[[email protected]]

APR was at ECS Tuning today, so I made the drive up (with a couple of other Vortexers

) to have my 337 chipped.
First of all, this is a fantastic mod. The car pulls amazingly through each gear and the power seems endless. It's a huge improvement over stock and well worth the money.
My only critique is that I experienced a fair amount of surging, especially in 5th and 6th gears. The surging was most noticeable at 1/2 throttle or when I would abruptly lay off the gas. So like a good little Vortexer, I hit the search function hard trying to find a solution.
Some of the posts I've read (like this one: http://forums.vwvortex.com/zerothread?id=354538) indicate that replacing the stock F N75 valve with an older C N75 valve has eliminated surging altogether in some applications. I have also read posts that indicate that the ECS Tuning N75 valve is another surge fixer.
Now the questions:
1) Would/should this N75 swap work on our 337s? I haven't read any posts from 337 drivers that have done the swap.
2) How difficult is it to replace the N75 valve? None of the posts I've read go into much detail about the job.
The surging issue is just one of those tradeoffs for more power, but I'd love to try and solve the problem if at all possible. Thanks for any help you can give.
http://****************.com/smile/emthup.gif


[Modified by Justin @ 3 Rivers VW, 11:10 PM 9-26-2002]

 

[Cdn'337]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Justin @ 3 Rivers VW)

Does APR not provide any service in regard to this issue?....since its their product causing the problem, they should provide a solution/fix. I'm sure they are asked about it quite a bit.

 

[[email protected]]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Cdn'337)

quote:[HR][/HR]Does APR not provide any service in regard to this issue?....since its their product causing the problem, they should provide a solution/fix. I'm sure they are asked about it quite a bit.[HR][/HR]​

I plan to ask APR and ECS Tuning, but since neither of them are open right now I thought I'd give the forum a shot. I'd rather go into tomorrow morning with a part number in hand that I need to order and a plan of action instead of having to make phone calls to two different companies to get the same answer.
If APR has been asked about the problem a lot like you say, then I'm sure that someone around here has been given the answer.

 

[Cdn'337]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Justin @ 3 Rivers VW)

You are very likely right.....unfortuneatly, i am not one of those people....best o luck.

 

[Mindflux]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Justin @ 3 Rivers VW)

quote:[HR][/HR]APR was at ECS Tuning today, so I made the drive up (with a couple of other Vortexers

) to have my 337 chipped.
First of all, this is a fantastic mod. The car pulls amazingly through each gear and the power seems endless. It's a huge improvement over stock and well worth the money.
My only critique is that I experienced a fair amount of surging, especially in 5th and 6th gears. The surging was most noticeable at 1/2 throttle or when I would abruptly lay off the gas. So like a good little Vortexer, I hit the search function hard trying to find a solution.
Some of the posts I've read (like this one: http://forums.vwvortex.com/zerothread?id=354538) indicate that replacing the stock F N75 valve with an older C N75 valve has eliminated surging altogether in some applications. I have also read posts that indicate that the ECS Tuning N75 valve is another surge fixer.
Now the questions:
1) Would/should this N75 swap work on our 337s? I haven't read any posts from 337 drivers that have done the swap.
2) How difficult is it to replace the N75 valve? None of the posts I've read go into much detail about the job.
The surging issue is just one of those tradeoffs for more power, but I'd love to try and solve the problem if at all possible. Thanks for any help you can give.
http://****************.com/smile/emthup.gif

[Modified by Justin @ 3 Rivers VW, 11:10 PM 9-26-2002][HR][/HR]​

Dude, you just got chipped, the let ECU re-adapt to your driving style, if it doesn't clear up in 72 hours give ECS or APR a ring (Monday really, so more like 96 hours)..

 

[[email protected]]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Mindflux)

quote:[HR][/HR]Dude, you just got chipped, the let ECU re-adapt to your driving style, if it doesn't clear up in 72 hours give ECS or APR a ring (Monday really, so more like 96 hours).. [HR][/HR]​

I have no problem being patient. But keep in mind that the drive home was almost 2 hours of both highway and stop & go traffic - around 120 miles in all from Cleveland to Pittsburgh. And 3 days of normal driving for me would probably only be half of that.
You're right, though...I should still probably give it a bit more time before I act. Thanks for the advice. I guess I was just a little excited from the drive home.

