Jump to content
SAU Community

Recommended Posts

I aggree that there are a few posts in the making of a flaming...

But i do respect Dan and the work he does.

Maby you could pm dan or post in that topic for him to explain what he meant... As squizz did, I see why you both are asking your self how you can get 110% duty cycle, but i believe that i can see what dan is trying to say, and he has not used the best wording for it...

I aggree that there are a few posts in the making of a flaming...

But i do respect Dan and the work he does.

Maby you could pm dan or post in that topic for him to explain what he meant... As squizz did, I see why you both are asking your self how you can get 110% duty cycle, but i believe that i can see what dan is trying to say, and he has not used the best wording for it...

Thank you Col.

And yes I could have worded it better but choose not to edit my post due to the fact it seems to amuse small minded people who have more dollars than sense.

Thank you Col.

And yes I could have worded it better but choose not to edit my post due to the fact it seems to amuse small minded pricks who have more dollars than sense.

Dont people like that just f**k you of mate wankers

Edited by gts-t 4 life

please feel free to enlighting us to how we get over 100% duty cycle.

I think I know what you were getting at (Increase fuel presure to increase flow), it just sound funny wording it as duty cycle.

Obviously you have never used a diagnostic tool before so I will explain.

When the scan tool does a calculation for duty cycle it measures rpm and injector timing then divides this value by 1200 to get a reading as a percentage.

For example. 6000 rpm with an injector time of 15ms will give you a duty cycle of around 75%.

Obvisously if you increase either rom or injector timing, the final value will also be higher, like 7000rpm with an injector time of 18ms will give out a reading of 105%.

Now just before you find amusement in that final figure I will explain this AGAIN. As I said to Col...I could have worded it better and taken the time to write out this massive message explaining myself to everyone about what I meant by 110%, but I thought...hmm hang on, maybe people who know me will understand where I'm coming from without me having to write out an essay.

I KNOW YOU CAN'T PHYSICALLY RUN AN INJECTOR AT 110% DUTY CYCLE...I'M NOT STUPID

However, you can run an injector at 100% and increase rail pressure to add more fuel meaning that a 260cc/min injector is well capable of over 280cc/min.

Thank you for wasting 10 minutes of my life....

Oh and next time you want to attempt to amuse people with your quick wit, or at least half of it, how about you quote me acurately as I NEVER said 110% duty cycle. I did, however, say that I ran my RB20 injectors at 110%. Think back to the post before that even...when I mentioned about pump flow.

Edited by 3lit3 32

so which is it?

bad to run your injectors at higher than 80%?

or ok so long as you have a shitload of fuel pressure behind it ie uprated pumps ect?

i remember being told a while back by a well known mechanic that theoreticly you shouldnt be running your injectors at their maximum performance figure

edit:- i understand that you CAN run them at 100% but is it safe and or wise to do so?

so which is it?

bad to run your injectors at higher than 80%?

or ok so long as you have a shitload of fuel pressure behind it ie uprated pumps ect?

i remember being told a while back by a well known mechanic that theoreticly you shouldnt be running your injectors at their maximum performance figure

Theoretically, injectors should not exceed 90%. However, if the vehicle is set up with the right equipment and fuel system, it can run at 100% IDC as long as it has been tuned correctly.

There are some injectors that are literally restricted to about 60% IDC like some of the Gen II rotaries.

And, in fact....Honda run most of their cars at 100% IDC at WOT on redline, like the B16A Vtec for example.

For cars like Nissan Skyline/Sylvia/Pulsar, Toyota Supra/Soarer, Honda or any other good quality manufacturer, the injectors can happily run at 100% IDC as they are exactly that...good quality.

Don't expect your mums Excel or Lanos to be able to handle this kind of treatment lol.

The ECU loses all control of the fuel system once the injectors reach 100% IDC but as long as the car has been tuned on a dyno with an accurate A/F ratio meter, there is no reason why it cannot operate safely...provided that nothing else in the system fails. All it would take would be a blockage in the fuel filter to lean it out. So on one hand you can have no problems as long as everything is well maintained, or it can be devastating if one link in the chain breaks.

Does that answer your question?

Guest
This topic is now closed to further replies.


  • Similar Content

  • Latest Posts

    • For once a good news  It needed to be adjusted by that one nut and it is ok  At least something was easy But thank you very much for help. But a small issue is now(gearbox) that when the car is stationary you can hear "clinking" from gearbox so some of the bearing is 100% not that happy... It goes away once you push clutch so it is 100% gearbox. Just if you know...what that bearing could be? It sounding like "spun bearing" but it is louder.
    • Yeah, that's fine**. But the numbers you came up with are just wrong. Try it for yourself. Put in any voltage from the possible range and see what result you get. You get nonsense. ** When I say "fine", I mean, it's still shit. The very simple linear formula (slope & intercept) is shit for a sensor with a non-linear response. This is the curve, from your data above. Look at the CURVE! It's only really linear between about 30 and 90 °C. And if you used only that range to define a curve, it would be great. But you would go more and more wrong as you went to higher temps. And that is why the slope & intercept found when you use 50 and 150 as the end points is so bad halfway between those points. The real curve is a long way below the linear curve which just zips straight between the end points, like this one. You could probably use the same slope and a lower intercept, to move that straight line down, and spread the error out. But you would 5-10°C off in a lot of places. You'd need to say what temperature range you really wanted to be most right - say, 100 to 130, and plop the line closest to teh real curve in that region, which would make it quite wrong down at the lower temperatures. Let me just say that HPTuners are not being realistic in only allowing for a simple linear curve. 
    • I feel I should re-iterate. The above picture is the only option available in the software and the blurb from HP Tuners I quoted earlier is the only way to add data to it and that's the description they offer as to how to figure it out. The only fields available is the blank box after (Input/ ) and the box right before = Output. Those are the only numbers that can be entered.
    • No, your formula is arse backwards. Mine is totally different to yours, and is the one I said was bang on at 50 and 150. I'll put your data into Excel (actually it already is, chart it and fit a linear fit to it, aiming to make it evenly wrong across the whole span. But not now. Other things to do first.
    • God damnit. The only option I actually have in the software is the one that is screenshotted. I am glad that I at least got it right... for those two points. Would it actually change anything if I chose/used 80C and 120C as the two points instead? My brain wants to imagine the formula put into HPtuners would be the same equation, otherwise none of this makes sense to me, unless: 1) The formula you put into VCM Scanner/HPTuners is always linear 2) The two points/input pairs are only arbitrary to choose (as the documentation implies) IF the actual scaling of the sensor is linear. then 3) If the scaling is not linear, the two points you choose matter a great deal, because the formula will draw a line between those two points only.
×
×
  • Create New...