Thanks again Russ.
Scott

 

I understand pulse width and fuel pressure. What I am missing is how one determines that an injector is too small? do tuners look for this while tuning? I guess what I am getting at is when does the issue come into play? Only large displacement engines with high flowing heads and high lift, long duration cams? What is it about a build that makes a tuner think to him self, "self, we better check injector size"?

 

dj,
I know that when www.joescyclerepair.com tunes, he is all over this.
He even has an outfit that checks/test/adjusts actual output, if in question.
To answer the question as to "how they know", I'll ask him, and post his response.
Scott

 

Interesting, so he can actually adjust the injector output? Can't wait to hear how this is done. What machine is this exactly, an ANSU? something better maybe?
Once again the simple answer to the how to know if they are too small would be seeing a lean condition that cannot be overcome with adding fuel with the tuning software but even this is not a 100% guaranteed test. Reading it in the data stream of the software like the the dtt that already does the calculations real time while tuning is still the best.
Here is some interesting reading on the injector subject. http://www.robsdyno.com/injectors_tu...achusetts.html
He mentions that even 90 percent is not considered to high for a motor under 6000 which is where the majority of the street ridden Harleys reside.

 

djl,
When we recieve the info I mentioned, I'll send a PM..........
Scott

 

Oh come on, please do share, after all these forums are for the free sharing of information not just advertising. I am sure others would like to hear the process used in testing and adjusting the injectors at your tuners shop.

 

.................as usual, only more than evident as to where this is heading, so disclosure will be done, ONLY thru a private message........

 

so you want to post and advertise your business, but do not want to share? i do not even change my own oil and have no interest in doing any kink of performance upgrades to my bike. there are many others on here that are mechanically inclined and belong to this forum for technical questions.
you throw out a tid bit that interests some people and then don't want to go into detail...very poor way of doing business. as someone in the "know", you should be happy to help others. it is not going to hurt your business and may in fact make people think better of you. merry christmas.

 

Its all math.
The right way to figure out injectors is.....
A naturalley aspirated engine will have a B.S.F.C .50lbs which means .50lbs/.55lbs of fuel per hour horsepower.

A blower engine will use on avg. .60lbs/.65lbs per horsepower

B.S.F.C
Means---Brake-Specific-Fuel-Consumption.

120R stock 5.3 injector= 42.06 lbs/hour = 442cc/min= it will handle 150/158hp at 80-90% duty.

Some thing like we build. big hp's
10.06 g/s= 80lbs hour = 842.93 cc/min= it will handle 220/245hp at .60lbs at 80-90% duty

These numbers are just a starting point
Horse power X BSFC
example 31.25 x 90% = 28.125 / .50 = 56.25 x 2 injectors = 112.5 hp
This is rule of thumb.

To convert cc / min to lbs. / hr. - Divide by 10.5
To convert lbs. / hr to gal. / hr. - Divide by 6
To convert cc / min to gal. / hr. - Multiply by .015873

You learn this from building them in house for many shops and diesel shops.....

 

We share a TREMENDOUS amount of inside information, covering a very vast spectrum on this message board, and on other message boards also.
Very happy to alert folks, to aid with problems and preventive measures, in order to help steer them in the right direction, to save money, time, and frustration, so they can enjoy their motorcycle(s).
The individual prodding us has an agenda, and the typed words cannot even begin to touch on this ongoing, persistant issue, that the moderators, and owners of this site, along with other moderators on other boards, are fully aware of.
Only trying to defuse a pontential fracas.
More than happy to share this with you.........via pm.
Happy Holidays to you as well.
Scott