[Poosik]

Originally Posted by TDIwyse

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.

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

Thanks for the read and words of caution.

[TDIwyse]

Originally Posted by DWR

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

Let me sum up...

Finally got around to doing the manometer measurements on this modification.

In short, the ram-air affect starts to occur around ~40 mph cruising speeds, and at a 65 mph there's a ~0.3-0.4 inh2o pressure. For some 3rd gear full fueling pulls the highest vacuum reported is just over 2 inh2o. That's a significant improvement over the OEM configuration for those modified people moving a lot of air...

Also, went to the strip last weekend. Was super crowded and somebody broke down and shut everything down while they had to re-prep the surface and only got a couple pulls in. But here's an example of a nearly smoke-free pull that, if I could've hooked, would've been in the 11's using this modification. This involved short-shifting the trans a little before peak hp levels where things become a little smokey...

[Poosik]

Originally Posted by TDIwyse

That's a significant improvement over the OEM configuration for those modified people moving a lot of air...

Please elaborate on this. This applies to jr stg 2 tune right??

Also, how is moving more air quantified?- by reading MAF in lb/min?

How is the RAM air effect created since air box openings are inside the engine bay, protected from positive pressure created at speed?

With reduced vacuum/higher flows, is there an increase engine growl? (like similar to CAI)

[TDIwyse]

Originally Posted by Poosik

Please elaborate on this. This applies to jr stg 2 tune right??

Also, how is moving more air quantified?- by reading MAF in lb/min?

How is the RAM air effect created since air box openings are inside the engine bay, protected from positive pressure created at speed?

With reduced vacuum/higher flows, is there an increase engine growl? (like similar to CAI)

Well, this is way beyond the power output of just a stage 2. I am using a tune from jr, but there's a lot of other things that are adding power.

MAF would tell you the amount of air, but I'm fully saturating the MAF at these levels (see previous posts for MAF data). So I'm not exactly sure how much air is being moved. But its over 44.1 lb/min.

The ram air affect is created at the kidney grill openings as air velocity increases and causes a high pressure to buildup in the front of the car, which is where the intake snorkel openings are located. It would appear from the data that at low MAF levels (low power) and higher speeds, even with the holes in the OEM airbox, there's more air being pushed in through the snorkel than is needed and this causes a slight pressure buildup. At high power conditions there's MUCH more air needed than the snorkel can support without vacuum restriction (it necks down before entering the airbox ... see previous pic with measurements). This is where the extra openings in the box allow for additional flow that doesn't need to flow through the snorkel, thus lowering the overall vacuum on the clean side of the filter/intake before the turbo. Reducing the loss before the turbo has a multiplicative benefit related to the pressure ratio of the turbo.

There would come a point if the extra holes are too big that I'd expect the ram air affect to be lost. Unless the entire engine bay area is under vacuum, which I haven't measured/quantified.

With the extra holes in the airbox there is an increase in the intake sound. But it's less pronounced than with the AEM cone filter.

[DWR]

Originally Posted by TDIwyse

MAF would tell you the amount of air, but I'm fully saturating the MAF at these levels (see previous posts for MAF data). So I'm not exactly sure how much air is being moved. But its over 44.1 lb/min.

If you can use Torque Track Recorder to capture the water manometer and MAF PID (with just MAF as a logging parameter, Torque should do a fair good job), we can (I will help, if you like) determine the true air flow at clipping. Just would like to confirm what the calculations say should happen.

[TDIwyse]

Originally Posted by DWR

If you can use Torque Track Recorder to capture the water manometer and MAF PID (with just MAF as a logging parameter, Torque should do a fair good job), we can (I will help, if you like) determine the true air flow at clipping. Just would like to confirm what the calculations say should happen.

Yep. It should also be in a 4th gear pull so it lasts longer, which means I'll need to find the right time when no one else is around... heading out of town for several days, so it'll likely be no sooner than late next week.

