Author Topic: 2.25" Turbo Compressor Inlet + 3" Turbo Inlet Hose = ???  (Read 3949 times)

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Offline Airboy

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2.25" Turbo Compressor Inlet + 3" Turbo Inlet Hose = ???
« on: January 22, 2014, 11:13:30 AM »
Sometimes improvising to make things "fit" will neither save time nor money.



For this 2004 STi, the wrong inlet hose (or compressor housing option) was ordered for the turbo, a Blouch DOM2.5XTR.  Instead of getting the correct parts, they decided to stuff sections of rubber and silicone hoses inside of the turbo inlet hose to make up the difference.  Once assembled, it was really hard to spot that there was a mismatch in size.

The result?  The turbo was unable to hold 18psi past ~5300RPM.  Once it was found that there were hoses within inlet, it became apparent that the hose sections were folding over as air flow increased, closing off the inlet to the turbo.  In other words it looked like a large inlet but behaved like a very small one.  Replaced the inlet with a proper sized one and things were back to normal. At 6500RPM, the 4psi difference is worth about 40-45WHP.



In trying to save time and get the car "ready", the owner ended up paying for the extra time to diagnose the problem, another turbo inlet, and labor to install it.

Gain 50 ft-lbs, ask me how! :-)

Offline Asstuna

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Re: 2.25" Turbo Compressor Inlet + 3" Turbo Inlet Hose = ???
« Reply #1 on: January 22, 2014, 11:19:11 AM »
I'm curious. Were the internal edges definitely lifting? Or was the bore mis-match generating a hydraulic jump over the lip and creating turbulent air flow into the turbine?

Offline funk32

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Re: 2.25" Turbo Compressor Inlet + 3" Turbo Inlet Hose = ???
« Reply #2 on: January 22, 2014, 11:19:59 AM »
WOW

Offline LilDrunkenSmurf

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Re: 2.25" Turbo Compressor Inlet + 3" Turbo Inlet Hose = ???
« Reply #3 on: January 22, 2014, 12:19:38 PM »
If the sea was vodka, and I was a duck.
I would swim to the bottom, and drink my way up.
But the sea isn't vodka, and I'm not a duck.
So give me the vodka, and stfu.
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Offline darthekai

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Re: 2.25" Turbo Compressor Inlet + 3" Turbo Inlet Hose = ???
« Reply #4 on: January 22, 2014, 03:44:58 PM »
I'm curious. Were the internal edges definitely lifting? Or was the bore mis-match generating a hydraulic jump over the lip and creating turbulent air flow into the turbine?

at 5300 rpm in a 2.457L engine, I would expect flow in both a 3" smooth pipe and a 2.25" smooth pipe to be fully turbulent.

Could be (as slower v's start moving the reynold's # into the transitional zone) that the "start" of fully turbulent flow helped the air pick that lip up and flap it around.
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Offline Nick1234

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