Hooking up an abandoned JHM Boost Controller

[Ryes7]

Hi guys,

I’ll get to the point: Bought a sweet avant that is in overall pretty darn good shape. It does have a JHM boost controller that was ran through the firewall, but was either never hooked up or abandoned at some point.

I found one forum post from 2018 that says I will just need to connect it to either side on the N75 valve but leave the tube that goes to the PCV valve. Is this in fact the case? Attached is a photo of the unit in the engine bay.




Thanks - Sean

[Ryes7]

Came across this video, going to give her a shot tomorrow! Thanks.

https://www.youtube.com/watch?v=WB1W...5s&pp=2AEtkAIB

[LJS]

This should help
Check out post#13 here-
https://www.audizine.com/forum/showt...to-n75-results
FWIW-
A proper tune doesn't need a manual boost controller-this as been discussed at length

[CELison]

I wouldn’t be messing with that unless you have a wideband in the car at a minimum.

[Ryes7]

Thanks for the replies Accordingly to the guy I bought the car from, it has a JHM stage 2 tune. I hooked up the boost controller this AM before the replies and it made it even worse, I’m peaking at about 7 psi now, even when I swapped it back to the n75. Feeling way less power for sure. Hope I didn’t lose a turbo Looked for boost leaks but couldn’t find anything obvious, unfortunately. Kinda stumped. Going to eat a lot of food and forget about it for the day lol. Thanks team Happy T-day! - Sean

[Ryes7]

Got a smoke tester coming

[Ryes7]

Got a smoke tester coming

[Ryes7]

Update: Spent 2-3 hours today spraying soapy water on all the turbo/intake lines and joints I could find. Nothing showed. It sounds like it’s being electronically interrupted, if that makes sense. I hear a buzz/whirring when the power stops going and I no longer hear the turbos spooling. And the car becomes totally weak. Does this sound like limp mode? How does one get past limp mode, if that’s the case? Fixed a couple oil leaks on what looks like oil cooler lines at least while I was in and under there. Definitely pretty oily around the turbos too. No oil in the intake though.

[CELison]

You need VCDS. The Lite version is free and you can use a $20 cable to connect. ET Spec has them. Must have if you own a b5.

[Ryes7]

Thank you for the reply, is this the correct cable you’re referring to?

https://etspec.com/products/etspec-a...e7-flash-cable

After obtaining VCDS, what am I looking for, specifically? Thanks for understanding that I’m not as experienced in the B5 world. I appreciate your patience CELison.

I’m on the fence between getting the car running “normally”, with no leaks and enjoying it at its current pace. Or pulling the motor and putting in the rs6-rs turbos from JHM and going full send with new gaskets, seals, clutch, fuel system and all supporting mods. My rs7 is plenty fast but there’s something about the B5 that makes it a bit more special.

Hope you had a good Thanksgiving and are having a great weekend.

[Ryes7]

Ordered the cord per your recommendation CELison, thank you. It has shipped.

[Ryes7]

Got the cord, any advice on what to look for would be greatly appreciated. Thanks SV

[Ryes7]

Have also downloaded VCDS Lite - ready to rock

[CELison]

Start by just scanning for codes. If it’s in limo mode you’ll have some stored. I would check your fuel trims too.

[LJS]

You may find this helpful---snippets I've collected from knowledgeable forum posts.....

Long and short term fuel trims (LTFT/STFT) from VCDS group 32/33 respectively.
IDLE trim adaptation spec is +-5%. PARTIAL trim adaptation spec is +-10%.

Negative values indicate that the engine is running too rich and oxygen sensor
control is therefore making it more lean by reducing the amount of time that the
injectors are open. Positive values indicate that the engine is running too lean
and oxygen sensor control is therefore making it richer by increasing the amount
of time that the injectors are open.

