expectations than others."

I definitely agree with that statement. Along with that, some riders feel, and sometimes swear their bike runs just fine without a tune.
I have found 99% of those riders have not had the pleasure of riding a bike that the EFI was "properly" recalibrated to assure both cylinders operate to their maximun efficiency with improved throttle response, power, smoothness and fuel mileage.

It is only after the tune do they realize these improvements. Fortunately for me, since we do not advertise, their word of mouth keeps the calendar booked.

IMO, there is nothing like a rider getting on his bike after the tune, taking it for a good long test ride, and coming back with a Shite eating grin on his/her face.

Bob

[Valley]

IMO, there is nothing like a rider getting on his bike after the tune, taking it for a good long test ride, and coming back with a Shite eating grin on his/her face.