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THE COMPLETE GEEK'S GUIDE TO TURBOCHARGING YOUR B23F/B230F
By: Kenny Howard

First off, the normal disclaimers apply.. We're not responsible for anything you incur whilst turbocharging your car or thereafter. While this has worked well for me and others, your mileage may vary. Your car, your engine, your responsibility :). Read this all the way through before attempting to do this or you could find yourself with a taken apart car and in need of parts :)

This how-to is going to be divided into several sections: Why, How (more than one method), and Issues and concerns.


Starting off with the why. Why would you want to turbocharge your NA engine when turbo engines are fairly plentiful, and prices for turbo cars are reasonably cheap? The short answer there is, its up to you.

There are benefits for using a turbo setup: It's already there, you don't have to fabricate anything, just turn up the boost and let it ride. For a nice turbo car, look to spend $2000 on up, for the non-faint of heart (why are you reading this if you are? ;) ) turbo cars with bad turbos or blown headgaskets can be had for very little money in good shape.

Also, there are some subtle design differences between the turbo and the NA engines. Volvo's turbocharged engines have a lower static compression ratio than their NA engines, for the B21F its 9.3:1, for the B23F its 9.5:1-10.3:1 (depending on year and transmission), and for the B230F it's 9.8:1. Their turbo counterparts are: B21FT is 7.5:1, B23FT is 8.7:1, and the B230FT is also 8.7:1. **The lower compression does have its benefits.. you can get away with more, it's a little less detonation prone, a little better equipped for higher boost levels. Turbo engines also have sodium filled exhaust valves for better heat dissipation characteristics. So what does this mean? NA engines have no sodium valves (unless you put em in there) and generally 1.0 higher in compression. For some people, this is reason enough to dismiss the boostability of the B2XXF engines as not plausible. This is definitely not the case, and in the past 8 or so years, the thought process on turbocharged engines has been changing, Audi's 1.8T engine has 9.5:1 compression, and aftermarket chips and turbos push 20+ psi through them with no problems whatsoever. So what does that mean for us? Basically that it'll work both in theory and at the track. With this in mind, lets proceed to the how of the matter.

So tell me pinky, how do I achieve boostly greatness with my NA? Its fairly simple. Whereas other car owners (Honda owners, for example) have to buy custom kits to turbocharge their cars, us Volvo owners have it relatively easy..

Since volvo made thousands and thousands of turbocharged cars in the 80s and 90s, we can just go to a junkyard and pick up the hardware that's needed (well, most of it. More on the small stuff in a bit). It should be remarked that you do not need to pull all of the parts you will use from Volvo donors. Other turbo cars may have the smaller parts, as well as similar turbochargers which may fit directly or with minimal modification. Ford Mustang SVO and Thunderbird Turbocoupe turbos seem to work well. That said, the easiest source by far is a Volvo.

You will want to get the piping from an intercooled car, and preferably the turbo as well. Which turbo you get isn't really important at this point, however I personally prefer the Garrett ones. The exhaust manifolds will interchange with all 8v ohc heads, if you're pimping around in a '75-'82 200 series you'll probably want to get the intake manifold as well (there are other problems with these cars as well, those will be addressd in the issues & concerns section). For just a basic low boost get-you-running setup, you will need the following pieces: Turbocharger (duh), exhaust manifold, intercooler and all of its piping, if it's a Garrett 700 series, grab the Compressor Bypass Valve mounted on the front of the head (**insert pic here) and the brakets and retainers for the intercooler and radiator, fan shroud is helpful too. For 700 series conversions you'll want a 700 series downpipe, for 200 series, you'll want the 200 series downpipe (though some have successfully used a 700 series pipe). Radiator hoses would help but the NA ones will work if you don't want to switch. On watercooled turbos, don't forget to get the radiator hose and the expansion tank hose. Also grab the oil feed and return lines (**insert pic here), you might need them (or pieces of them) later.

When selecting the turbo you wish to use, do check for shaft play, it stands to reason that the car is in the junkyard for some reason (of course if the back end is missing and under the hood is immaculate, you're probably ok but check anyway), so get the best one you can.

For oil supply to the turbo, you'll want to get a Tee block (autozone sells this piece) with the same threads as the oil sender (**insert pic here). You will also need some line and fittings to run from the block to the turbo, brake line works well. If you got a later model garrett (off a 7 series car) you can get a 90 degree fitting that will thread into the oil feed and also thread into the brake line. Teflon tape, some 5/8s hose, exhaust manifold gaskets (don't forget the coolant!)and you should be ready to go.

If you want, you could also grab a spare oil pan from the yard, this might make things easier for you during the swap, as that is the only thing that has to be modified on the car. So you've got everything all together, have the tightest nicest turbo you could find and now you're itching to go.. Remove the exhaust manifold and the pipe between the headers and the cat, the radiator, intake, airbox. You should have a fairly empty engine bay to work with now, so lets dig in.

Getting into specifics about the oil feed line: There are many ways to do this, partially dictated by your choice of turbocharger. As stated, the mitsu's feed can be threaded right into the turbo. For a Garrett, the easiest way to do this is to use the stock oil feed pipe. The pipe should be new to avoid having caked on oil break off and go into the turbo. After you've pulled the exhaust manifold, lay the pipe in place so you have a general idea of where it should go. Bend it to aim it toward the oil sending unit, and cut it off so that there is 3-4" of gap between the line and the sender. Use a rotating pipe cutter ($6 at home depot) to make the cut as smooth as possible. The hose to cross the gap should be petroleum resistant, which includes brake line and oil line. It is not recommended that you use heater hose or fuel hose, but they will work for a short period of time. Be sure to use clamps on all non-threaded ends of these hoses.

