N54 How do I program the exhaust valve behavior? E-series

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Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Does anyone know if it is possible to program the vacuum activated exhaust valve behavior somehow. On my E89 it basically opens when you push the car (although in 1st and 2nd it is open by default). It then closes in 3rd or higher as well as on cold start. I would love it to only close in 7th gear.

I have had this problem where my exhaust valves do not always open when I go WOT from low rpm in high gears. It causes under boost, apparently because my custom exhaust is too restrictive for the power I am running when the flaps are closed. What is weird is that it always opens on any first pull I do after start up, and then sometimes stays shut from the second pull onwards. If I lift off mid-pull for a split second, the exhaust valves open properly and boost is back up by 3-4psi. It also always opens if I go WOT at higher rpms in 3rd or higher gears.

Here's in an example of how the car underboosts as the exhaust valves stay shut even under wot

https://datazap.me/u/asbjoern/bq-v20-air-leak-sound?log=0&data=3-21-26

I am currently running with the exhaust vacuum disconnected, and now all problems are gone, except I am missing the function it self. I would like it back for highway cruising.
 
Last edited:

RSL

Sergeant
Aug 11, 2017
395
He's on a locked tune, so won't be able to adjust it, but the tables are in the XDF and could keep it open in all gears except 7th. His tuner could do it for him.

I'm not sure it would make a difference if operation is wonky though. Might have a vacuum leak, bad solenoid or electrical problem to the solenoid. If it's not doing what it's told now, telling it to do something different isn't going to fix it.

I think you've got other problems though. WGDC is absolutely ridiculous and I assume you have GC Lites by the filename. I can't imagine any custom exhaust is that bad unless you used 1" pipes. If it is that bad, get rid of it tomorrow, but something else is probably the issue.
 
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Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
He's on a locked tune, so won't be able to adjust it, but the tables are in the XDF and could keep it open in all gears except 7th. His tuner could do it for him.

I'm not sure it would make a difference if operation is wonky though. Might have a vacuum leak, bad solenoid or electrical problem to the solenoid. If it's not doing what it's told now, telling it to do something different isn't going to fix it.

I think you've got other problems though. WGDC is absolutely ridiculous and I assume you have GC Lites by the filename. I can't imagine any custom exhaust is that bad unless you used 1" pipes. If it is that bad, get rid of it tomorrow, but something else is probably the issue.
Thanks for explaining. I will take it up with @BQTuning

What is weird is that in order to open the flaps, no vacuum is needed. And it is also rpm dependent as well as dependent on whether it was the first pull or not, and consistently.

As for the custom exhaust vs wgdc, it is actually just an oem exhaust with de catted mid pipes and a passenger side muffler on the drivers side. This means I have two exhaust flaps instead of just one on the passenger side. This also means my total muffler flow is more restricted than oem, but only when the flaps are closed. Down pipes are still oem catted. Here's my latest log

https://datazap.me/u/asbjoern/bq-v20-session-three-pulls
 

RSL

Sergeant
Aug 11, 2017
395
Yeah, you definitely need at least one open, and both on boost, but I did look through all of your logs before I posted and saw you've been chasing leaks, replacing o-rings, vacuum lines, repairs, etc. for some months. The stock DPs aren't the problem, one of the most efficient logs I saw was when they were put back in, more boost and nearly 20% less total DC.

https://datazap.me/u/asbjoern/bq-v10-map-session-2?log=0&data=3-23-31

I think it's still a little high for the turbos, but much better than the 75-max WGDC you've got going on now. Have you checked the cats lately? Since you do track and it's been getting worse over time(?), maybe cats are slowly melting and creating a blockage.

I saw some dude checked his cats using a cylinder compression test adapter in the O2 bungs, which was a pretty slick idea and faster than pulling the DPs off. Could be anything still, but just a thought.

If there are no leaks or blockages and turbos are OK, it is what it is, but if it were my car, those DCs would bug the hell out of me, so don't let my OCD rub off if you're not concerned about it lol
 
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Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Yeah, you definitely need at least one open, and both on boost, but I did look through all of your logs before I posted and saw you've been chasing leaks, replacing o-rings, vacuum lines, repairs, etc. for some months. The stock DPs aren't the problem, one of the most efficient logs I saw was when they were put back in, more boost and nearly 20% less total DC.

https://datazap.me/u/asbjoern/bq-v10-map-session-2?log=0&data=3-23-31

I think it's still a little high for the turbos, but much better than the 75-max WGDC you've got going on now. Have you checked the cats lately? Since you do track and it's been getting worse over time(?), maybe cats are slowly melting and creating a blockage.

