I've got a 1990 CRX Si with the stock D16A6, simple bolt-ons, cold air intake, aftermarket catless catback exhaust, with racing header and test pipe, everything else is pretty much stock to my knowledge. What kind of mods or improvements do I need to make to the engine or internals to properly and reliably run about 10psi of boost?

Sidenote: This is my first project car and am just getting into the car scene and doing every bit of work on this car and engine myself, so bear with me on some things in understanding.

Thanks in advance! Any info is appreciated!
**EDIT** the Odom currently reads 134xxx miles, no knowledge of past rebuilds of motor or anything else.

 

Go to the forced induction forum and read the threads on SOHC builds. I've got a current one, Txdragon has one that's pretty recent as well.

What kind of improvements you need to make will be driven by your power goals and your goal with the car. How much power (not psi) do you want to make, and how will the car be driven - daily driver, full drag car, circuit racing, or something in between?

Do you have a dedicated daily driver to use that is not this car? I do not recommend forced induction on a car if it's your only car. Even spare-no-expense builds that use the best parts have issues causing down-time.

What is your budget for the build?

 

I will have to check out that thread. I only want around 300hp as a goal to start, I eventually want to have it be a track car, and will be k swapping it once I finish building up this d16.

Once I do start doing bigger mods, this car won't be used as a daily anymore. I don't necessarily have a budget, just getting the parts and things I need a the time goes by.

 

Here is my thread
Here is Txdragon's thread

If you're planning to swap to another platform in the future, you've got to decide how much money you want to sink into the D-series. Don't bank on being able to recoup a bunch of money by selling your setup when you go to change platforms - in my experience, you can get about 20% back.

Your goals are similar to what mine were when I started my build - you can check my thread out to see what parts I used. IMO, I did not cut any corners on my build...maybe not a "spare-no-expense" build, but certainly not a budget build either. My goal was a car that I could drive several days per week back and forth to work and also to go to the drag strip a few times per year. Reliability, driveability, and retaining creature comforts were a must. Just to be clear, I had over $10K into it by the time I hit the dyno. You can read that thread for what I considered to be required for reliability.

If you're wanting to know what the minimum requirements are, that's debatable. Personally, here's my recommendation for bare bones (only listing internal engine stuff, since that's what you seemed to specifically be asking about):

• New bearings, new seals/gaskets throughout, new timing belt/tensioner/water pump, new coolant hoses.
• H-beam rods and aftermarket pistons in the 9.0:1 - 10.0:1 range for compression ratio. I'm not a fan of the cast "Vitara" pistons, but they are cheap and people do use them to make power within the range you seek.
• Bore/hone the cylinders and have the deck machined. Bore +0.5mm to get a fresh surface.
• Measure your oil pump clearance - if it's in spec, you can re-use it.
• Stock valves, stock retainers, stock cam, stock cam gear, stock port head. You can even keep stock springs unless you want to increase the redline. Have the head inspected, resurfaced, and valves re-lapped. If any of the valves need replacing, Ferrea 5000 or 6000 series (you can buy them individually and I think they are cheaper than OEM). If any of the guides are a little worn (but not severely worn or damaged), have them knurled instead of replaced.
• New head gasket and ARP head studs
• A clutch and a resurfaced stock-weight flywheel

 

300 is a lot for an a6. do the swap. if you are already thinking of a swap in the future leave the a6 alone and enjoy driving it while acquiring parts for the swap

 

For a bone stock A6, this is what I would do. You will not get 300 HP out of a stock A6.
8~9 psi boost max, the stock MAP stops reading at around 10 psi
Replace the fuel pump, its 30 years old.
Get a wide band O2 sensor/gauge AEM is a great value.
Get a boost only gauge like Autometer's 15psi gauge. It makes a huge difference being able to tell your exact boost. Avoid the vacuum and boost combo gauges, not enough resolution.
Install an adjustable fuel pressure regulator
450CC injectors
Install a fuel pressure gauge.
Find a reputable tuner that can dial your engine right.

I've been daily driving a D16Z6 for the last 17 years on 8 psi with mostly ebay parts. I just had to replace the wastegate, it began to stick closed.
I do recommend a small turbo that you can use with the small 1.6 non VTEC engine. A T3 anything is a bit too big, those take significantly longer to spool up.
Get a T-28/T-25 sized small turbo, like a Holset HX25 which is what I have. Instant boost and it boost all the way to redline.

I change the oil every 2000 miles and I have no idea of the engine's mileage, it came from a junk yard.