O2 Cheater Sucees! Please post what the untuned guys are using and sucess rate

[2015S3]

Down Pipe: Unitronic
Exhaust: OEM
Piggyback: Yes, JB1
O2 Cheater used: Custom Made Sparkplug Fouler
Success: No CEI but only had on the car for a week

O2 Cheater #2: Vibrant with middle sized jet - All good for three weeks then CEL
O2 Cheater Trail #3: Vibrant with large sized jet - Good for three weeks then CEL

The Vibrant cheater I used was the straight type cheater, I am now going to try the smallest jet first and then switch to the curved Vibrant version and then put my custom spark plug fouler back in and try that.

If possible also list your code reading from Vag-Com

[Stubek]

Roc Euro spacer with catalyst. I ran it for over a year with no tune and never had a CEL. That was on a B8A4

[2015S3]

Do you have a link to that type spacer?

[DarkSideGTI]

Why not just get a cat that works?

[HurrayFive]

Roc Euro spacer with catalyst. I ran it for over a year with no tune and never had a CEL. That was on a B8A4

This. I'm not sure what brand my shop uses but they install an O2 spacer that has a 10 cell catalyst inside the spacer itself for folks who are not running a tune w/ their dp or who need to flash back to stock for emissions testing, you can run it indefinitely and it completely eliminates the CEL according to their experience.

I have a hi-flow cat DP without any spacer but I'm only CEL free because of the tune, every time I flash back to stock for service I've got about 70 miles and/or 3-4 start/stop cycles before I throw a cat under-efficiency code.

[WildHareMS]

Why not just get a cat that works?

I'm not so sure that's possible anymore for these guys. Even a high flow cat will generally have almost no difference with the sampling rate of the downstream sensor, in relation to the upstream. When that happens, the two appear to be mirroring each other as if the catalyst is no longer functional and it sets the code. A catalyst that would restrict the flow to stock would limit power.

If you've got a quality supplier of a high flow cat that will keep the codes from setting, I'm pretty sure there are a LOT of AZ members that would be interested.


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[coolwater]

I'm not so sure that's possible anymore for these guys. Even a high flow cat will generally have almost no difference with the sampling rate of the downstream sensor, in relation to the upstream. When that happens, the two appear to be mirroring each other as if the catalyst is no longer functional and it sets the code. A catalyst that would restrict the flow to stock would limit power.

If you've got a quality supplier of a high flow cat that will keep the codes from setting, I'm pretty sure there are a LOT of AZ members that would be interested.


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Had 100 miles on the AWE tuning DP before stage 2 tune.
Did not get a CEL. It is guaranteed to be CEL free and also EURO6 compliant.
Only negative is the price.

https://www.moddedeuros.com/products...0s0aApl08P8HAQ

-cW

[GramCracker]

I'm not so sure that's possible anymore for these guys. Even a high flow cat will generally have almost no difference with the sampling rate of the downstream sensor, in relation to the upstream. When that happens, the two appear to be mirroring each other as if the catalyst is no longer functional and it sets the code. A catalyst that would restrict the flow to stock would limit power.

If you've got a quality supplier of a high flow cat that will keep the codes from setting, I'm pretty sure there are a LOT of AZ members that would be interested.


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When I was running my catless CTS downpipe with no tune (still havne't been tuned) it was causing the car to act real odd under load. The ECU was definitely trying to compensate for the increased exhaust flow and keep the power delivery, and map parameters, as similar to OEM with a cat - which isn't happening with no cat and the sensors reading wildly different data than the ECU expects.

It really messed with the cars head, ultimately another reason I chose to reinstall my OEM downpipe.

[Stubek]

When I was running my catless CTS downpipe with no tune (still havne't been tuned) it was causing the car to act real odd under load. The ECU was definitely trying to compensate for the increased exhaust flow and keep the power delivery, and map parameters, as similar to OEM with a cat - which isn't happening with no cat and the sensors reading wildly different data than the ECU expects.

It really messed with the cars head, ultimately another reason I chose to reinstall my OEM downpipe.

That isn't normal. The second O2 sensor (the one post catalyst) only tells the car how efficient the cat is, aka, is the cat still functional. It does NOT change any performance parameters and the car does not try to adjust anything based on that.
If you have an HFC, Test Pipe, or other DP that is higher flow, the first sensor shouldn't be able to tell and therefore shouldn't be adjusting anything.

[XLR8 Craig]

When I was running my catless CTS downpipe with no tune (still havne't been tuned) it was causing the car to act real odd under load. The ECU was definitely trying to compensate for the increased exhaust flow and keep the power delivery, and map parameters, as similar to OEM with a cat - which isn't happening with no cat and the sensors reading wildly different data than the ECU expects.

It really messed with the cars head, ultimately another reason I chose to reinstall my OEM downpipe.