[Mik325tds]

Originally Posted by DWR

Now, if you can plumb back up to the front end and have sufficient flow area, you'll get a small ram air effect. The stock system does this well at highway speeds and low load. With your 1/4 mile trap speed that would be ~ 2% increase.

Dumb question - why wouldn't the scoops help for the ram air effect (without the filter box cut open)?
Apart from the fact that they have to be red in order to work properly...

[DWR]

Originally Posted by Mik325tds

Dumb question - why wouldn't the scoops help for the ram air effect (without the filter box cut open)?
Apart from the fact that they have to be red in order to work properly...

They do. In fact, I register a higher ram air pressure than TDIwyse (at high speed/low load), as I have not cut the holes. But as explained above, when the turbo is bringing in lots of air, the flow through the scoops cannot keep up. So,the direction of flow for the cut hole changes from relieving ram air pressure to relieving some vacuum during high flow. If the scoops could provide more volume, then there would be no need for the cut holes. That's what I have been pondering recently ... now if I could get some time to do something about it.

[Hoooper]

The last car I had we called this the ghetto airbox mod. It outperformed all other intakes so I'm not surprised to see this works well.

[DWR]

LOL, ghetto is ripping out the box and using dryer vent hose.
Reminds me of the old Thunderbolts ...

[TDIwyse]

So DWR and I had been going over manometer/mass air flow measurement ideas and testing methods. He had a lot of experience and helpful insights into using this method.

Initial results using Torque's Track Recorder and videoing while having gauges for speed/rpm/MAF were looking like >50 lb/min flow capability, but there was some aspects to this method I didn't like. One is there's some latency in the gauge response vs the video. And there's the possibility of bias in reading the manometer level off the video.

We discussed using the DPF pressure sensor as a means of measuring pressure drop instead of a manometer. Similar to what I did with the SCR back here (http://www.e90post.com/forums/showpo...7&postcount=60) but using his new DPF pressure sensor PID.

However, the pressure drop across the air filter wasn't sufficient to get above the noise floor of the sensor.

So today I played with moving the other side of the differential vacuum line to the CCV inlet on the pipe that goes to the turbo cold side. This is setup to be a venturi for sucking the CCV fumes, but if you're using an Open CCV approach, this means you can tie into this unused port... And that venturi affect creats WAY more vacuum. And the level is high enough for the DPF pressure sensor to read accurately.

Attaching some example data showing the curve fit and error between measured MAF results and vacuum pressure sensor calculated MAF readings for low/mid airflow cases. And then from a 4th gear pull across rpm. This at 58F and lower than normal ambient atmospheric pressure conditions.

Peak flow on this vehicle seems to be >51 lb/min for this ambient condition for this method of measurement.

[DWR]

Three things:

That's the curve, that's the curve, that's the curve!
It is showing the VE (indirectly) that I would expect and have seen so many times before. Excellent job!

I assume you are measuring across the air filter. If so, have you tried/can you try differential pressure from clean side of the air filter and the CCV port? If there is enough resolution, then we can standardize on the method for everyone. And I'll build a PID that incorporates the correlation fit.

Interestingly, this method measures airflow via a voltage signal. That could be used to control water injection, or fuel rail manipulation or ....

[TDIwyse]

Originally Posted by DWR

Three things:

That's the curve, that's the curve, that's the curve!
It is showing the VE (indirectly) that I would expect and have seen so many times before. Excellent job!

I assume you are measuring across the air filter. If so, have you tried/can you try differential pressure from clean side of the air filter and the CCV port? If there is enough resolution, then we can standardize on the method for everyone. And I'll build a PID that incorporates the correlation fit.

Interestingly, this method measures airflow via a voltage signal. That could be used to control water injection, or fuel rail manipulation or ....

Thanks for your help and insights on this exercise.

So, this data is measuring on the clean side of the filter (where my Filter Minder connection port is located) to the CCV tube. That venturi affect is quite large... it's measuring ~2.5 psi peaks (actually it was showing 25 psi, but I forgot to change your PID back from the 10X magnification we tried earlier), so there appears to be good margin on the resolution when using this connection scheme.