I saw some dude checked his cats using a cylinder compression test adapter in the O2 bungs, which was a pretty slick idea and faster than pulling the DPs off. Could be anything still, but just a thought.

If there are no leaks or blockages and turbos are OK, it is what it is, but if it were my car, those DCs would bug the hell out of me, so don't let my OCD rub off if you're not concerned about it lol
Thanks for going through my logs. As it turns out you were absolutely right. My wgdc was too high for the boost produced. What is weird now is that it sometimes does that and sometimes doesn't.

It is ok-ish here today

https://datazap.me/u/asbjoern/bq-v20-session-two-pulls?log=0&data=3-20&mark=57-59

Also looks okish before this point last Friday (just before a simple hose failure)

https://datazap.me/u/asbjoern/gic-temperature-logging?log=0&data=3-22-30&solo=3&zoom=1995-2080&mark=2063

Here it was also okay in January

https://datazap.me/u/asbjoern/bq-v20-without-air-leak-sound?log=0&data=3-4-21-30&zoom=13-54


Then it was not okay during second session today (I didn't touch anything)

https://datazap.me/u/asbjoern/bq-v20-session-two-more-pulls?log=0&data=3-22-30&mark=55

And also not okay last Wednesday

https://datazap.me/u/asbjoern/bq-v20-session-three-pulls?log=0&data=3-21

So very random, and seemingly unrelated to the exhaust flap issue. Sometimes the car barely hits target with high wgdc, and sometimes it does hit and with less wgdc.
 

RSL

Sergeant
Aug 11, 2017
395
Intermittent problems or those that develop slowly over a long time are the absolute worst, especially with no codes to give a direction.

I'd go the usual routine: boost leak test, vacuum test, BCS, lines are on WGs solid, etc. What's your intake setup? Silicone inlets that might be collapsing under vacuum? Last time you cleaned your filter(s)?

Just trying to think what might be physical problems since the DME isn't complaining about anything yet (right?) and you haven't reported any obvious mechanical problems.
 
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Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Intermittent problems or those that develop slowly over a long time are the absolute worst, especially with no codes to give a direction.

I'd go the usual routine: boost leak test, vacuum test, BCS, lines are on WGs solid, etc. What's your intake setup? Silicone inlets that might be collapsing under vacuum? Last time you cleaned your filter(s)?

Just trying to think what might be physical problems since the DME isn't complaining about anything yet (right?) and you haven't reported any obvious mechanical problems.
When I had the problem where the car under boosted due to the exhaust flaps not opening we basically tested everything. We thought it was a boost leak due to the boost not hitting target, and because all we could hear was air whoosing when the exhuast was closed and muted. It sounded like a boost leak. So,

What I am 99% sure of:
- No DME codes
- Boost leak test done, no problems. All hoses and pipes have been inspected. We even had the manifold out.
- Vacuum test done. Anyway, all T-pipes and vacuum lines are new. I can also hear a shhh sound if I pull a vacuum hose, even if the car has been parked for days.
- Air filter is essentially brand new.
- During daily spirited driving (ie not WOT), car has intermittent boost oscillation, and also and intermittent "jump" in accelleration when passing around 4k rpm at low accelleration: https://datazap.me/u/asbjoern/bq-v18-map-session-4-bonus-logs?log=0&data=3-22 it does not happen every time.
- If the problem was related to the down pipes, I assume it would not be intermittent.

What I am not sure of
- Intakes collapsing. Can they even do that at my boost level? Obviously they look fine when the car is parked.
- Oil filter. It could be the wrong type... Could it cause intermittent problems without throwing codes?
- Boost solenoids. They are only 1.5 years old, but live right next to that hot cast manifold. Could they cause intermittent problems without throwing codes?
- Turbosmart kompact diverter valves (not the dual type). My mechanic had them out, disassembled and lubed last month, but I wasn't there to inspect it myself. Could one of them be leaking intermittently? My tuner says he has seen bad reviews of these starting to pop up. I could try and put in my oem charge pipe and oem DV valves.

Here's an overview of my setup.

