Am I correct in assuming that if I get a 3-post MBC I can cap one of the side lines

Hal_TT::CBP · 02-26-2006, 07:07 AM

to run it in parallel with my N75? Looking at a Forge 3 post currently. TIA.

PSmalls::DoggieStyle · 02-26-2006, 07:55 AM

and N75 electronically plugged in.

C'mon Hal, you know this.

Turning your "normal" stage 3 into a science project, eh? ;p

Hal_TT::CBP · 02-26-2006, 07:59 AM

Adding a protection "feature" mostly in case my N75 poops again. Running 710Ns at high spikes is proving to be a no-no.

Mike2kS4 · 02-26-2006, 10:19 AM

When an N75 fails it *should* revert to stock boost, ~8psi on my car. I'd think adding complexity to the boost-control system would invite even more potential for failure, no?

Please elaborate on the 710N comment.

DAP@EPL · 02-26-2006, 10:49 AM

~4psi of the wastegate spring (unless they've been adjusted).

I think Hal is more concerned with the N75 becoming wonky and leading to boost spiking issues.

-Dave Pramanik

Hal_TT::CBP · 02-26-2006, 10:58 AM

N75's seem to lose control of the ramp mostly, making boost control irracic at best and allowing spiking on WOT in lower gears. My "bad" valve would allow boost(running the APR "stock levels" program on K04s) to rise to 1.1B and then it would ping-pong with TC a bit until the act got closer to the req. Running it on the 93 code just caused that 1.8B WOT spike in 3rd and 4th that would eventually come back down to ~1.5-1.6B fluctuating. Not normal behavior on this code. Programmed duty cycles seem to remain as before, the valve just can't follow or keep up, or is stuck, unsure of the mechanical issue with it.

Replacing the N75 on mine has solved the irratic behavior/spiking however every time the DTCs/ECU is cleared you go through that learning curve again and I'll see a 1.7B spike once or twice until the ECU adapts. Then its back to the initial 1.6B spike with immediate taper to 1.4B just as programmed... and thats the concern I have with the 710Ns, rated to a 1.6B sustained level iirc. Blew one up with the bad N75 spiking earlier and since I plan to stay on these valves I'd like a cap at 1.6B with a MBC vs taking the chance of ripping another and possibly having other damage.

Hal_TT::CBP · 02-26-2006, 10:59 AM

Mike2kS4 · 02-26-2006, 11:02 AM

Didn't know what pressure it was though. My car it's ~9.5psi.

It's not worth worrying about, especially since I'm fairly certain you can't hurt much even if you get a pretty massive spike on a fully-fueled K04.

DAP@EPL · 02-26-2006, 11:07 AM

Mike2kS4 · 02-26-2006, 11:09 AM

I wouldn't try to band-aid that with an MBC until you find it. Maybe a leak in your boost control circuit? I'm not a fan of adding complexity to a system that should be effective by itself.

I've run 710N's to 2.1bar with no issues. I now run 1.7 bar sustained and 1.85 in the midrange. I've never killed one, ever. I replaced two as PM but they were perfectly fine.

02-26-2006, 07:07 AM	#1
Hal_TT::CBP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 9,755	Am I correct in assuming that if I get a 3-post MBC I can cap one of the side lines to run it in parallel with my N75? Looking at a Forge 3 post currently. TIA. __________________ Hal. My German car history... '11 S4 Premium +, 6sp, Ti, Nappa, Carbon, SportDiff, B/O, Nav/Park current Audi '01.5 S4 Shizzle #3 ... purchased 09/03/10, Nogaro/Blue Sport '10 Dodge DS Gen4 Ram 1500(designed by Germans lol) '03 TT 225QC ... sold 09/23/10, Ocean/Sea '01.5 S4 APR Stg3 ... sold 09/10/08, Silver/Silver '01.5 S4 Ordered, Silver/Silver, Lemoned 5mos after purchase '00 996 Cab, Blk/Blk on Silver '98.5 A4 QMS Avant, Santorin/Ecru with blue trim '96 Jetta GLX VR6 '95 Jetta GLX VR6 '92 E36 Coupe - Lemoned 4mos after purchase

02-26-2006, 07:55 AM	#2
PSmalls::DoggieStyle Elder Member Garage is empty, add now Join Date: Jan 2004 Posts: 30,257	Regardless of parallel or solo setup, MBC only needs 2 lines on it. Leave ambient on N75.... and N75 electronically plugged in. C'mon Hal, you know this. Turning your "normal" stage 3 into a science project, eh? ;p

02-26-2006, 07:59 AM	#3
Hal_TT::CBP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 9,755	Well I am just too lazy to pipe the secondary side into the spider feed a'la N75... Adding a protection "feature" mostly in case my N75 poops again. Running 710Ns at high spikes is proving to be a no-no. __________________ Hal. My German car history... '11 S4 Premium +, 6sp, Ti, Nappa, Carbon, SportDiff, B/O, Nav/Park current Audi '01.5 S4 Shizzle #3 ... purchased 09/03/10, Nogaro/Blue Sport '10 Dodge DS Gen4 Ram 1500(designed by Germans lol) '03 TT 225QC ... sold 09/23/10, Ocean/Sea '01.5 S4 APR Stg3 ... sold 09/10/08, Silver/Silver '01.5 S4 Ordered, Silver/Silver, Lemoned 5mos after purchase '00 996 Cab, Blk/Blk on Silver '98.5 A4 QMS Avant, Santorin/Ecru with blue trim '96 Jetta GLX VR6 '95 Jetta GLX VR6 '92 E36 Coupe - Lemoned 4mos after purchase

02-26-2006, 10:19 AM	#4
Mike2kS4 AudiWorld Super User Garage is empty, add now Join Date: Jun 2002 Posts: 12,096	Not sure what you're trying to accomplish there Hal. When an N75 fails it should revert to stock boost, ~8psi on my car. I'd think adding complexity to the boost-control system would invite even more potential for failure, no? Please elaborate on the 710N comment. __________________ 2002 S4 Avant, 6spd. Bone stock. <a href="http://www.autospeed.us"> </a> Caveat: Any advice I express regarding potential tuning and such is purely informational. If your knowledge and abilities are not up to the task, no amount of advice can assist.