I am not surprised either!. Down pipes without the proper tune are now becoming more of an issue because of the more sophisticated torque based engine management. Earlier cars don't have much of an issue because they were calibrated with a far more simple equation. Sure maybe a down pipe might not cause a check engine light, but that doesn't mean anything anymore!

You made the right decision.

[S3Danny]

When I was running my catless CTS downpipe with no tune (still havne't been tuned) it was causing the car to act real odd under load. The ECU was definitely trying to compensate for the increased exhaust flow and keep the power delivery, and map parameters, as similar to OEM with a cat - which isn't happening with no cat and the sensors reading wildly different data than the ECU expects.

It really messed with the cars head, ultimately another reason I chose to reinstall my OEM downpipe.

I'm not sure why you would think that running a catless downpipe without a tune for it would result in anything but strange behavior from the car?


Zero issues and no CEL with my Revo catless downpipe and Revo stage 2 flash.

[2015S3]

The unitronic has a Cat in it although a HFC still a cat in the same place as the OEM DP.

That said thanks for the help guys.

[HurrayFive]

The unitronic has a Cat in it although a HFC still a cat in the same place as the OEM DP.

That said thanks for the help guys.

Yup, as does mine, but the factory cat is a 400 cell catalyst and any aftermarket HFC is 200 cell at best...it's still always going to eventually result in a cat under-efficiency code if you're not tuned. If that's the only CEL the DP causes, it's not detrimental other that showing the CEL in the dash.

My shop says they get around it (for folks without tunes) with a 10 cell "mini cat" in the spacer itself, but I've never tried it. Most tunes simply disable the under-efficiency code, and while tuned I've never thrown a CEL, which at least means I've never caused any other codes to persist long enough to trigger a CEL.

[2015S3]

I ordered the roceuro one last night we will see. For the time being I installed the smallest jet in the Vibrant kit. I will keep everyone informed.

[DarkSideGTI]

I'm not so sure that's possible anymore for these guys. Even a high flow cat will generally have almost no difference with the sampling rate of the downstream sensor, in relation to the upstream. When that happens, the two appear to be mirroring each other as if the catalyst is no longer functional and it sets the code. A catalyst that would restrict the flow to stock would limit power.

If you've got a quality supplier of a high flow cat that will keep the codes from setting, I'm pretty sure there are a LOT of AZ members that would be interested.


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I'm not sure who AWE uses, but they do guarantee a no CEL exhaust. Although I talked to my buddy that makes parts for Audi/VW and he said even cats like what AWE sell will throw a CEL after a year or so, so I guess the cheaters is really the only way around it if you want a HFC.

[XLR8 Craig]

I'm not sure who AWE uses, but they do guarantee a no CEL exhaust. Although I talked to my buddy that makes parts for Audi/VW and he said even cats like what AWE sell will throw a CEL after a year or so, so I guess the cheaters is really the only way around it if you want a HFC.

AWE uses HJS, some of the highest quality units on the market, and TUV approved. These MQB cars really should not be running a downpipe without the proper tune.

Thanks,

Greg

[DarkSideGTI]

Yeah I had a feeling they were using HJS. I'm sure that's what I will run as well when I get a DP. they are like $4-500 for the cat alone which is why the good DP's are so expensive.

[GramCracker]

I am not surprised either!. Down pipes without the proper tune are now becoming more of an issue because of the more sophisticated torque based engine management. Earlier cars don't have much of an issue because they were calibrated with a far more simple equation. Sure maybe a down pipe might not cause a check engine light, but that doesn't mean anything anymore!

You made the right decision.

Definitely made the correct decision for now, that's for sure. Tuna and catted DP down the road

That isn't normal. The second O2 sensor (the one post catalyst) only tells the car how efficient the cat is, aka, is the cat still functional. It does NOT change any performance parameters and the car does not try to adjust anything based on that.
If you have an HFC, Test Pipe, or other DP that is higher flow, the first sensor shouldn't be able to tell and therefore shouldn't be adjusting anything.

I'm just talking based off of my experience running a completely catless and resonatorless downpipe on this motor without a tune. If the post-cat O2 sensor is not reading the cat as being efficient or functional, isn't it going to mess with things? I'm probably mixing up the that with the AFR (long day at the office), because then that reading the exhaust gas without a cat, IMO would definitely throw things off. The way the car started acting under full-load WOT situations after I puts some miles on the car with the catless setup definitely wasn't right.

One thing is for sure, the OEM tune with a catless DP was causing my car to DRINK petrol at an almost hilarious rate - seemed like I was driving a V12 without the amazing sound or power.

[Blaine]

I'm not sure who AWE uses, but they do guarantee a no CEL exhaust. Although I talked to my buddy that makes parts for Audi/VW and he said even cats like what AWE sell will throw a CEL after a year or so, so I guess the cheaters is really the only way around it if you want a HFC.

AWE uses HJS, some of the highest quality units on the market, and TUV approved. These MQB cars really should not be running a downpipe without the proper tune.

