Ben's 914 TURBO Official World Premier, 'cuz it didn't blowd up. Options

[airsix]

Ok, so it isn't as cool as Chapman's 914-6 Turbo 3.0, but it's a turbo 914 all the same. Ladys and Gentlemen, at about 10:00 PST I got boost and there was much rejoicing. I took the car out, filled it with premium, tuned it with the laptop a little to make sure it got plenty of fuel under boost, and the mission was a sucess. Boost starts to come on at ~2,700rpm and is going full-steam by 3,500rpm.

I stand (ok, sit) here before you my brothers to declare that yes indeed, you can turbo a 914. (IMG:style_emoticons/default/clap56.gif)

Details:

Engine: '73 1.7, stock internals
EFI ECU: Perfect Power MIC3 (Cost ~$500 to get on the car and running 3 years ago)
Misc EFI stuff: Subaru 1.8T injectors, Holly throttle body off a 3.0 Chrysler, BMW 5xx fuel pump, foam motorcycle aircleaner (temporary)
Turbo: IHI off 1.8L Subaru (including wastegate)
Misc Turbo stuff: Bosch blow-off valve (for a Saab I think). Cheap. Plastic. Works great.
Total cost to add turbo: $175 (EFI was already on the car. Use Megasquirt+turbo and you can do this for <$400 easy)

I tried to modify my fuel pressure regulator with a boost-reference port like the in the dune-buggy.com article but I broke off a wire guage drill bit about 1.5" deep into the bolt. Dang. Only had about a quarter-inch to go too. So I just bolted it back on the car and set the fuel pressure at the 30psi I have the ECU turned for. I tried to crank up the injector pulse width under boost to compensate, but they hit 100% duty cycle at 5,000rpm because at that point they only have 20psi effective pressure (because there's 10lb of boost by that point). So I'm keeping it under 5k rpm until I get a rising-rate pressure regulator. The wideband O2 says mixtures are just fine below that point. I estimate I'm getting 110hp (That's not a WAG. I really did the math) which doesn't sound like much but is sure better than the 80hp I had before. I would still like to add an intercooler which could put it in the neighborhood of 130hp without getting too boost-happy. Even as it is now I would say it's 100% more fun to drive. I'm really happy about it. I'll get the pressure regulator issue squared away so I can run it up to 6k and I think it'll keep me happy for quite a while.

Rick said "This thread is worthless without pictures" so here's the best I could do. If you missed the earlier thread I'll throw in one of the earlier pics too. I tried to make a video but all you hear is wind noice and the blow-off valve between shifts.

[lapuwali]

I'd do an intercooler first, and just lay it across the top of the engine, or across the front of the engine bay. Perhaps do a GT-style all-mesh engine lid to help with temps. If you look at a number of the "across the top of the engine" OEM intercoolers (2nd gen RX-7 turbo, turbo Soobs), they have a scoop to get air in, but no where for the air to GO afterwards. Measurements on the RX-7 setup showed the scoop could basically be closed off with no real difference. Airflow would be nice, but just the intercooler itself will help. Ducting more air into the upper engine bay is (and should be) something to do, anyway, and can be done w/o ugly scoops visible from the outside. Adding one would cost much less than $300. There are lots of junkyard intercoolers out there, from any number of Japanese turbo setups. Some are pretty small, too. If you wanted to get quite fancy, you could try to obtain (or even fabricate) a water/air intercooler. Build a watertight box around a regular air/air intercooler, and circulate the water with an electric pump to a small radiator (oil cooler type) mounted more into the airflow. One possible place for it is directly in front of the engine, below the front shelf. You'd catch under car airflow (which is considerable), yet be in front of all of the exhaust heat, and no having to carve up a trunk or run really long hoses.

Water or alcohol injection always seemed like a drag-racing hack to me, and I think is mostly suitable if you're running really high boost for short spurts. An intercooler will improve VE some, and should allow a modest boost increase. 12psi with good VE should give you 150hp or so, which I'd think would be plenty from an elderly 1.7.