b8 GIAC stage 2 6MT bypass

[sonic32]

So I've had this issue for a while where I shift fast and upon starting in next gear car feels like it hit a brick wall. I finally caught it on logs. It appears the bypass stays open in next gear for a very long time. I'm gonna send logs to Giac but I wanted to see if anybody has an idea or same issue. See logs attached below. It's the last log from the file with the highlighted part being in next gear and bypass significantly opened



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[FromRagsToS4]

Does it almost feel like it's a really badly slipping clutch? Like, the clutch pedal is all the way out and you're completely in gear, but when you press the gas it revs up to redline like it was in neutral?

If no, what do you mean by hitting a brick wall?

[xpoweruk]

What fuel are you using ?Is it the wright map for your fuel ? Looks like you are getting knock & timing is being pulled (4-5 *),also your IAT's are into the 60's when it happens, so a little on the hot side

[KRp220]

Does it almost feel like it's a really badly slipping clutch? Like, the clutch pedal is all the way out and you're completely in gear, but when you press the gas it revs up to redline like it was in neutral?

If no, what do you mean by hitting a brick wall?

no... i think he means that the tach just pauses where it is and it takes a second to 'catch its breath' and start accelerating again
is that correct OP? if so, i've had that happen before

[FromRagsToS4]

I've had that happen too. I figured it was just clutch slip so I let off and put it in neutral then tried again.

[doug97gxe]

this might not be tune related and more audi design related

[sonic32]

I wish I could get a video of it but I don't feel comfortable on that shift. When i said it feels like it hits a brick wall I meant in terms of acceleration, it accelerated as you can see on the logs but car is very slow because bypass is open. Also I'm running E85/93 mix, same mix that everybody is running and I usually get that timing retard and iat's should be around 70-80c for the bypass to open due to excessive heat soak. Also clutch isn't slipping, stage IV JHM and ECS LW SMFW. I know what clutch slip feels like from the stock clutch days


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[bhvrdr]

Thats interesting the bypass is opening for 500rpm after the shift which puts you in that next gear at around 5400rpm. During that time the ECU is also only targetting from 0psi of boost to 4ish psi of boost. The non outlined part of the log showing the before shift gear shows you targeting 17psi from 5100rpm up to shift. Thats odd. Do you feel anything like stumbling at all when this happens or just not as much power? Do you see any misfiring going on? Any fuel pressure issues?

[rtl5009]

My car does it occasionally when shifting really fast. If I have ESP completely off it has never done it. I think it's a function of traction control.

[sonic32]

Thats interesting the bypass is opening for 500rpm after the shift which puts you in that next gear at around 5400rpm. During that time the ECU is also only targetting from 0psi of boost to 4ish psi of boost. The non outlined part of the log showing the before shift gear shows you targeting 17psi from 5100rpm up to shift. Thats odd. Do you feel anything like stumbling at all when this happens or just not as much power? Do you see any misfiring going on? Any fuel pressure issues?

No weird stumbling to misfiring, just feels like a really slow NA v6 car lol if I get off the throttle for a split second and get back on it bypass closes and it starts pulling like it's supposed to

My car does it occasionally when shifting really fast. If I have ESP completely off it has never done it. I think it's a function of traction control.

I always pull logs with everything in the car off and traction completely off.




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[rtl5009]

hmmmm. Very interested in what GIAC says. Can you send me the full log, [email protected] Thanks.

[sonic32]

hmmmm. Very interested in what GIAC says. Can you send me the full log, [email protected] Thanks.

Emailed it to you, I have a few more where the bypass opens to 66% when off throttle and as soon as I'm back on it it goes straight to 0 as it should.


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[rtl5009]

It took over 2 second for the file to request full boost after you lifted your foot off the accelerator when it lagged. That is so weird. It started to see a lot of knock correction right at the top before the gear change. It was really lean while the flap was open too, low to mid 12's. It seems to be protecting from further knock.

[sonic32]

It took over 2 second for the file to request full boost after you lifted your foot off the accelerator when it lagged. That is so weird. It started to see a lot of knock correction right at the top before the gear change. It was really lean while the flap was open too, low to mid 12's. It seems to be protecting from further knock.

I wouldn't really blame it on the fuel and the map because this sometimes happens on 93 fuel on the 93 map, I'm gonna see if I can go out and replicate it on pump map and catch it on logs, not sure I have time though. And I'm not sure if you can interpret the AFR's like that due to the mix


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[rtl5009]

Lambda is lambda, I just assumed you were on gas changing the scale is easy. So you are on an E mix!

[Loe]

Can you email me your fuel pressure and lambda logs? I'd like to see what happened after that "point of no return." You were on your way to hitting the timing targets (ecu is seeing everything it likes), but then it went downhill from there (ecu is seeing something it doesn't like, so its bypassing). The amount that you were bypassing almost resembles what the bypass looks like when the engine is idling.