February 2019.jpg
 

RSL

Sergeant
Aug 11, 2017
395
An abnormal air sound would be something to look into for sure. Hard to tell when you work on a car a lot, but did it start happening immediately after working on something in particular?

I have TS Kompact plumb back in for 3+ years without issue, but maybe the shop missed something when they had it apart or put it back together. Might be worth swapping the stock CP/DVs in or at least make sure o-rings aren't torn, etc. and DVs seal, move freely with vacuum, connected to CP ok, etc. I assume the problem existed prior to that work though.

Short of strapping it on a dyno or a camera in there, not sure how to check inlets collapsing. Are you at least using a higher flowing filter?

If the snorkel is off, are you sure that isn't the source of the air noise? I wonder if the air filter might be deforming under pressure change. I think you'd be better off with snorkel + scoops, but haven't tested them alone. It should reduce intake pressure loss any time the car is moving at least and possibly help pressure ratio/reduce WGDC. Turbos wouldn't need to pull all the way through, they'd have help. A quick check that it's not the airbox/filter would be to grab a set of cheap DCI and slap them in for a test. I use AFE sealed without issue up to 24psi so far (15Ts) for several years.

I'd check that the inlets haven't popped off the turbos too. That really shouldn't effect boost unless they're blocking an inlet somewhat or touching a wheel somehow, but being off the turbo could/would cause different noise (and let in unfiltered air) for sure.

I wouldn't expect a cat problem to cause on/off issues, but BCS might be worth testing for the heck of it. They do seem to fail intermittently over time until they're just done.

At some point you will want to check the turbos if the culprit hasn't been found. If a wheel drags here and there, it would make funny noises and effect boost/WGDC.

For the part throttle log, requests are smooth, responses are not. Could just be VANOS settings or something else. It looks like potentially a derived issue somewhere when setpoint moves. Load/MAF bounce quite a bit for 1-1.5psi move. PT/low load/around 0psi areas aren't always the easiest to guess what's happening or tweak. Might just be moving off intake MAP to TMAP or something, not sure what point that occurs.
 
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Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
An abnormal air sound would be something to look into for sure. Hard to tell when you work on a car a lot, but did it start happening immediately after working on something in particular?

I have TS Kompact plumb back in for 3+ years without issue, but maybe the shop missed something when they had it apart or put it back together. Might be worth swapping the stock CP/DVs in or at least make sure o-rings aren't torn, etc. and DVs seal, move freely with vacuum, connected to CP ok, etc. I assume the problem existed prior to that work though.

Short of strapping it on a dyno or a camera in there, not sure how to check inlets collapsing. Are you at least using a higher flowing filter?

If the snorkel is off, are you sure that isn't the source of the air noise? I wonder if the air filter might be deforming under pressure change. I think you'd be better off with snorkel + scoops, but haven't tested them alone. It should reduce intake pressure loss any time the car is moving at least and possibly help pressure ratio/reduce WGDC. Turbos wouldn't need to pull all the way through, they'd have help. A quick check that it's not the airbox/filter would be to grab a set of cheap DCI and slap them in for a test. I use AFE sealed without issue up to 24psi so far (15Ts) for several years.

I'd check that the inlets haven't popped off the turbos too. That really shouldn't effect boost unless they're blocking an inlet somewhat or touching a wheel somehow, but being off the turbo could/would cause different noise (and let in unfiltered air) for sure.

I wouldn't expect a cat problem to cause on/off issues, but BCS might be worth testing for the heck of it. They do seem to fail intermittently over time until they're just done.

At some point you will want to check the turbos if the culprit hasn't been found. If a wheel drags here and there, it would make funny noises and effect boost/WGDC.

For the part throttle log, requests are smooth, responses are not. Could just be VANOS settings or something else. It looks like potentially a derived issue somewhere when setpoint moves. Load/MAF bounce quite a bit for 1-1.5psi move. PT/low load/around 0psi areas aren't always the easiest to guess what's happening or tweak. Might just be moving off intake MAP to TMAP or something, not sure what point that occurs.
So the car doesn't have any abnormal air sounds now. What I meant to say is that when the exhaust valves didn't open, the car sounded like it had a boost leak. There was a whoosing air sound that increased with boost pressure that I wouldn't normally hear. The sound would immediately disappear when the exhaust opened. Whatever intake noise there might be, it is buried by the exhaust note when the mufflers are open.