Now, we've gotten the oil feed to the turbo squared away, but what about the return? If you were paying attention in the junkyard, you noticed the drilled out bung on the turbo block where the return line from the turbo goes. B230 blocks all have the casting, but only the turbo engines have it drilled out. If you really want, you can drill it out and just use a regular return line, however most of us don't have those kind of tools and/or time and patience to do this. So the next best thing is to drill a hole in the oil pan as high up as possible right beneath the original casting, and then you can either weld a short piece of tube (bent upwards), use a plumbing fitting, or have a piece of pipe brazed on. I had the third one done. Once the hole is drilled and you have the piece you need, any shop should be able to weld or braze it for you for very cheap (like $10 or less cheap.. maybe free. Ask your favorite mechanic if he'll do it).

This is where the spare oil pan comes into play, but don't fret if you didn't get one, its only 14 some odd 12mm bolts to get yours off (and you have to drop the subframe.. 2 bolts on each side of the engine bay, by the strut towers, and you need to loosen the steering knuckle and unbolt the motor mounts. Pulling the oil pan is kinda tricky, many "power words" will be employed in the process (but it's a lot harder putting it back in..) I don't think you have to pull the oil pump out to get it out, but you might. If you do, I highly recommend you replace the two seals for the oil pump, they will eventually break and cause you much heartache and discomfort (esp. if you aren't paying attention when they do :) ). Reverse for installation (its tricky take your time).Take the turbo, and tighten the wastegate actuator rod as far as it will go (**insert pic here).

Alternative 1 for oil pan drilling: You can drill out the pan with the pan still in the car if you're very careful about it. Tools/equipment you'll need: goggles, 3/4" drill bit (preferably a stepped bit that goes to a slightly larger size so you don't have to work it around), a moderately compact drill, powered air pump (even an electric pool toy inflator will work), lithium grease, 1-2 gallons of mineral spirits, and some hose to fit between the PCV box and the air pump (about 1/2" diameter, but check to be sure). Mark off the spot you're going to drill, and start with a small bit. If you get a stepped bit like the UniBit, made by American Tool Company, you will only need one bit. Cover all bits you use with the grease to catch shavings. Hook your air compressor/pump up to the PCV box, and set it to the lowest setting possible. Turn it on, and start drilling. When you first break through the pan, you'll notice that the air coming through it is a powerful jet. Since pressure is being relieved through the hole, increase the compressor's pressure a bit to compensate. Now just keep drilling until you've got it big enough to fit your pipe. When you're done, stick your finger in and around the hole to feel for shavings. There should still be some, but not a lot. If you can, hook up a hose system leading into the drilled hole from above so you can dump the mineral spirits where the shavings are. A half gallon of this should get most of them floating toward the bottom. Keep pouring until spirits splash out the hole, which should be just as you're about empty. Open the drain, and let the stuff pour out. You should be clean now. To be sure, feel around in the hole again for shavings. If there still are some, repeat the procedure with a new bottle of spirits.

Now, we should have the oil feed and the hard part of the oil return taken care of, take a hacksaw to the oil return that came with the turbo (try and get it as close to the pipe in the oil pan as you can) and then bolt it to the side of the engine. Hook up the feed to the top, (derh) hook up the return, and put the water lines (if you got one of those turbos) on so you don't forget them. Put the intercooler in, in front of the radiator, remember to use the supports that came out of the turbo car (you did get them, right?) hook the radiator back up, fill the system (before you forget) and then put the rest of the turbo plumbing on. On 200 series cars you do not need to lengthen the MAF wires, however I suspect on a 700 series you will. Do this so the MAF goes on the inlet side of the turbo (**insert pic here). Make sure you got the hose clamps on tight. Replace the vacuum line to the wastegate actuator on the turbo (**insert pic here), run vacuum line to the CBV, and make sure you've got a calibrated boost gauge floating around.

Bolt the downpipe on if you haven't already, make sure the o2 sensor is hooked up, make sure the connections you lengthened (if you did) to the MAF are soldered and free of interference.

Start the car, and check for any leaks. Common places for things to leak: the tee for the oil feed, the feed at the top of the turbo, and the flange on the return line. Also check for coolant leaks. Take it for a test drive (yes, I'm aware that NA exhaust doesn't match up with the downpipe.. I think) open downpipe and all, and listen for detonation, or any other weird things.

If all seems to be well, its time to make another decision. The setup as is installed on your car will work for only very low boost, 6 or 7 psi. If that's all you want, you're in good shape, however, and I suspect this is the case, you're going to want more.

There are a couple of approaches one can take here, you can get a turbo fuel computer from a corresponding turbo car (same year or close to it, otherwise you hafta swap the MAF and perhaps other things as well), fuel pump, injectors, fpr, and ballast resistors. That setup on a stock turbo in my car got me into the 14's, and I was able to trap 94mph (at 14 psi and 14 degrees timing advance). You also might want to go ahead and get a different cam. If it's in your budget, an enem or vx would be nice, but a T or better is pretty much a must. The M cam does alright to a point, but I noticed a dramatic improvement over the M when I installed a T in my car.

The next step up from that would be some form of EMS, megasquirt would work well here, then there's haltech and other more expensive units. If you don't want to go to the hassle of installing a turbo fuel system, a rising rate fuel pressure regulator could buy you some more boostage, a a/f meter and fuel pressure regulator (or a dyno and wideband o2 would be really nice) will be needed to get that tuned in right. The ignition computer doesn't really need to be changed (you can if you want), both the turbo and NA units function the same way, have the same amount of retard, use the same sensors.

 

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