FOLLOW THESE BASIC RULES
- Go Easy
- Take Your Time
- Shape It, Don't Shine It
- Use The Correct Tools
- Machining if available
- Safety First
- Keep It Clean
You Will Need the following:
- Emery cloth (coarse, medium and fine grit)
- Safety Glasses
- Air compressor
- Die Grinder
- Air gun
- Grinding Stones (Aluminum tends to gum up the grinding stones)
- Carbide Bits (work best for removing massive amounts use with cutting fluid or "Grinder's Grease" best spun at 15,000 -22,000 rpm)
- DREMEL and Dremel bits: high speed steel bit (cylindrical and pointed) x 2, sanding wheel
- Stock turbo gasket
Note: Use carbide bits or high-speed steel cutter when grinding aluminum. Steel and cast iron respond well to grinding, as well as sandpaper.
For those of you who have access:
A milling machine
A 15/16" end mill bit
Turbo Porting (turbine exhaust gas inlet, and the turbine exhaust gas outlet, O2 housing, and down pipe)
What does porting your turbo do?
Porting your turbo can help with top end power delivery but will not help spool-up time. Porting essentially allows for more air to flow through it (or exhaust) at higher RPMs. Unfortunately, you will sacrifice exhaust velocity and lower end torque and create more turbo lag. Turbo lag is no fun. But you will make it up in overall power delivery in the top end.
Note: It is a good idea, if you are going to port the turbo, to start by porting the exhaust manifold or "Gasket Match" the two respective housings to make a turbulence free port as well as the runners.
*Disassemble the turbo completely* *Caution* Do not remove any surface area on or near the compressor wheel area which is adjacent to the compressor blades.
Before you begin clean the turbo housing well, de-grease and let it dry thoroughly.
Inspect the housing. If you have a gasket use paint or die like Dykem (machinist's dye) to trace the area you are going to remove. When you are finished the two housings ports will match the gasket.
If you have the stock turbo, you should see a 0.1" to 0.15" lip all the way around the inlet and possibly a little ring gasket that allows the housings to mate together without leakage.
Grind/sand away the small lip until it is smooth and makes a nice bell shaped transition. When you are finished, take a fine emery cloth to smooth out the rough areas to reduce frictional loss, it robs you of horsepower.
Port the waste gate outlet or dump area. This is not necessary however can solve some boost creep issues in larger turbo setups. Performing this procedure is not a direct power adder, but it will increase your turbos ability to dump hot exhaust gasses and control boost at higher RPMS. *Do not remove area on or near the waste gate opening that will allow it to leak* Then smooth out that area as well with your DREMEL then with the Emery cloth.
When done, clean and de-grease thoroughly with soap and de-greaser. If you have compressed air, blow it out, and let it dry.
O2 HOUSING PORTING is essentially widening or increasing the channel the exhaust gasses will pass through. The O2 housing and the down pipe are the final stages to the porting job. Failure to do the complete porting will result in poor or undesirable performance. (as stated above it is best to start with the Intake manifold, cylinder head, exhaust manifold, turbo, down pipe, flowing into a upgraded wider exhaust system in that order.)
DOWN PIPE PORTING (gasket-match)
For many turbo system flanges the gaskets are interchangeable with other gaskets from other vehicles.
EXHAUST MANIFOLD PORTING
What does porting an exhaust manifold do? Exhaust manifold porting helps with turbo spool up by increasing the volume of exhaust gas that spools the turbo.
As with the Turbo Inlet you will see a ring gasket step area that needs to be removed as it is only a restriction. This area should be ported to match the larger hole preceding the step area.
There is a center divider that directs the flow of gases. This should be ported to a knife-like edge or removed.
For DSM owners Port to match the stock 1G composite gasket, NOT the new stainless one. Porting out to the stainless one is largely a waste of time, as you can't port the runners that large, and if you port the head to match the SS gasket also, you'll have a dead spot in the airflow due to the head flaring out, then the exhaust manifold flaring back in. If you don't have the stock composite gasket, it is less than 1/8" larger than the openings in the exhaust manifold runners, so you barely need to open it up. When I port them now, I only clean up any protrusions in the entrance, and leave it at that.
CYLINDER HEAD PORTING
Porting a cylinder head is a delicate task combining craftsmanship, artwork, and science. Before you begin you must commit to finishing the task. As long as you take it slowly and pay close attention to what you are doing you will be successful.
Porting a cylinder head is increasing your engines ability to ingest air or increasing the volumetric efficiency on the intake stroke. More air means more potential power. With a modified engine the flow demand changes, in this case, it is more air flow.
It is possible to hog out the ports and make then too large, and as a result, lower the flow velocity. Lower velocity means less inertia, less inertia means less potential energy. Some symptoms to over porting are sluggish response and poor bottom end performance along with a rough idle.
The basic idea is to create smooth transitions in areas that were formerly air restrictions. A 1/16 of an inch in most cases is a safe area of removing.