I found my old CP/DVs and they are ready to go in if there is the slightest chance that it could solve such an intermittent leak. I have had the TS kompact plumb backs since the very beginning, so less than a year.

As for the intake, I haven't done anything to it other than swapping in a new filter and removing the snorkel during v16 logging. I cannot run the snorkel now as it would be partly blocked by the additional coolant radiator I am running. The silicone inlets are definitely also securely attached.

I am not sure how to test BCS (I assume this stands for boost control solenoids), but what you said makes me want to move in this direction. They do see alot of heat on track with those GC lite cast manifolds.

As for the turbos, they don't make any funny noises. They do have a tiny bit of turbo "siren", like the stockers did, but much less. I believe the siren is mainly there when the turbos are somewhat cold.

I have had vanos problems in the past which seem to have been solved by now. 2A87 (exhast vanos, mechanism) happened on track once, then I replaced the solenoids. Then it happened again on another track. Then I replaced the vanos seal (installed the N55 teflon version). Since then the code hasn't come back. But I will let my tuner comment on what you wrote when the other issue has been solved. It sounds unrelated to my intermittent boost leak.

So, these are my possible to-dos:
- Swap in oem DV/CP (low chance of solving the problem)
- Use camera and light to capture silicone inlet behavior on WOT (also low chance)
- Test BCS (best guess at this point?)

Thanks for all of your comments!
 

Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Quick update. I went to pick up my old DVs at the shop that did my turbo install. This, just in case I needed to try them. On the way back I noticed the exhaust was louder than usual. I then realized I had zero boost. So WGs must be permanently open. This is good news, because I now have a permanent problem which is much easier to troubleshoot than an intermittent/progressing one.
 
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RSL

Sergeant
Aug 11, 2017
395
I rarely say "great" when something breaks, but at least there's something more definitive to zero in on now lol I'll be curious what it is.

I also saw their inlets are wire reinforced, so they'd be much less likely to collapse in vacuum. I still think you might be doing yourself a disservice with the stock air box and no snorkel+scoops to raise upstream pressure, but I'm actually going to test that myself one of these days and I'll report back on it.
 

Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
I rarely say "great" when something breaks, but at least there's something more definitive to zero in on now lol I'll be curious what it is.

I also saw their inlets are wire reinforced, so they'd be much less likely to collapse in vacuum. I still think you might be doing yourself a disservice with the stock air box and no snorkel+scoops to raise upstream pressure, but I'm actually going to test that myself one of these days and I'll report back on it.
Looking forward to seeing your results.

I initially ran the stock air box because it was quiet, and I didnt care for the intake air sound I had heard on other cars with modified intakes. Then I removed the snorkel because I worried more about airflow to the engine bay than loosing a few horses. Now the radiator is down there, so I cant go back even if I wanted. Also now the car is somewhat noisy anyway with the bearings-only front end, aluminum rear sub-frame mounts, permanently open exhaust flaps, M4 flywheel etc, but at least everything is good when the roof is down. :smiley:

In the ideal world I would have had a dual stock intake like the one on the S55 - I think that looks cool...
 

Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Alright problem found. It was a vacuum hose that was cracked near one of the T-couplers near the boost control solenoids. The vacuum hose was brand new, and installed in November last year. It makes no sense, and I do not understand why it failed. There were no signs of melting or rubbing. Anyway we installed a new temporary line, and turbos are spooling again.

https://datazap.me/u/asbjoern/bq-v20

It makes sense that a crack would cause an intermittent vacuum leak, until it became big enough that vacuum disappeared completely.

We have ordered new high temp vacuum hoses and will be replacing all of these once again. I also intend to install a quick and dirty manifold heat shield similar to the one hydra came up with.
 

RSL

Sergeant
Aug 11, 2017
395
Wow, that was a quick failure, but at least cheap and easy fix. Good idea on the shield, Hydra's is good. If under hood temps are a concern for the track, might consider getting the manifolds/turbines coated. I can't imagine how much more heat the cast manifolds give off compared to the stock double-wall. That's another thing I liked about Hydra's 650s. I was on the fence, but should've ordered while they were on intro. I can't believe no one has any installed yet, mine would've been in, tuned and dynoed on pump 2 months ago already lol

Glad it was something simple, I'll let you know on the intake tests.
 