"Add" means additive trim, which is addressing an imbalance at idle. When the ECU
is using additive trim, it is telling the injectors to stay open a fixed amount longer
or shorter. The malfunction (e.g. vacuum leak) becomes less significant as RPM increase.
For additive adaptation values, the injection timing is changed by a fixed amount.
This value is not dependent on the basic injection timing.

"Mult" mean multiplicative trim, which is addressing an imbalance at all engine speeds.
The malfunction (e.g. clogged injector) becomes more severe at increased RPM.
For multiplicative adaptation values, there is a percentage change in injection timing.
This change is dependent on the basic injection timing

If you have boost leak on the pressure side of the intake generally you
will see this as rich in boost, if it is pre turbo you will see lean conditions
If the car had a vacuum leak the fuel trims would be lean and the trim number at idle would be positive
PS--
CAM TIMING can be checked via Measuring Block 93---tolerance is generally accepted to be +/- 4 degrees

[Ryes7]

You may find this helpful---snippets I've collected from knowledgeable forum posts.....

Long and short term fuel trims (LTFT/STFT) from VCDS group 32/33 respectively.
IDLE trim adaptation spec is +-5%. PARTIAL trim adaptation spec is +-10%.

Negative values indicate that the engine is running too rich and oxygen sensor
control is therefore making it more lean by reducing the amount of time that the
injectors are open. Positive values indicate that the engine is running too lean
and oxygen sensor control is therefore making it richer by increasing the amount
of time that the injectors are open.

"Add" means additive trim, which is addressing an imbalance at idle. When the ECU
is using additive trim, it is telling the injectors to stay open a fixed amount longer
or shorter. The malfunction (e.g. vacuum leak) becomes less significant as RPM increase.
For additive adaptation values, the injection timing is changed by a fixed amount.
This value is not dependent on the basic injection timing.

"Mult" mean multiplicative trim, which is addressing an imbalance at all engine speeds.
The malfunction (e.g. clogged injector) becomes more severe at increased RPM.
For multiplicative adaptation values, there is a percentage change in injection timing.
This change is dependent on the basic injection timing

If you have boost leak on the pressure side of the intake generally you
will see this as rich in boost, if it is pre turbo you will see lean conditions
If the car had a vacuum leak the fuel trims would be lean and the trim number at idle would be positive
PS--
CAM TIMING can be checked via Measuring Block 93---tolerance is generally accepted to be +/- 4 degrees

Awesome, thank you for the info. About to scan now, just got off of work Happy Friday

[Ryes7]

Start by just scanning for codes. If it’s in limo mode you’ll have some stored. I would check your fuel trims too.

On it Cap’n, thank you

[Ryes7]

Okay, so, did some scanning and results didn’t point to anything clearly.

The exhaust has no cats and the sensors are ziptied down below. I believe a couple of the codes are related to that.

I am curious about the p1555 - maximum limit exceeded? Maybe that’s what’s limiting the boost from going to desired levels? - photo attached.

New thing is my ABS has a couple weird messages. photo will be in the next post.

I am waiting to hear back from JHM to let me know that the stage2 tune is ready for upload. They only sent me a stage 3 rs6r turbo tune.

Appreciate the kind folks with abundant b5 knowledge on AZ you guys are heros.

[Ryes7]

[Ryes7]

[Ryes7]

Also, had a weird message when trying to access 33. Not sure what this means.

[CELison]

I would pressure and smoke test it. You may have a leaky wastegate line, plus you’ll probably find some other leaks here and there. Also worth a tune with the rear 02s coded out so they don’t throw a code. If you search meowisfat on here, I posted a k03 tune for free with them coded out. You would just have to flash it.

[Ryes7]

I would pressure and smoke test it. You may have a leaky wastegate line, plus you’ll probably find some other leaks here and there. Also worth a tune with the rear 02s coded out so they don’t throw a code. If you search meowisfat on here, I posted a k03 tune for free with them coded out. You would just have to flash it.

