I am interested in finding out where i can squeeze more power out of my 20v I-5. if anyone has ideas where i can get the tubular headers from the coupe pre 1990 coupe, or other performance upgrades and prices let me know

1. Increase airflow
- K&N filter
- 12v V6 MAF replacement plus 4 wire to 3 wire conversion ($150)
- Ported Throttle body

2. Improve Head
- Port and polish Head and intake manifold
- Get new cams ~$900 + ~$200 cam followers

3. Stroke it
- Eurospec 2.5L stroker kit - ~$1800

4. Improve Fuel
- replace injectors and fuel rail ~$800
- Stand-alone fuel or full ECU replacement ~1-2k

5. Scrap all that and go turbo.

I'm just guessing on prices and labor is based on what you can do.

I've got one....email me.

Where can I find a ported throttle body? Also if you change the size of injectors or fuel line would you need to change the ECU ?

For the injectors, not necessarily ( <a href="http://www.injector.com/fuelinjectors.php?PHPSESSID=8fc2d0155020e0f0c92ae4 40c6b6d36b">like if you get the Marren Bosch conversion</a> ) but to get the most out of it, an add-on fuel controller or ECU reprogram would be needed.

If you find someone who knows how to reprogram the ECU let me know =)

you are probalby not getting the expected flow if they are old. The Marren kit doesn't release specs on thier kit but I beleive it's matched to stock flow whatever that is.

7a fuel injection is at 4bar which is already pretty high. Adding an adjustable FPR would increase it across the range. A Fuel computer could adjust it only where it's needed. Of course then you have to ask why do I need more fuel? Ok more fuel equals more horsepower but in this case it just means running rich. Until cams or head work or big intake changes are provided to increase air intake are injectors necessary?

I'm planning on upgrading my injectors only after I get new cams and matching their flow to about 200hp. By the way I found adapters to convert the fuel rail to Bosch injectors for $160 so now I just need to find the right injectors for stock and then post cam/head work. Check on VWVortex if interested.

First fix the MPI/Hitachi problem (post above). From there ide start with the horribly restrictive 20v exhaust. Brullen makes a nice cat back.. Cold intake is nice but, the stock box is desigjned well. Many have found the stock box gave them more HP then when they had the cone filter setup.
Now you dip into actual motor work. Cams, cranks, all kinds of fun stuff. Just do thigns smart, not all half assed and youll get good results. The 7A responds very kindly to simple modifications.

I remember one guy in the 80/90 forum that did so, but he was having trouble with running lean above 4000 rpm and he didn't answer my follow up questions.

Due to a wreck involving my 12v, I might be getting a 20v soon, and you can bet that the MAF swap will be the first thing I do (I'm the one who came up with it on the 12v after all.) Of course, the MAF won't last long, since I'll be swapping in a 20vturbo with megasquirt within a year.

I'm going to use the 7A FPR on my 10vt actually. One less thing to buy. I also doubt that the stock injectors are as high as 300-360cc/min, when the 3.6L and 4.2L V8's use 240-ish cc/min injectors.

Then worry about the stock exhaust from the cat back (at 60mm, it is the same size as the turbo cars, so it isn't too shabby).

Also, something to think about is just simply replacing the ECU with something different, like a Megasquirt system or better yet, an 034EFI stage IIB (dist. fire) system. Nate Stuart is running a 3.6L 32v, and is making low to mid 200hp at the wheels, when the factory quoted the PT engine to make 240 at the crank. That puts him closer to 300hp at the crank, running the stock injectors but a very tailored ECU map set on his Stage IIC (coil packs).

Thanks for doing the research!