RSL

Sergeant
Aug 11, 2017
395
I need to improve the testing conditions, but preliminary results on the intake. This has to be done on the street to make actual use of the snorkel+scoops (i.e. not a shop fan/blower on the dyno) and I cannot get to 6500-7000rpm in 3rd. This is just some BS tune I dropped in, little more than stock bin with raised boost. 2nd gear blows the tires up on it, so I need to whip something up reasonable that will stick in 2nd (to get to high RPM at a more reasonable speed).

  • Stock no scoops = stock air box, generic paper filter with ~10k miles on it, snorkel is not connected (and by extension neither are the scoops). That's pretty much what you're running right now with a better flowing filter.
  • Stock scoops = stock air box, same POS filter, snorkel connected between scoops and air box.
  • AFE = AFE Elite with scoops, filter cleaned about 600 miles ago.

- RB stock location inlets, RR600s (15Ts), Wagner Evo 2, 4 cats.

Since the acceleration is obviously not identical between setups/pulls, I aligned high RPM points to match.

24261


As you can see above, RPM is as close as I can align and target is identical, boost is similar and aside from the spastic PID, stock air box with no scoops is higher WGDC. It's a PID bounce, so difference is relative, but regardless of PID smoothness right now, it's obvious that the no snorkel+scoop WGDC is trending higher. The moving average for WGDCs indicates that clearly and expect it will get worse when I can run higher RPM.

You can see below, the AFE (dotted line) and stock air box/snorkel with scoops (solid) run pretty close to the same for actual boost and WGDC. The stock air box with no snorkel/scoops (dashed) boost lays flat at similar WGDC through the middle. What you might not really notice with the RPM aligned on the higher end is the boost onset. The dashed line starts earlier and has a longer spool WGDC. The no snorkel IATs are also +11-13F through the entire pull and that's after intercooling and a 2 mile cruise before the pull to stabilize FMIC (after stopping to pull the snorkel).



24260

It may or may not look like a big difference in logs right now, but at the tires and even in the driver seat, no help getting air into the box using snorkel/scoops is noticeable.

These are the same 3 logs above, all done today, same tune, same gas, same section of the same road on the same side.
  • Blue = AFE Elite
  • Green = stock air box, generic paper filter with ~10k miles, stock snorkel + scoops
  • Yellow = stock air box, same filter, no snorkel+scoops

24262



I'm semi-surprised how well stock air box with snorkel + scoops (and generic, old paper filter...it's literally been in the air box in a box in the garage for 5+ years) keeps up with the AFE, at least for now. For all the intake rhetoric that goes around, looks like $40 set of scoops on a stock air box is probably all anyone really needs on stock turbos, especially just for OTS tunes.

What I was planning to test in the first place is how much does the upstream pressure increase created by scoops actually help closed intakes. I've tested DCI straight against sealed AFE+scoops a few times on the road in the past at 20psi+ (with DCI losing in both power and WGDC), so I've long had a suspicion that sealed intake + scoops is no more or actually less restrictive than DCI when moving, on top of pulling only ambient air. Shop fans/blowers at usual dyno places don't move nearly enough air in volume at sufficient speed to make scoops work effectively, which makes it look like the stock air box sucks on the dyno (and it might without scoops). DCI is obviously less intake to pull through and lose pressure when going 130mph at a standstill lol

I'll tune something up for solid 2nd gear high RPM runs and redo this, then I'm going to keep the stock box/old paper filter in and turn it up to 22-24psi for some 3rd pulls at least to 5500rpm to see if there's any obvious restrictions in the stock air box with scoops anywhere.

As far as your car is concerned @Asbjorn, if you can't connect the snorkel and scoop to the stock air box to get the pressure benefit from moving, you're probably better off just getting rid of the box. It's pulling in under hood air anyway, so you're just forcing it to be sucked through the snorkel opening without any help for no reason (other than maybe a little less noise). If you dropped DCI in without touching anything, your WGDC would surely drop.
 

Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Great work, and thanks for testing a my power level first haha! My only concern here is that these deviations look a bit similar to what I might get from one pull to the next on the same day. But I guess you were expecting to see a much bigger differences, which is the main conclusion of relevance to me: they were not.

