back to stock N75...

**ScaryGary** · 09-11-2008 02:42 PM

After running the "J" style valve for about 8 months, I'm going back to the stock n75 valve. I liked the different powerband available from the J, but did not like the occasional limp mode and CEL.

......... So how do I put this thing back in???

I've searched for diagrams, but it seems that the pictures in the original threads are no longer available.

If anyone can help me differentiate between the two short connections on the valve, I'd appreciate it.

If you are looking at the valve with the plug opening facing you, and the long connection pointing to your left, where does the short hose connector, facing upward, go?

Deductive logic will allow me to figure out what the other short one is for!

Thanks

**ScaryGary** · 09-11-2008 03:47 PM

I put in the "F" valve, which I believe is now the stock part, and went for a drive....

The OEM part had a C stamped on it and I used that until about two months after going APR 1+. With that valve, I was consistently boosting 15-16psi, which I thought was slightly low for 1+, and heard that the J allowed for a slight increase of boost for most people.

I did move up to 16-17lbs with the J valve, and held more boost higher into the RPM range, but it obviously isn't intended for use in our cars.

With the F valve in today, the car was making 20-21psi and throttle modulation was much improved over the J valve, which would cause something to make a whining noise at about 5psi. With the J valve, it seemed as if you could only drive with full boost or no boost for the powerband to be smooth. Any attempt to precisely modulate the throttle, like cruise control does, would cause the whining noise and typically put the car into limp mode.

Hope this deters someone from using the J valve.

**widgget** · 09-11-2008 04:03 PM

I have the N75H, what is the delay difference between the different models (H, J, C, F)?

The H valve is marketed as the "Race" version that ECS tuning sells and is the one that people here told me to get for an upgrade when my stock one died.

**ScaryGary** · 09-11-2008 04:13 PM

delay difference?

You must mean the 1 minute delay for getting out of limp mode, and a 10 minute delay for clearing the CEL with VAG-COM.

So, in that case, the J has an 11 minute delay.
F and C seem to have no delay.

**widgget** · 09-11-2008 05:40 PM

No, the difference between the valves is the amount of time it stays open due to a delay built into it. the "race valves" from my understanding have a longer delay then the stock one which causes it to stay open longer which in turn makes the turbo run with the waste gate closed creating more spool and boost.

maybe i got it wrong, but why else would there be all the different versions, something is different between them.

**old guy** · 09-11-2008 06:02 PM

The difference between the various N75 valves is the reaction rate. In other words, it will take longer for it to react in both directions (longer to open and longer to close). The coil resistance is different between the different models thus changing the reaction times.

**b6onboost** · 09-11-2008 06:23 PM

widgget and oldguy both have it right. From OEM -> Race the delay to actuate the wastegate is increased. So you do grab a few lbs of boost and it seems to hold longer. the more delay the more on/off your throttle and boost feels.

Delay. Shortest to Longest

C/F (oem 1.8T F is the newer version)
J
K
H (Race)