# N75 J Install and Review....



## Jedi20VT (May 18, 2003)

*N75 J Installation, Write-Up and Review....*

So my stock "F" valve was giving my wastegate fits with APR 91 V2, and I was experiencing extremely noticable surging in almost every gear, except at WOT. This had been occurring since the day I got the software loaded, and I had been on the lookout for a solution since.
While trolling in the archives a few weeks ago, I started reading up on a few different topics, one of them being N75 swaps. I couldn't decide which one would be best for my application, the H or the J valve, so I decided to go with the J valve first to see if it helped. I figured that if it didn't work out, I could always sell it to another Vortexer who needed it, or trade it for an H valve without too much hassle. I have a friend at a local stealership, so I got the J valve ordered on the cheap, and got it yesterday afternoon.
In my journeys through the archives, I never actually found a decent write up on the J valve install, and since it is a bit different than the stock valves and the H valve, I figured I would fire up the digi and take a few pics to help my Vortex brethren in their future N75 adventures. Enjoy!

Make sure you disconnect the negative terminal from your battery before attempting this. This allows the ECU to reset all stored adaptation blocks, and will essentially force it to adapt to the new N75 and boost curves.
Here is a pic of the N75 J right after I opened the package. Notice the part number, 034-906-283 J.








Here is a pic comparing the two valves. Notice how the J valve is backwards, with the electrical connector facing the _opposite_ direction compared to the F. This means that when installed correctly, the J will have the electrical connector facing the _rear_ of the car.








In this pic, you can see from a different angle the differences between the two valves. 








Here is a pic of the stock "F" valve on my 2003 AWP Jetta. Notice how the electrical connector plugs in towards the front of the car, and how the hoses connect. The top hose goes to the wastegate, the side hose goes the charge pipe behind the engine, and the bottom goes into the intake hose after the MAF sensor.








Here is the F valve from a slightly different angle.








After cutting / removing the factory one-use clamps, I replaced the F with the J, and secured the hoses with hose clamps. Some people use zip ties to do this, but with my turbo pushing 18-20psi, I wasn't taking any chances.









Here you can see how the electrical connector on the J faces the other way. I had to run the wires under the intake hose in order for it to reach. You should have just barely enough wire to reach, but it will get there.








Here is the finished install, and how it should look if done correctly.









After installing the J, which took about 15 minutes, I waited an additional 30 minutes or so to make sure that the ECU was reset. 
After I reconnected the negative terminal, I did a Throttle Body Adaptation, and started the car. It fired right up with no CEL's & no drama!















I took it for a spirited drive down the street, and immediately noticed the folllowing: My boost spools quicker, I have absolutely no surging in any gear, and I hold peak boost (20psi) for a little longer before settling to 17psi or so. 4th and 5th gear are where the differences are most noticable, however, with boost holding much higher in both gears waaaaay up into the rev range. 5th gets scary after 4000 rpm or so, it just puuuuuuuullllls.
http://****************.com/smile/emthup.gif







http://****************.com/smile/emthup.gif








For me, this mod was well worth the $50 that I paid for the valve, and made a noticeable difference. I will be putting on a custom 3" CB exhaust next week, and will make sure to post up if my car freaks out after that. For now it is perfect!
_Modified by Jedi20VT at 9:35 AM 1-14-2004_


_Modified by Jedi20VT at 11:48 PM 1-14-2004_


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## Nonlinear Optics (May 14, 2003)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*

Good stuff.
Let us know how it works in 2-3 weeks (part throttle surging).
Thanks.


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## JettaRed (Aug 14, 2000)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*

Yes, the J valve does face "backwards". Your findings are consistent with mine--the F valve sux above 15 psi and the J/H are consistent and smoother in their boost climb rate. The only difference that I have found is that the H valve will peak at 22-23 psi and is more likely to cause limp mode. 
The other _only_ difference







is that the H valve _feels_ a little stronger than the J. Either it rises slightly more quickly or.... I dunno.







It just feels a little stronger until you hit limp.


