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Discussion Starter #1
Is it possible if anyone could send me the On3 turbo install instructions via email for a foxbody? I would really appreciate it. Email- [email protected]

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Discussion Starter #3
No not really. Just wanted something to have a general idea to go off of.

1,803 Posts
Here's my attempt at general instructions for the on3 Fox 5.0 kit. People can add to it and maybe it'll sticky'd for all the people asking about it.

This process begins after you've already opened the boxes and inspected your components for functionality. Or maybe you ended up with a box full of loose parts like I did. These instructions are aimed at converting a stock N/A fox to turbo so if the car is currently supercharged or turbo, you'll obviously have a different tear down process. If you're using an aftermarket ECU, a few things will differ also.


  1. You'll want to start with the tear down of your car.

  2. Jack the car up using a well maintained hydraulic floor jack or two-post hydraulic vehicle lift for convenience (lol). You want the wheels/axle to hang down for ease of exhaust removal so place the jack stands in a manner that allows it.

  3. Remove the o2 sensors then spray the exhaust clamp studs with WD40 or any decent penetrant then remove exhaust clamp nuts. You'll do this for all 4 clamps on the H-Pipe. Slip the hangers out of the rubber crossmember grommets and discard the H-pipe.

  4. Remove the inner fender liners and associated hardware then store them in a safe place for reuse. There will be screws around the inner fender radius and maybe a couple at the bottom near the tire.

  5. Unplug the headlight and side marker bulbs then remove the front bumper cover by removing the nuts securing it to each fender (accessible when fender liners out) and also the bolts holding it to the core support. Store bumper cover and hardware for reuse.

  6. Remove the actual bumper/crash bar for ease of intercooler mounting.

  7. Under the hood, remove the factory airbox and ducting. Unplug MAF and store in a safe place if reusing.

  8. Remove the 8 bolts securing each exhaust manifold to each cylinder head. Remove both manifolds and
    discard with hardware. I was able to keep my dipstick in place.

  9. Remove your gargantuan FL-1A oil filter and either install the new adapter/filter or source some Purolator L10101 short filters since no other filters will clear the manifolds.

    We are now ready for assembly of the turbo kit

  10. The first major step to consider is the turbo oil drain fitting on the oil pan. You can either drill, punch, and tap the pan for the NPT fitting (according to the Vortech directions), or you can weld a fitting on. I've done it both ways and both work. I did not remove the pan when doing the drill/punch/tap method. I just used a LOT of grease on the drill and tap flutes in order to capture metal shavings, then flushed the engine with oil after the turbo install was complete to get any other mess out before firing it up. I had a fitting welded to the pan on my second try but it required pan removal, cleaning, new gaskets, etc. Both worked fine for me.

  11. At this point I took a break from the car and installed the oil feed and drain fittings on the turbo. the 90° NPT/JIC fitting threaded directly into the center section. I used the 2-bolt NPT adapter along with the large NPT hose barb on the bottom side of the center section.

  12. Next, it's typically good to mock the hot side up on the engine before final torquing to ensure proper fitment. If you have issues with fitment, it's better to realize/fix it before everything is full of RTV. You are supplied new hardware for everything so you'll need the 16 new exhaust manifold fasteners, the two different sized V-bands that secure the crossover to the manifolds, the large V-band for the downpipe, then the 4 bolts, nuts, and washers that secure the turbo to the flange.

  13. Clean the exhaust manifold threaded holes out and bolt the manifolds (ITEMS A & B) on by holding the manifold to the head and slowly threading every fastener in a few threads at a time. This is the most tedious and annoying part of installing this kit. Take your time and don't cross-thread. Snug the bolts up, don't fully torque.

  14. When both manifolds are snugged up, bring the two crossover pieces (ITEMS C & D) in and use the correct V-band to secure the ITEM C to the driver's side manifold (ITEM B). Using another correct sized V-band, secure ITEM D to the passenger side manifold (ITEM A). snug the V-bands to allow the pipes to rotate while being supported.

  15. Position the crossover pieces as straight as possible then tighten the crossover flange bolts fully, ensuring the crossover doesn't shift positions when you remove it. It will now act as one piece for the rest of the install (for me at least).

  16. You can tighten the V-bands up a bit and make sure the two flanges at each joint are concentric with eachother. Misalignment nearly guarantees exhaust leaks. My flanges aren't male/female so they did leak until I aligned them better.

  17. Bolt the turbo to the t4 flange on ITEM A using the 4 bolts, nuts, and washers.

  18. Slide the downpipe (ITEM E) down the firewall, twisting and turning as needed until it is in position, then secure it in place with the proper V-band. The sensor bung should be on the side nearest the turbocharger, not below the car.

  19. Hopefully by now you've got your hot side mostly mocked up without clearance issues. It should look like the below image.

  20. Assuming everything is lined up correctly without interference, remove the turbo, crossover, then manifolds and prepare your RTV (or gaskets if you dare).

  21. Now you'll install it all back for good. Since I use red RTV (the big caulking gun tube), I ran a generous bead around every port, inserted two bolts in the most accessible holes of the manifold (A & B), then bring the manifold near the head to get the two bolts threaded in. You want to keep the manifold as far from the head as the bolts will allow so that you can get all the bolts started while supporting the weight of the manifold with your hand. once all the bolts are started (and manifold still not touching the head) slowly thread all the bolts in simultaneously. A few threads on each bolt at a time. Takes a lot of time but guarantees they all go in without interference and your RTV won't smear. Eventually the manifold will seat against the head and you can torque them all up. Repeat on other manifold.