02-26-2006, 10:49 AM	#5
DAP@EPL Audiworld Sponsor Garage is empty, add now Join Date: Jun 2000 Posts: 19,700	If the N75 fails electrically, it'll revert to open to wastegate (aka limp mode)... ~4psi of the wastegate spring (unless they've been adjusted). I think Hal is more concerned with the N75 becoming wonky and leading to boost spiking issues. -Dave Pramanik __________________

02-26-2006, 10:58 AM	#6
Hal_TT::CBP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 9,755	They don't in the few cases I've seen. Stock levels, uh no =-) N75's seem to lose control of the ramp mostly, making boost control irracic at best and allowing spiking on WOT in lower gears. My "bad" valve would allow boost(running the APR "stock levels" program on K04s) to rise to 1.1B and then it would ping-pong with TC a bit until the act got closer to the req. Running it on the 93 code just caused that 1.8B WOT spike in 3rd and 4th that would eventually come back down to ~1.5-1.6B fluctuating. Not normal behavior on this code. Programmed duty cycles seem to remain as before, the valve just can't follow or keep up, or is stuck, unsure of the mechanical issue with it. Replacing the N75 on mine has solved the irratic behavior/spiking however every time the DTCs/ECU is cleared you go through that learning curve again and I'll see a 1.7B spike once or twice until the ECU adapts. Then its back to the initial 1.6B spike with immediate taper to 1.4B just as programmed... and thats the concern I have with the 710Ns, rated to a 1.6B sustained level iirc. Blew one up with the bad N75 spiking earlier and since I plan to stay on these valves I'd like a cap at 1.6B with a MBC vs taking the chance of ripping another and possibly having other damage. __________________ Hal. My German car history... '11 S4 Premium +, 6sp, Ti, Nappa, Carbon, SportDiff, B/O, Nav/Park current Audi '01.5 S4 Shizzle #3 ... purchased 09/03/10, Nogaro/Blue Sport '10 Dodge DS Gen4 Ram 1500(designed by Germans lol) '03 TT 225QC ... sold 09/23/10, Ocean/Sea '01.5 S4 APR Stg3 ... sold 09/10/08, Silver/Silver '01.5 S4 Ordered, Silver/Silver, Lemoned 5mos after purchase '00 996 Cab, Blk/Blk on Silver '98.5 A4 QMS Avant, Santorin/Ecru with blue trim '96 Jetta GLX VR6 '95 Jetta GLX VR6 '92 E36 Coupe - Lemoned 4mos after purchase

02-26-2006, 10:59 AM	#7
Hal_TT::CBP AudiWorld Super User Garage is empty, add now Join Date: Mar 2000 Posts: 9,755	Maybe these have never failed in the ones I've seen. Certainly wonky lol. __________________ Hal. My German car history... '11 S4 Premium +, 6sp, Ti, Nappa, Carbon, SportDiff, B/O, Nav/Park current Audi '01.5 S4 Shizzle #3 ... purchased 09/03/10, Nogaro/Blue Sport '10 Dodge DS Gen4 Ram 1500(designed by Germans lol) '03 TT 225QC ... sold 09/23/10, Ocean/Sea '01.5 S4 APR Stg3 ... sold 09/10/08, Silver/Silver '01.5 S4 Ordered, Silver/Silver, Lemoned 5mos after purchase '00 996 Cab, Blk/Blk on Silver '98.5 A4 QMS Avant, Santorin/Ecru with blue trim '96 Jetta GLX VR6 '95 Jetta GLX VR6 '92 E36 Coupe - Lemoned 4mos after purchase

02-26-2006, 11:02 AM	#8
Mike2kS4 AudiWorld Super User Garage is empty, add now Join Date: Jun 2002 Posts: 12,096	Yea, that's what "stock boost" is usually defined as when referencing turbo circuits :P Didn't know what pressure it was though. My car it's ~9.5psi. It's not worth worrying about, especially since I'm fairly certain you can't hurt much even if you get a pretty massive spike on a fully-fueled K04. __________________ 2002 S4 Avant, 6spd. Bone stock. <a href="http://www.autospeed.us"> </a> Caveat: Any advice I express regarding potential tuning and such is purely informational. If your knowledge and abilities are not up to the task, no amount of advice can assist.

02-26-2006, 11:07 AM	#9
DAP@EPL Audiworld Sponsor Garage is empty, add now Join Date: Jun 2000 Posts: 19,700	Agreed. The K04s seem very robust and resilient... quite the opposite of the K03s. __________________

02-26-2006, 11:09 AM	#10
Mike2kS4 AudiWorld Super User Garage is empty, add now Join Date: Jun 2002 Posts: 12,096	There's something else wrong there Hal... I wouldn't try to band-aid that with an MBC until you find it. Maybe a leak in your boost control circuit? I'm not a fan of adding complexity to a system that should be effective by itself. I've run 710N's to 2.1bar with no issues. I now run 1.7 bar sustained and 1.85 in the midrange. I've never killed one, ever. I replaced two as PM but they were perfectly fine. __________________ 2002 S4 Avant, 6spd. Bone stock. <a href="http://www.autospeed.us"> </a> Caveat: Any advice I express regarding potential tuning and such is purely informational. If your knowledge and abilities are not up to the task, no amount of advice can assist.

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