[jippii ensio]

I hear some believe inlet tubes being a restriction for upgraded stock frame twins. However, 34mm restrictors are good for >300 bhp per turbo, and the stock inlet tubes neck down to only one mm short of that diameter just before the turbos. RBs are the largest upgraded stock frame twins available, but even they are not really more than around 300 bhp per turbo. So the restriction is negligible for RBs, and non-existent for any other stock frame turbo upgrade.

[Ænema]

It's not ID at the filters or turbo inlets. It's when they pancake to clear the front and rear of the engine that it possibly becomes a restriction. There is a turbo inlet upgrade from DEFIV being tested that will prove one way or the other if the stock inlets are as big of a restriction as they look.

[135Pats]

Originally Posted by Ænema

It's not ID at the filters or turbo inlets. It's when they pancake to clear the front and rear of the engine that it possibly becomes a restriction. There is a turbo inlet upgrade from DEFIV being tested that will prove one way or the other if the stock inlets are as big of a restriction as they look.

That’s where I always figured the “restriction” was taking place, it just looks awful seeing it flatten out to clear the motor. I wasn’t aware DEFIV was working on it, so that’s good news.

[Jeff@TopGearSolutions]

Originally Posted by Ænema

It's not ID at the filters or turbo inlets. It's when they pancake to clear the front and rear of the engine that it possibly becomes a restriction. There is a turbo inlet upgrade from DEFIV being tested that will prove one way or the other if the stock inlets are as big of a restriction as they look.

Originally Posted by 135Pats

That’s where I always figured the “restriction” was taking place, it just looks awful seeing it flatten out to clear the motor. I wasn’t aware DEFIV was working on it, so that’s good news.

I agree. That pancake can't be good for flow characteristics.

[Ænema]

Originally Posted by 135Pats

That’s where I always figured the “restriction” was taking place, it just looks awful seeing it flatten out to clear the motor. I wasn’t aware DEFIV was working on it, so that’s good news.

The upgrades are already on a car and running(@uniter). The problem is they don't have before and after dynos or logs so Rick is looking for another car to test it to demonstrate gains.

[135Pats]

Originally Posted by Ænema

The upgrades are already on a car and running(@uniter). The problem is they don't have before and after dynos or logs so Rick is looking for another car to test it to demonstrate gains.

Do you know roughly what DEFIV did as a workaround? There isn’t much room in the space we’re talking about, so I’m very interested to see how he managed to alter the design of the piping. If you’re not privy to talk more in depth about a rapid prototype, that’s totally understandable

[uniter]

The pipes are not routed to the driver's side, rather the two are snaked around into the passenger side front bumper area, near the foglamp. Both pipes are covered in gold reflective heat foil and are equi-length. The install process is invasive and labor intensive, the pipes themselves are complex. It is not an inexpensive or easy upgrade.

[Transport3r]

I agree. That pancake can't be good for flow characteristics.

I'm waiting for someone to come out with empirical results until i draw a conclusion about these tubes. I'm sure the Germans spent more than a few hours optimizing the 'pancake' shape in a finite element environment. I'm very interested to see if a constant diameter tube would make a significant difference. Believe it or not, a flared out flatter shape might be beneficial for the flow characteristics keeping in mind the bends in the piping. A 90 degree corner (of which there are two in each pipe) is a much bigger cause of head loss in pipe flow than a change of the shape of the cross section, assuming it retains a similar cross-sectional area.

[jippii ensio]

Originally Posted by Ænema

It's not ID at the filters or turbo inlets. It's when they pancake to clear the front and rear of the engine that it possibly becomes a restriction. There is a turbo inlet upgrade from DEFIV being tested that will prove one way or the other if the stock inlets are as big of a restriction as they look.

Did you measure the pancake? It looks wide to me. What are the dimensions?

[Jeff@TopGearSolutions]

Originally Posted by Transport3r

I'm waiting for someone to come out with empirical results until i draw a conclusion about these tubes. I'm sure the Germans spent more than a few hours optimizing the 'pancake' shape in a finite element environment. I'm very interested to see if a constant diameter tube would make a significant difference. Believe it or not, a flared out flatter shape might be beneficial for the flow characteristics keeping in mind the bends in the piping. A 90 degree corner (of which there are two in each pipe) is a much bigger cause of head loss in pipe flow than a change of the shape of the cross section, assuming it retains a similar cross-sectional area.

I dont think their (BMW's) concern was maximizing inlet tubes for modded vehicles.
For a 300 HP stock vehicle they are more then adequate.

In the quest for maximizing efficiency and power it's definitely a reasonable upgrade.

We are not the first platform to suggest better flowing turbo inlet piping. Every other platform does this as one of their first upgrades on any many popular turbo charged applications, I.E. Mitsu Evo's.

Although I can see your point, a turbo inlet upgrade done correctly should yield better results...in theory.

[Transport3r]

Originally Posted by Jeff@TopGearSolutions

I dont think their (BMW's) concern was maximizing inlet tubes for modded vehicles.
For a 300 HP stock vehicle they are more then adequate.

