Anyone done a "over/under" style compounds with primary on top?

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BigBlue12V

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Apr 27, 2008
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Like the title says, looking for pics and info on doing an over/under style compound mounting, with the primary on top. in the "turbo piping pictures" thread I found ONE person doing this, I apologize I can't remember the username, not digging through 39 pages to find it right now. Anyway it was a 3rd gen and he painted his stuff green.

I'm looking to do this setup on a 96 with a HX35/40 hybrid and an HT3B. Headcase98002 and I built his setup which is over/under with primary on bottom. We have good reason for needing to put my primary up top but I'll save that until its done and then the pics will explain :charger:

The secondary will be mounted in stock single charger configuration, likely spaced down an inch or so, the person who did it on the 3rd gen had the primary offset to the passenger side just a tiny bit more than I am aiming for. I will be using a downpipe going to tailpipe exhaust. I plan on likely using a air filter mounted directly to the turbo, and battery relocated to top of inner fender if possible (or put it on driver side or in the bed whatever I have to do)... and a York V-twin air compressor (engine driven off the alternator) to be mounted somewhat close to where the battery and radiator overflow bottle is currently..... gonna be very tight quarters under the hood.

If anyone has any pics to share I would greatly appreciate it!!!! It's my daily driver and I will be doing this in my time off work around the holidays and my short term layoff that will follow, so any pics that would help give me ideas of what obstacles I may come across are great since I can't spend a week just trying to mock it up. That being said I do plan on taking my time to get it right.
Thanks in advance!
Eric
 
What about like this, with the primary out front, and the manifold turbo backwards?

IMG955424.jpg
 
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Short hot pipe like that is the way to go.

I had my secondary mounted normal and the primary vibrated at idle and had a noticeable difference in lag when the pipe was not heatsoaked real good.
 
Rich from Dog House Diesel just did a build with the primary on top... Not completed yet. Still waiting for him to finish..
 
Big Swole said:
Rich from Dog House Diesel just did a build with the primary on top... Not completed yet. Still waiting for him to finish..
Click to expand...

This setup he is working on looks interesting. I saw it on facebook the other day. If I remember correctly, 88mm GT47 on the manifold and a 75mm as the primary mounted after the primary. I have to assume that the primary has one of the bigger turbine wheels in it. So even though the primary is first in the flow path, the larger turbine wheel is still second in the system.
 
JQmile said:
What about like this, with the primary out front, and the manifold turbo backwards?

IMG955424.jpg
Click to expand...

Thanks for the pic, but that puts the primary too far forward for me. This air compressor is LARGE and on top of that it must be mounted in a certain angle. I would use a medium duty truck compressor that's factory for the engine where vac pump is but I need vacuum too. I don't think my hot pipe will be too long. I might try to use thicker pipe and will definitely wrap the crap out of it.
 
Also to the pic above, the manifold looks to be flipped upside down. Not sure is BigBlue12v pointed out, but the manifold can not be flipped.
 
If it works out better to turn the secondary around backward that's ok with me but I don't think it will. I can't see the hot pipe being much longer than if it was a traditional over/under setup.
 
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Twin piping pictures, page 9, 8UPRACIN.

With a ht3b the hot pipe will route slightly different due to their opposite rotation direction.
 
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