  22. Hardest part over! Ensure your turbo has the boost reference fitting installed on the compressor housing for Wastegate actuation.

  23. Goop the RTV around the turbine flange (or place your gasket on the flange), drop the turbo on the flange, and turn the bolts/nuts in. Gonna need a combination of long and short wrenches as well as some sockets and a rachet. Space is a little tight so this is the reason.

  24. This is a good time to attach the turbo drain hose between the lower fitting on the turbo charger center section and the fitting you previously installed on the oil pan. Go ahead and tighten the hose clamps for good.

  25. Now V-Band the crossover (C & D) to the manifolds and tighten them down real good-like.

  26. Reinstall your downpipe (E) and clamp it on with the V-band.

  27. At this point, if you use the on3 Y-Pipe, you can go ahead and install that between the downpipe and cat back. This should use a V-band and factory style clamps if I recall correctly.

  28. Take your Wastegate and install the hose fittings on the top and side port. Install the dump tube on the gate then mount the gate to ITEM D using the 4 supplied bolts (or V-band if upgraded) ensuring the dump tube is angled rearward and downward. I used RTV here as well between ITEM D and the gate.


  29. I started this process by mounting the intercooler. I didn't have the on3 brackets and fabricated my own but apparently you just bolt the intercooler hanging brackets to the intercooler then fasten the brackets to the core support, either in existing holes or with new hols. I aimed to have the intercooler inlet/outlet right under the bumper shocks and used the bumper cover mounting holes. See below image for reference

  30. Next I decided to mount the new adjustable Alternator Bracket. You'll want to get it mounted and tuck the alternator as close to the water pump as possible to allow room for the turbo to move a bit. This will likely require a new serpentine belt when complete.. See below for reference.

  31. Next, you can take the U-shaped aluminum bend (ITEM F) and mount it to the intercooler using a silicone coupler and 2 T-Bolt clamps. The shorter end interfaces with the intercooler.
    *NOTE: My kit had the BOV flange on this part so I mounted my BOV to it before installing it. Newer generation kits place it elsewhere so BOV is covered in the following steps*

  32. Attach the long end of ITEM G to the other end of the U-bend using a silicone coupler and 2 T-bolt clamps.

  33. Using the silicone reducer and 2 T-bolt clamps, attach the other end of ITEM G to the turbocharger compressor. This may require clocking the turbocharger in the downward direction (this is why you tucked the alternator in).

  34. Next, take ITEM J and mount the blow off valve to it using the supplied V-band. Ensure the BOV has the hose fittings installed as well.

  35. Affix the short end of item J to the intercooler using a coupler and 2 T-bolt clamps. The long end should be angled up toward the round hold in the passenger side fender apron. slip a coupler over the long end now and temporarily slip some T-bolt clamps onto it as well.

  36. Snake the straight end of ITEM H through the round hole in the apron to where it is near the long end of ITEM J.

  37. Slip the loose coupler from ITEM J over ITEM H and tighten the 2 T-bolt clamps. This may require reaching through the wheel well or through the ovular air box opening in the fender apron. I believe this is also where the MAF would be installed if you use a MAF. Pretty self explanatory installation if you need it.

  38. Now you slip the remaining 90° coupler over the funky end of ITEM H and over the throttle body and tighten 2 T-bolt clamps over them.

    It should look about like this now

  39. Remove your oil pressure sending unit from the pressure log on the Driver's side of the timing cover.

  40. Install the provided Tee here and reinstall the sending unit on the Tee. Attach the oil supply line (long stainless braided line) to the Tee and also attach it to the top port of the Turbocharger center section. This completes your oiling system upgrades.

  41. Grab some vacuum line and install it between the TOP PORT of the BOV and an intake manifold port (or vacuum tree on firewall). You want to use the Intake Manifold because it'll supply vacuum to open it when the throttle body snaps closed.

  42. Now install vacuum line between the SIDE PORT of the wastegate and the Turbocharger Compressor Boost Reference Fitting. You want to use the compressor fitting here because it typically provides a really good boost signal for proper wastegate actuation.


  44. After this install, I elected to source a new serpentine belt. I took a piece of string and wrapped it around all the pulleys (for me this was just the crank, water pump, and alternator) then cut the string where it intersected (you want it tight). I then measured the string length and took that measurement to the parts store to pick up a belt that was just a hair longer than my measured length. I was able to throw the belt on and use the alternator adjustment rod to tighten it. The alt came close to my turbo but worked fine. I have A Magnum Performance T72 and the housing is a little larger than the on3 turbo so you should be fine.


Go ahead and throw some colder plugs in the car if converting from N/A. If using stock heads and up to 14psi, you can throw some Autolite #24 plugs in it gapped around .024-.028. If using an aftermarket head with the .750" reach spark plugs, you could use an autolite #3923 for gapped around .024-.028. If you'd rather use NGK's or something else, cross reference the autolite numbers to get the right heat range (1 step colder)

You should be ready to tune now. Obviously you'll want to tune the car since it'll run way differently. Your tuner will give you the right plugs, boost numbers, etc for your combo. The above is just a starting guideline.

Hope this covers the basic install of the on3 turbo kit. Turbo all the foxes!

1,250 Posts
Good write-up. Thanks.

Are you able to keep the sway bar with this kit?
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