View Full Version : Where to buy N75F...

12-19-2005, 10:23 PM
and how much are they? Thanks in advance. PS, I searched already and googled it.

12-19-2005, 10:26 PM
Why do you want an F? Aren't they the same thing as the stock C valve?

12-19-2005, 10:30 PM
Nope, here's a quote from another 2001 A4 owner:

Anyway I had purchased the N75F from badktty and threw it in just to try. Whoah! 20 PSI holds to 4800 RPM and then it slowly drops. That's a good 2-4 PSI more (depending on where in the RPM band). It drops off much less, and the slow boost build is gone! Went out on a long drive after putting the N75F in.. she's running strong!

and then again in a later post o the same thread:

Nope.. just swapped the F in for the C. Not getting throttle cut on my 2001. (when I tried the N75H, I was getting throttle cut all over due to overboosting)

12-19-2005, 10:48 PM
Try to look over on vortex, F valves come stock on GTI's / Jetta's.

12-20-2005, 04:40 AM
I think I had a brand new F somewhere in my garage

12-20-2005, 05:45 AM
I got my F from the dealer. I think it was around $60-$70

12-20-2005, 07:33 AM
Whoa, or try $92.03 from the dealer. Anyone got one for sale? Let me know, I'm in the market. PM me a price.

12-20-2005, 07:36 AM
I'll have to give it another look. Who knows where the hell I put that thing.

12-20-2005, 07:38 AM
Originally posted by BranCKY3
Why do you want an F? Aren't they the same thing as the stock C valve?

It's a newer N75 for the 1.8T. I still have no idea why anyone would want one.

These are all the ones I've ever seen out there:

034906283C - Oldest valve, A4 1.8T original
034906283F - Newer revision for 1.8T (maybe 170HP or TT 225)
034906283H - 1991/1992 ABY engine and AAN Engines in S4/S6
034906283J - 3B engine in early S2
034906283K - ADU and ABY engines in late S2 and RS2

The H, J and K versions seem to have the best "boost increase" effect.

The H is the same valve that ECS markets as their " N75 Race valve".

I've had a J for about 2 years now and it's very smooth. The K valve is supposedly as smooth as the J but, it spikes higher. I recall Dahlback using the K valve as a part in their upgrade kits for the 1.8T.

12-20-2005, 08:18 AM
I remember reading somewhere that leaving the N75 valve stock was the best ??

12-20-2005, 08:28 AM
I had the J installed for a while, but it gave me so much throttle cut that I put the stock C back in.The F should get me over the 15 psi mark without going past the horrible 21 psi mark. Let me know if you can find yours Evil, otherwise anyone know where to buy one?

12-20-2005, 08:33 AM
It really depends upon the combo of your program/turbo/etc..

My chip upgrades for the stock K03 respond better to the N75J than the N75C.

For example, my boost curve was all over the place with the C valve once I got chipped. I had a surge until 3500 and then a dip till 4000 and then another surge. The J valve made the boost curve nice and flat for me. Many APR and GIAC users have had the same effect too (this includes VW folks too).

Most programs are written for the C valve but, it just seems that the C valve's response time is too slow even when the ECU supplies a high duty cycle value. In addition, most chip tuners are not against the use of a different N75 as long as it doesn't cause a long lasting boost spike or limp mode. A GIAC X-chip would be a bad match for an upgraded N75 like the H, J or K.

12-20-2005, 08:43 AM
How well are the J's with a K04 and GIAC (MP_K01.03a), 5 Bar FPR?

12-20-2005, 09:35 AM
You asked me the same question in 2004...lol

Since BurntAudi answered you back then, I'll repost his answer:

Originally posted by Hassmeister
My car is a '98.5 ... how about the GIAC K04 Chip?? Too much, toowild??

Originally posted by Burntaudi

Hassmeister, I'm running the H valve on my car which is even more aggressive than the J valve. I would recommend it for your car.

I did a little research after I got my K04 in my car and what I found was.

J valve excellent for stock or chipped cars will hold 2-3psi of boost.

H valve excellent for K04 or larger turbo upgrades will hold 2-4 psi more boost. Not good for a chipped cars will posibly cause overboosting problems.

The N75 H valve is the same thing as what ECS sells as their N75 "race valve" like I said too aggressive for a chipped car.

As far as performance with the "C valve" I was seeing 18PSI spikes and holding at15-16PSI this was with GIAC K04 software.

Performance with the H valve in 75 degree weather 22PSI spikes in 1-3 gears holds at 18PSI spikes at 24-26 PSI in 4-5 gears did'nt see where it held since I backed off.


12-20-2005, 11:28 AM
All the "F" valves now supercede the "C" (discontinued from production) valves... or at least at all the VW/Audi dealerships I've gone too. The "C" (came on my 03) valve tends to be very slow and unresponsive. Switching to the "F", I actually lost about 1-2psi of boost during ramp up, but it was actually a good thing, for the "F" valve is a bit more responsive and made my powerband much smoother and linear. All I had to do is offset the boost response curve, and if I wanted to I could easily regain that 1-2psi by invoking the ECU to do so (it was doing it prematurely before). This was on a GT28RS though, of course...K03/04's is another story (I like the "J" for that as well).

12-20-2005, 11:29 AM
Daft, you don't have the stock S4 valve on that list, the B valve.

12-20-2005, 11:53 AM
Seems like I'm getting older. Thanks for the re-post. I needed that. Lost it.


12-20-2005, 03:08 PM
I just happened to dyno a couple weeks ago with the H(or ECS Race) valve and I boosted to 19psi. I normally boost between 17-19, depending on the weather. WHP and TQ numbers in my sig. My air/fuel ratio stayed at 11.9-12.0 from 3k rpms up to 6500, where I let off. If I can get my hands on a scanner, I'll post up the dyno graph but my hp and torque lines were nice and smooth along with my a/f ratio. So, IMO the H valve is not too aggressive for chipped cars but then again, every car will react differently to the different valves. I had the J in for a week and it boosted to 22psi and went into limp. The H-valve felt the same just peaked less boost and it eliminated the boost spike found in chipped cars. It just goes to 19 and stays there until ~4500 then it tapers down.

Hassmeister: Love your sig. Thank you for the support![:)]

12-20-2005, 11:43 PM
Thanks for all the info, but again, looking for a place to buy an F valve for cheaper than the stealership. Or if you have one sitting around PM me. The valve discussion has been gone over many times, I just need an F.

12-21-2005, 12:27 PM
Originally posted by pigliiit
Thanks for all the info, but again, looking for a place to buy an F valve for cheaper than the stealership. Or if you have one sitting around PM me. The valve discussion has been gone over many times, I just need an F.

You may want to try it at a VW dealership, which is typically 10-20% cheaper than the Audi stealerships on average. Same part number, etc, and is what's used on the MK4 GTI's and others in case they need to reference it to a car.

12-21-2005, 12:42 PM
check with www.worldimpex.com

They probably can get it for alot less than the dealerships. Otherwise, the VW dealership will be the best solution.