Turbo on the SUPER cheap.

I did this on a 1988 Fiero GT and ran it for twenty years.  Needed an earlier ECM which for whatever reason had a reference for positive pressure - IIRC I used one out of a 1984 Pontiac Sunbird that had a 1.8 engine with a Garrett turbo on it from the factory.

You need  a fuel regulation system that can deal with positive pressure induction and you really should have a boost limiter (mine simply cut fuel completely when it over boosted, which it would only do on a long straight) as well as a knock sensor for when you go too far.

If you don't have all this, your experiment will likely be exciting but transitory,, when something lets go.  And it is always a bad idea to throw a turbo on an old engine rather than a fresh rebuild which can hopefully handle it.

My results were quiet gratifying - about 300 bhp from a 3.2 engine gave me 0-60 in the mid 4 second range, a 1/4 time of right around 13 secs, and it was faster than an Accura NSX and equal to the twin turbo Supras. And it lasted for almost 20 years until I finally sold it, mostly because I had invested in a custom set of forged pistons . Had a practical limit of about 10 psi of boost as there was no IC (would have been a pain to locate and plumb on a mid-engined car).

For 5% you actually need to lean it out. Doing what you said ruins engines, so does being "pretty sure." My fuel pump can make 1000hp on methanol on boost, about 1200 on the motor even with 5bar fuel pressure. Not my first rodeo. You need about 12x the fuel flow from gasoline, and about 3x compared pure methanol for a 98% nitro to not melt. 

Boost limiters are hard to do if you're not inside the ECU. GFB has a cool little toy that turns the BOV into a pop-off if you exceed a certain pressure. I think it's just a ball and spring setup that cuts the signal to the BOV, which lets the BOV open and dump pressure. You could build one out of Home Depot parts and it would protect your engine against a stuck wastegate or a blown-off wastegate line.

In reply to jj :

That's what I did on the Jaguar V12 I turbo'd. We richened the fuel mixture as much as we could get away with and then triggered the cold start injector at 2 psi. 
That was enough to live at 6 psi boost.  
What made that work is Champion made gold palladium plugs  back then.  The "soot" burned off and the plugs didn't foul.  
Today I'd use bigger injectors and E85. Plus the cold start injectors set at 3 psi. The alcohol in E85 isn't as sensitive as gasoline. It will run decently over a much broader mixture  than gasoline will. That plus the cooling effect  of alcohol  really would allow  more power.  

Paul_VR6 said:

For 5% you actually need to lean it out. Doing what you said ruins engines, so does being "pretty sure." My fuel pump can make 1000hp on methanol on boost, about 1200 on the motor even with 5bar fuel pressure. Not my first rodeo. You need about 12x the fuel flow from gasoline, and about 3x compared pure methanol for a 98% nitro to not melt. 

OK I'll accept that you know what you're talking about but I think we are talking about different things.  
Hillborn injection is a bypass system.  The fuel pump puts out surplus pressure that you control with the "pill" 

The bigger the hole in the "pill" the more fuel bypasses and the leaner the engine runs.  

So I understand what you said, Are you saying that if I want to run 5% nitro I should lean the engine out?   
Assume for purposes of this discussion I'm using alcohol. 

If you want to run small amounts you will reduce fuel volume until about 25% nitro where it is about even with methanol again. After that you need to add fuel. How you do it depends on the system, with mechanical injection its the pill, so small amounts you will start with the same pill as methanol and watch the plugs. To hit the same tuneup you will go up in pill size (less fuel). 
I do this all with electronic fuel injectors, widebands and egt probes but I learned it the hard way.