[Puerto Rican 335d]

Tdi is this your substitute for the urea and does it work w/o compromising effects.

[TDIwyse]

Originally Posted by Puerto Rican 335d

Tdi is this your substitute for the urea and does it work w/o compromising effects.

The urea is coded out and I had previously drained the urea tanks, but not "flushed them". Was concerned with the remaining residue the urea would've left behind in the tanks/lines and was waiting for things to warm up so I wouldn't have to worry about freezing the fluid and not being able to drain it.

Also, I may at some point use the urea tanks for water/methanol injection instead of the washer fluid tank I have been using. Having urea deposits in that setup wouldn't be a good thing.

Interestingly, on the way to work this morning the car flagged a P205B - Reductant Tank Temperature Sensor Circuit Range / Performance which I've never seen before. It didn't throw it last night after I test drove the setup after the flush. Will be keeping an eye on that. Seems to be a fairly common issue. See below for example:

http://www.bimmerfest.com/forums/sho...d.php?t=739009

[Puerto Rican 335d]

cpould be the DEF tank going bad on you Ive gone thru 2 sets in a year, palnning to remove but your idea about using is as meth tank is SUPERB!!

[BB_cuda]

Funny, that 4" PVC could have easily been in your sewage drain system instead of draining pea (residue anyway) out of your urea tank. Glad to hear it is "flushed out" now. Sorry, another pun.

[TDIwyse]

Originally Posted by TDIwyse

Also, I may at some point use the urea tanks for water/methanol injection instead of the washer fluid tank I have been using

...

Interestingly, on the way to work this morning the car flagged a P205B - Reductant Tank Temperature Sensor Circuit Range / Performance which I've never seen before.

As I'm getting closer to attempting using the urea tanks for the H2O/methanol solution I've moved my pump (and its solution tank) to the rear of the vehicle about 4 weeks ago. This is an interesting placement as I pulled 6lbs off the front of the car (pump + bracket) to the center/rear of the car and that pump weight is between the axles. There's just enough space in these areas to allow the pump and filter to fit. Not sure why these spaces are there, but it worked out just right.

Also, I added ~1/2 gallon of distilled water back to the active tank to get the P205B code to go away. This might be a good thing if I go to the urea tanks for the H2O/methanol storage, as it would trigger a code to let me know the solution needs to be refilled...

[Puerto Rican 335d]

sweet

[Ajs_435d]

So, i dont quite follow.

Are we saying removing the CAT and putting straight through tailpipes - deleting mufflers will release some power?

Cheers

[TDIwyse]

Originally Posted by ajs_335d

So, i dont quite follow.

Are we saying removing the CAT and putting straight through tailpipes - deleting mufflers will release some power?

Cheers

There's 2 cats on the US 335d: Diesel Oxidative Catalyst and the Selective Catalytic Reduction units. The DOC was in the same canister as the DPF directly after the turbo. The SCR is in the mid-pipe section.

The biggest advantage to sustained power on 1/4 mile pulls came from modifying the DOC/DPF section. The SCR is not demonstrating any negative issues that I can measure at my present power levels and on the 1/4 mile pulls (pre DPF mods with ~12.6 sec capability the EGT's were rising to the point the car would de-fuel to protect itself shortly before crossing the line).

I was sneaking up on exhaust mods to see at what point the sounds/noise/turbo whistle would become objectional to me (others opinions may vary). From some of the video's on youtube I did not like the sound of the full straight pipe. The SCR in the midpipe along with Ecotune downpipe and muffler delete (muffler delete also saved a lot of weight) produces a really nice low, throaty sound with just a little turbo whistle.

At this point with an 11 second car I don't see any data from my measurements indicating removing the SCR would help power or efficiency.

[TDIwyse]

Originally Posted by TDIwyse

...
It seems that the EGT's with the diffuser in place are lower. But until I do a back to back test I'm not going to claim any advantage on any aspect with it in place.

Well, took me a lot longer to test this than I originally expected.

Yesterday I did some back to back testing on the interstate at a GPS specified 70 mph and using the cruise control. First run with diffuser on, 2nd with it off, 3rd with it back on.

Attached are comparisons of logs for the same stretch of interstate for the 2nd and 3rd run. Comaring raw data shows better aerodynamics with the diffuser ... no real surprise, but good to see it verified.

Another interesting aspect of the data is a way to tease out the "feel" of the better handling aspect. Did this by doing a standard deviation of the rpm and speed. Since the cruise control was being used both times there's no human interaction involved in maintaining the speed. But you can see the computer is having to work harder to maintain the set speed because the standard deviation of rpm/speed is larger for the non-diffuser test.

[iaknown]

Very interesting!

[Yozh]

Awesome. The aerodynamics of the d are not super great and as such anything will help. But this fully confirms diffuser's contribution in a quantifiable way. As soon as mufflers are coming out, diffuser in going in.

[Puerto Rican 335d]

Tdi are u going to market this im interested in it

[TDIwyse]

Originally Posted by Puerto Rican 335d

Tdi are u going to market this im interested in it

Oh good gracious no. As an extreme introvert that would be the last thing I'd want to do with a hobby. Would kill the fun aspect ...

[Puerto Rican 335d]

Really😁at least I tried

[austinla335d]

Originally Posted by TDIwyse

Oh good gracious no. As an extreme introvert that would be the last thing I'd want to do with a hobby. Would kill the fun aspect ...

You were kind enough to link us directly to your source and a pretty well rounded description of what and how as well. Anyone interested can have at it!

I wish I had the time and garage (and a few grand) to tune out my dpf, replace the downpipe and so on. Someday!

[TDIwyse]

Got a chance to test out my new lift and used it as an excuse to test the pressure on the exhaust system post downpipe as I hadn't seen anything posted on this and was wanting to get some data on it.

