1988 Mustang GT Restoration/Modification

Build includes a Dart block 331, 76mm Turbo, Cobra IRS, and much more

  1. Turbo mounting and piping modifications

    RacEoHolic330
    Here's the turbo. Comp 76mm triple ceramic ball bearing, water cooled, 0.96A/R

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    Here's a picture of the overpriced restrictor/adapter/filter I received from Comp. The orifice on this thing is SMALL. It's sitting next to a .041" restrictor. I can't believe how tiny that hole is. Comp was not kidding when they told me that these ball-bearing turbos hardly use any oil.

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    I had a bad feeling that the turbo was not going to sit the way I wanted it to being that the kit was originally configured for a 60mm turbo. I decided to cut away at the fender apron until I was able to get the turbo to fit. Unfortunately, this is how much I needed to cut out for it to work:

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    I didn't take any pictures of the turbo mounted, but the half the compressor housing was sticking into the fenderwell and the turbine housing was sitting inside the valley of the framerail. It was sitting WAY too low and too far outward. I needed to get it to sit higher and in towards the engine bay more. They only part I wanted sticking into the fenderwell is the inlet.

    So, I need to chop away at the flange:

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    You can see the difference between the original flange mount and the "new and improved" mount.

    Doing this enabled my to get the turbo to sit in the engine bay the way I intended:
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    I then needed to build a new downpipe, because the original one was beat to hell. Here is a comparison between the two:
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    I then used a combination of new pipe and old stuff to finish the rest of the exhaust:
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    It took FOREVER, but I was actually able to make everything fit without hitting anything.
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    I'm pretty happy with the way everything came together. I'm glad I got the kit for cheap, because I needed to put a serious amount of time into it to get everything to fit and look the way I wanted. I bought a "rough" kit for that reason, because I knew I would want to make tweaks to it.

    Once I weld everything up, it will all get shipped off to Jet-Hot so those pipes can look as pretty as they deserve to be.

    Oh, and I will be repairing that fender apron as well as re-boxing the frame rail. There will just be a 5" diameter hole in the apron so the inlet can stick through.

    I fully welded up all the downpipe sections. I also welded a 3/8" bung for the ACT sensor and two 1/8" bungs for the methanol nozzles. You can't see the one nozzle bung in the picture.
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    I also made the template to repair the gaping hole in the inner fender.
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    Mocked up the coldside. Everything fit together great. I'm going to have to get some tabs welded to the intercooler to have it supported from above.
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    The only conflict that I ran into was between the blow off valve and the wastegate. Because I am recirculating the wastegate back into the downpipe, I need to install a 1-3/4" pipe from the discharge side of the gate to the downpipe. The HP kit was not designed to recirculate the gate, so my discharge pipe sits too close to the blow off valve for my liking.
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    I do not really have any other good location for the BOV, and I really don't feel like cutting off the flange, moving it, and repairing the pipe. Soooo, being that I'm not even really happy with the condition of the passenger side of the crossover pipe and I plan to replace it anyway, I'm going to relocate the wastegate closer towards the flex bellow.
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    I'll install a 90 degree bend right off the crossover into the wastegate inlet. This will allow me to run a straight pipe (and flex bellow) directly up into the downpipe. I'm going to install a 90 degree bend off the downpipe facing down. This will ensure that the exhaust gas getting dumped into the downpipe is going the same direction as the exhaust gas coming out of the turbo.

    The other option is to keep the wastegate inlet in the same place on the crossover, but instead of it coming straight out, I'll install a 90 degree elbow, which will provide enough clearance to the BOV. I'm just going to have to re-check the clearance to the radiator/fan shroud for that option. It may be close.
    Part of the challenge for the wastegate placement was that I needed to position it so that I could fit a flex bellow between the discharge and the downpipe. I also wanted the discharge to connect to the downpipe in a configuration that would enable the exhaust from the wastegate to flow in the same direction as the exhaust from the turbine housing. I didn't want the wastegate discharge to have to "fight" the exhaust from the turbine in fear that it would affect its ability to control boost.

    Here are the pipes that I labored over for hours (literally) to get them just the way I needed them to be:
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    Attached to the wastegate:
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    And tack welded in place:
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    Good radiator clearance:
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    Finished up the welds on the rest of the exhaust piping:
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    Bent an exhaust hanger and welded it to the y-pipe:
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    This is the only hanger between where the downpipe mounts to the turbo and the tailpipes right behind the mufflers. I had everything tightened down and it seemed solid, but if I need another hanger down the road, I can just get one of those deals that strap around the exhaust pipe.

    I also bought some AN adapters so I could tap my heater lines for the water feed to the turbo:
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    Because of the location of the flange and the way the turbo sits, I had to clock it slightly so one water line would clear the flange. It's only clocked about 10 degrees. The general rule of thumb seems to be not to clock it any more than 20 degrees, so I should still have adquate oil drainage.
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    Here are the water lines all done:
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    I figured out a combination of AN fittings that would allow me to more easily install the oil drain. I had to notch the frame rail for the fitting to have the right pitch.
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    90 degree fitting out of the pan:
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    Line installed:
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    For those that are curious, here are the tools I use to assemble the AN fittings. Adjustable aluminum wrench and aluminum vice inserts. Works really well.
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    I just need to weld up the turbo mounting flange on the passenger header and then I'm going to drop off all the piping at the local powder coating shop so they can sandblast everything. I want to make sure the imperfections in the pipes are all gone (or at least visible so I can fix them) before I send it away for ceramic coating.
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