And yeah, I like the low noise of the stock intake, and live in the often polluted and dusty china, which is why I like to keep it over gains in power. As for the snorkel, there's no way back for me personally. On the positive side, the air pressure that would have normally helped the turbos, now helps cool the general engine bay instead. I like this, given the fact that I melted one of my canisters at the very first track session with the GC lites, and because I have seen my charge pipe silicone hoses fail a few times as well.

For my car and application, the turbos are still asked to do much less work than they are capable off. So until someone tells me I am actually killing then by running oem catted down-pipes and stock intake at 19psi, then I am to focus on engine temps instead.
 
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RSL

Sergeant
Aug 11, 2017
395
Yes, environmental factors will move WGDC up and down a few %, but it's limited. I did 6 runs, 2 each to make sure there were no anomalies. If time/traffic permit, I usually do a lot more for testing to verify a change. It could still be more controlled and complete than it was though. All runs were done yesterday, biggest time gap was AFE to stock since I had to come home and swap. There was a 3-4F ambient increase between, but even the scooped stock intake pulls showed little difference to AFE in that time. The stock with/without snorkel were done at the same time, there's only a 7 minute difference between them. I have about a 4 mile loop that I do here. 2 pulls with snorkel on first loop and stopped to pull the snorkel about half way for the next 2.

I know you're not worried about missing power over the engine bay temps, but I was actually shocked at the output difference in VD, and it's across the board. To me, that's big efficiency loss. Could have more power at current DC or same power at lower DC (and heat) simply by doing something with the intake.

I've thought about dumping the stock cats back in to test at least 4-5 times over the years. After having high-flow catted in for 3-4 years, I finally bought a set of catless to test last year, which was the total waste of time I expected it to be. High flow catted went back in the following weekend lol No gains and sounded gross on catless.

If I ever work up the energy to swap in the stock DPs for fun, I'll let you know how the test goes. I personally wouldn't be concerned about running them at this point, but on track, you will have higher EGTs for extended periods, so you may be the best test for their longevity at these levels. EGTs, not power, were the only reason I went to high flows in the first place. I ran stock DPs on 19-20psi stock turbos for probably 8 months without issue before I caved and got high flows, but did no tracking during that time. If anything is potentially at risk, it's probably the cats themselves, not the turbos.
 
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Asbjorn

Sergeant
Mar 10, 2018
481
Europe, based in China
Yes, environmental factors will move WGDC up and down a few %, but it's limited. I did 6 runs, 2 each to make sure there were no anomalies. If time/traffic permit, I usually do a lot more for testing to verify a change. It could still be more controlled and complete than it was though. All runs were done yesterday, biggest time gap was AFE to stock since I had to come home and swap. There was a 3-4F ambient increase between, but even the scooped stock intake pulls showed little difference to AFE in that time. The stock with/without snorkel were done at the same time, there's only a 7 minute difference between them. I have about a 4 mile loop that I do here. 2 pulls with snorkel on first loop and stopped to pull the snorkel about half way for the next 2.

I know you're not worried about missing power over the engine bay temps, but I was actually shocked at the output difference in VD, and it's across the board. To me, that's big efficiency loss. Could have more power at current DC or same power at lower DC (and heat) simply by doing something with the intake.

I've thought about dumping the stock cats back in to test at least 4-5 times over the years. After having high-flow catted in for 3-4 years, I finally bought a set of catless to test last year, which was the total waste of time I expected it to be. High flow catted went back in the following weekend lol No gains and sounded gross on catless.

If I ever work up the energy to swap in the stock DPs for fun, I'll let you know how the test goes. I personally wouldn't be concerned about running them at this point, but on track, you will have higher EGTs for extended periods, so you may be the best test for their longevity at these levels. EGTs, not power, were the only reason I went to high flows in the first place. I ran stock DPs on 19-20psi stock turbos for probably 8 months without issue before I caved and got high flows, but did no tracking during that time. If anything is potentially at risk, it's probably the cats themselves, not the turbos.
Well, you probably already saw what happened in my logs when I went from race-catted to oem-catted down-pipes. The car felt like it spooled slower, and my tuner said vanos had to be adjusted afterwards. The difference felt a bit similar to when I de-catted the mid-pipes. Torque comes on harder when de-catted, but peak hp is the same.

Anyway, I actually had the race-catted down-pipes custom made because I thought I could pass annual inspections in China with such cats. As it turns out my emissions were way too high when the car went in. On the positive side, given my exhaust setup, I actually like how the car sounds better with OEM down-pipes.
 

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