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## 3wheelinWolf (Mar 25, 2002)

*Re: N75 J Installation, Write-Up and Review.... (JettaRed)*


_Quote, originally posted by *JettaRed* »_Yes, the J valve does face "backwards". Your findings are consistent with mine--the F valve sux above 15 psi and the J/H are consistent and smoother in their boost climb rate. The only difference that I have found is that the H valve will peak at 22-23 psi and is more likely to cause limp mode. 
The other _only_ difference







is that the H valve _feels_ a little stronger than the J. Either it rises slightly more quickly or.... I dunno.







It just feels a little stronger until you hit limp.









I'm not trying to hijack, but I'd like more info. How do you know what N75 you have? And which valve is morea agreeable with an AWW with a boostvalve? 
Thanks for the write-up, I'll be using this in the future.


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## SILVERWOLFE03 (Jul 31, 2003)

*Re: N75 J Installation, Write-Up and Review.... (3wheelinWolf)*

look on the valve itself and the last prefix of the part #
either C , F , H , or J
the C & F valves start with 056 908 283
the H & J valves start with 034 906 283


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## Jedi20VT (May 18, 2003)

*Re: N75 J Installation, Write-Up and Review.... (SILVERWOLFE03)*

Bump


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## GTIKunst (Jul 6, 2003)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*

I predict Limp mode in the near future for you. Good luck.


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## 3wheelinWolf (Mar 25, 2002)

*Re: N75 J Installation, Write-Up and Review.... (GTIKunst)*


_Quote, originally posted by *GTIKunst* »_I predict Limp mode in the near future for you. Good luck.

Wow..nice prediction..50/50 odds. LOL
Ok...any word so far. I just read JettaRed's thread, and he felt the J was less agressive (spike) with his revo vs. the H. Are you getting the same findings?


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## exS4 (Nov 8, 2002)

*Re: N75 J Installation, Write-Up and Review.... (GTIKunst)*

"I predict Limp mode in the near future for you. Good luck"
In Old Testiment Dayz, those who make predictions that turn-out to be wrong, would get dragged-out the gates of the city, and stoned to death!
See here's to hoping that you're right!


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## JettaRed (Aug 14, 2000)

*Re: N75 J Installation, Write-Up and Review.... (exS4)*


_Quote, originally posted by *exS4* »_
In Old Testiment Dayz, those who make predictions that turn-out to be wrong, would get dragged-out the gates of the city, and stoned to death!
See here's to hoping that you're right!









Only if they claimed to be prophets of God. If you practiced divination, you'd get stoned whether you were right or not!


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## exS4 (Nov 8, 2002)

*Re: N75 J Installation, Write-Up and Review.... (JettaRed)*

Either way, they got Stoned! 
As that Jewish Scholar Bob Dylan once said "Everybody must get stoned!"


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## Jedi20VT (May 18, 2003)

*Re: N75 J Installation, Write-Up and Review.... (exS4)*

Ok, here's an update on my situation. I have APR 91 DPP w/ stock exhaust. The J valve was working awesome for a day or two, but on a spirited freeway drive yesterday, I was cursed with a visit from the feared and much-hated limp mode fairies. I was spiking 21 in 4th and 5th, and was settling at a solid 18, until I got into town and turned off the car. As soon as I turned it back on, I was spiking 10-11 for the rest of the day.






















I reset the ECU, put the F valve back in , and everything is bueno for now. I really liked the way the car behaved with the J valve in , so I think I will try the Boostvalve.com overboost kit to prevent the higher spikes which are sending me into limp........*sigh* 
This never ends, does it? More power, more money.....


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## GTI Rennfahrer (Jul 10, 2003)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*

I think you should wait untill you get your exhaust on to screw around further with the N75s. The exhaust has a profound effect. Many people have had no problems untill they get their exhaust on and the hit limp.
You said you hit 10-11 psi... I thought limp was 5psi?
I think you should get your exhaust on and see how the car behaves with the different N75s. Then, if you are still having problems, get the overboost kit.


