GT2x fitted - major lag !!

[Cupra_Jeff]

Right I need peoples help here. I recently got my motor back after having a GT2x, 3” ATP inlet, S3 injectors (with 4 bar FPR) and 3” MAF fitted.

I got it all mapped with wideband lambda and its holding good a/f ratios right through to 7,000, with very little/no timing pull. However it seems extremely laggy…. At first I thought it was just me getting used to it, so I did a log of requested vs actual boost and its rubbish (not meeting requested boost till 5,000 !!!). Once the thing is on boost it bloody flies all the way to 7,000 and is a lot quicker than the K03s used to be.

At the same time I logged air flow and it was pulling a pathetic 125g/s (my K03s used to pull around 185g/s IIRC)

Basically I bought a cheapo 3” MAF from a member on here which when I plugged it showed was knackered so I swapped the element from my original MAF (obviously 2.5”) and put it in the 3” housing. I also have the cheapo open air filter that came with the kit fitted. Do you think either of these may contribute to the problem ??

By the way for reference my other mods are A&M manifold, 2.5” miltek d/p and cat, Miltek full cat back, Forge FMIC, Forge DV007 and N249 bypass.

Now there are few running the same mods who see full boost by 3.5k, cupra_matt, robdon maybe you can confirm this ??

I’ve got a log but my work internet security won’t let me access photobucket, anyone be able to host it for me ??

 

[acidstrato]

post the log data into the thread as

 tags

certainly sounds wrong

 

[PhilW]

Am i right in sayin your MAF scaling will be wrong as you've gone up a maf size diameter?


But i remember seeing actual v requested logs before and thinkin its a laggy turbo for an actually small one.

Worth a boost controller?

 

[Feel]

Who's mapped it? Restricted air inlet, perhaps? Dodgy N75 or bad N75 installation (crimped hose)?

I guess we need to see the logs.

 

[Cupra_Jeff]

 Sunday	20	May	2007	17:40:11						
6K0 906 032 AA 		1.8L 20VT EU3       0002								

	Group A:	'115				Group B:	'002			
		RPM	Load	Absolute Pres.	Absolute Pres.		RPM	Load	Inj. On Time	Mass Flow
	TIME					TIME				
MARKER	STAMP	 /min	%	 mbar	 mbar	STAMP	 /min	%	 ms	 g/s
	0	2280	15	1000	1010	0.59	2280	15	2.05	6.89
	1.15	2320	17.3	1000	1010	1.72	2360	53.4	7.38	26.17
	2.32	2480	60.2	2130	1160	2.82	2560	63.9	8.61	32
	3.32	2640	66.2	2140	1290	3.82	2720	68.4	9.02	35.97
	4.42	2840	69.9	2140	1360	5.02	2960	71.4	9.43	40.61
	5.53	3040	73.7	2130	1440	6.27	3200	76.7	10.25	48.22
	6.82	3320	80.5	2160	1560	7.33	3440	84.2	11.48	55.44
	7.92	3560	87.2	2160	1670	8.53	3720	92.5	12.71	66.47
	9.14	3880	97.7	2210	1820	9.73	4040	103	13.94	80.42
	10.34	4160	106	2220	1970	10.93	4320	109	15.17	90.53
	11.59	4480	112	2180	2070	12.15	4640	115	16.4	101.31
	12.74	4800	116.5	2150	2130	13.33	4920	118	16.81	112.36
	13.93	5080	118	2130	2140	14.53	5200	116.5	16.81	116.64
	15.14	5320	115	2100	2150	15.73	5440	114.3	16.4	119.86
	16.23	5520	113.5	2060	2200	16.95	5640	111.3	15.99	119.42
	17.52	5760	106.8	2020	2000	18.05	5800	105.3	15.17	115.58
	18.65	5880	104.5	2000	1980	19.22	5960	105.3	15.58	120.14
	19.72	6040	104.5	1980	1980	20.24	6080	104.5	15.58	123.11
	20.84	6160	103.8	1950	1980	21.45	6200	103.8	15.17	122.89
	22.09	6240	103	1940	1970	22.7	6320	103	15.17	124.94
	23.23	6360	102.3	1920	1960	23.84	6280	18	2.46	7.69

 

[Feel]

Have you got a 118 log?

 

[PhilW]

I was just gonna ask for that.

I'd ignore your MAF figures tho as it hasnt been scaled and you're seeing good A/F figures, which i had a check with on the A/F ration calculator as a guide.

 

[Cupra_Jeff]

yer i need to get some 118 logs, thats wastegate duty is it ? what kind of figures should I be expecting to see there ?

Would this MAF scaling issue account for the major lag that I’m seeing ?

I.e if the ECU only thinks its getting 125g/s would it adversely affect the boost delivery ??

 

[Feel]

I think if that was the case, you'd have a problem throughout the rev range.

Anyway, I think the MAF element itself is the same, a 3" MAF Tube would cause it to under-read, but then you'd just have fuelling issues.

If you suspect the MAF, or scaling issues, try unplugging it

It might jsut be a physical restriction, duff wastegate or badly adjusted actuator. I take it it's a new turbo?
Is it still running stage 2 or have you gone to stage 3?

 

[PhilW]

I reckon 118 will let you know what the score is.



Also, what TIP, filter etc... are you using?

