1987 Iroc TPI 350 - Turbo installation and photos
Turbocharged 1987 Iroc TPI 5.7

October 25, 2009 - A dream stretching back over a dozen years became realized on Sept 15, 2009!  It was on this day that I finally drove my very own turbocharged V8. The turbo manifold, crossover pipe, wastegate and throttlebody inlet box were purchased in 1997 for my previous 86 Camaro. At the time I had just built a V8 Astro van and lost interest in the Camaro project.  My friend ended up with the turbo setup but never used it.  The manifold and crossover design were specific to the third generation FBody (85, 86 and 87 to be specific). Fast forward to 2008 -  I had a 1981 Z-28 which I had planned to fuel inject and turbocharge. While searching Craigslist for any used LQ4/LQ9/LS1 and L98 engines,  I ran across a nondescript listing for a 1987 Iroc with a 5.7 TPI. The moment I saw the condition and options I knew I would be driving the Iroc and dumping the 81. When I drove the Iroc to show the same friend who'd ended up with the turbo kit, he told me it was still in his storage building!   Thus my single turbo Iroc project was born and I immediately began planning the eventual install. Check out my other pages for more info on the car and other preparations.

From the very beginning (starting with a $700 Iroc), this is a project all about budget.  I want to keep this car as stock as possible and use lower cost parts where it is safe to do so. Obviously things like injectors, wide band O2 sensor, fuel pump, and internal engine parts will be high quality components.  But if I can get away with an Ebay turbo, stock TPI manifold and stock ECM then I will do so.  Of course in the case of the ECM, that didn't work out, so I ended up with a Megasquirt II 3.0. Of all choices though, the MS was the lowest cost so I'm still on budget!

This is the manifold I am using.  I think it is an old Gates design.  If you know for sure, contact me.  It is made with heavy steel tubing and weighs about 20 pounds.   The pipe coming down to the center connects to the driver side manifold.  The wastegate mounts on the front - I later had to cut off this flange and rotate it 90 degrees to get good clearance from my T-70 turbo compressor housing.
I first removed the stock passenger side manifold and test fit the turbo manifold. Everything cleared and looks good. The space for the downpipe looks tight, but a 3" pipe does fit!  A 4" oval also fits great, should the need arise for a larger downpipe. The AC system is going to be close to the downpipe and turbine housing, but clears!
I borrowed my friend's 67mm Precision Turbo for more clearance testing and planning.  It looks great on there!  Eventually I plan to run an intercooler and will route it alongside the cold air inlet.  The battery will relocate to the trunk area and the filter will be under the battery tray.  There is about 1" of clearance between the low pressure AC line and turbine housing!
Here is a 4" ovalized tube - fits great with room to spare BUT these pieces are expensive and I'll be using 3" to stick with my very strict budget.  Eww my engine bay looks dingy in this pic!  Time to start building the downpipe.
The first cut is made!   To make the downpipe,  I went to a local trucking parts/supply house and purchased 3" mandrel bend aluminized pipes in 90 degree and 45 degree bends. They cost around $20 each locally. I use a chop saw to cut the pieces to whatever sizes I needed to fit.  Everything is tacked together until final welding. For welding I used a Harbour Freight TIG welder - another budget item at only $200 on sale!
Finally some real progress!  The first piece is the best and then it gets more complicated.  I was able to maintain reasonable distance from the AC dryer/filter.
I'm going to build it in two pieces between the turbo and catyletic converter. The first section will go from the turbine outlet down past the manifold. Next to the starter the pipe will have a V Band clamp. The second section will clamp to the first and then follow the stock Y pipe path to the cat.   Here I have tacked the first few pieces together.
The completed first piece - still tacked together in case I need to make a change (and I did).  Somehow this thing twists and turns and actually fits down between the manifold and frame rail.  It is a tight fit to get in place but has about 1/2" total clearance once in place. The second half of the downpipe is made in the same way.  Measure and eyeball the next section, make a cut to another elbow and tack in place. Trim if needed.. grind off the tack and retack if needed..  and move on to the next.  Time consuming but not too diffiicult.
Here is the completed assembly from the cat all the way up to the turbo.  The V-Band clamp in the center is located next to the starter. After this photo,  I wrapped most of the downpipe in header wrap, including the first 90 degree bend after the middle V clamp.  There second bend from the top is not fully wrapped because of clearence issues with the manifold.  The entire downpipe can be removed in about five minutes of work once the car is up on jacks.  Servicing spark plugs is pretty easy with the downpipe out of the way.
My new Ebay T70 turbo arrived and I could not wait for the first startup. The oil feed line will come from a T fitting at the stock oil pressure sending unit location. Oil return will go (for now) through the fuel pump blockoff plate using AN8 fittings. When the engine comes out for rebuilding,  I will be installing a larger return line and it will go directly into the side of the pan. Also in this picture is the air inlet box that came with this setup.  It's quite unusual, being fabricated instead of cast, and has some interesting features. For some reason there is a second inlet. It also had two square covers, one of which is removed in this photo.  The bolt pattern fit my $20 Ebay blowoff valve almost perfectly so I decided to mount it there. Please excuse my old blue silicone couplers - it's just part of my budget limitations for now.  I wish I could find orange ones to buy new but will probably go for readily available red. Also on top of the intake is a spark plug heat boot.  I only used two of these for plugs 6 and 8 as they are very close to the down pipe.
Finally I completed my 4" cold air inlet, battery relocate and oil return line. The cheap blowoff valve is seen here also and works very nicely.  Best $20 I've spent and sounds wonderful.  You can also see some of my heat barrier efforts for the AC system.  Look closely and you can see two pieces of stainless wire holding the airbox to the throttle body. It kept blowing off with boost! Also I have a black PTP Turbo Blanket on which I am very pleased with.  It really helped reduce some of the heat soak I was getting with the AC lines.
Here is a look at some of my thermal barrier efforts.  The silver on the AC box is thermal barrier tape (available at autozone and others).  I also put this tape on the dryer/filter and both AC lines. Additionally I ziptied header wrap on the side of the low pressure AC line that is closest to the turbo, leaving the other side open so heat can radiate out of the line. You can see some of the wrap on the downpipe here also. The final thing I did was remove the rubber gasket that runs along the back edge of the hood.  This lets a ton of heat escape from the top of the engine bay, but will let heat get in through your vent so be sure to run AC on  MAX so it doesn't pull in vent air.

Well that is the basic setup.  I hope this page helps a little if you're working on the same thing. Right now I'm running 8 psi non-intercooled and love it.  I plan to stay here for a while until I get an Ebay intercooler and build the tubing for it. I'm working on the cosmetic things with the car for now and will get back on the engine stuff after I get my interior finished.  Be sure to keep an eye on my Youtube Channel for the most recent mods/action with this car.

August 31, 2010 - Please check my other pages.. I've now added an intercooler to this setup!

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