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

 

[ResistUnlearnDefy]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Justin @ 3 Rivers VW)

hey justin go to the 1.8t forum, there are a bunch of threads on surging and the n75 valve
good luck

 

[FrankiEBoneZ]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Justin @ 3 Rivers VW)

On the APR chip supposedly both of the valves ECS and "c" valve will help fix surging. A more sure surging fix is generally the "c" valve. ECS valve might work, but in some cases it doesn't, but that valve (ECS) also adds about 7+HP. If your not interested in getting a couple of extra HP, then go with the "c" valve. Its 50$ plus shipping at http://futrellautowerks.com/ . If it doesn't work, get the ECS valve, its 90$ bucks and can be found here http://www.ecstuning.com/ .
It wont be hard on your pocket really either. If it doesn't work, post it in the classifieds, those things walk like hot cakes! You might take a 20$ loss or something, but that aint that bad.
Also, if you talk to APR they might say trying a new DV. The one we have on the new 180HP AWP motors (337 motor) has an upgraded DV stock. Supposedly the same as the Audi TT. I dont think that would be your problem though. Try the 2 above valves, first the "c" if power isn't a concern now, otherwise try the ECS valve first. If it dont work, sell it in the classifieds and try the other one.
As far as installation goes, its easy. Take off the engine cover. There will be to valves by the back of the engine above the turbo. The one with the wires going into it is the N75 valve. It is the valve more to the right, directly next to your MAF. The valve next to the N75 on the left is your DV. The N75 is in between the MAF and DV.
Good luck!

 

[[email protected]]

Re: Questions about APR chips, surging, and replacing the N75 valve... (FrankiEBoneZ)

FrankiEBoneZ, you are THE MAN. That's exactly the kind of info I was looking for. Much obliged.
I still may opt to wait a few days, but I have my suspicions that the surging will be a permanent fixture unless the C valve works.
Thanks again! http://****************.com/smile/emthup.gif

 

[GammaRay27]

Re: Questions about APR chips, surging, and replacing the N75 valve... (Justin @ 3 Rivers VW)

I dont know for SURE, but I dont think the ECU "adapts" to driving style. As fas as I know, its a compurter program. Not artificial intelligence.

 

[icuravwnut2]

Re: Questions about APR chips, surging, and replacing the N75 valve... (GammaRay27)

Ummmm.....
Here goes......
As i see many of you are totally confused about the N75 valve (what it does, how is it working), just exactly as i was before digging myself into the topic quite deeply. My car was seriously down on power - i even posted some desperate topics here too, but noone was able to give me any usable suggestions/answers. At the end, i found that there was some problem with my N75 valve (though it was working OK) which prevented the car to produce more boost than stock.
So, if any of you has problems with the N75 valve - or just got problems but don't really know what is it related to, then read more further.
The turbo, the boost it produces, the N75 and the ECU.
These are the most important things which you have to focus on. As we know, we got a turbo on our engine which produces boost. The turbo is "driven" by the exhaust gasses our engine produces. Exhaust spools up the turbine in the turbo which is mounted on the same driveshaft as the compressor which then generates boost. I persume it is all clear for everybody.
There is a wastegate on our turbos (as usually on every turbo) which looks like a simple valve, just exactly like in the cylinderhead. There's a difference though, the valves in the head are operated by the cams, the valve (wastegate) in the turbo is operated by pressurized air. When pressurized air is introduced to the wastegate, it will open, enabling the exhaust gasses to escape and skip the turbo. This will result in a dramatical loss of boost, because there will be no gas which would spin the turbo. I bet this is (was) also clear for everybody.
But how is this all hooked up???
Quite simply. The wastegate is operated by the turbo itself. The boost the turbo produces is directly fed to its own wastegate. What does this mean? When the turbo spools up, it will create boost and this boost will open its own wastegate, shutting itself automatically down.
But where's boost control? And wheres ECU?
Here comes the N75 valve. The N75 valve is inserted between the turbo's high pressure output and the wastegate. If the turbo would directly linked to the wastegate, it would not be able to produce lets say more than 0.3-0.4 bar of boost, because it would shut itself down immediately. When the ECU wants more boost (because you are stepping on it for example), it WENTS some air from this loop (turbo--->wastegate) so the wastegate will not open at all, or will open later.
The N75 has got 1 boost input, and 2 outputs. At the input, boost is entering into the N75 and exits on one of the outputs going to the wastegate. When N75 is closed (default state), all the boost goes to the wastegate. When ECU opens the N75 valve (because it has got an electrical plug too coming from ECU), so when ECU opens it, some of this boost (which would operate the wastegate) is leaving/leaking back to the inlet (and not opening wastegate). Since the N75 valve has NO state in between, is is opened or closed. The ECU switches it ON/OFF all the time (several times a second) to generate the desired amount of boost. Doesn't it reminds you to something???? ... Yeah, it's surging. But it is absolutely normal, this is how ECU controls the wastegate. When a car is chipped, the boost is a LOT higher than it is designed to operate on, so this kind of boost control will be noticable.
By adjusting the N75 valve, you can adjust the amount of air which should leave when the N75 is opened. If you adjust the N75 to the right, you will "close" the N75 valve, so just a few amounts of air is wented from the wastegate which will result in a lot smoother drive (eliminating surging, because the boost will be more constant), BUT at the same time it will introduce more boost to the wastegate, causing LESS overall boost. Adjusting the N75 valve to the left will "open" it, enabling more air to escape from the wastegate when N75 is opened, which will result in more boost (coz wastegate wont open), BUT at the same time it MAY cause surging as the N75 opening/closing will be more obvious.