Stop Screw Adjustment 1749VC Hybrid

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Well it appears we have the same tuner, only just realised doh!

John has been extremely helpful and very patient.

I'm only going to be running about 1.7-1.75 bar with the turbo so your 1756 outflows mine by quite a bit!
 

Badger

Active Member
Dec 2, 2012
2,891
7
Newcastle, Staffs
Well it appears we have the same tuner, only just realised doh!

John has been extremely helpful and very patient.

I'm only going to be running about 1.7-1.75 bar with the turbo so your 1756 outflows mine by quite a bit!

Haha! Small world.

John is very helpful, now we know it isn't the mapping which is the issue :D
 

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Haha! Small world.

John is very helpful, now we know it isn't the mapping which is the issue :D

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?
 

Dan FR

Meth addict. Stage 2+ Yo!
Nov 14, 2013
1,795
8
Caerdydd
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??
 
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S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Thanks Dan! That's some detailed responses!

I will fix the stop screw before pondering on other causes for the issue.

I'm going to be doing a MAF log when I drive home tonight so will post that with RPM on the secondary axis, boost requested on current map is currently set at 1.64 bar.

Shame that the stop screw adjustment has to wait till Monday!

Really do appreciate both of your expertises, will update later on.

Thanks
 
Last edited:

Adam4D

Active Member
Oct 2, 2011
349
0
peterborough/cambridgeshire
Also reading through quickly on my break.
Your maf log looks crap, a stock pd130 sucks more airmass than yours currently is going by that graph with the s2000 air filter on. As said the resolution in the graphs are making it hard to diagnose this properly. The bump in airmass is it 1200,1300,1400? You just canny see properly.
 

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Before I started the run I cleaned the contacts with contact cleaner on the MAF, N75, MAP and Fuel Temp Sensor just to make sure these weren't an issue.

Getting really f****d off with Photobucket keep on resizing my photos to 1024x700 so here's the raw log:

0 2016 850 806.3 4.8
0.4 2121 850 968.8 4.8
0.8 2205 850 975 4.8
1.2 2331 850 1000 4.8
1.6 2436 850 1093.8 4.8
1.98 2541 850 1125 4.8
2.38 2646 850 1156.3 4.8
2.78 2751 850 1168.8 4.8
3.18 2856 850 1237.5 4.8
3.58 2961 850 1250 4.8
3.98 3066 850 1268.8 4.8
4.37 3150 850 1306.3 4.8
4.77 3255 850 1250 4.8
5.17 3360 850 1237.5 4.8
5.57 3465 850 1231.3 4.8
5.97 3570 850 1218.8 4.8
6.37 3675 850 1218.8 4.8
6.75 3759 850 1212.5 4.8
7.15 3864 850 1181.3 4.8
7.55 3969 850 1125 4.8
7.95 4053 850 1075 4.8
8.35 4137 850 1050 4.8
8.73 4221 850 1025 4.8
9.13 4305 850 993.8 4.8
9.53 4368 850 968.8 4.8
9.93 4452 850 937.5 4.8
10.33 4515 850 925 4.8
10.72 4578 850 912.5 4.8
11.12 4620 850 887.5 4.8


Thanks,

S10EAT
 

Dan FR

Meth addict. Stage 2+ Yo!
Nov 14, 2013
1,795
8
Caerdydd
No use in that format mate, upload the original excel documents to a shared dropbox folder and post the link up
 

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Ok well I've just come across another problem, I have oil in my coolant which I suspect is the oil cooler that has failed, but on an even worse side of things I believe I have coolant in my oil as well! What are the causes for coolant/water in oil?

I know headgasket can be one of them but are there any other less serious places this can happen?

Thanks,

S10EAT
 

Badger

Active Member
Dec 2, 2012
2,891
7
Newcastle, Staffs
Other than the head, oil cooler. Just thinking about that tandem pump though. Can't remember from the top of my head but don't think they're joined with coolant.
 

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Ok well, I've had the oil cooler, oil, coolant tank and coolant changed along with wishbone arms, track rod, track rod ends and droplinks replaced.

Good news is I appear to no longer have oil in the coolant however, the new oil appears to be very transparent and diluted has risen about 2-3mm when it was originally around the half way mark on the dipstick.

I'm also getting a strange problem now where I have to give it alot of gas to get it moving from stand still, almost wants to stall and if not given the right revs will slowly lag it's way up the rev range from standing.

I want to get this sorted and be told one way or another whether I need a new engine or if it's something that can be fixed repaired, in your opinions in the south east/ Kent / Surrey area which garage is the most knowledgeable in diagnosing running issues like I'm having?

Thanks,

S10EAT
 

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
Well the tandem pump + gasket has been replaced already so really the only other two options I've got is either injector not seated correctly (had all four seals replaced in the last few months) or a crack in the one of the fuel lines within the head. Are there any other options?
 

S10EAT

Active Member
Jul 31, 2010
407
8
Eastbourne
UPDATE: Well I still have issues with my car but after much effort I have managed to file down the damn stop screw from above and I've now got the adjustment to 192.

Spool isn't much better but having said that I haven't asked for a new map from John!

Will keep you posted...
 
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