What is the maximum amount of injector opening time (mls)

[strokerjlk]

cool...I'm following you Jim.
No need to run both.
So in Bob's case...he ran a smaller injector and just boosted up the pressure to get what he wanted.
Makes sense.

Ray

example Ray
remember the xenia race ,where you pitted with us and Darrell was having all the trouble with his v rod?
you can probably remember me asking him several times " did you do anything that would affect the tune".
he was having all that trouble starting his bike. you mentioned the key fob. and that did end up being his problem.
meanwhile ...we played puck puck trying to get him qualified . once we got the bike started it would run off the number, but he got qualified  . he kept saying it felt lean .I was reluctant to fatten it up ,since he went 6 rounds to lose in the finals ,the race before. (runner up)

all day Saturday  it was a bitch to get started in the pits/staging lanes. and he though it was lean.

sooooo... I did what he wanted ,I fattened it up. he slowed down another 1/2 sec. (it was actually fat already)
finally Saturday night in general conversation he mentioned that he might put the stock fuel pump back in. I was like  ...he had installed one of Vreeland's modified destroyer pumps.
once he put his stock pump back in and I put his original map back in ..it ran the number .
he still had the key fob problem. it bit him in the butt because the bike failed to show the second round. bike wouldn't start in the lanes

remember how when the bike was cranking over on the charger ,and the key fob was operating correctly ,the throttle had to be cranked open in clean out mode to start.
the extra fuel pressure was causing the mixture to be fat everywhere all along .
it would have done the same thing if he had installed bigger injectors and tried to run the same tune.

[joe_lyons]

How about this?

[rigidthumper]

That actually works well if needed- I used one like that when I did the Procharger experiments, based on SC suggestion, and tied the manifold pressure to the regulator barb. Made fuel pressure reduce when MAP was low, and higher when on boost.  Good fuel control on both ends.

[1FSTRK]

Jim the difference is the fuel pressures have been going up every sense fuel injection came out. The high pressure smaller injector will usually make better power because the spray is finer and more precise. I have seen it on both bikes and car when testing on the dyno.

[joe_lyons]

That actually works well if needed- I used one like that when I did the Procharger experiments, based on SC suggestion, and tied the manifold pressure to the regulator barb. Made fuel pressure reduce when MAP was low, and higher when on boost.  Good fuel control on both ends.

Didn't you use the sierra/Silverado 4.5 one?

[rigidthumper]

I think so- Caddy/GM replacement -i remember it had the barb on it. Thought it was Bosch. Have to find the box

[hrdtail78]

Jim the difference is the fuel pressures have been going up every sense fuel injection came out. The high pressure smaller injector will usually make better power because the spray is finer and more precise. I have seen it on both bikes and car when testing on the dyno.

I agree.  It doesn't have to be one or the other.  Both will work just fine.

[1FSTRK]

Jim the difference is the fuel pressures have been going up every sense fuel injection came out. The high pressure smaller injector will usually make better power because the spray is finer and more precise. I have seen it on both bikes and car when testing on the dyno.

I agree.  It doesn't have to be one or the other.  Both will work just fine.

I did not mean to use pressure as a band-aid for too small of an injector. I meant that you use the highest possible pressure the rest of your equipment allows and then properly size the injector. This will generally lower IPW and improve BSFC.

[strokerjlk]

Jim the difference is the fuel pressures have been going up every sense fuel injection came out. The high pressure smaller injector will usually make better power because the spray is finer and more precise. I have seen it on both bikes and car when testing on the dyno.

There are many reasons to raise the pressure of the pump .
Yes the pressure has went up in the automotive world . Again specific reasons as to why . None really pertaining to performance . Factory emissions being the  driver . 

In the automotive performance world . They use pressure as a cost effective way to deliver more fuel . It's cheaper to run the pressure up, then buy bigger injectors .
As it would be in rays case . Lets say he could get a 68 psi regulator for 65.00 . Then yes he saved about 150.00 if he had purchased two harley , HPI injectors .