In the quest for maximizing efficiency and power it's definitely a reasonable upgrade.

We are not the first platform to suggest better flowing turbo inlet piping. Every other platform does this as one of their first upgrades on any many popular turbo charged applications, I.E. Mitsu Evo's.

Like I said, at this point this is all speculation and armchair engineering. Empirical results are the only thing that will determine whether there is a significant benefit, especially considering the cost involved. Forced airflow is very complex and there is much more going on than piping diameter and shape. Sometimes increasing the diameter of a pipe will negatively affect the mass flow through the pipe because the fluid will unnecessarily slow down and then speed up again, which also alters boundary layer propagation.

On other turbo platforms like the Mitsu's, Vw/Audis, etc. The TIP is a common upgrade as you said, their main concern however is to eliminate the collapsing of the pipe under vacuum, as the stock pipe is rubber. We don't have that issue since ours are hard plastic.

[Jeff@TopGearSolutions]

Originally Posted by Transport3r

Like I said, at this point this is all speculation and armchair engineering. Empirical results are the only thing that will determine whether there is a significant benefit, especially considering the cost involved. Forced airflow is very complex and there is much more going on than piping diameter and shape. Sometimes increasing the diameter of a pipe will negatively affect the mass flow through the pipe because the fluid will unnecessarily slow down and then speed up again, which also alters boundary layer propagation.

On other turbo platforms like the Mitsu's, Vw/Audis, etc. The TIP is a common upgrade as you said, their main concern however is to eliminate the collapsing of the pipe under vacuum, as the stock pipe is rubber. We don't have that issue since ours are hard plastic.

I really have no dog in this argument. I guess we will see what they come up with.

Historically, on other platforms, there are advantages to a better flowing inlet pipe and or larger diameter inlet pipe. Both could be theoretically accomplished on this platform.

There are other reason they change the piping besides the rubber. Many companies offer different routing, shorter routing, and larger diameter piping too. (que ETS)

Worth it?

[Transport3r]

Originally Posted by Jeff@TopGearSolutions

Worth it?

Time will tell, I'm curious too.

Sorry if i came off as argumentative, I just enjoyed the discussion and wanted to explain the logic behind my opinion.

[135Pats]

Originally Posted by uniter

The pipes are not routed to the driver's side, rather the two are snaked around into the passenger side front bumper area, near the foglamp. Both pipes are covered in gold reflective heat foil and are equi-length. The install process is invasive and labor intensive, the pipes themselves are complex. It is not an inexpensive or easy upgrade.

Thanks for the info. I figured it would be labor intensive, there's no simple way around that.

Originally Posted by Transport3r

Like I said, at this point this is all speculation and armchair engineering. Empirical results are the only thing that will determine whether there is a significant benefit, especially considering the cost involved. Forced airflow is very complex and there is much more going on than piping diameter and shape. Sometimes increasing the diameter of a pipe will negatively affect the mass flow through the pipe because the fluid will unnecessarily slow down and then speed up again, which also alters boundary layer propagation.

On other turbo platforms like the Mitsu's, Vw/Audis, etc. The TIP is a common upgrade as you said, their main concern however is to eliminate the collapsing of the pipe under vacuum, as the stock pipe is rubber. We don't have that issue since ours are hard plastic.

QFT. The n54 community has dicussed the inlets plenty, but there is basically nothing empirical out there. Hopefully that changes soon.

[boris]

I was wondering about the inlets as well..

Are there any diagrams of them?

Did a search, but yielded awful, non-relevant results.

[Ænema]

Originally Posted by 135Pats

Thanks for the info. I figured it would be labor intensive, there's no simple way around that.


QFT. The n54 community has dicussed the inlets plenty, but there is basically nothing empirical out there. Hopefully that changes soon.

Hopefully Rick can get a second tester and we have plenty of WGDC logs to compare. IMHO those logs are just about the best practical data we can aquire. Theory is all well and good but application is what's important.

[jippii ensio]

Btw. I was talking from sea level perspective. At 6000ft with 20% less oxygen, they are restrictive with upgraded turbos.

[nitehawk]

Alpina_B3_lux has also been running the upgraded tubing similar to the one on the B3S. Not sure if he's had a chance to provide before/after results.

[SfValley335i]

In my experience, the inlet pipe didnt provide any whp gains but it did improve throttle response

[uniter]

Hey guys.
Here are two logs taken today at 80 Deg Farenheit,
They are on bone stock Stg 3 Procede maps (9/10/12)
Keep in mind the 7" ETS FMIC may alter the WGDC numbers, so when comparing it should be with a comparable setup as mine
Also note that my Fueling is maxing out in tip-in and I'm overboosting.
I will make changes to the Stg 3 map to get rid of the fueling issues then address the overboost. I wanted to take some logs on stock maps though for best-possible comparison (and armchair analysis.)

[jippii ensio]

Does anyone have an inlet tube for measuring the pancake'd part's width, depth and wall thickness for calculating the flow area of it.