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Discussion Starter #1
I have a 4BTA- CAC, CPL 1260 that someone before me has changed the Turbo. The turbo has a 4 Inch air intake and 3 inch out to manifold. The following info is on the Turbo Tag;

Assembly 3533320
Serial C028268
Customer 3925740-0-08/3
WH1C

There is no visible wastegate

The Bosch IP appears to be stock as the factory caps are still on the adjustments. Its obvious someone did some work prior to bolting on this turbo, The Turbo and Manifold have been bead blasted, new gaskets and bolts on the manifold and manifold/turbo and a new high pressure oil line to the turbo.

Any idea why this turbo may have been put used, what performance gains could be expected. ON the test stand, this engine runs great.

Is it good on this engine in a stock configuration, or should I change it back to a H1C.

Thanks
Paul

 

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look in the turbo thread at the top of the performance section

look at the turbo thread in the performance section it speeks of this turbo
 

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Discussion Starter #4
My Apologies, I did not search before I asked a question. I have been here since the beginning and did not remember discussion on the HX-35/WH1C. I have now read the entire thread and have two questions;

A question was asked on 1/24 in post #39, What Is Surging? Previously Compressor Surge was mentioned so I guess its related. what is Surging?

My WH1C must have a non waste gate housing as there is no waste gate anywhere. On a stock engine or with a little fuel up, its there a danger of to much boost and blow head gasket ? What boost is considered to much boost on a 4BTA Stock.
***
Ggg, Now that I understand the Wh1C, I will hang on to her for later use

Thank
Paul (who will use search first
 

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Paul - Surge means that the airflow in the compressor side actually reverses direction and goes backwards thru the compressor wheel. Any centrifugal compressor wheel (which is what the air side of these are) has what is called a "surge curve" which specifies the relationship between pressure ratio and flow. Pressure ratio is discharge pressure in psi absolute divided by suction pressure in psi absolute. Flow is measured in various units, say ACFM. For this application, the suction pressure is essentially constant at ambient atmospheric pressure less inlet filter pressure drop. When the discharge pressure (boost) reaches a certain level with no increase in suction pressure (which would lower the pressure ratio and increase flow) the airflow will actually reverse and blow backwards out thru the filter. Also heard it called a turbo fart. :D
 

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Discussion Starter #7
Paul - Surge means that the airflow in the compressor side actually reverses direction and goes backwards thru the compressor wheel. Any centrifugal compressor wheel (which is what the air side of these are) has what is called a "surge curve" which specifies the relationship between pressure ratio and flow. Pressure ratio is discharge pressure in psi absolute divided by suction pressure in psi absolute. Flow is measured in various units, say ACFM. For this application, the suction pressure is essentially constant at ambient atmospheric pressure less inlet filter pressure drop. When the discharge pressure (boost) reaches a certain level with no increase in suction pressure (which would lower the pressure ratio and increase flow) the airflow will actually reverse and blow backwards out thru the filter. Also heard it called a turbo fart. :D
Ok, thanks, I understand. I have had it called Turbo Bark. I knew it by that name.

Thanks
Paul
 

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The W in WH1C designates the wastegate. So this turbo has been built by someone using a WH1C core and an H1C exhaust housing.

Whether that makes it identical to an H1C I don't know.
 

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It's anyones guess what it is today...since at a minimum the turbine housing has been changed out. Or it could just have a compressor housing/data tag from a WH1C.. But if it is the original core it could have a 54+mm dia inducer compressor wheel. You should measure both wheels and inspect the core. The core could be well worth using as is... or an easier upgrade if it was an WH1C. Knowing the turbine housing critical area would be valuable information with the wheel sizes.

Additional worthless trivia.... based on the serial # it was made in Charleston, SC... probably during start of production for that turbo plant in 1989. The serial numbers were sequential for many years. I think that plant has produced well over 4 million turbos since it was started up.
 

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The WH1C will have the large compressor wheel and map width enhancment ring. That compressor will flow better than an H1C. The map width enhancment helps widen the flow map and make the compressor some what more versatile. I would not hesitate to run it and see what happens. It should spool just like the H1C and will have more capacity if you want more in the future.
 

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Discussion Starter #11
The WH1C will have the large compressor wheel and map width enhancment ring. That compressor will flow better than an H1C. The map width enhancment helps widen the flow map and make the compressor some what more versatile. I would not hesitate to run it and see what happens. It should spool just like the H1C and will have more capacity if you want more in the future.
Thanks, Turbos10
Paul
 

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They are nice turbo's ,I have one on my 6b in my truck.I would run it ,would be nice to find out what parts you have .Hard to tell because so many parts can be swaped from turbo to turbo.

Blocked off waste gate will net 37psi to 40 psi which is maxed out.

CrewCab59
 

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Discussion Starter #13
They are nice turbo's ,I have one on my 6b in my truck.I would run it ,would be nice to find out what parts you have .Hard to tell because so many parts can be swaped from turbo to turbo.

Blocked off waste gate will net 37psi to 40 psi which is maxed out.

CrewCab59
The engine this turbo is on is for a new project, probably in the spring. When I start that project, I will determine what parts are in this turbo. Its not all original since there is no wastgate. I have to much going on right now to start another engine project ha ha

Paul
 

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I had this turbo on my 4BTA and did whats been done to that one, swapped the housing for a non wasted gated housing (12cm2 in my case). Loved it and it ran absolutely great, miles ahead of my old stock H1C turbo. It is a weird 94 only Dodge turbo that is a little rare. They replaced it with the HX35 in 94/95 which has almost identical performance characteristics, from what I've been told..
 

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Surge...

I am trying to visualize the surge process... I assume the pressure is equalizing briefly via the combustion chamber-intake manifold-compressor side of turbo and finally the airfilter?
 

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I am trying to visualize the surge process... I assume the pressure is equalizing briefly via the combustion chamber-intake manifold-compressor side of turbo and finally the air filter?
A centrifugal compressor is not positive displacement like a roots-style blower, so it is dependent on its speed to maintain dynamic pressure. If the compressor wheel is too large and the speed is too slow or the pressure too high (for a given flow number), The pressure tries to flow backwards over the wheel and out the inlet, but as soon as pressure drops, the compressor tries to build pressure again. This happens over and over VERY quickly, and has a unique sound when it happens. The cure is either more flow, less pressure, or a smaller compressor wheel.
 

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Surge at low pressures and low compressor wheel speeds is common and harmless. When it happens at high pressures and high wheel speeds, it can be a violent occurrence. It can even bring the compressor to a near stop, or force the wheel backwards. It can even loosen the compressor wheel nut or damage the blades, but that is only in extreme cases. (like when a throttle plate slams shut quickly, but diesels don't have that problem)
 

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I am trying to visualize the surge process... I assume the pressure is equalizing briefly via the combustion chamber-intake manifold-compressor side of turbo and finally the airfilter?
Basically, the turbo temporarily builds boost higher than it can sustain. The pressure wave blows back through the turbo compressor, then the cycle starts again.
 

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In the business I worked in for 31 yrs we ran very large (up to 60,000 HP) air and various gas multi-stage centrifugals. When one of those babies surged you knew it, very complex control loops with blow off and recirculation valves to prevent it but sometimes they didn't work. Saw some very big crashes as a result, wheels in pieces, bearings, shafts, gears junk. Huge $$ both for rebuild and downtime costs.
 
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