Bell Mouth Inlets

[rob123456]

Hi all. I was recently looking at the GCG catalogue and came accross Bell Mouth Inlets for all different sized turbos. I was wondering if they are just for looks or are used for power gain???

Below are example pictures from the GCG site. (www.gcg.com.au)

All replys appreciated...

RoB

[GTRgeoff]

A bell mouth allows the air to transition smoothly into a runner. If it had square edges a turbulent layer sets up near the walls effectively reducing the size of the runner so the amount of air that can be drawn in reduces. I have conducted multiple experiments in labs to verify the existence of this phenomena.

[Adriano]

In some instances, these would definately make a difference, however the two cars i have tried them on(sr20 376rwkw, and 4g63 246rwkw)it didn't make any difference.

[rob123456]

OK so i understnad that the difference in power would be in proportion to the car, the amount of power the motor is producing and what mods are being used but what sort of power difference are we talking about???

[WazR32GTSt]

if they were so effective, then that would mean the stock design of the ribbed rubber inlet would be terrible for power

when in reality the stock ones don't really affect anything...

[GTRgeoff]

And it is Waz. Not only does it introduce horrendous turbulence, the bastard can suck closed at higher boost levels.

Nissan did an amazing job of the stock setup for the era, but it falls far short in some areas when the hammer drops.

[drgnball34]

do this bell mouths change spoolin sounds?

[Bliksem]

OK so i understnad that the difference in power would be in proportion to the car, the amount of power the motor is producing and what mods are being used but what sort of power difference are we talking about???

They fitted one of these in one of the High performance Imports DVD's and tested the power gains, if I remember correctly there was a 1-2kw improvement.

[Adriano]

They fitted one of these in one of the High performance Imports DVD's and tested the power gains, if I remember correctly there was a 1-2kw improvement.

I thought they were just a funnel so it can suck more rocks in LOL

Seriously the power increase depends on what you are comparing it to, if you compare it to a high flow with a stock intake there would be gains(as the standard intake sucks closed) However compared to a well setup intake, there is minimal gain.

[Omurru]

I should know all about this, I have an exam on it next week . What Geoff said is spot on. Bellmouth intakes are generally used because the duct loss is so slight it's considered to be zero, makes it easier to calculate things. I'd be interested to see the cfm output of a turbo compressor at a given rpm with/without a bellmouth intake. Maybe if you went from stock intake piping to bellmouth intake sticking out your bonnet you might notice a difference but otherwise I doubt it.

[nizmonut]

lets not forget a map sensor for all you Afm boys and girls out there. .....initial cost of the exercise for a 1 or 2 kilowatt gain....it's a little impractical

[R34NRG]

im sure it would make a bigger difference if you fed it cold air rather then sucking in hot engine heat.

just like any intake system.

[Omurru]

im sure it would make a bigger difference if you fed it cold air rather then sucking in hot engine heat.

just like any intake system.

Thats not the point of the topic.

[GTRgeoff]

lets not forget a map sensor for all you Afm boys and girls out there. .....initial cost of the exercise for a 1 or 2 kilowatt gain....it's a little impractical

No, you use it inside a larger pipe or in an airbox. Take a look in the stock ones on a Skyline. Little bellmouths. Also in the HKS pod (which is a piece of junk BTW) there is a nice one with a gradual flare. Made a nice exit from the custom airbox on my race car which has the AFM, twin turbos and high compression 3 litres of goodness. But what would us engineers know hey Kyle. Drifters have invented everything so far, just ask them. Do well on the exams mate.

They don't need to be a full rolled lip either, just a nicely curved entry into the piping.

[Gav]

Hi all. I was recently looking at the GCG catalogue and came accross Bell Mouth Inlets for all different sized turbos. I was wondering if they are just for looks or are used for power gain???

Below are example pictures from the GCG site. (www.gcg.com.au)

All replys appreciated...

RoB

The bellmouth assists with the induction of small mammals and young children into the turbine without arms and legs getting caught up on the lip of the compressor housing

[frozenwaffles]

i love it! that is all...