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## Nonlinear Optics (May 14, 2003)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*


_Quote, originally posted by *Jedi20VT* »_Ok, here's an update on my situation. I have APR 91 DPP w/ stock exhaust. The J valve was working awesome for a day or two, but on a spirited freeway drive yesterday, I was cursed with a visit from the feared and much-hated limp mode fairies. I was spiking 21 in 4th and 5th, and was settling at a solid 18, until I got into town and turned off the car. As soon as I turned it back on, I was spiking 10-11 for the rest of the day.






















I reset the ECU, put the F valve back in , and everything is bueno for now. I really liked the way the car behaved with the J valve in , so I think I will try the Boostvalve.com overboost kit to prevent the higher spikes which are sending me into limp........*sigh* 
This never ends, does it? More power, more money.....

What you report doesn't seem normal for the J-valve. The worst case of true limp mode (with an operational N75 and nothing else causing the problem) goes away after stopping and restarting the car.
Usually the J-valve acts best after a TBA (your ECU reset trick). It then degrades slowly but surely from there (at least on my car).
Glad you reported back.


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## Jedi20VT (May 18, 2003)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*

It didn't feel like limp mode to me either, as the car still pulled pretty well. (Felt like a stock 1.8T) The turbo would just not push more than 11psi, period. I am still troubleshooting what the problem was, but I expect it was ECU related, as resetting it and doing a TBA solved the problem. 
I am going to throw my J valve back in tonight and see what I can come up with. I will let everyone know how it goes.


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## 099-RBN (Jan 8, 2004)

*Re: N75 J Installation, Write-Up and Review.... (Jedi20VT)*

You mentioned that you bypassed the N249 solenoid, did you notice any difference in how your DV behaved?


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## Kendrick 337 (Dec 29, 2004)

*Re: N75 J Installation, Write-Up and Review.... (099-RBN)*

UN-achives by me cuz i just bought a n N75J and used the post to install it, great review / diy http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif http://****************.com/smile/emthup.gif


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## JettaManDan (Feb 7, 2001)

*Re: N75 J Installation, Write-Up and Review.... (Kendrick 337)*

I have the J on my GLI (SEE MODS BELOW) and while i have had no CEL'S or limp mode..i do have part throttle surging....in every gear..WOT is good and 21 PSI smoothe spikes....but the part throttle surging sucks..with my loud exhaust it's VERY noticeable.....wonder if anyone else has had this and tried another valve with better results? 
Dan


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## TurboPGT (Apr 23, 2005)

how was your car behaving with GIAC X+ and the stock n75?


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## jrs02gti (Apr 13, 2005)

*Re: N75 J Installation, Write-Up and Review.... (JettaManDan)*

i think mine is upside down because my connector is the same as the factory.








i have the n75 race from ecs is this the same thing???










_Modified by jrs02gti at 1:14 PM 6-9-2005_


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## ruso (Jul 29, 2004)

*Re: N75 J Installation, Write-Up and Review.... (GTIKunst)*


_Quote, originally posted by *GTIKunst* »_I predict Limp mode in the near future for you. Good luck.

I've been running the "J" valve for over 2 years now. In the history of owning my car, I have yet to hit limp mode or any form of soft limp mode. I've never had any part throttle surging with the "J" valve as well. With the "J" valve, in conjunction with my APR 93 software, I spike between 20-21 psi and hold between 15-17 psi. tapering off to about 10 or so psi near redline. http://****************.com/smile/emthup.gif


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## placenta (Jun 3, 2003)

i find that my J starts feeling better.. but that nice peak soon tapers down as car adjusts.. if it would just stay there, then i'd love it.


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## TONE1000R (Oct 31, 2004)

*Re: (placenta)*

someday I will be chipped and will need this info.


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## jrs02gti (Apr 13, 2005)

*Re: N75 J Installation, Write-Up and Review.... (jrs02gti)*


_Quote, originally posted by *jrs02gti* »_i think mine is upside down because my connector is the same as the factory.








i have the n75 race from ecs is this the same thing???