Thanks for the reply. I am definitely going to download the meowisfat tune, thank you . I did make a video of a smoke test but I didn’t dip the camera down to the driver’s side turbo. Maybe that’s where the compromised wastegate line is. Would make sense. I wasn’t seeing any smoke for the 7-10 minute I had the test running though. I did not do a pressure test. I’ll try that next. Thanks for your patience as I am new to the platform.

https://youtube.com/shorts/VnuqWl9gH...w9dTXmJaeRyj9y

[Ryes7]

Quick update: got an updated tune back from JHM (stage 2 91 octane) and the car is boosting to around 20 and feels great, SO MUCH better. I only drove it for around 40 mins as it is late and the car is loud, but I will drive it some more over the next few days and report back. I’m back on the n75 with the manual boost controller disconnected.

[Ryes7]

Ok…latest update. Hooked MBC back up. Combined with the updated Stage2 91 tune from JHM, the boost is holding steady at 22 at WOT. Totally different car. Feeling great about it. Now onto the various oil and coolant leaks Also both rear brakes are leaking ever so slightly. Special thanks to everybody that weighed in for their input. Appreciate everyone’s time and advice. I feel good about closing this case, for now. - Sean

[CELison]

22 is way too much for K03s.

[Ryes7]

22 is way too much for K03s.

Shoot, that’s a bummer. Thanks for your input, as usual...

So…what would you do in this case? Should I contact JHM and ask them to please decrease the requested boost pressure? I have the MBC turned all the way down, to my knowledge. Only drove it for about 10-20 miles yesterday and didn’t push it until warmed up. Did give it WOT 3 times for a few secs at a time to test, in different gears. Haven’t driven it today.

Thanks for your patience with someone who is interested in the platform and accepts that it’s unique and takes patience and understanding as well as commitment…

[james 408]

something like 18 peak down to 12 at redline for k03s. this is why you don't use a MBC. some agressive chips ran it high, you're just well outside the operating range. This generates heat, losing power, and is overspooling the turbo causing damage to the turbo. Most moderate chips were running like 15/16 peak and tapering. Check out myaudis4.com or flyboys data as he actually maps against efficiency curves if you wanna understand the details. But basically MBCs were fringe in 2005 and were dead to us shortly after.

The days of MBCs and crappy piggy backs converting sensor values was shortlived and functioned poorly even with very name brand tuners on other platforms.

[Ryes7]

something like 18 peak down to 12 at redline for k03s. this is why you don't use a MBC. some agressive chips ran it high, you're just well outside the operating range. This generates heat, losing power, and is overspooling the turbo causing damage to the turbo. Most moderate chips were running like 15/16 peak and tapering. Check out myaudis4.com or flyboys data as he actually maps against efficiency curves if you wanna understand the details. But basically MBCs were fringe in 2005 and were dead to us shortly after.

The days of MBCs and crappy piggy backs converting sensor values was shortlived and functioned poorly even with very name brand tuners on other platforms.

Thank you for the reply and the info/explanation. I’m not looking for crazy power. I just sincerely love how it looks, sounds and feels, even at normal speeds. I will ask them to tone it down to the ~15psi range and remove any specific programming that involves the MBC. These cars are so beautiful to me when cared for. I also keep learning interesting things about it from nice folks like you and it keeps me intrigued. Am excited to dig into myaudis4.com and learn more. Thanks again and happy holidays.

[LJS]

Here's a log of a proper Stage II tune.
This was a Daz tune an used on my S4 for a bunch of years with no MBC.
You'll see that the KO3's run out of breath at some 5900 RPM---note how the boost tapers as RPM increases.
PS- back in the day this was considered an aggressive / safe tune for a stock motor


Sent from my SM-A146U using Tapatalk

[CELison]

Meowisfat is the sauce.