One interesting aspect I see is that the DPF pressure sensor is faster responding than the MAF. In other words, the DPF sensor leads the MAF response slightly, in both increasing and decreasing air flow (see attached of a zoom in of the two mid MAF responses in plot 1 above). Not sure if that's something related to Torque being a little slow, or if there's more latency in the MAF circuitry?

[DWR]

Originally Posted by TDIwyse

So, this data is measuring on the clean side of the filter (where my Filter Minder connection port is located) to the CCV tube. That venturi affect is quite large... it's measuring ~2.5 psi peaks (actually it was showing 25 psi, but I forgot to change your PID back from the 10X magnification we tried earlier), so there appears to be good margin on the resolution when using this connection scheme.

That's fantastic. Anyone can use this method. Who's making the new PID you or me?

Originally Posted by TDIwyse

One interesting aspect I see is that the DPF pressure sensor is faster responding than the MAF. In other words, the DPF sensor leads the MAF response slightly, in both increasing and decreasing air flow (see attached of a zoom in of the two mid MAF responses in plot 1 above). Not sure if that's something related to Torque being a little slow, or if there's more latency in the MAF circuitry?

My guess is latency in the MAF. Being frequency based, it takes some time to 'count' the frequency. Voltage reading of the DPF sensor is instantaneous.

[TDIwyse]

Originally Posted by DWR

That's fantastic. Anyone can use this method. Who's making the new PID you or me?

It might be a pretty easy tweak of your DPF sensor PID. All I'm doing in the spreadsheet is taking that sensors value, subtracting off the bias (in my case my sensor reads 0.088 psi when there's no flow, so I'm subtracting that value off), taking the square root of that, then multiplying by a scaling factor to get the magnitudes at the low/mid MAF readings to line up.

I'd like to take more data and see if the scaling factor changes with varying ambient conditions. If so, then the equation might need to draw on things like ambient temp/pressure/etc. Or from your experience, does this pressure/flow relationship stay pretty constant with varying ambient conditions?

[DWR]

Originally Posted by TDIwyse

I'd like to take more data and see if the scaling factor changes with varying ambient conditions. If so, then the equation might need to draw on things like ambient temp/pressure/etc. Or from your experience, does this pressure/flow relationship stay pretty constant with varying ambient conditions?

It will vary with ambient density. I agree, let's do this right. Good call.

[Got-Torque]

So did you end up using the dp sensor for controlling water injection or fuel rail pressure manipulation?

I must say, out of all the forums I've joined over the years, this one absolutely has the most in-depth knowledge and sharing of info/data than any other... It really is eye opening and informational to follow along from start to finish with data shared that proves or disproves the theory or modification.

[TDIwyse]

Originally Posted by Got-Torque

So did you end up using the dp sensor for controlling water injection or fuel rail pressure manipulation?

I must say, out of all the forums I've joined over the years, this one absolutely has the most in-depth knowledge and sharing of info/data than any other... It really is eye opening and informational to follow along from start to finish with data shared that proves or disproves the theory or modification.

Agree on the forum comment. There's been an amazing group of individuals sharing and helping and teaching. I've learned a significant amount from the contributors here.

I did make a Torque PID for this method of airflow measurements: http://www.e90post.com/forums/showthread.php?p=19151674

I've only used this for validating/testing modifications, and it's not "in the loop" of any power related modifications.

[335stoner]

I cut the box this weekend. I think I opened it up a bit more than what was pictured.. Got to drive it today and noticed the intake gurgle was way louder!

[Asonchadwick]

So in short, the airbox and not the filter is the restriction?

I have a filter I bought from a brand called simota.

They claim it can be run oiled or dry, just clean it more frequently dry. So far so good, i will say This has an extremely durable and heavy duty construction. I periodically check to see how it is filtering as i dont want to risk any dust particles flowing past. Anyone use these?