Like I said before, DT Zach told me that a F1 engineer who they hired to consult with said the direct injector duration shouldn’t exceed a given value, which is why they don’t go beyond that value. I might still have that email to verify that statement, but that is their rationale.

They ask for a log then do a revision most often after each log. In total I had 8-9 revisions. I had an idle log, another idle with different rpms, a steady state cruise log, a few tip in logs, a bunch of 2k to WOT/redline logs. I did add larger injectors and a flex fuel kit along the way at no extra charge because I bought them in the revision phases to get my fueling right like Captain Awesome.

His duration was already 5.6ms. I agree that other cars must have a longer duration because they don’t have D4S and only direct injectors, but what size are their injectors and what is their duration?

I m not rrally sure the intercooler affects the boost, only the ability to knock more or less depending on how much it cools the charge, because it is after the air is already compressed
But not sure. What i am sure of is, colder AMBIENT temperature will surely bring more boost to the manifold

considering also the modifications along the way, I assure you they work with base maps and modify them a bit... and it shows, seeing the LTFT and CL% they leave you with. Less work for them, less hours wasted, sloppy result for my standard but that s just me.
Anyway from the logs, after he reaches 5.6ms, it goes down... it could be made like 5.8-5.9ms or 6-6.1 in cold weather, to redline, and there is a trick i only see used by european tuners, to overload the high pressure fuel pump to 22psi instead of 20psi (or bar? whatever the unit for it is) at high loads and that would bring down the PI usage.. it increases parasitic loss, yes, but the benefits override this, and also cools more the charge and increases detonation threshold... win-win
the stock mapping for High pressure fuel pump, reduces the pressure to 18 at redline to reduce pumping/parasitic losses because NA this car is already too slow :P but with boost and more than 300 bhp you do not care about that loss at all... damn, you almost don t even care of the loss that carrying a belt driven charger brings...


About the F1 engineer... they work with 20000rpm with narrow band of torque, in a range of rpm that are so high that is known the DI brings disadvantages..
our engine has MUCH lower rpm and i do not see or ever had a problem in raising the DI usage, stock DI can easily open more than 7ms at maximum nominal pressure without bringing fuel delivery issues, 6ms is not THAT much, as soon as you keep an eye at the time between end of injection and the spark firing and keep it more than 1.5-2ms away.. and we can even modify the DI firing angle to avoid that

I was researching and found some information from the WRX guys. They are only running direct injectors, so apparently they are saying OEM is 1500cc or 2000cc injectors from the factory, but they note that the equivalent size is less because of the shorter max duration. Our direct injectors are only 440cc, right? That makes them pretty insignificant in terms of delivery, which is why DT might limit their duration and just leaves them for fine tuning/close-loop activity. I'm not a tuner. I'm just trying to convey what DT could be thinking.

https://forums.nasioc.com/forums/sho....php?t=2891316

yoy do not look only at cc size with DI because it depends also on high pressure provided to them
and 20-22MPa gives you a lot of fuel, even if you are only limited to inject in a window of half the time , compared to PI that can inject at any time
And our DI delivers LOT of fuel if you want.. and remember that the fuel passing through cools the injector, and they are off for 2 stroke out of 4
PI is potentially more prone to overheating

Until 7ms of opening at 20MPa, it doesn t lean out, meaning it provides the fuel needed, so 6ms is a reasonably limit for a cold weather situation, just need to watch you are away from the spark a couple ms at high rpm

I logged my car in NA form time ago, first with PI disabled and then with DI totally disabled
with DI it works all the time providing all the fuel
with only PI you reach 20ms of opening at like 5000rpm, leaning out like the log of OP

Guys, colder air is denser, your balloon analogy is the opposite in this case.
Colder air = denser, = more air into the engine = more fuel to compensate the ratio = more power.

CSG can help. Zach left DT over a year ago, and is now a partner at CSG.

Any idea on price considering my current information?

https://www.counterspacegarage.com/csg-spec-fi86-tunes

No additional upcharge for injector scaling or ethanol, if you happen to have either of those.

Includes as many revisions as needed to make the car run to Zach's satisfaction.

Also, quick turnaround times!

Sounds good. If I don't switch to flex fuel until later, what kind of revision charge would that be? I know I'm going to add it in at a later date, but it's going to be a few months.

You'd also need injectors with the FF upgrade, but subsequent tunes carry a heavy discount. I'll let Zach handle that since that's his dept.

He has upgraded injectors, just not installed.

Zach at CSG fixed my issue. We went through 13 revisions. Highly recommend. Car drives so much better. Also if you have different injectors I know sometimes the tune needs to be adjusted.

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It always needs to be rescaled to the injectors, but he is on stock injectors right now.