Project Nissan Sentra Spec-V Part 7: Installing a Turbo System

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Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
The surfacer is used to help fit the tubes exactly.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
A very tight fit.  For working in stainless a tight fit is needed.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
Getting ready for some welding.  Mike prefers to make his TIG torch tungsten very sharp as fine welds work better for thinwall stainless.  He puts it in a drill and sharpens it on a sander.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
Nice and sharp.

To help make our downpipe fabrication easier, ATP supplied the special divorced flange that mates to their turbine housing.  This flange is grooved to accept a 3” turbine discharge and a 2” wastegate discharge tube. 

Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
Scotchbrite is used to clean oxidation from the area to be welded.  Yes stainless forms a thin oxide film that can inhibit a good weld.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
When fitting a part it is first tack welded to temporarily hold the parts together while the fit is being checked.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
The small tack welds can easily be broken and rewelded if the fit is off.

Since the available space to fit the turbo was quite limited, we had to use some specialized bends from Burns Stainless and The Chassis shop to fabricate our downpipe which is a work of art 3” with a merged collector for a 2” wastegate discharge.

Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
Once the fit is perfect, Mike welded the parts together.  With thinwall stainless it is important to backpurge the part when seam welding.  Backpurging is filing the tube up with argon gas to prevent oxygen from getting to the back side of the weld.  This can make the weld up to 30% stronger.  Here you can see the argon hose taped to one of our tubes during welding.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
Mike seam welds our part.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
The completed weld.
Project Nissan Sentra Spec-V Part 7: Installing a Turbo System
Mike then marks where the hole in the downpipe for the wastegate discharge must go with a sharpie marker.  Up to 40% of the engine’s entire flow can pass though the wastegate so a nice merged union is best for flow.

 

4 comments

  1. Mike, how is the time attack coming? For years I’ve been toying with the idea of a primarily off the shelf parts V12 with enough capability to be worthy of the investment. Sure anything V12 would be cool but for genuine interest, I need two things. For larger displacement, (the impossible find! Every OE is making baby bores for economy) that 87mm is the absolute “sweet spot” for single sparkolator flame front propagation, meaning lowest possible chance of detonation while still having room for valves. For displacement and having a minimal chance of detonation, I need a dual plug 4.5 inch bore. I’ll have to compromise with a single plug at 4.150-4.185 bore. Nissan has a 4.41 bore space, Mopar has a 4.46 bore space. The Mopar 3.5 SXT and 4.0 R/T Nitro have SOHC 60 degree blocks. Beefier than the Nissan with closed deck design. VQ37HR or VK56 heads oughta do.
    The point is, I found your T/A build here searching for QR25 bore spacing, wuuuh waaah, too small. This is an awesome build! Can’t wait to see it go. I’m thinking of a LS mid sleeved VK56 for a 94 Sentra rwd conversion!! Lotta work, but cool factor off the charts. Wheel well and opening hackery for to the Nth degree to get any decent size diameter tires.
    When is this thing gonna make some runs?

    1. We scrapped the car mostly because the QR engine is a piece of trash and there was no interest in the car besides maybe 50 people in the world which made sponsorship impossible. Basically what you are planning isn’t really possible and your assumptions of bore size and understanding of bore spacing are not correct either. Your considered build won’t have any sponsorship or fan interest either. It is also several hundred thousand dollars to do what you think you want to do. I suggest sticking to cars that have more interest and technology that is off the shelf.

  2. Well I’m interested in what you have to say about my following comment…

    I’ve already poured a couple thousand dollars into my qr25 build with over two years of research and it might very well be a waste of money but it’s one I’ll see through. I just got my stage4 clutch from 2j-racing, they have been a big help to fill in some of the gaps. I to am aiming for 400hp-450 safely but for street, still taking the massive extra steps to make my bearings happy and oiled. my last piece of the puzzle “was” going to be sleeve the block but I see you used a different method, one that I only heard of a couple weeks ago. Now, I read you didn’t finish the project but how do you think the engine would have held up with the aluminum filled epoxy resin?

    1. Hows your build coming Emily D?

      I’m in the middle of my turbo build, shooting for 280hp on my 02′ with 34k miles and still running strong. Concerning your block try reaching out to VisionRacing, or better yet you can do a VQ swap with Nissformance kits.

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