If your out of injector then a regulator with more pressure is effective . Is it cost effective ? It could be . Or in rays case he would save what 30-40.00 and have to pull the pump and replace it. Personally I like the stock pump . Mine has 90,000 trouble free miles . It even has the orininal stock filter .
You can get there either way . Based on what I have seen   It dosen't matter how it gets there .
As long as you provide enought fuel to control BSFC your gonna make the same power .
So I am not against either theory .

[No Cents]

 $92.72 for two 60lb injectors to my door...and my 6.2 injectors have been spoken for already so I promised them they could have them if these 60lb injectors work out.

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Ray

[hrdtail78]

Jim the difference is the fuel pressures have been going up every sense fuel injection came out. The high pressure smaller injector will usually make better power because the spray is finer and more precise. I have seen it on both bikes and car when testing on the dyno.

I agree.  It doesn't have to be one or the other.  Both will work just fine.

I did not mean to use pressure as a Band-Aid.  Raising the pressure for performance is nothing new.  The benefits have been documented. 

If you are making 8lbs of boost on stock 55psig.  That's 155kpa and spraying at 32.5psi.  8lbs is kind of mild. 

There are many reasons to raise the pressure of the pump .
Yes the pressure has went up in the automotive world . Again specific reasons as to why . None really pertaining to performance . Factory emissions being the  driver . 

In the automotive performance world . They use pressure as a cost effective way to deliver more fuel . It's cheaper to run the pressure up, then buy bigger injectors .

As long as you provide enought fuel to control BSFC your gonna make the same power .
So I am not against either theory .

I don't think that is what is driving things at all.  The pressure has been raised on many performance vehicles pertaining directly to performance.  F1 doesn't care about EPA or does much on a cost basis when we are talking $100 either way.  But then again if we really look at F1 and bring it like we know something.  Let us understand that they are dealing with DI and fuel pressures for those systems are running 2000psi.  Why?  Not because they run 115% IDC.  It is because with DI you actual have a shorter time to get things done. 


I will call BS on "it doesn't matter or affects performance"  What are we basing this on?  Opinion is what it sound like.  A lot of different definitions of performance.  Maybe my 250i can't show these performance benefits but that doesn't mean they are not there.  Throttle response performance can see gains.  Low end manners as well.  This can help in performance gains with on, off, on throttle.  We can go full circle back to DI and it's benefits and draw backs.  Just my 2cents

Like I stated above.  I am not saying Ray needs to buy anything that will raise his pressure.  I would do it for a cheap way to get more fuel.  I would do it, and do it for other benefits.

[barrybasinger]

Hi Guys,my standard injectors on my 103 peak at about 17 milliseconds at 6400 rpm , can anyone tell me if that exceeds the limit . Max

Just to answer the question for other setups: One way to calculate on-time (in ms) is (DutyCycle/RPM)*120000.

• If you want to know what the maximum on-time at any given RPM would be, insert 100 as Duty Cycle, and use RPM.
• If you want to know what the maximum recommended on-time at any given RPM would be, insert 80 as Duty Cycle, and use RPM.

(Duty Cycle is the time (in ms) the injector is actually on divided by the maximum amount of time (in ms) available at a particular RPM, more correctly expressed as a percent, as in 80%--but often written as a decimal, as in 0.80).

Some FYIs:
The rate of failure in injector-driver circuitry in ECMs goes way up as duty cycle exceeds a certain value. That is the reason for the 80% recommendation.
Injector delivery rates are not truly linear. They tend to deliver fuel at a greater rate in the first ms or so after opening. They also tend to be very erratic at very short open times. This is why it is usually best to not use a bigger injector than is necessary to support the power you are shooting for. (They would require shorter open times at idle, and would not idle as well as a smaller injector).

[No Cents]

  so are you guys saying that the 60lb injectors I bought to put in my 66mm T/Hog are going to be too big for an almost 12.1 compression 124" ?
I went with these because of them saying the idle and off idle performance was excellent and better than most smaller injectors. 
I'll take the 6.2 injectors with me to Jim's when he tunes it. If he finds they are wrong and won't tune properly...the 6.2's will be there for back up.

Ray

[To The Max]

I have posted some information on the Thundermax Injection timing thread it may be of help to you guys.