I'm using the built in OEM DPF differential pressure sensor (part #3 here http://www.realoem.com/bmw/showparts...87&hg=13&fg=15) and the Bavarian Technic tool to measure the data.

I'm using the first NOx sensor port to feed a line to the first input of the differential sensor and leaving the other line of that sensor open. So the data is the pressure being measured is the entire exhaust system from this point back relative to the pressure in the engine bay (which I'm not sure exactly what the pressure in the engine bay does vs speed ...).

Had to fashion my own fitting with an NPT to hose barb adapter. After this test I used a NPT "plug" to keep the exhaust from leaking out the hole...

This is at power levels high enough to push the vehicle down the 1/4 mile track in sub 12 seconds at ~120 mph.

Bav Tech tool reports boost in mBar and it's absolute, so this includes ~1000mBar for normal atmospheric conditions. So "boost" is what the turbo does + what the atmosphere is providing. So the Ecotune remap is requesting and getting ~3100 mBar (or ~2100 above atmosphere which is ~ 30.5 psi above atmosphere).

Bav Tech reports the DPF diff pressure in hPa. 650 hPa is ~ 9.4 psi.

The initiation of the plots includes some coasting in gear before the full fuel initiation to show a baseline of pressures.

Run #2 has some traction issues ... my winter tires were spinning and the nannies cut into some of the fuel fueling ...

[iaknown]

Looks like you're putting that lift to good use

I have not gotten a chance to do testing on this because I have some other issues but from my boost logs the midpipe is definitely making a difference.

So if I understand your post correctly, you are showing 9.4psi of pressure?? That's pretty high in my opinion. I wonder if anything is to be gained from the straight exhaust. In any case, so far I am finding the stock wastegate won't support it....

[TDIwyse]

Originally Posted by iaknown

Looks like you're putting that lift to good use

I have not gotten a chance to do testing on this because I have some other issues but from my boost logs the midpipe is definitely making a difference.

So if I understand your post correctly, you are showing 9.4psi of pressure?? That's pretty high in my opinion. I wonder if anything is to be gained from the straight exhaust. In any case, so far I am finding the stock wastegate won't support it....

Ha. Having the lift would've made the DPF experience much less painful...

Yes, it appears ~9 psi of pressure at full tilt is what is being measured. Was surprised at the readings. Higher than I expected. However, as you and others have described, having too little is also not good for the stock turbo/wastegate setup. Gets me thinking about playing with the SCR unit now and trying to sneak up on a happier middle ground ...

[Yozh]

Interesting that your differential pressure sensor is functional with a remap.
And if your pics are correct and you are using the first NOx sensor port then you are measuring pressure pre-SCR. Wouldn't it also be good to measure the pressure differential between that first (pre-SCR) and second NOx sensors (past-SCR) to see the difference?

[TDIwyse]

Originally Posted by Yozh

Interesting that your differential pressure sensor is functional with a remap.
And if your pics are correct and you are using the first NOx sensor port then you are measuring pressure pre-SCR. Wouldn't it also be good to measure the pressure differential between that first (pre-SCR) and second NOx sensors (past-SCR) to see the difference?

Having two probes right before/after the SCR would be the optimum way to measure what the SCR by itself is doing. That could be added in the future, but just means more fussing around time...

At least now the car has a reference point for future exhaust modifications and there'll be a way to monitor post downpipe pressure and the affect on turbo behavior.

[BB_cuda]

I can see both TDI and yozh point of view. True delta P across SCR is exactly what yohz suggests. It also gets you away from wondering what sort of Bernoulli's effect is going on with pressure in engine bay. Bernoulli comment is for high velocity air flowing along bottom of car. High velocity air means lower pressure unless I'm misapplying the principle. Perhaps the large engine lower cover/tray thing would isolate bay from flowing air close to roadway though.

On the other hand, once the SCR were removed if you can sort out the too little of waste gate issue (like iaknown is trying to work through), you have now lost your reference. If you keep doing it TDI's way, your reference of comparison is not messed with.

Perhaps that ambient pressure in the engine bay needs to measured directly rather than as a delta. There are dynamic and static pressure sensors. I'm familiar with the dynamic ones as I used to design accelerometers. Only difference is accel has ref mass and pressure doesn't with proper calibration. Static pressure is done using strain gauges internally.

[TDIwyse]

[on edit: iaknown has brought up some concerns about the accuracy of the Bav Tech "Actual Boost" numbers. I've verified his concern. Looking into this further ... so don't take the boost numbers as accurate ...]

Well, after seeing the ~9psi of pressure ... just had to know...

Had concern about removing too much backpressure due to warnings from others about overboost on the turbo's when all restriction was removed. Also wanted to see how "high flow" the catalyst was.

Well, the material doesn't look very high flow to my eye (or the ~9 psi of back pressure measured previously). And some of the channels were clogged with carbon. This is likely a consequence of running the downpipe.

First picture shows some of the material being removed. There's a 45 deg stainless oval pipe I purchased last year for the possible delete of the SCR. It looks like it could work if the canister were deleted.

Wanted to test the boost behavior with the empty SCR welded back shut to see if the tune could handle the lower restriction. Did several low/medium pulls in 3rd/4th/5th a few times and then checked the Bav Tech data. It looked good, so went back this afternoon and pushed it harder. The roads are still a little damp so traction is an issue, but was able to get some decent full skinny pedal runs. Attached an example full rpm 3rd gear pull and also a partial 4th gear pull (let up ~2900 rpm to avoid potential license loosing speeds).

Interestingly, not seeing any issues with overboost.

Exhaust sound is a little deeper than with the SCR material in place, and not noticing any additional turbo whistle.