Thanks,

Greg

^ Theres the CEL fix for DP's. Just gotta pay the big $$. A year wo/a CEL is a LONG F'n time. Stock cars get a CAT CEL more than that! The awe DP is "No Check Engine Light - Guaranteed," and they are the only DP that claims that.

If your tuned and the CEL come on just reset the code. Not going to harm anything. Now the Untuned guys an aftermarket DP wo/running NO CATS.. well your just rolling the dice. AFR's will be all out of wack.. Lean/Rich issues. Not good on a boosted engine. At least run a log on dyno to make sure... heck of alot cheaper than a new motor.

[XLR8 Craig]

Definitely made the correct decision for now, that's for sure. Tuna and catted DP down the road



I'm just talking based off of my experience running a completely catless and resonatorless downpipe on this motor without a tune. If the post-cat O2 sensor is not reading the cat as being efficient or functional, isn't it going to mess with things? I'm probably mixing up the that with the AFR (long day at the office), because then that reading the exhaust gas without a cat, IMO would definitely throw things off. The way the car started acting under full-load WOT situations after I puts some miles on the car with the catless setup definitely wasn't right.

One thing is for sure, the OEM tune with a catless DP was causing my car to DRINK petrol at an almost hilarious rate - seemed like I was driving a V12 without the amazing sound or power.

The reason for using a lot of fuel Graham is because the Simos ECU's use torque based fuel management. The ECU is compensating more fuel based of the engines volumetric efficiency. More air, more timing = more fuel. These ecu's are so smart they actually can predict what the calibration is calling for boost wise by monitoring turbine power and shaft speed to set the wastegate duty cycle before it even happens to help aid in driveability and smoothness.

^ Theres the CEL fix for DP's. Just gotta pay the big $$. A year wo/a CEL is a LONG F'n time. Stock cars get a CAT CEL more than that! The awe DP is "No Check Engine Light - Guaranteed," and they are the only DP that claims that.

If your tuned and the CEL come on just reset the code. Not going to harm anything. Now the Untuned guys an aftermarket DP wo/running NO CATS.. well your just rolling the dice. AFR's will be all out of wack.. Lean/Rich issues. Not good on a boosted engine. At least run a log on dyno to make sure... heck of alot cheaper than a new motor.

We love AWE Tuning, and love that there are no CEL's using their downpipe. But, I am a firm believer in not using any downpipe on an un-tuned car. Whether it has a high flow cat or even no cat etc..it can be detrimental to the engine and the car will not perform right. Graham is a testament to that. These MQB engines need tuning to allow safe efficient operation. There are values that are limitations in the engine calibration that determine volumetric efficiency and AFR. Parameters such as preturbine exhaust speed, low pressure and high pressure fuel values, turbine shaft speed, intake air, and EGT all play a key role among with other limiters from the ABS, traction control, oil and coolant temp, VSS, DSG torque limiters that are other road blocks. All of these values are effected, not just AFR, boost, fueling etc like it used to be.

[GramCracker]

The reason for using a lot of fuel Graham is because the Simos ECU's use torque based fuel management. The ECU is compensating more fuel based of the engines volumetric efficiency. More air, more timing = more fuel. These ecu's are so smart they actually can predict what the calibration is calling for boost wise by monitoring turbine power and shaft speed to set the wastegate duty cycle before it even happens to help aid in driveability and smoothness.

I absolutely love this shit, keep going - I could listen/talk forever.

[Z32drifter]

I'm a little confused. The ECM is designed to adapt to various conditions that the engine might see. It's smart enough to calculate turbo shaft speed but can't adjust to a free flowing exhaust system. I have been running the USP catted down pipe on my car for around 2000 miles. No excessive fuel consumption and no unusual driving issues. My car picked up 3 mph vs the stock setup. I am working on the MIL related to the down pipe. No spacer will trip the efficiency fault, my current spacer trips a slow response type fault. It took about 700 miles after the DP install to trip the first fault. Once you have cleared the fault the system is much more picky and faults return more quickly. The trick is getting the right size sample to sensor 2.

[will13k7]

for the hundred or so miles I ran the AWE DP without a tune, no codes or engine running odd, noticeable, but small, response/power increase.

[GramCracker]

I'm a little confused. The ECM is designed to adapt to various conditions that the engine might see. It's smart enough to calculate turbo shaft speed but can't adjust to a free flowing exhaust system. I have been running the USP catted down pipe on my car for around 2000 miles. No excessive fuel consumption and no unusual driving issues. My car picked up 3 mph vs the stock setup. I am working on the MIL related to the down pipe. No spacer will trip the efficiency fault, my current spacer trips a slow response type fault. It took about 700 miles after the DP install to trip the first fault. Once you have cleared the fault the system is much more picky and faults return more quickly. The trick is getting the right size sample to sensor 2.

Catted, not cat-less.