Increase Intake Manifold Size: Tips & Experiences

Hello,

After reading the technical article about flow losses on the intake side of the turbocharger, I have some questions about it.

Here's the translation:

"On my engine (ASV), the entire intake system looks like this:"
LuFi-Kasten --> Air filter housing --> Thick, accordion-like pipe (approx. 12cm diameter) --> Curved pipe (A) that runs down from behind the motor to the turbocharger.

The diameter is approximately 4 cm at its thinnest point.
I would like to replace this hose with something thicker. My loader (standard model) already runs with a slightly increased boost pressure, around 1.1 to 1.2 bar.
I initially thought about using Samco hoses. They are certainly reasonably temperature-stable, but unfortunately, they are also very expensive.
Does anyone have a good recommendation for suitable hose material?
What about the temperature at the turbocharger inlet for the intake air? I assume that the turbocharger, being made of metal, transfers heat relatively well from the exhaust side of the engine. What kind of material must that hose be made of in order for me to be able to use it there?

Best regards,
Georg.

Okay, so my 1Z has a 76mm pipe from the air filter to the turbo inlet, which gradually tapers down to 46mm.

Da der Turbo keinen groesseren Ansaugstutzen hat, bringt jeglich erweiterung wohl ..... NIX

To the right, the 76mm pipe.
http://www.luxus-wg.de/~martin/auto_bilder/AGR_Saugstutzen/viele_Teile.jpg

Unfortunately, I don't have a picture of the "funnel" that leads down to the turbocharger.

But here he goes in.
http://www.luxus-wg.de/~martin/auto_bilder/Kruemmer/Oel_in_wastegate_dose.jpg

My opinion: Feel free to tinker, but behind the air filter, it won't make any difference.

m;

dieselmartin wrote:

My opinion: Feel free to tinker, but behind the air filter, it won't achieve anything.

I agree.

For some (as yet unexplained to me) reasons, the inlet openings of the compressors are designed to be so small that the air rushes in at nearly the speed of sound when the "charger" is operating at full load.

The gradual tapering of the pipe from the LMM (mass airflow meter) to the intake manifold is, in my opinion, likely to be more aerodynamically efficient than a stepped transition, for example, from 10 to 4 cm directly in front of the intake manifold.

Regardless of that, the additional pressure loss caused by the usual constricted intake nozzles is noticeable, and in practice, this is practically not compensated for on the way to the turbocharger, AFAIK.
The principle that the weakest link determines the strength of the chain doesn't necessarily apply here, but removing the restriction on the intake manifold still makes sense.

"I completely agree with Ulf. The inlet of the charger is the limiting factor. What bothers me about my ASZ engine is the constriction of the aluminum pipe near the exhaust gas recirculation system. Something could be done about that, but I think the effort and cost wouldn't contribute significantly to the performance gain. The result wouldn't exceed the measurement tolerances."

Regardless, the additional pressure loss caused by the usual constricted intake nozzles is noticeable, and in practice, this loss is practically not recovered on the way to the turbocharger, AFAIK.
The wisdom about the weakest link in the chain, which determines everything, doesn't necessarily apply here -> Removing the restriction from the intake manifold still makes sense.


I can confirm that. I replaced the air intake boot on my AXR engine with a 60mm flexible hose. To do this, I disconnected the clutch pedal switch, and the EGR valve is 'defective.'
The turbo kicks in better below 1800 RPM. The engine responds better to changes in RPM in the lower gears, especially in first gear. Previously, it felt like a torque limiter was engaged in first gear, but that's gone now. If you're not careful and overdo it, the ASR (traction control) will have a hard time because the engine revs up almost like a gasoline engine. The engine also revs higher. You no longer feel the need to immediately floor the accelerator when accelerating because something starts to happen earlier. Everything feels smoother overall.
In the 5th gear, however, not much changes. The maximum speed remains the same.
So, the smaller the step, the more progress you make.
But don't expect anything drastic. The change is small, but it's definitely noticeable.


It's important that the pipe has as straight a run as possible. I also tried using a 70mm plastic pipe with a bend. However, the bend is more of a kink. The resulting turbulence (noticeable by a louder intake noise) likely confused the mass airflow sensor.


Unfortunately, I am missing a diagnostic device (software + laptop) for the measurement trip.
Unfortunately, I am unable to provide any images, as I do not have access to a camera.

ulf wrote:

For some (as yet incomprehensible to me) reasons, the inlet openings of the compressors are designed to be so small that the air rushes in at nearly the speed of sound when the "charger" is operating at full load.

Okay, the goal is to have small compressors that respond quickly. In a simplified way, the pressure gain in a radial compressor depends on the ratio of the inlet diameter to the outlet diameter.

christians wrote:

The pressure gain in a radial compressor, in simplified terms, depends on the ratio of the inlet diameter to the outlet diameter.

Aha - I've learned something new again