[DWR]

Originally Posted by Gearhead51

In the RX7 world, there are people that run h2o nozzles pre turbo to make the turbo act larger... most obvious concern pre turbo is compressor wheel erosion, but I don't know that it has ever been proven.

Yes, compreessor wheel erosion is real. However, wet compression is commonly used in commercial turbine installations and large marine diesels. There have been numerous studies on the long term effects. High pressure and smaller nozzles seems to be the key, as that assures small droplet size.

For automotive diesels, methanol is often added. Methanol helps speed evaporation and thus decrease droplet size rapidly. At least one study shows that water droplets @ 10um do not impact the wheel, but follow the air flow. Wheel erosion takes hours of continuous operation in the worst cases and days, weeks, or months otherwise. Used twice a day for 10 second bursts, it would take years to see any significant effects, in a poorly executed installation.

Finally, there are several OEM examples of wet compression. Carbs can do a nice job of atomizing liquid. The factory Pontiac 301 turbo V8 was a draw-through, the factory Buick 231V6 (pre Grand National) was a draw-through, the Maserati bi-turbo was a factory draw-through, and the early Ford 2.3 Turbo (1979-1982ish) was a factory draw-through.

[TDIwyse]

Originally Posted by Chief Orman

Over the past couple of years I have also noticed the weird filter/dirt pattern in the airbox. However I have noticed a variety of aftermarket airbox replacements. Has anyone out there used one of these? I personally am not a fan of K&N filters given the amount of mist/soot thrown off by our engines.

I had used an AEM dryflow filter for a couple years (see attached with the homemade heat shield configuration). It gives much more intake sound, is a tiny bit less weight, and multiple used oil analysis showed it was doing a good job with filtering (and I live on a gravel road in a rural environment with a lot of dust). However, it significantly altered the MAF readings due to how it changes the pattern of the air going into the MAF. The MAF will see a much lower air flow. It would throw a MAF code the first time I swap it in if I didn't reset adaptations first. And even then it would still throw an initial code sometimes...

Compared to the OEM airbox in its stock configuration, the water column tests I did awhile back, using a shop vac for flow, showed it had a small % benefit. However, with the mods I've recently done to the OEM airbox, and the change in the filter minder behavior, the AEM should be a large % worse.

[DWR]

Originally Posted by TDIwyse

Maybe something like this? His thread has some good pics in there...

http://www.e90post.com/forums/showthread.php?t=183780

Real nice example. I've used shop vac attachments in the past.

[GottaBeKD]

Originally Posted by TDIwyse

Well, I don't have enough resolution to say it's at a 0 vacuum (the gauge is on the clean side of the airbox, not in the area where the holes are). The filter minders lowest reading is ~12 inh2o. So it's somewhere lower than 12 inh2o. I may order another filter minder with a lower range now that I've got the losses reduced.

A positive pressure pre-turbo would help, per DWR's explanation above. It would have a compounding affect.

Maybe red scoops will help with positive pressure. :

[DWR]

Originally Posted by TDIwyse

Well, I don't have enough resolution to say it's at a 0 vacuum (the gauge is on the clean side of the airbox, not in the area where the holes are). The filter minders lowest reading is ~12 inh2o. So it's somewhere lower than 12 inh2o. I may order another filter minder with a lower range now that I've got the losses reduced.

Pretty easy to build a water manometer. Materials list: yard stick, plastic tubing, tape, food coloring, H20. Plus, it will satisfy any redneck inclinations.

[TDIwyse]

Originally Posted by DWR

Pretty easy to build a water manometer. Materials list: yard stick, plastic tubing, tape, food coloring, H20. Plus, it will satisfy any redneck inclinations.

Yup. I've got my redneck water column out a lot over the last few years :-) I like the filter minder as it's a permanent installation. Driving around with the water column in the cabin creates some undesired 'splaining when carrying passengers...

[DWR]

You just like the filter minder because it's made by your neighbors

Engineered Products Company
2940 Airport Blvd.
Waterloo, IA 50703

[TDIwyse]

Ha. Had no idea who actually produced those. Just looked on Amazon and got the prime shipping option with the range I wanted. They must be the supplier for the AC Delco unit.

[Poosik]

TDi, are you able to quantify any benefits with increasing air permeability to stock filter box?

[Puerto Rican 335d]

GottaBeKD yeah bet on the red scoops jajajajaja still running fine

[TDIwyse]

Originally Posted by Poosik

TDi, are you able to quantify any benefits with increasing air permeability to stock filter box?

Yes.

First, I got a lower reading filter minder installed last night. I starts registering at ~6 inh2o. On the full fuel runs its still not budging. So there's measured evidence of at least 0.5 psi reduced vacuum pre-turbo.

The log data shows some interesting behavior in terms of the MAF and AFR and Boost. I'm convinced I have proof the MAF clips at 44.09 lb/min, as the logs show better AFR and more boost despite having the same clipped MAF response as shown in post #1. If the air flow was the same for the same fueling, the AFR could not be higher ...

I use PerfExpert app for on road dyno data. I've posted many times comparing its usefulness. I'm not claiming it's numbers are accurate*, just that it's very repeatable for the way I'm using it. And it shows more whp as the losses pre-turbo were reduced.

* Regarding it's accuracy, it was predicting whp of 416 for the configuration I took to the dragstrip and did 11.9 ET into a strong headwind. Online references (http://www.stealth316.com/2-calc-hp-et-mph.htm) and dragstrip calculators (Hot Rod Calc is one DWR turned me onto) would indicate upper 400 whp numbers based on dragstrip performance. So I'd suggest that the way I'm using it gives conservative numbers compared to on-road results.

