Wanted: N75 Boost Control Valve etc - Page 3

geneandbolly · 20-06-14, 12:18 PM

thanks chaps - i'll gingerly approach that cover and see if the fuses are in there and not a gigantic airbag that's going to burst in my face!! (just trying to think what crew are on day shift today . .

)

as for that bleed valve gizmo, do you reckon that they've had the ecu altered to accomodate this thing or should it be ok just to remove the section of hose that contains it and run it from there?

Error404 · 20-06-14, 02:54 PM

Remove that piece of shit bleed valve and replace the vacuum hose.
Send your ECU to PRJ for some proper software that will see you around 280 safe hp.

Andy10v · 20-06-14, 06:15 PM

It depends how its been done, I suspect somebody has just stuck in a boost valve to try and up the boost, or as a bodge to return the car to stock boost levels rather than fix it properly.

If it was a superchips setup then it would have a boost chip to allow higher boost, and a fuel chip to match, however they were done with a big waste gate spring wound down AFAIK.

Just remove the bleed valve, and rejoin the line with a barb or replace as required.

Once everything is back to stock I would see how the car goes, check for codes, and do a boost leak test.

If everything is ok and you want more power then best bang for buck is a stage 1 remap, about 280bhp from PRJ or spink. Be aware if everything is old and tired this will show any flaws in hoses, weak ignition etc.

The ecu will currently be having a spastic fit if boost is X percentage out from the boost is is requesting.

geneandbolly · 21-06-14, 03:07 AM

thanks for your comments, chaps - i'll get that hose off over the weekend and take it for a spin and see what's what. this is all a new experience, this turbo lark, so thanks for bearing with me!!

K Simmonds · 21-06-14, 07:53 AM

Good plan! Just remember to disconnect the battery for 1/2 an hour or so to clear any faults caused by the bleed valve, ie unhook the power before you start removing it.

As Andy says the best bang for buck with these motors is a good quality generic remap on a well maintained stock set up, you really can't go wrong for a couple of hundred quid. The next stages rapidly start to get expensive even if you can do the work yourself.

Another thing worth considering is the fitment of a boost gauge though I'm not sure if you may already have a digital one as a function of the on-board computer, it can tell you an awful lot at a glance.

geneandbolly · 21-06-14, 09:41 AM

Quote:

Originally Posted by K Simmonds

Good plan! Just remember to disconnect the battery for 1/2 an hour or so to clear any faults caused by the bleed valve, ie unhook the power before you start removing it.

As Andy says the best bang for buck with these motors is a good quality generic remap on a well maintained stock set up, you really can't go wrong for a couple of hundred quid. The next stages rapidly start to get expensive even if you can do the work yourself.

Another thing worth considering is the fitment of a boost gauge though I'm not sure if you may already have a digital one as a function of the on-board computer, it can tell you an awful lot at a glance.

thanks for that - i'll unhook the battery before i get started. i'm not sure about re-maps etc just at this stage - the power is more than enough for me right now!

geneandbolly · 21-06-14, 10:04 PM

so, after unplugging the battery to clear the ecu memory, i managed to get that weird valve/ hose combo off the turbo/ boost control valve with some persuading. the clip holding it on at the turbo end couldn't be persuaded with good old wd40 and had melded together from years of being fried by the turbo (where have i heard that tale recently??). airbox out for a better view . .

so with some help from the hacksaw it was off..

ever seen anything like this? >>

a new length of hose, minus that weird valve was cut and clipped back into place again . .

and the engine fired up to burn off all of the wd40 that had fallen on to the turbo!

so, that was that. next i checked that relay box and this is how it looks - is this normal? >>

and i checked all the fuses (yup they were there in that driver's end panel just like you said!) and they were all fine . .any idea where i can find a diagram of what fuse does what?

and last job of the afternoon was to fit a nice little cd player i got cheap on ebay . . sounds fabulous and goes nicely with the dash >>

so, i took the car out for a blast there and it feels like it's down on power now

the dash has a factory boost gauge in the computer display and i noted that at around 5000rpm the boost was at 1.9bar - is this normal? it certainly didn't feel like it was pulling as well as it was with the weirdo valve set up but also there was no missing on the climb through the rev range. just that the acceleration didn't feel as fast as before . .

any thoughts?? (ps sorry for the amateur night description of these things!

)

Andy10v · 21-06-14, 10:18 PM

1.9 bar on the stock gauge is absolute, including 1 bar atmospheric pressure, so you have 0.9 bar boost.

In overboost you should get about 2.15 absolute

SJM has a good 20vt page if you are not familiar with the setup and how motronic controls boost. It has a lot of common faults to check as well.

http://www.sjmautotechnik.com/troubl...ost.html#intro

I take it you are putting good fuel in it? No 95 rubbish?

Andy10v · 21-06-14, 10:19 PM

Boost graph from SJM

geneandbolly · 21-06-14, 11:00 PM

Quote:

Originally Posted by Andy10v

I take it you are putting good fuel in it? No 95 rubbish?

erm . . .

funny you should say that as i noticed what we used to call in the old ford days, "pinking" when i gave it full boot . . .

does it really make a huge difference? checked the s6 handbook and right enough, it does say to use the high octane stuff . .

