Over my winter break, I installed a single turbo on my ’86 trans am. The whole process took about 2 weeks, and now I am left with some fine tuning. I began a few months before by ordering all the parts that I would need. I used eBay, Summit, Racepartsolutions, and some local automotive stores to acquire everything.

Some of the technical information on the car before the build up: ’86, 305ci, carb, ~110,000 miles, no prior engine mods. The turbo is a remanufactured Garrett. The compressor has a 4” air inlet and 2½” outlet. The turbine is a T6 1.05ar and 4” outlet.

So the first thing was to start tearing stuff off the engine. I removed the dual snorkel intake, carb, distributor, intake manifold, coolant overflow bottle, battery, fuel pump, exhaust manifolds, and the rest of the exhaust.



Then, I modified the Carter mech. fuel pump to increase fuel pressure with boost pressure by connecting the vent holes to the bonnet.



Next, the new Holley 600 double pumper had to be made for blow through. This included removing the choke horn, sealing off areas where boost could escape, and enlarging the jets and PVCR’s.



I replaced the stock intake manifold with an Edelbrock Torker II intake.

 

Now, the real fabrication would begin. I used C4 Corvette exhaust manifolds for my turbo headers (like Joby did). The driver side header would be flipped upside down to clear the power steering pump.



For the passenger side I had to do a little more work with the header to have the downpipe clear it and also support the turbo.



I then combined the two headers with a 2½” crossover pipe with a slide-joint in the middle. This was the final result.

 

Next, I moved on to the cold-side plumbing. I mounted the intercooler in front of the radiator. It was a tight squeeze, but it fit. I also made the 2½” piping from the turbo to the intercooler and from the intercooler to the carb. I used couplers/clamps to connect everything up.



I then worked on the oil supply line. I used a T fitting from the oil sending unit to split the oil to the gauge and to a 3AN braided line. Also, I connected the vacuum and throttle lines at this time.

The air conditioning condenser box was going to be in the way of the downpipe, so now was a good time to eliminate that. Next, where the battery used to be on the passenger side, I cut a 4” hole so that the 4” aluminum flex pipe for the air intake would get cool air from underneath the engine bay.



The oil pan had to be removed so that I could weld in a steel bung for the 12AN braided steel oil return line.



Then, I started working on the carb bonnet. This consisted of a 5” canister to mount to the carb and a 4” to 3” exhaust reducer to act as a diffuser for the incoming dense air.

 

Next was to fabricate the wastegate plumbing. I ran 2 smaller pipes from each exhaust pipe to feed the wastegate.



I then put the distributor back in so that I could fire the engine up, without the turbo, to make sure the new carb, intake, fuel pump, and exhaust plumbing were all working correctly with no leaks. The new combo worked great.

The air filter was mounted right below where the battery used to sit and the new hole was made. Next, I worked on the downpipe. I used a 4” to 3” reducer from the turbo and joined the wastegate exhaust into it.



I routed the lines for my boost gauge and BTM boost retard dial. I set the timing without the boost retard at first, because I screwed up the wiring and didn’t figure that out until later.

 

Tonight was the first test drive with boost! It made 8psi which is what the wastegate is set at. Boost starts to build at 3,000rpm and full boost around 3,500rpm.

The next day I worked on routing the rest of the exhaust from the downpipe out to the back of the car. A muffler shop bent me a piece of 3” pipe and I installed it.



I then installed a manual boost controller to increase boost at a later time. Also, my digital air/fuel ratio gauge shows if I am too rich or lean at different speeds. I welded a bung in the downpipe for the oxygen sensor.



The last thing to do was fabricate a replacement box where the A/C condenser used to be. I bent some sheet metal and used caulk to seal it up.

I am now at the point where all the physical components are done, and all that’s left to do is tuning. This will be in the form of changing jet sizes and adjusting timing. Right now, I am getting a sputter at high RPM’s with the boost (possibly a lean surge). I jetted the secondaries up and currently I have 68 in the primaries and 86 in the secondaries, with the PVCR’s drilled to ~.68”.

This project ended up taking two weeks to fabricate (120hrs). The total cost was around $2,000. Research prior to starting the project could be estimated in the thousands of hours with my sources being: thirgen.org, turbomustangs.com , Turbochargers by Hugh Macinnes, and Maximum Boost by Corky Bell. I plan on going to a track or dyno once tuning is finished.

 

What kind of turbo is that?

 

I got the turbo off eBay. It's a remanufactured Garrett turbocharger Part Number 408096-9002, Model number TE0644, Serial Number 031031. It was big, very clean, and cheap.

Here's me and my dad working on its placement.

 

Very nice sequencing! Great job!

 

Is that JB-weld I see on the oil drain to the pan... Not a bad idea; that seems like it could be done while in the car (for others to try in the future). let me know how it holds up, unless its not JB-weld.

 

Yes, it's JB weld. I first MIG welded the bung to the pan and then used the JB weld as sort of a backup in case the weld had a pin hole. It should never leak.

The problem with doing it while the pan is still on the car is that you risk the chance of shavings falling in the pan when you drill the hole. That's why I took it off.

 

If you make the hole with a punch, like Vortech does for supercharger kits, there shouldn't be any shavings.

If you think about it, let me know how the JBweld holds up to the heat over time.

 

Never underestimate the power of JB Weld....

A buddy of mine were cruising through New Mexico at 2:00 in the a.m. on a
Sunday morning when his 72 Javelin decided that the axle flange didn't need
to be connected to the axle any longer....

The only thing around for many, many miles was a Cirkle K....We bought a
can of brake parts cleaner, a wire brush, a drop lamp and a pack of JB Weld-
this was before the days of JB Kwik....We scrubbed it as clean as possible,
gooped 'er up with JB and hung a drop lamp on it (using Circle K's power,
thanks very much...) for about 8 hours while we slept in the car....got up, and
re-assembled it, hoping to limp to the next big city for a new axle. Well, it
held long enough to get all the way back to Phoenix, and it's still on to this
day. This was 1987, and this car still is a daily driver!

 

Great job, brilliant idea with the mech fuel pump by the way!
I am almost done with a twin setup on an 87 Formula, does your intercooler have enough room for airflow? Can I ask what size intercooler you used?

 

Thanks. The idea for modifying the mech. fuel pump came from the guys over at turbomustangs.

The intercooler I used had a core of 24"x10"x3" and 2.5" outlets (30" length with the endtanks). I'm guessing there is enough flow to the intercooler. It covers about 2/3 the area in front of the radiator. Firebirds don't have a great amount of air flow to the engine in general. I was happy it fit without modification to the front of the T/A.

Good luck finishing your project.

 

That is amazing, Excellent job. What kind of power are you making from that setup? I would love to do something very similar.

Tim

 

Nice job on the detail of the install.