Low RPM + High boost = Bent rods?

[BennVenn]

The only thing vacuum operated on this car is the brake booster which is a vacuum reservoir in itself. And the turbo actuator but that's being converted to electric

[BennVenn]

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Pulsar_16Apr2021_Pull2.xdl

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O2 sensor in, down pipe wrapped, beanie on, big injector in. (No cooling fan installed....)

It looks like the big injector is too big... Can't get the idle up past 10 afr. I recall a setting which will fire every second request, this should clean up the idle when I find the flag and work out how to switch over to single shot. The good news is at 3600rpm at 4psi, we're only at 40% duty so we should hit our taget of 5000rpm @ 6psi safely on this injector.

Now for the problems - at 3600rpm WOT we're at 4psi with zero VNT request. There is adjustment which can actively slow the turbine (negative nozzle angle) which may be required to keep boost under control. This will add restriction. A 1.6L diesel turbo is clearly too small for a 1.6L petrol given the exhaust flow differences. As a daily driver I won't be running it to 5000rpm around town so I think this will be OK. I've got a 2.0L diesel VNT I plan on fitting to the 1.8L but I might shop around for a 2.2-2.4L instead. Spooling won't be an issue with VNT on an oversized turbo.

Duty cycle jumps from 20% (40% real measured, some quirk with 12p on TBI mode) to 400% as soon as it crosses into the 100kpa+ region. Requested AFR goes to 0 too on the gauge readout once we cross 100kpa. AFR's start to lean out which was what stopped me at 3600rpm. I'm not sure the cause of this, I've gone through everything I can think of. Any ideas?

The attached map... Don't read too much into it. I just threw some 'safe' numbers in there to keep AFR's fat and timing safe.

IAT's. The turbo inlet is right near the radiator so it'll be pulling hot air. Even so, and even with the heated manifold the temp does drop with injector duty. I've got some fittings ordered to redirect the intake somewhere a little cooler. It's early but I think the injector will provide enough charge cooling at 6psi given a cold air intake.

If there's light when the engine cools down I'll go fit a thermo fan and try get to the bottom of this Duty/AFR issue and the odd/even injector firing mode

[BennVenn]

After another look through, "MAP A: Boost Cold Engine A/F ratio vs coolant temp" table is all Zero. I'll fix that up and see if it resolves the Target AFR issue. Subsequent pulls were all with the engine at 100deg so that shouldn't have influenced AFR's if my understanding is correct.

[BennVenn]

Double fire set up, Afr's better but still too low at idle.

Boost still creeping, hit 153kpa before the injector failed and is now stuck open... Or an oring has failed. Walking back home to get the old injector and we'll see...

The old pulsar is much livelier at 7psi

I'll try get the nozzle to a negative angle and see if i can manage boost a little better. Might need a bigger turbo or a wastegate...

['quipt4it]

Can you post your updated bin.
Your old one shows AE Multiplier vs Engine RPM at 2.55 to 2400 RPM. Did you set this for a reason?
Did you mean Single Fire set up.
Hate those long walks back lol.

[BennVenn]

The AE would have been from when it was running on the VW with the meter long intake runners, I've turned them all down this morning to get rid of that excess fueling on cracking the throttle. I'll grab the bin after lunch.

Looks like the ECU is bad, the coolant temp is all over and now its stuck at 20degrees. Tried another sensor and same results. Will swap it out after lunch too.

The TBI needs single fire all the time, one injector, one squirt per trigger. That larger injector is sticky now so I guess that's irrelevant. Or do i have single/double fire back to front?

I think the dead times are a bit off too, fueling isn't tracking the duty cycle, higher duty leans out and I know I'm not out of fuel system and duty is reading 40% (80% real duty) so I've got some injector left. Unless efficiency is climbing as the turbo starts breathing? I might need to wait for this electronic actuator to arrive before I end up damaging something from over-boost.

I have confirmed that IAT's drop under boost so that's one of my goals confirmed. Rediculously quick spooling is also confirmed on the VNT so that's another.

The walk wasn't too bad, just dirt roads out here where we are

['quipt4it]

...The TBI needs single fire all the time, one injector, one squirt per trigger. That larger injector is sticky now so I guess that's irrelevant. Or do i have single/double fire back to front?...

Maybe mixed up. Previous post mentioned Double Fire set up.

[BennVenn]

Yeah so the injector was too big to idle on this motor so double fire means one shot every two triggers? This moves the pulse width into an area the injector is capable of operating?

['quipt4it]

Single fire for a finer control at low Pulsewidths.
From what you say, it has enough flow for Single throughout?
I noticed in your tune you hadn't set Min BPW double fire for upper and min. values.

[BennVenn]

Pulsar_17apr21.bin

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New ECU in (now we're getting CLT), VNT nozzle is hard up against the zero stop and boost is behaving itself. This setup might just work after all!

This is the current tune and the last pull i did. This is with the small injector back in and it is maxed out (0ver 100% duty) at 5000rpm at 6psi though we're still seeing 12.4aft which I believe is just getting out of the 'safe' territory. With the VE tables fixed up I think we're OK for 6psi. Maybe a turn or two on the fuel reg will give a bit more safey margin.

This engine never did much over 3500rpm, it revved higher but just felt flat and labored. Under boost it wants to just keep on going. I think i might move this setup over to the manual n13 when the controller arrives. I'm excited to see IAT's when the cold air intake is fitted.

I've got no idea where I should take the boost timing to. It feels like just 2 degrees makes a huge difference, any thoughts? Should I just listen for knock and keep adding timing?