[DWR]

Originally Posted by TDIwyse

First, I got a lower reading filter minder installed last night. I starts registering at ~6 inh2o. On the full fuel runs its still not budging. So there's measured evidence of at least 0.5 psi reduced vacuum pre-turbo.

Ahah! You're gunna hafta splain the wateer mainometer in da frunt zeet, mah frend.

[Poosik]

Thank you sir.
I'm surprised more users aren't excited about these findings.

[Poosik]

I want to piggy back the JBD on my stage 2 JR tune. Firstly I'd like/need to understand the meaning and relationships of data pulled by apps like BMWhat/PerfExpert. Can you guys recommend reading material that covers these topics?

[ninja_zx11]

Nice work TDIwyse and thanks for sharing!!
Any suggestions for X5 35D M57 engine?haven't checked the shape and profile of the airbox but will look into.

[Mark M]

I will confess this thread inspired me to change the air filter this week. Seems the old one was much dirtier than I had expected.

Next week sometime my car will receive a dose of maple leaf magic in the form of 1s and 0s from our guru friend in Oakville.

[temporaptor]

Originally Posted by ninja_zx11

Nice work TDIwyse and thanks for sharing!!
Any suggestions for X5 35D M57 engine?haven't checked the shape and profile of the airbox but will look into.

The air box sits right on top the engine (part of the engine cover), it will be a lot harder to chop up and get good results. Maybe you could add another duct from the core support to the air box like the v8 x5's have

[TDIwyse]

Originally Posted by Poosik

I want to piggy back the JBD on my stage 2 JR tune. Firstly I'd like/need to understand the meaning and relationships of data pulled by apps like BMWhat/PerfExpert. Can you guys recommend reading material that covers these topics?

Some thoughts and things to consider...

It would be in your best interest to be logging some key parameters to know if you're going to be damaging your engine/turbo's. Just stacking stuff without monitoring and measuring and quantifying results is a quick way to start breaking expensive things. One good thing to understand is your EGTs. Here's a pretty good read: http://www.bankspower.com/techarticl...t-is-important

But note our EGT probes are after the turbo, which will read lower than what's going on in the exhaust manifold.

Also, the way the DDE adapts/learns, just stacking the JBD on top of something else may cause adaptations to remove the stacked affect.

You should also be concerned on the amount of peak torque this stack can introduce into your drivetrain.

It would be unfortunate for people to start breaking/damaging things by being over zealous and jumping into deep waters without being careful.

[DWR]

Decided to do a simple experiment to verify the MAF is near the edge of its ability to measure air flow. Blocked @ 1/5 of the MAF tube to cause greater velocity over the sensor.


The result was clipping at 44.1 lb/min. It was interesting that the orientation of the foam had dramatic effects.
In one particular orientation it actually caused the MAF to read lower flow.


Crude chart is due to the slow sampling rate of Torque vs rapid acceleration in 3rd gear. Still the effect is clear. What should have happened was a multiplier effect; the 2 curves diverging with increasing air flow.

So to measure these higher flows we either need to go to a larger MAF tube and remap the MAF transfer function OR need to use pressure drop to extrapolate.

[TDIwyse]

Thanks for confirming the clipping value DWR.

One thing I find interesting is that the clipping MAF doesn't limit the fuel injection rate (at least with the DDE remap I'm running now). It will continue to increase fuel flow rate as rpm increases, even when the MAF clips.

I am, however, curious as to how much air is actually going through the system so I can better use the matchbot calculator as a sanity check. It would appear the redneck manometer may have to come out again at some point...

Although, the AEM cone filter actually produced something like a ~ 15% lower MAF reading (would have to go back and double check logs) than the OEM airbox due to how it altered the airflow pattern. Hmmmm...

[DWR]

Originally Posted by Poosik

I want to piggy back the JBD on my stage 2 JR tune. Firstly I'd like/need to understand the meaning and relationships of data pulled by apps like BMWhat/PerfExpert. Can you guys recommend reading material that covers these topics?

You can start by reading this: Don't do it. Sorry, I could not resist
Seriously, you have the right idea - study the subject first.

Many folks want to buy the tools first and then figure out what to do with them. I think you will find if you figure what you want to do first (technically, not just desire), then the why and how of the tools comes naturally.

The attachment is a good place to start for specific information about sensors and actuators and their function for the 335d engine.

Here's a link to some info on how AFR affects a diesel. http://www.4btswaps.com/forum/showth...A-F-Ratios-etc.

If you don't have some background fiddling with automotive things, the learning curve can be quite steep. TDIwyse is giving you some very good direction that may not be obvious, yet. You can learn alot by reading his posts.

My sage advise is mind the torque in the mid range rpms, watch EGT and AFR, sneak up on the mods, be patient and persistent or pay someone else.
Good luck.

[DWR]

Originally Posted by TDIwyse

Thanks for confirming the clipping value DWR.

One thing I find interesting is that the clipping MAF doesn't limit the fuel injection rate (at least with the DDE remap I'm running now). It will continue to increase fuel flow rate as rpm increases, even when the MAF clips.

As you know, I am always happy to assist you with your last mod

As I said, in one configuration it was actually under reporting airflow. Readings were down about 10%. Didn't seem to make a difference in fuel flow. So, we have tested it from both sides and come to the same conclusion. If the MAF is a limiter, it is a very loose constraint.

If we under report MAP will the same thing happen - I don't think so. And we already know AFR, as reported by the O2 sensor, doesn't do much until you practically get fuel quenching. Hmm, I think we just learned something ...