NefMoto

Ok so ive been lurking about the forum for some years now and don't think I have got the full potential from my setup, can you guys please give me some advice on my tune. I used to run a WOT fix n75 for boost control but decided that for a smoother pull I should be using the correct way of controlling boost via PID, since doing so I have always experienced a drop in requested boost and timing being pulled at around 4750-5000rpm. Im aiming for a flat boost profile to the redline holding between 21-22psi.
My setup is On my 2002 audi a4 1.8t quattro,
K04 hybrid (rs6 internals)
380cc s3 injectors
3" maf
Fmic and WMI
Equal length exhaust manifold
custom exhaust turbo back and decat.
file and log attached

thank you

High knock correction and fueling is terrible. Bout as far as I looked

Terrible is maybe a bit harsh. On the second part of the log the ecu goes overly rich because of high cf. So, first take out some timing. On the first part of the log, you are not very rich, so might want to add a little bit of fuel after spool.
Also, I think you need to request a bit less load, you are on (or over) the limit. Better make the requested load follow actual load a bit more.
It seems the turbo flows nicely with great spool!

injectors are maxxed out as well

Good point, I overlooked that. If you want to be safe better install bigger injectors, you cant request anything under 0.8 lambda. Above 6500rpm your injectors are static!

Comments taken on board guys, I'll lower load a little and bring back timing.
Honest I didn't look over the fueling for that log, it must of went into BTS as it usual sits at a steady 12afr after spool to the red line. Bigger injectors wouldn't be a bad idea for more head room.

Turbo's solid, from one of the best guys in my opinion.

Thanks again, I'll post some more logs giving the chance.

Its not about headroom, you are already out of injector in the upper rpm range. You should at least increase fuel pressure if you dont want to swap the injectors.

High EGT as well

(https://media.giphy.com/media/8Az9cUlTJOq88/giphy.gif)

I converted to a return fuel system from a b5 a4 1.8t which has a 4bar regulator so can't really increase fuel pressure any higher. Swap injectors it will be then.


I know about the Egt's WMI ain't really doing a whole lot for my engine, might move up a nozzle size and see if it helps out a little more

I would suggest a set of EV14 550cc Bosch injectors then. They work very well for me, and are not too expensive. They are available with both long and short body (to match whatever rail you have). For example I have long body in my AEB manifold and short body in my AJQ.

It looks like BTS fuelling kicks in at 6500, and then you run out of injectors. Maybe if you tame BTS (by increasing EGT threshold), you'll not run out of injectors. But how high can EGTs go before it's dangerous?

Yes I got a look over them logs last night, bts don't normally kick in but the 4gear run briefly before the log in the op probably had the Egt's well up already kicking in the Bts, I've already increase to 1050 so wouldn't want to increase anymore.

I'm back again,
so I took advice onboard and done the following,
Not requesting as much load as in the first log
Smoothed out fuelling on spool, ( think it's to rich to soon TBH)
Reduced timing in the areas were it was always pulling.
I've managed to keep injectors to about 85% at the redline, until I pickup some new ones.

Even doing all this I'm still getting the same issue as in the first post. The boost request tapers from after peak then at 5000rpm it just drops and flattens out.(apart from the mad spike at the end!!)
I have been reading through the converted modules for example EGT control and it doesn't mention lowering boost to control egt's.
To me it is hitting some sort of cap that is causing this at 5000.

Need some more advice, even on what other areas to read so I can figure this out for my self.
Thanks
Sean.

A flat LDRXN doesn't equal a flat boost curve, it's more or less "inverted" (so 180 at 2000rpm isn't the same pressure as 180 at 6000 rpm) :)

This! Took me a while to understand/realise but increase LDRXN in the areas where it's not giving you a nice requested boost. Take some more logs and you'll start to get your requested boost where you want it.

Thank for the replies, that should be simple enough to do to get my flat boost request.

Don't forget KFLDHBN

BTW you are out of injector anyway.

I'd keep your boost taper exactly the way it is.

Maybe tweak timing up top to get more power.

Yea KFLDHBN was altered a long time ago, was limiting me on my tuning path at one stage.Going to order some injectors 2day, took another look at that last night after getting my flat request and it's not good for tuning purposes as its limiting me from doing anything else really.
Thanks.