N75 help

[CupraJay]

Wondering if any1 can help me out.

Iv order'd an N75 J. It came and when i went to fit it tonight, its a different configuration to the standard one.

For example, on the standard valve, when the plug faces towards the front of the engine bay as it should, the Long pipe faces down, and the short pipe upwards.

Now the J valve is different. With the plug faces towards the front of the engine bay, the long pipe faces upwards, and short pipe downards.

I ponderd for a while, and thought id try it with the j plug towards the front, meaning the different length pipe would be in opposite places compared to the original.

Test drove it, and the boost didnt come in any earlia..id say it came in later...So im wondering was it fitted wrong. I have put the original back on for now.

It just means, for the lengthed pipes to match the original N75, then the plug would face towards the back of the engine bay.

Can any1 give me some advice on if it was fitted wrong ect.

 

[RobM]

Thought I'd bump this thread instead of creating a new one asking the same thing.

I've just fitted an N75 J and as described above, the pipe lengths are different to the standard N75. I've not driven the car yet, will be doing so in a little while, but I wonder if anybody knows if this different configuration will cause a problem?

I can't see how it would, as it's only the tube lengths that differ. And if you turned the N75 around so the lengths matched the layout of the original, the electrical connection would be on the opposite side.

Can anybody that has fitted an N75 J, or just knows what's-what, let us know if this is ok?

Ta

 

[jonathanp]

you need to install it the other way around, the pipe lengths need to match the original layout and this will mean the connector will be the on opposite side as you've said.

From memory you have the longer tube going into the TIP, shorter hose opposite goes to the wastegate and the other hose goes the charge pipe

 

[Big_daddy]

how common are the n75 to fail? whata re the signs for n75 failing? how much is a replacement?

 

[cordobabrendy]

stick to standard fellas, they really dont make any difference.
These runs were taken on my car same day with ecu resets before and after each run for a little more reliability figure wise. Also for what its worth, the c was left on afterwards for a run down the road and hit limp mode as the car was revo'd at the time.

n75J RR Run															
		Idle speed	Engine load	Inj. period	Air mass in		Idle speed	ECM Voltage	Coolant Temp	Intake Temp		Engine Speed	Engine Load	Spec. Boost	Actual Boost
	TIME	700-820 rpm	15-25%	2.0 - 4.0 ms	2.0-4.5 g/s	TIME	700-820 rpm	12-15V	80-110 C	-48-110C	TIME	700-6800 RPM	15-150%	990-1800 mbar	<=1800 mbar
	STAMP	 /min	%	 ms	 g/s	STAMP	 /min	 V	°C	°C	STAMP	 /min	%	 mbar	 mbar
	32.66	2520	77.4	8.16	43.58	32.96	2640	13.86	93	34	32.36	2480	43.6	990	970
	33.56	2920	133.1	11.22	81.69	33.86	3120	14	94	30	33.26	2800	115	2280	1350
	34.47	3560	182.7	16.66	129.11	34.77	3800	13.93	93	27	34.17	3360	172.9	2290	2050
	35.37	4320	177.4	17.34	145.06	35.67	4560	14	93	24	35.07	4080	183.5	2280	2240
	36.28	4960	163.9	17.34	154.44	36.59	5200	14	93	23	35.99	4800	167.7	2170	2030
	37.18	5560	151.1	16.32	160.14	37.49	5760	14	93	23	36.88	5400	154.9	2090	1840
	38.1	6080	139.8	14.62	162	38.4	6240	14	93	23	37.79	5920	143.6	1990	1760
	38.99	6520	130.8	13.94	163.61	39.3	6680	13.93	93	24	38.69	6400	134.6	1880	1680
	39.91	6760	12.8	1.36	0.47	40.2	6200	14.07	93	24	39.61	6800	127.8	1850	1640

