UPDATE: Mapping is coming along much better now, holding boost with no dip in the mid to high end now.
I've just realised something quite strange though, I was reading through some of my older emails and realised that I had a similar
problem with low end spool even with the original PD150 turbo which was one of the reasons I was thinking about replacing it (other was siren noise)...
So, my question is what else can cause low end spool other than a turbo that is not set up correctly? It may also be the case that it does need slight adjustment on the stop screw but thinking about it 144mbar 011 basic settings should be giving better spool than I'm getting surely?
Injectors?
Any opinions on that?
Sort the stopscrew, then look for further causes if need be. you cant look to diagnose something whilst you already have an issue that needs resolving
Shouldn't have a
problem with exhaust as I have the cat removed and 2.25" piece fitted in place and have an aftermarket cherry bomb type muffler on the back.
What do I need to look for in the logs for injectors? low mg/str?
Thanks,
S10EAT
Only thing you can check is injector balance but thats for idle control mainly, all other IQ values are based on what the ECU THINKS it is injecting
Exhaust restriction mainly. Blocked CAT.
Injectors would show on VCDS logs.
Difference between injectors and a fuel flow/supply issue
Badger,
No, that is the thing that is strange, I can't remember a time when I have seen anything more than a slight grey haze, it feels like it's lacking fuel delivery.
Most of time I see nothing out the back.
This is a graph of the IQ I did last month on original map.
Thanks,
If you dont have any black smoke, ask the mapper for more fuel on spool up, as this should
help significantly, i would expect a poor spooling turbo to have lots of smoke until on boost. This could well be map related but without seeing the map its difficult to say. Do you have the CSV files so i can see values?
From that graph, the ECU is limiting fueling as the turbo isn't sucking enough air in. Hence why the yellow line looks similar to your boost line.
What intake setup are you running?
Thats because the MAF limiter is based on airflow which is obviously down to the turbo, they should be very similar
If it helps, here's a MAF log I did yesterday:
MAF log with that kind of scale is useless, either plot RPM on a secondary axis or post the values.. Do you still have the diagnostic limit of 1249.5mg in place or has the mapper adjusted this in your map file?
Not really sucking in that much air. I've got the GTB1756VK and that is sucking in over 1500 from 2000rpm.
Wonder if the N75 mapping isn't low enough from idle.
My PD130 VA turbo hit a peak of 1450mg! lack of boost is the reason why.
N75 map from previous graphs was fine - requesting as much boost as possible
I tested out a S2000 air filter on mine and just found a MAF log I did just after the change, looks a lot better doesn't it?
Should I change back to the S2000 air filter?
You have a strange peak... overboost? The airbox wont be a restriction at your current boost/airflow level
Wouldn't harm doing so. I'm running the S2000 filter and it's loads better. You could ask the mapper to swap to MAP based smoke limiter and go that way to see if it's the fueling that's an issue.
MAP based shouldnt be needed unless the MAF is no good, adding more fuel in the MAF based limiter will suffice for now
I've read about your build! I didn't get to do much testing with the filter, do you get much heatsoak with the filter? As it's getting hotter I worry about it without an enclosure.
Ok I'll ask my tuner about that.
Thanks,
Heatsoak is only a major issue at slow speed when there is little airflow in to the engine bay
I shouldn't have any trouble then as I've got the S3 FMIC
Going to get the stop screw looked at on Monday, my gut tells me my low spool is something else though.
Fix this first, then address again if needed. Ask for more fuel at spoolup to see if it helps.
Yep it is indeed!
Well I've just drove home at lunch got the S2000 filter and installed it, logged it on the way back, damn it flys! Still lag down low but once it gets going it's fast (2700-2800RPM onwards).
Below is a comparison of logs side by side top is the s2000 air filter fitted and bottom is standard airbox, boost curve does appear to be smoother with the s2000 air filter...
What do you reckon?
Throttle applied a lot more briskly on one graph compared to the other, actual intake pressure starts at different levels too, un fair comparison.... Looks no different to me in terms of restriction and it wont be the issue anyway...
Also, plot N75% on a seperate axis! Would be good to see whats going on with boost control.. And why not log to 4000+ rpm??