_Modified by jrs02gti at 1:14 PM 6-9-2005_


someone help me out.


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## ruso (Jul 29, 2004)

*Re: N75 J Installation, Write-Up and Review.... (jrs02gti)*

The ECS and the "J" are not the same thing. You'd know if it was installed backwards. http://****************.com/smile/emthup.gif


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## rstenros (Oct 27, 2003)

*Re: N75 J Installation, Write-Up and Review.... (ruso)*

my car with x+ and stock n75 surges bad between 16-21 psi at WOT


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## JettaManDan (Feb 7, 2001)

*Re: N75 J Installation, Write-Up and Review.... (rstenros)*

my car with APR 93 - 2.5 TB - And hyperboost surges at low throttle settings with my "J"valve...smoothes out at WOT and spikes at 21 PSI...wondering what the deal is...


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## 1turbo8 (Oct 24, 2004)

*Re: N75 J Installation, Write-Up and Review....*

Why is it that i get the limp mode when i start my car in the morning and to get ride of the limp mode i have to turn off my car, start it back up then no more limp mode.
and i do have the j valve...
help me


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## jrs02gti (Apr 13, 2005)

*Re: N75 J Installation, Write-Up and Review.... (ruso)*


_Quote, originally posted by *ruso* »_The ECS and the "J" are not the same thing. You'd know if it was installed backwards. http://****************.com/smile/emthup.gif 

i check it and its in right. is the j better than the race???


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## JettaGLI18t (Jun 28, 2004)

*Re: N75 J Installation, Write-Up and Review.... (jrs02gti)*

I just threw the J on my car with the X+ and I am still getting some surging. What do you guys recommend for me?
Try the H (race) valve?


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## Slapahoe (Sep 22, 2004)

very informitive thread.
ROCK THE BUMP.


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## Slapahoe (Sep 22, 2004)

Another problem could be your DV? maybe? I know the stock DV's have a weak spring and when people throw in a nice 007 Forge they eliminate their problems. I have one but it has the weaker spring in it. But you can buy them from Forge.


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## ZinK (Aug 6, 2001)

*Re: N75 J Installation, Write-Up and Review.... (JettaManDan)*


_Quote, originally posted by *JettaManDan* »_I have the J on my GLI (SEE MODS BELOW) and while i have had no CEL'S or limp mode..i do have part throttle surging....in every gear..WOT is good and 21 PSI smoothe spikes....but the part throttle surging sucks..with my loud exhaust it's VERY noticeable.....wonder if anyone else has had this and tried another valve with better results? 
Dan

I had the very same thing with my J so I put my F in for winter, along with the stock 710N (DV).
This spring I put the J back in and so far i do not get partial trottle surging. I would try the J with a stock DV and see what happens.
Dave


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## sounrealx (Apr 4, 2007)

*Re: N75 J Installation, Write-Up and Review.... (ZinK)*

i just installed the a n75 j valve in my awd 1.8t, had it backwards at first ( since it's supposed to be mounted the other way) and thought it didn't like my car, but it completely eliminated my surging issues with my n75C (stock) valve.


_Modified by sounrealx at 7:47 PM 6-9-2008_


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## Rav_VW (Apr 2, 2005)

Using the J eliminiated boost oscilation I got at WOT. Didn't notice too much difference other than that. Never tried the H though.


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## Audi TT 2003 (Jul 8, 2012)

*Hi! I need help resetting the ECU*

Hi! I am trying to install the N75J on my Audi TT. After It was installed the boost doesnt go up from 25psi. I read your instructions and it says that i will have to re-set the ECU. Can you please tell me how to re-set it?

Thanks!


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## All_Euro (Jul 20, 2008)

Audi TT 2003 said:


> Hi! I am trying to install the N75J on my Audi TT. After It was installed the boost doesnt go up from 25psi. I read your instructions and it says that i will have to re-set the ECU. Can you please tell me how to re-set it?
> 
> Thanks!


Just unhook the battery for a min. :thumbup:


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