N75C RR Run															

		Idle speed	Engine load	Inj. period	Air mass in		Idle speed	ECM Voltage	Coolant Temp	Intake Temp		Engine Speed	Engine Load	Spec. Boost	Actual Boost
	TIME	700-820 rpm	15-25%	2.0 - 4.0 ms	2.0-4.5 g/s	TIME	700-820 rpm	12-15V	80-110 C	-48-110C	TIME	700-6800 RPM	15-150%	990-1800 mbar	<=1800 mbar
	STAMP	 /min	%	 ms	 g/s	STAMP	 /min	 V	°C	°C	STAMP	 /min	%	 mbar	 mbar
	57.7	2720	16.5	1.7	8.17	58	2720	14.07	93	30	58.31	2720	34.6	1060	960
	58.61	2760	82.7	8.5	51.44	58.91	2880	14	93	30	59.21	3040	132.3	2270	1580
	59.51	3240	159.4	13.94	107.58	59.81	3480	14	93	27	60.12	3760	188	2280	2300
	60.42	4000	187.2	18.36	143.08	60.72	4240	14	93	24	61.02	4480	178.2	2210	2160
	61.32	4720	174.4	17	156.31	61.62	4960	13.86	93	23	61.94	5160	165.4	2130	1980
	62.34	5440	160.2	17	165.78	62.64	5600	13.79	93	22	62.93	5800	150.4	2000	1830
	63.23	5960	147.4	15.98	165.94	63.55	6160	13.93	93	23	63.84	6280	138.3	1890	1790
	64.15	6480	138.3	14.62	168.08	64.45	6600	13.93	93	23	64.75	6760	131.6	1860	1760
	65.05	6880	130.1	13.94	169.42	65.46	7040	13.93	93	24	65.76	7080	68.4	990	1720

when graphed against each other (the f is very similar to the c variant) the j isnt realy much different so isnt worth the effort in changing, especially if remapped as 9/10 remaps are done with standard valves in mind.

 

[Big_daddy]

Cheers for that

 

[jonathanp]

also worth bearing in mind if you do see a performance gain with a different N75 the ecu will adapt eventually and change the duty on the valve to match what a standard valve would normally give

 

[RobM]

also worth bearing in mind if you do see a performance gain with a different N75 the ecu will adapt eventually and change the duty on the valve to match what a standard valve would normally give

If that's the case, why are there different variants of N75? Surely if the ECU can control it, any changes per-car setup would be done there and all N75's would be the same?

 

[acidstrato]

because not all the other valves are intended for 1.8Ts or the same cars

 

[cordobabrendy]

they have different tolerances, ecu's adapt a certain amount, if they are already running off standard (say dodgey fuel and hot intake etc) a loopy n75 could tip the balance and throw error codes and limp mode.
Seriously dont bother changing, been there done that.

 

[DPJ]

Just to add my tuppenceworth.......

N75J + Revo = limp mode. I have RR plots to prove it. Stick to standard.

 

[RobM]

Just to add my tuppenceworth.......

N75J + Revo = limp mode. I have RR plots to prove it. Stick to standard.

Is this a proven point for everybodys LCR, or something that happened to yours only? Luckily I have both variants still so if there is a problem in the future, I'll swap them back over.

 

[acidstrato]

its happened to alot of people not just LCRs

i dont even get the big deal its not even that great of a mod? i didnt feel owt

 

[RobM]

its happened to alot of people not just LCRs

That's good to know, cheers

The reason I went for it, is I wanted to get a new one anyway just in case mine was shagged. And I went through a load of posts on this forum and some other VAG forums and I managed to find two opinions in the main: 1) It would help the car boost better and squeeze a little more performance out of it. Or, 2) it would make naff all difference.

So working on a worst case scenario of it making no difference, I thought why the hell not? If it performs the same as the standard one and I was going to buy a standard one anyway, then nothing lost. If it helps matters, even a little, then bonus

 

[cordobabrendy]

worst case scenario rob, is sureley that you think your own one is shagged (did you cehck it on vagcom?) if it is, you bought another valve that wont work terribly well (read: random limp mode) so now you will need to obtain another standard valve??? you will be out of pocket mate. WE are here to help not poo hoo everything!

 

[RobM]

worst case scenario rob, is sureley that you think your own one is shagged (did you cehck it on vagcom?) if it is, you bought another valve that wont work terribly well (read: random limp mode) so now you will need to obtain another standard valve??? you will be out of pocket mate. WE are here to help not poo hoo everything!

Yeah checked VAG-COM and it showed no errors directly pointing to the N75, but the error I did get was quite vague and could have been a number of things according to the searches I found.

 

[cordobabrendy]

best way to check your n75 is to have a run in say, 4th gear. Log your boost duty cycle (cant remember block off hand) when under gfull load it should be reading fairly high up towards 85-85% if its much less you probably have an issue there somewhere, probably better to borrow a mates for an hour to test than buy a new one until you know for definate.

 

[acidstrato]

block 118