 

[Martyn]

Jeff, have you reset the ECU and done a TBA? Are you getting 100% throttle?

Like the others say a 118 log will tell us what the N75/WG is doing. Are you still running the N75J?

 

[Cupra_Jeff]

I reckon 118 will let you know what the score is.



Also, what TIP, filter etc... are you using?

Will do a 118 log tonight ... i'm using the ATP 3" inlet which relocates the gear shift linkage and the cheapo filter that it came with.... was planning on seeing how much room i've got and getting a green or similar filter.

 

[Cupra_Jeff]

Jeff, have you reset the ECU and done a TBA? Are you getting 100% throttle?

Like the others say a 118 log will tell us what the N75/WG is doing. Are you still running the N75J?

I tried doing a TBA but not resetting the ECU, do i just disconnect the battery for a bit to do this....

Still running the N75J yes, was considering running an Apexi or Blitz boost controller, but overboost is the least of my worries right now !!

Persumably its not the A&M exhaust manifold as the turbo is designed to be put on a stock car in its most basic form, also didn't you have reasonable results with the mani when you had the car Martyn ??

Also how do i check if i'm getting 100% throttle ? ?

 

[Martyn]

Yup, leave it off for 10-15 mins mate. Then do the TBA after with vag-com.

The manifold will be fine mate, my WG duty was lower than most K03s cars and my Revo settings were maxed so it was clearly doing something!

Your issue sounds like the WG isnt being slammed shut at low revs hence the boost is taking a while to build. Chop chop with the 118 log

 

[PhilW]

Wastegate cranking time i reckon.

 

[cupra_matt]

I reckon its the N75 as it doesn't work very well with this turbo.

The actuator on the GT2X is preset at approx 1 BAR were as K03/s is approx 4 - 5 PSI.

Mine is on full boost at approx 3500 ish.

I have my old Forge manual boost controller lying about somewhere if you wanna try it.

My MAF logs are useless too, alot less than my K03s so i wouldn't worry too much about this.

How did they get the 3" ATP TIP in, i was told it was no good for the ibiza.?

 

[Cupra_Jeff]

right got out and did some playing around, it appears you were right martyn, when I undid the actuator arm the wastegate appeared to stick and not close up properly.... so I readjusted it and tightend it up.

It now seems to spool a lot better and is a lot less laggy on the road, although when i logged it doesn't really back this up and it only seems slightly better than before and still not reaching requested boost till 4,750 rpm.

Is it worth resetting the ECU and doing TBA through VAGCOM and let the ECU adapt to the different wastegate settings ?

The wastegate duty backs this up and shows 100%

Monday	21	May	2007	19:01:08					
6K0 906 032 AA 		1.8L 20VT EU3       0002							
									
	Group A:	'118				Group B:	 Not Running		
		RPM	Temperature	Load	Absolute Pres.				
	TIME					TIME			
MARKER	STAMP	 /min	°C	%	 mbar	STAMP			
	0	1880	35	0	1030				
	0.54	1920	35	0	1030				
	1.12	1960	34	100	1050				
	1.72	2040	33	100	1110				
	2.26	2080	32	100	1150				
	2.92	2160	31	100	1190				
	3.52	2280	30	100	1230				
	4.12	2360	30	100	1260				
	4.72	2440	30	100	1290				
	5.34	2560	30	100	1320				
	5.93	2640	29	100	1340				
	6.52	2760	29	100	1360				
	7.12	2840	29	100	1380				
	7.78	2960	28	100	1410				
	8.37	3080	28	100	1450				
	8.94	3160	29	100	1500				
	9.52	3280	29	100	1550				
	10.03	3400	29	100	1610				
	10.61	3520	29	100	1670				
	11.21	3680	29	100	1750				
	11.74	3760	30	100	1820				
	12.31	3920	30	100	1910				
	12.82	4040	30	100	1960				
	13.53	4200	31	100	2020				
	14.13	4360	32	100	2070				
	14.73	4520	32	100	2110				
	15.33	4680	33	100	2140				
	15.93	4840	34	100	2170				
	16.53	5000	34	99.2	2180				
	17.13	5120	36	96.5	2210				
	17.72	5280	36	91.8	2220				
	18.33	5400	37	85.1	2220				
	18.98	5480	38	80.4	2170				
	19.56	5600	39	78.8	2120				
	20.13	5720	39	76.9	2090				
	20.72	5800	39	76.5	2030				
	21.22	5880	39	76.1	2000				
	21.82	5960	40	75.7	2000				
	22.42	6040	41	75.7	2010				
	23.04	6120	42	75.3	2000				
	23.62	6160	42	74.1	2010				
	24.35	6200	43	72.9	2000				
	24.94	6280	44	71.4	2000

 

[Cupra_Jeff]

How did they get the 3" ATP TIP in, i was told it was no good for the ibiza.?

The 3" inlet went in apparently with a little persuation and an angle grinder to the gearbox housing !

 

[Martyn]

Reset the ECU and then go play mate, after a few miles it should start pulling like a train. The WG duty is all over the place due to the sticking actuator.

 

[cupra_matt]

I still dont think it it will much good on N75, when i plug mine in the boost pressure is all over the place and the car runs like a bag of crap.

Manual boost controller works ok, but apexi is the bollocks, mine now runs 1.4 BAR and pulls very very hard hold ing 1.4 BAR to the redline.