Can you also log cylinder activity across all cylinder + bypass? Interesting to see if the corrections are isolated to one bank to narrow down what's going on.

[rtl5009]

My car did this today second to third gear, flap just stayed open and I was building zero boost with the accelerator mashed. I was not logging. I literally looked down at the boost gauge and it was drawing a vac at full throttle. Not much but some which makes sense with air ridding past the bleeder in the sandwich plate for the boost gauge. Did you happen to figure anything out? My car literally fell on its face. It wasn't missing, just no boost. I had ESP completely off.

I was on the pump file and have 3.5 gallon of e in the tank so knock (logs show zero knock) is not the issue and in no where close to maxing out the fueling system (in on roughly e25). Logs from a few days ago are super healthy and the car feels strong.

[lukasB8]

Giac stage 2 here, my car does this aswell and i always run the pump map with 93 octane, while doing a pull you shift into next gear and feels like it hits a wall and if you keep it floored you can feel the boost then start to creep up about 3-5 secs later, i cant figure out it...

[rtl5009]

Sonic did you figure anything out?

[sonic32]

Giac stage 2 here, my car does this aswell and i always run the pump map with 93 octane, while doing a pull you shift into next gear and feels like it hits a wall and if you keep it floored you can feel the boost then start to creep up about 3-5 secs later, i cant figure out it...

Sonic did you figure anything out?

Are you both tuned by GIAC? I got in contact with them and after a few back and forth emails it seems like the issue arises because the tach moves slower than actual rpms and we're hitting the rev limiter throwing us into soft limp mode. It also could be that the ecu cannot react fast enough to give fuel back in time and close the bypass. Also it turns out we have no lift shift so if you want to actually get on it like that just don't lift off the gas and it reacts better than letting off and getting back on it in next gear. I only tried no lift a few times and it didn't seem to hit that wall in next gear. It happened to me a lot of times and on logs it seems like when I let off and switch at 7000-7200 per tach, sometimes it goes as far as 7400 at which point it's already passed rev limiter. Hope that made sense, im a little under the influence haha


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[rtl5009]

We're both on GIAC. Why don't other tuners have this problem?

[sonic32]

We're both on GIAC. Why don't other tuners have this problem?

They might have it and people haven't stumbled upon it, most cars are DSG, maybe most people don't shift as fast as we do. Before I got the clutch done it happened once or twice because those were the only times I said fuck it and shifted fast knowing clutch will slip so I blamed it on that. Try not lifting off the gas and shift very fast around 7150 or before


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[rtl5009]

I shift fast as fuck- One time a tech at the VAG proving grounds (outside of phoenix) was in the car next to me doing and we were doing pulls and he came up after and asked if my car was a DSG cause I was shifting so fast. lol.

You are right, I only notice it if I am really deep in the tach when I shift.

[sonic32]

I shift fast as fuck- One time a tech at the VAG proving grounds (outside of phoenix) was in the car next to me doing and we were doing pulls and he came up after and asked if my car was a DSG cause I was shifting so fast. lol.

You are right, I only notice it if I am really deep in the tach when I shift.

Yeah and I think that really fast shifting paired with us trying to squeeze every rpm out of the car pushes us into soft limp mode and ecu cant recover fast enough. I haven't drunken the car due to the shitty weather but as soon as it gets nice I'm gonna log under same circumstances I caught the issue on logs and not lift of the gas. Give it a try and report back if you have the means to open it up like that


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[rtl5009]

Are you sure all GIAC files have nls and not just AWE or forge?

[sonic32]

Are you sure all GIAC files have nls and not just AWE or forge?

I don't have a forge nor an awe pulley, so i dont even know what file I have. I did a launch and I no lifted 2-3 and it was awesome lol I have no lifted the car before but I switched so late in the rev band that I thought I banged off the limiter but it seems like it's holding wherever you clutch in.


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[lukasB8]

so has anyone with logs contacted GIAC? curious to see what they say. My car bogs now every other pull i do its getting ridiculous...

[MrFunk]

Just reading this.
I've had this happen a couple times while shifting very fast at WOT.

[withENEMYin]

My car does it occasionally when shifting really fast. If I have ESP completely off it has never done it. I think it's a function of traction control.

I have experienced exactly this, I thought my belt was too loose. I just put on a tighter belt last week and it happened 4 days later under hard shifting. It makes me check as if I forgot to turn traction control off.

[rtl5009]

I have experienced exactly this, I thought my belt was too loose. I just put on a tighter belt last week and it happened 4 days later under hard shifting. It makes me check as if I forgot to turn traction control off.

I have gotten mine to do it with ESP completely off. Rev it high and shift fast and it will happen.