20-06-14, 12:18 PM	#21
geneandbolly 4 ring whore! Classic Audi Club Member Join Date: Sep 2011 Location: The Psychiatric Ward, North Ayrshire Posts: 7,490	thanks chaps - i'll gingerly approach that cover and see if the fuses are in there and not a gigantic airbag that's going to burst in my face!! (just trying to think what crew are on day shift today . . ) as for that bleed valve gizmo, do you reckon that they've had the ecu altered to accomodate this thing or should it be ok just to remove the section of hose that contains it and run it from there? __________________ 1997 Audi S6 Ruby Red

20-06-14, 06:15 PM	#23
Andy10v Grown up member Classic Audi Club Member Join Date: Dec 2008 Location: Stirling Posts: 861	It depends how its been done, I suspect somebody has just stuck in a boost valve to try and up the boost, or as a bodge to return the car to stock boost levels rather than fix it properly. If it was a superchips setup then it would have a boost chip to allow higher boost, and a fuel chip to match, however they were done with a big waste gate spring wound down AFAIK. Just remove the bleed valve, and rejoin the line with a barb or replace as required. Once everything is back to stock I would see how the car goes, check for codes, and do a boost leak test. If everything is ok and you want more power then best bang for buck is a stage 1 remap, about 280bhp from PRJ or spink. Be aware if everything is old and tired this will show any flaws in hoses, weak ignition etc. The ecu will currently be having a spastic fit if boost is X percentage out from the boost is is requesting. __________________ 2005 350z GT Sold-1992 3B S2 coupe-RS2+, 996s, konis, forged rods, rear torsen.... Sold-1993 ABY coupe

21-06-14, 03:07 AM	#24
geneandbolly 4 ring whore! Classic Audi Club Member Join Date: Sep 2011 Location: The Psychiatric Ward, North Ayrshire Posts: 7,490	thanks for your comments, chaps - i'll get that hose off over the weekend and take it for a spin and see what's what. this is all a new experience, this turbo lark, so thanks for bearing with me!! __________________ 1997 Audi S6 Ruby Red

21-06-14, 10:04 PM	#27
geneandbolly 4 ring whore! Classic Audi Club Member Join Date: Sep 2011 Location: The Psychiatric Ward, North Ayrshire Posts: 7,490	so, after unplugging the battery to clear the ecu memory, i managed to get that weird valve/ hose combo off the turbo/ boost control valve with some persuading. the clip holding it on at the turbo end couldn't be persuaded with good old wd40 and had melded together from years of being fried by the turbo (where have i heard that tale recently??). airbox out for a better view . . so with some help from the hacksaw it was off.. ever seen anything like this? >> a new length of hose, minus that weird valve was cut and clipped back into place again . . and the engine fired up to burn off all of the wd40 that had fallen on to the turbo! so, that was that. next i checked that relay box and this is how it looks - is this normal? >> and i checked all the fuses (yup they were there in that driver's end panel just like you said!) and they were all fine . .any idea where i can find a diagram of what fuse does what? and last job of the afternoon was to fit a nice little cd player i got cheap on ebay . . sounds fabulous and goes nicely with the dash >> so, i took the car out for a blast there and it feels like it's *down* on power now the dash has a factory boost gauge in the computer display and i noted that at around 5000rpm the boost was at 1.9bar - is this normal? it certainly didn't feel like it was pulling as well as it was with the weirdo valve set up but also there was no missing on the climb through the rev range. just that the acceleration didn't feel as fast as before . . any thoughts?? (ps sorry for the amateur night description of these things! ) __________________ 1997 Audi S6 Ruby Red

21-06-14, 10:18 PM	#28
Andy10v Grown up member Classic Audi Club Member Join Date: Dec 2008 Location: Stirling Posts: 861	1.9 bar on the stock gauge is absolute, including 1 bar atmospheric pressure, so you have 0.9 bar boost. In overboost you should get about 2.15 absolute SJM has a good 20vt page if you are not familiar with the setup and how motronic controls boost. It has a lot of common faults to check as well. http://www.sjmautotechnik.com/troubl...ost.html#intro I take it you are putting good fuel in it? No 95 rubbish? __________________ 2005 350z GT Sold-1992 3B S2 coupe-RS2+, 996s, konis, forged rods, rear torsen.... Sold-1993 ABY coupe

20-06-14, 02:54 PM	#22
Error404 Thobbing Member Classic Audi Club Member Join Date: Sep 2008 Location: Staffs Posts: 490	Remove that piece of shit bleed valve and replace the vacuum hose. Send your ECU to PRJ for some proper software that will see you around 280 safe hp.

21-06-14, 07:53 AM	#25
K Simmonds Senior Member Classic Audi Club Member Join Date: Dec 2009 Location: Mid Wales Posts: 1,060	Good plan! Just remember to disconnect the battery for 1/2 an hour or so to clear any faults caused by the bleed valve, ie unhook the power before you start removing it. As Andy says the best bang for buck with these motors is a good quality generic remap on a well maintained stock set up, you really can't go wrong for a couple of hundred quid. The next stages rapidly start to get expensive even if you can do the work yourself. Another thing worth considering is the fitment of a boost gauge though I'm not sure if you may already have a digital one as a function of the on-board computer, it can tell you an awful lot at a glance.

21-06-14, 10:19 PM	#29
Andy10v Grown up member Classic Audi Club Member Join Date: Dec 2008 Location: Stirling Posts: 861	Boost graph from SJM __________________ 2005 350z GT Sold-1992 3B S2 coupe-RS2+, 996s, konis, forged rods, rear torsen.... Sold-1993 ABY coupe