[Ryes7]

Here's a log of a proper Stage II tune.
This was a Daz tune an used on my S4 for a bunch of years with no MBC.
You'll see that the KO3's run out of breath at some 5900 RPM---note how the boost tapers as RPM increases.
PS- back in the day this was considered an aggressive / safe tune for a stock motor


Sent from my SM-A146U using Tapatalk

Thank you for the data, you rock This looks oddly similar to what mine seems like it’s doing if I look at the boost gauge while doing a 3rd gear pull WOT. Even the very brief hold at 15-16 before climbing again. Was that on 91? Or 93? Am I seeing correctly that the WHP ended up around 260ish?

I’ve got a cart full of goodies via JHM including RS6-R turbos and supporting flanges, inlets, injectors, etc. Should I be looking at another brand if I’m going to go that direction?

I’m really enjoying it where it’s at power wise right now. It’s definitely fun, not as fast as my RS7, but makes me smile big time. Some of the comments make me feel like an idiot if I keep the boost where it’s at? I’ve got premium AAA tow coverage. Thinking of running it like this, and if a turbo pops, then it’s upgrade time.

Thanks so much, this community is amazing

[CELison]

I wouldn’t do anything bigger than K04s for a stock motor. K04s on E85 are the ticket. RS6 sized turbos need rods and E85 to come alive IMO.

[LJS]

Thank you for the data, you rock This looks oddly similar to what mine seems like it’s doing if I look at the boost gauge while doing a 3rd gear pull WOT. Even the very brief hold at 15-16 before climbing again. Was that on 91? Or 93? Am I seeing correctly that the WHP ended up around 260ish?

I’ve got a cart full of goodies via JHM including RS6-R turbos and supporting flanges, inlets, injectors, etc. Should I be looking at another brand if I’m going to go that direction?

I’m really enjoying it where it’s at power wise right now. It’s definitely fun, not as fast as my RS7, but makes me smile big time. Some of the comments make me feel like an idiot if I keep the boost where it’s at? I’ve got premium AAA tow coverage. Thinking of running it like this, and if a turbo pops, then it’s upgrade time.

Thanks so much, this community is amazing

NO- That's MAF (Mass Air Flow) in Grams per Sec....
ALSO
I totally agree with CELision's statement regarding a stock motor--K04's or Hybrids for a stock lower end......
PS- that'll start some arguments!!!!!
PSS-
I've a close friend with a K24 build (STOCK motor)...I'm running a K04 Hybrid
Our Audis are evenly matched up to some 125MPH where he starts to pull me beyond that---Just something to think about...
ALSO
At lower speeds I easlily pull a car length on him as my turbo's spool quicker than his....
ALSO
Many consider the RS6 turbo as the sweet spot for our small motors---good bottom end and real good top end grunt BUT a motor build is recommended (ROD's at a minimum)

[Ryes7]

NO- That's MAF (Mass Air Flow) in Grams per Sec....
ALSO
I totally agree with CELision's statement regarding a stock motor--K04's or Hybrids for a stock lower end......
PS- that'll start some arguments!!!!!
PSS-
I've a close friend with a K24 build (STOCK motor)...I'm running a K04 Hybrid
Our Audis are evenly matched up to some 125MPH where he starts to pull me beyond that---Just something to think about...
ALSO
At lower speeds I easlily pull a car length on him as my turbo's spool quicker than his....
ALSO
Many consider the RS6 turbo as the sweet spot for our small motors---good bottom end and real good top end grunt BUT a motor build is recommended (ROD's at a minimum)

Just wanted to come back and say thank you for taking the time to help me figure this out, very cool.

I’ve done a ton more quiet research and I am planning on just driving the car gently until I go for some K04’s. I really enjoy the power level that it’s at, even at partial throttle. It’s nowhere near as quick as the RS7 but it’s PLENTY fun and I think if I upgrade the turbos to K04 and diligently stay up to date on the maintenance I’ll enjoy it for many more years.

Don’t get me wrong, There’s a decent sized laundry list of other things to address, but that’s part of the fun, isn’t it?

Thanks everybody

-SV