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

    • Yeah I suspect even if you hold airmass per cycle/cylinder constant if you get too far away from stock you're still going to have problems running the factory tune within the bounds of the factory load scale. Cams, different displacement/rod ratio, etc. I'm just lucky that the GTIII-SS with wastegate boost + CA compliance cats is pretty much equivalent to stock turbos. When I have actual space I can finally get it tuned and modify the fuel system for flex fuel to 100% handle any detonation concerns when cranking the boost to whatever those dinky turbos can put out.
    • I would say no, why, because my daughter, who also lives in Goulburn, hasn't recommended us going there Pity, as we miss all the German joints around in Sydney, actually, the restaurants are the only thing I really miss about Sydney, and a special mention to Ishibanboshi at Bondi Junction, their Kara-age Don is heart cloggingly deliciousness (always added a special boiled egg...or 2) 😋 
    • Does that German restaurant still exist in the old place out the NW end of Goulburn? When I say "out the NW end of"...I am really being vague. It was 1997 when I was last there, and the only point of reference I can recall is that it was on the opposite side of the main drag from the big merino. And when I say "opposite side of the main drag", I don't mean "on the main drag". It was either a couple of streets back from there, or might have even been out in the sticks a bit further. Was an old farm building or mill or somesuch. And when I say "the big merino" I might actually be thinking of a completely different part of town, because I just looked on maps and the big bugger is not where I remembered him to be! The food was good, consisting largely of various German mystery-meat sausage/loaf things and kartofflen.
    • So while the second sentence is completely correct and the whole point of the conversation, the first sentence bears consideration. If this bloke is just hoping to throw big turbos on and drive it around, because there are no helpful facilities at all in his tropical paradise** then he likely has zero chance of even knowing what the TP is on the last column in the stock maps, let alone know whether the ECU is operating anywhere near it or past it. So the point is very very moot. And, per what I said before, at stock boost on those turbos, you may well be off the end of the map. **I'm just back from Vanuatu, so I know exactly what small Pacific nations can be like wrt paradise without requisite facilities. But it's not even that simple. I put a high flow on my car and had to drive it around without a proper tune because of the lack of opportunity*** to put the bigger AFM and injectors into it to allow it to be tuned. I had to turn the boost down to less than I had before, and back off the boost controller's ramp, because it was exploring parts of the map that it didn't drive in before, and really couldn't access for tuning on the dyno either, and so was pinging. It was still well within the last column, because when I first**** set up the Nistune on the Neo I rescaled all axes of the maps to give some more space to explore. ***Family dyno was broken ****This was 13 years ago, and the TIM thing wasn't a thing then and so TP would definitely grow when pushing past the stock tune's limits.
    • Yep, this bit another local owner. I caught it before putting the transmission back into the car, what I noticed was the pressure plate fingers weren't flat and even. It's more obvious with the pull style clutch because the throwout bearing ring was visibly not flat once everything is put together. Nismo should really update their instructions to call out this specific detail. I'm not even sure the clutch as-shipped orients everything properly.
×
×
  • Create New...