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

[Bnks334]

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.

I appreciate the effort here. Actually getting data and presenting it takes a lot of time. Most of the time it's not even worth sharing lol

There is a reason why every manufacturer in existence intakes air from an area of high pressure (windshield, rear of hood, or front fascia). A sealed intake works.

The only issue I have with what you did is that 2nd gear is not very meaningful. Do the same tests in 4th gear. You will see 2x as much airflow at the top of 4th gear vs the top of 2nd gear regardless of hitting 6000rpm in both gears. Stock box might get edged out by DCI when you are driving the stock turbos to their limits, but, the difference is marginal and not the massive gains like people claim. Dyno's are definitely misleading in this regard. I've been on a few dynos and none of them are done in a wind tunnel to even simulate 60mph let alone the 120+ that you hit in 4th gear. Like you said, of course taking the intake off on the dyno will free up some restriction... But once you get rolling the stock intake gets pressurized. You'd be crazy tot think that the turbo is intaking more air than what is damning up at the front fascia when the car is rolling.

 

[RSL]

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.

That hard initial hit and can be had on any, just needs some tweaks. I tend to keep that pretty minimal anyway. Traction is bad enough without the "just been rear ended at 45mph" on set lol

Agree, the high-flows are just as loud as catless for cold start or WOT. I keep the flap stock and it helps quite a bit the rest of the time.

I appreciate the effort here. Actually getting data and presenting it takes a lot of time. Most of the time it's not even worth sharing lol

There is a reason why every manufacturer in existence intakes air from an area of high pressure (windshield, rear of hood, or front fascia). A sealed intake works.

The only issue I have with what you did is that 2nd gear is not very meaningful. Do the same tests in 4th gear. You will see 2x as much airflow at the top of 4th gear vs the top of 2nd gear regardless of hitting 6000rpm in both gears. Stock box might get edged out by DCI when you are driving the stock turbos to their limits, but, the difference is marginal and not the massive gains like people claim. Dyno's are definitely misleading in this regard. I've been on a few dynos and none of them are done in a wind tunnel to even simulate 60mph let alone the 120+ that you hit in 4th gear. Like you said, of course taking the intake off on the dyno will free up some restriction... But once you get rolling the stock intake gets pressurized. You'd be crazy tot think that the turbo is intaking more air than what is damning up at the front fascia when the car is rolling.

Thanks and 100% agree. Those were in 3rd, but can't even get to 7000rpm with that around here, let alone a full 4th. I've never been a fan of DCI (or a believer in the sales pitches) and have only installed a few times to back-to-back test against sealed on the hybrids. I did the same with catless DPs.

This was the first time I've put the stock air box back in years though and was quite surprised how well it does and it appears scoops make the difference. I will test with/without scoops specifically, but it was interesting to see, especially on a crap used paper filter from the dealer.

Yeah, 2nd gear absolutely sucks for this, but at least I can wind it out without too much risk. It's not meant to be definitive in any way, shape or form, but is telling for speeds/acceleration I'm at 99.9% of the time.

WOT through 5th-6th would be great, but I don't go to airport events. If I ever do, I'm bringing all the intakes lol

 

[Asbjorn]

Just a quick update on my exhaust valve issue. I unpinched the vacuum line to the exhaust valves today, which caused them to close. This time however they stayed closed even after the cold start period. And even as I test drove the car. Shut, at all times.

So it seems that whatever was causing them to sometimes not open before has now failed completely. The lines get vacuum all of the time.

So I have pinched it back again to keep the flaps open. Puzzling....

 

[RSL]

If the actuators are getting vacuum all the time when the engine is running, seems like the solenoid would be dead mechanically/electronically or disconnected. Have you tried flashing back to stock or stage 0 to see if something is off in the rom? Can't imagine it is, it if it's not that, almost seems like it has to be a problem with the solenoid.

 

[Rob09msport]

If vacuum is being wasted cause of a bad solenoid couldnt that make wgdc read higher than the turbos are actually seeing?

 

[RSL]

Technically maybe, realistically it's highly doubtful. It would only be wasted if it's leaking to atmosphere, otherwise, it's going to terminate at the exhaust valve or in Asbjorn's case, tied off = no leak. It's so trivial, not sure it would have any impact on the BCS whatsoever, even if it were leaking to atmosphere.

I haven't followed that line all the way up, but always thought it was the hose tee'd into the brake booster under the hood, so a leak on that hose can't be a real big concern to engineers or is anything that the vacuum pump can't overcome and still produce target vacuum.

If I were remotely curious/concerned about it, I'd do the golf tee mod with and without the tee and measure at BCS, but doubtful there would be any measurable difference.

 

[Rob09msport]

Technically maybe, realistically it's highly doubtful. It would only be wasted if it's leaking to atmosphere, otherwise, it's going to terminate at the exhaust valve or in Asbjorn's case, tied off = no leak. It's so trivial, not sure it would have any impact on the BCS whatsoever, even if it were leaking to atmosphere.

I haven't followed that line all the way up, but always thought it was the hose tee'd into the brake booster under the hood, so a leak on that hose can't be a real big concern to engineers or is anything that the vacuum pump can't overcome and still produce target vacuum.

If I were remotely curious/concerned about it, I'd do the golf tee mod with and without the tee and measure at BCS, but doubtful there would be any measurable difference.

Makes sense. I wasnt sure if bad solenoid could or would leak to atmosphere or just would leak across its gate but I see your point that either wouldnt have that big of an effect

 

[Asbjorn]

I have noticed that when I drive on track, if I get on the brakes immediately after WOT, sometimes the brake feels harder to press. Sort of pumped up. I do not know if it is just in my head - but could it be that the failing solenoid that sends vacuum constantly to my (pinched) exhaust, is leaking a bit, causing the brake vacuum to be low when the turbos are also getting WOT-level vacuum? Otherwise it is just my brake fluid being cooked...

 

[RSL]

Honestly not sure. I really do doubt it, but on track maybe something would be noticeable. I don't have a vacuum gauge I trust or I'd measure myself out of curiosity.

Still have your vac canisters?

Maybe consider disconnecting/capping the exhaust vacuum source under the hood and eliminate the entire flapper hose as a question mark.

 

[Asbjorn]

Honestly not sure. I really do doubt it, but on track maybe something would be noticeable. I don't have a vacuum gauge I trust or I'd measure myself out of curiosity.

Still have your vac canisters?

Maybe consider disconnecting/capping the exhaust vacuum source under the hood and eliminate the entire flapper hose as a question mark.

Yes the canisters are still at the party.

So if I want to eliminate the entire exhaust flapper hose and solenoid, I just pinch this tube marked in red right? It is T-ed to the hose runing to the brake booster. I cannot for the life of me find it on realoem, and just want to make sure I am not cutting vacuum to something essential.

 

[RSL]

I've never been able to find out for sure either, but *think* that's it. Ideally, I'd follow that line all the way back to comfirm since it is connected to the booster line, but I'm too lazy for that these days lol

I'd test that there's vacuum on the input hose to the solenoid in back first. If there's vacuum with it connected under the hood and none with it disconnected (pull off and cap tee on the booster line), that should be it.

 

[Asbjorn]

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.

View attachment 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).



View attachment 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

View attachment 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.

Finally tried DCIs - posted about it here: https://bmw.spoolstreet.com/threads...-only-anyone-experienced-this.5600/post-81803

Basically they made no difference to wgdc, boost or iat at my power level. Have already reverted back to stock filter + snorkel. Still no scoops though.