NVRAM 11p tuning discussion thread.

[someguy360]

What changes are on yours for computed speed error?
I have 3.45 diff and 25.7" tall tyres (stock 3.08 and 25.3" respectively)

I've got 3.7 gears.

 

[someguy360]

Did some test hits for Roll Racing on the 17th today,

Looks like I've finally run out of injector, well over the 80% duty cycle threshold.

It's running a little rich at certain points at WOT so I'm hoping if I lean it out to around 12.5-12.8 at WOT I can keep it in the low 80% duty cycle range and hope for the best for this event.

I don't have the budget for $550-750 in injectors this close to xmas but will probably look at some new LS1 injectors in the new year, if I'm maxing out the injectors on 304ci I'll have no hope for 355ci.

Bosch 42lb 440cc 968 Green Fuel Injectors

Genuine Bosch 42lb 440cc Long Green Fuel Injectors 0 280 155 968. Ideal upgrade injector for BA/BF XR6 Turbo, LS1 V8, etc.

www.tiperformance.com.au

Looking at these maybe as a purchase in the new year, $550ish is pretty good for a genuine set.

 

[Immortality]

80% DC isn't to bad on injector duty cycle, it's what people recommend when calculating for new injectors to give some head room because we always want more power....

you'll be safe into the 90's% with injector duty cycle. Obviously they won't cope with your 355 but that will be a problem for future you.

Also, get that spark timing up to about 28° adv and see how it goes.

 

[someguy360]

80% DC isn't to bad on injector duty cycle, it's what people recommend when calculating for new injectors to give some head room because we always want more power....

you'll be safe into the 90's% with injector duty cycle.

Thanks mate good to know, I was always under the impression the risk was from 80% of them not opening/closing correctly at high rpm but that was from some pretty full on tuners obviously working on highly strung engines.

Duty cycle be damned I’ll up it to 28 degrees and send it.

I bought a 12v power adapter for my tuning laptop this time around so I can log each run and compare without having to worry about it going flat.

 

[Immortality]

The danger zone will be in the mid to high 90's area, it's the zone down from 100% DC less injector dead time and how ever long it takes for the injector to de-energize and shut off the flow. Basically it's when there isn't enough time for the injector to turn off and then turn on again so it looses control and starts to flutter causing reduced fuel flow.

There are benefits to running larger injectors and using a lot less duty cycle which should help with detonation as well as playing with injector end of injection timing (when it actually injects the fuel into the port although that is more for full sequential injection systems). But basically put, when you are close to max injector DC it means the injector cycle is very long, it means that some of that fuel is sitting for a very long time in the runner getting hot. Things that are hot are more prone to detonation. Detonation is caused by heat and pressure over time, a increase in any one of those and we get into trouble when we are pushing the limits.

 

[Deuce]

I would also lean it up some.
12.8 is plenty rich enough. I think I set 12.5 for WOT with pwr button down, but really anything under 13 is just extra cylinder cooling in my opinion.
No need for 11's or 10's afr unless running boost (my brothers WRX for example)

 

[someguy360]

@Immortality I believe you've used the kinjflow calculator before are you able to retard check me.

Swapped over to the 775 Blue Tops from the standard injectors.

VR, VS, VT 5.7L (215KW GTS)(Blue Tops)
0 280 150 775 (EV1)
25.9 LB/HR 265 CC/MIN 195.79 G/MIN 15.9 Ohm 3.3Bar OP

With a 304 with unleaded fuel am I correct in my flow rate of 0.116?

If you have a few mins to retard check my maths that would be great.

Also should flow rate be all I have to change in TunerPro? I've already adjusted the base fuel pressure from 3 bar to 3.3 bar.

 

[Immortality]

Just have a look at a tune from the relevant model the injectors came from and use that kinjflow number.

In theory yes, all you need to do is change that number but even in the stock kinjflow number (if you follow the math) there is a "fudge" factor.

 

[someguy360]

Just have a look at a tune from the relevant model the injectors came from and use that kinjflow number.

In theory yes, all you need to do is change that number but even in the stock kinjflow number (if you follow the math) there is a "fudge" factor.

Thanks mate, most of the blue top tunes I’ve got are for 355’s according to pcm hacking the kinjflow is different between 304 and 355 as the displacement impacts this number lol.

Muddies the waters a bit haha

 

[Immortality]

What is yours 304 or 355?

I'd look at a stock 304 tune with the 775 injectors.