Single Turbo RX-7's Questions about all aspects of single turbo setups.

How restrictive would this be?

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Old 12-17-05 | 11:49 PM
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LUPE's Avatar
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How restrictive would this be?

I need to tight radius bend for the outlet on my compressor housing so that it clears my hood.

How restrictive would this be, would it cause a decrease in hp or other?


Last edited by LUPE; 12-17-05 at 11:53 PM.
Old 12-17-05 | 11:52 PM
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That's a pretty stiff bend... I'd be hesitant to use it.

You can't rotate your compressor housing I guess...
Old 12-17-05 | 11:56 PM
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Originally Posted by Wargasm
That's a pretty stiff bend... I'd be hesitant to use it.

You can't rotate your compressor housing I guess...
No, my compressor housing is stuffed against the fenderwell. It won't move at all

If the affects are small, I can live with it.

What do you think?
Old 12-18-05 | 12:06 PM
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I think you wil have trouble keeping it on.
Old 12-18-05 | 12:17 PM
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Use metal.

Old 12-18-05 | 12:22 PM
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This will sound extreme, and I'm not sure if it's even possible... but perhaps if you removed the compressor cover, you could have a shop weld a 90 degree smooth-bend pipe on to the top. My gut feeling tells me that a -welded- pipe will have less overall height due to the fact that you can do it without rubber couplers (and the flanges that they clamp to). I'm not sure what the compressor cover is made from and if you want someone welding it, but I do feel that this would provide the most compact solution. Just make sure the insde edge of the weld is as smooth as possible.
Old 12-18-05 | 12:25 PM
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Originally Posted by finnicky7
I think you wil have trouble keeping it on.
If you would see what I have on there now, you would retract that statement
Old 12-18-05 | 12:28 PM
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Originally Posted by Asleep
Use metal.


these look like they would be your best bet. They seem much less restrictive than the rubber ones, plus they have a lip so probably wont come off as easily.
Old 12-18-05 | 01:47 PM
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You will lose hp with either of those options. I've read somewhere (don't remember where) that up to 5% for every 90 degree bend. Wargasm is pretty on with removing the comp cover. We have gained at least a 1" or more doing what he suggested. If you gain that or more than add that to the radius of the bend it will help.
Old 12-18-05 | 02:16 PM
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Originally Posted by Zero R
You will lose hp with either of those options. I've read somewhere (don't remember where) that up to 5% for every 90 degree bend. Wargasm is pretty on with removing the comp cover. We have gained at least a 1" or more doing what he suggested. If you gain that or more than add that to the radius of the bend it will help.
Where did you hear 5% loss? I've read only 1% loss per 90 degree bend.
Old 12-18-05 | 03:52 PM
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I don't remember what book I read it in, but if I remember the point that was being made was not 5% was a given, but more like the more power the higher the % lost. With losses seen as high as 5%.
Old 12-18-05 | 04:05 PM
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I've seen several compressor housings with 90 degree bends welded to them. Seems like the best bet given the situation.

-Destin
Old 12-19-05 | 03:06 PM
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A while back I was faced with the same issue that your having Eric. However, I chose not to weld on the compressor housing for 3 reasons. 1, If you choose to weld a bend on the compressor housing, and later down the road you decide to sell the turbo, your stuck selling it to the 3rd gen. community. This increases the time it will take to sell the turbo. Since it's configured around the 3rd gen. I doubt it'll fit something like a Mustang or Camaro. 2, I think it looks like ****, even with a great welder. 3, I like to have a "hump" (flex) coupler at the outlet of the turbo. This is just personal preference though.

I ended up making a fixture to bolt the compressor housing to, then placing it in my CNC wire EDM. I cut ~1/4" off of the outlet. I'm unsure of how your compressor housing looks, but below is a picture of my GT40R. (Picture taken before the cut) If you look at the outlet, you can see there's quite a bit length where the coupler slides on. When I took the cut, it pretty much took off the whole lip that helps keep the coupler from coming off. If I have issues with the coupler coming off, i'll have a welder place some small beads around the outlet. That should take care of any problems I might run into. Just something to be aware of if you choose to do this, try and get it cut on a wire EDM. I decided against putting it on one of my CNC mills because of small chips. I didn't want to take the chance of missing a small metal chip while cleaning, and having it damage something.



If that's still not enough clearance for you, try a casted 90 degree elbow. (Picture below) For a little added clearance, I set the elbow up on one of my manual mills, and took ~1/8" off. Since there's not any small areas for small chips to hide in an elbow, I wasn't worried about missing any during cleaning.



Just simply switching from a mandrel bend (3.75" center line radius) to a casted elbow (2" center line radius) you'll get 1.75" more in clearance. (I came up with 1.75" by laying out both bends in FeatureCAM, and taking a measurement) Then add a 1/4" to that if you take some material off your compressor housing, and then another 1/8" from taking material off the casted elbow. You'd end up with ~2.125" more in clearance over using a mandrel bend (3.75" center line radius) and coupler.

You'll experiance the highest power loss using a 90 degree coupler. A casted elbow will have a little higher power loss over a mandrel bend, but the power loss between the two isn't enough for me to weld on a mandrel bend to my compressor housing. As far as exactly how much power you'd loose between the 3, i'm unsure.

-Alex

Last edited by TT_Rex_7; 12-19-05 at 03:20 PM.
Old 12-19-05 | 05:56 PM
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Thanks for the idea Alex...... I just bought the aluminum elbow and I'm going to cut a portion of the top off and weld the elbow on. This should work, it better
Old 12-20-05 | 09:13 AM
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coupling

Check with Vibran Performance, coupling have perfect radius , many size also.
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