How To Turbo: LOOK HERE FIRST

[8695Beaters]

Okay, I have seen at least three "what parts do I need to turbo?" threads in the last month. So here is the most straight-forward guide I can think of. SO LOOK HERE BEFORE YOU ASK ABOUT HOW TO TURBO!!!

I am only going to discuss Honda motors here, since that's what i know best. So only take this info as good on a Honda.

So you want to go turbo. Good start, but first you need to work out some details. For example, a turbo is like an engine- there are a bunch of them and they are all different. Garrett is generally the preferred make of turbo (nearly all good turbo kits use them and most OEMs use Garrett turbos). But the only Honda that uses a turbo (non-Garrett) is the K23 in the Acura RDX (bikes and F1 cars do not count). This turbo is a very high-tech piece and has variable displacement to prevent turbo lag. Say what? Let's put it this way: you can't afford it.

No, you need to scrounge around some other import for your turbo. The best donors are by far the DSMs (Mitsubishi, Eagle, Dodge, Plymouth). The first and second gen Eclipse (Talon, Laser) use a turbo that is perfect for any Honda 4-cylinder. Since the engines are all nearly the same displacement, the turbos will be a perfect match.

The most important thing to do when looking for your turbo is to figure out what engine it is coming off of. You want to find an engine that has the closest displacement to your own. If you overshoot too much, then you will have nasty turbo lag. If you undersize, you will outrun the turbo and won't be making as much power. Neither will kill your engine, but they will kill your fun.

For anyone with a D or B16, no, almost nobody turbos something that small from the factory. The cool thing is that any 1.8 or 2.0 liter turbo will give you an awesome match and will be more than adequate. Plus you will get a hair more power than any 1.6-sized turbo without too much lag. You can overcome the lag with some bolt-ons anyway.

Now that you've picked the turbo, you need to plumb it. For N/A cars, there is no OEM piping that will fit. If you are cheap, you can fabricate your own. Generally, you want to start with 3-inch piping at the intake (pre-turbo), 2.5-inch after the turbo, and 2-inch after the intercooler. Stainless steel is the preferred material for piping. It looks cool, is strong, and won't corrode. It is fairly expensive and hard to machine. But it's worth it. Silicone connectors to connect the pipes together are the simple method, but if you can do or afford it, welding the junctions is better in the long run. Just be prepared for a lot of work when you want to upgrade the internals down the road.

To keep your turbo running correctly, you will want a blow-off valve and a boost controller. The boost controller is obvious, since it allows you to dial in exactly how much boost you want. Don't skimp here, since a cheap boost controller will read more boost on a cold day and less on a hot day. This may put holes in your block if you are not careful. Go electro! As for the BOV, it is not, contrary to poular belief, there to make you feel all manly. A BOV releases the extra turbo pressure when you let your foot off the gas. Otherwise it would slam around inside the piping and probably put a hole in something. Whether it's the intercooler, the piping, the turbo, or even the engine, is all up to luck and the quality of the parts you put in. And if you tune the BOV for the ricey 'pssht,' then you will end up with turbo lag. Don't let all the pressure out at once if you want to actually win races with your new setup.

On the exhaust side, you need some kind of manifold to hook your turbo to. You can either build (or have built) a custom tubular manifold (expensive), or buy a pre-built manifold (not so expensive). If you are lucky and/or good, some stock header sections can be made to mate with a turbo (the D16 manifold from the Civic VX is one such manifold). The key thing here is if you are cheap and buy a pre-built manifold, buy one that is made of cast iron. Tubular manifolds look cool and offer more power, but are prone to failure. Iron is heavy and ugly but does not break. If you haven't already, now is also the time to put on a 2.5 or 3 inch exhaust for your car. Your turbo will want to breathe, and stock exhausts don't do that very well.

Keep the cat converter too. You will fail emissions without it and you will only sacrifice a few horsepower by leaving it on. A good environment is something we all have to pitch in for. Besides it's always cooler to say your car makes such and such horsepower "through the cats."

Okay, you have the turbo in and plumbed. All that extra air is no good without fuel to help it burn. Starting from the back, it would be wise to invest in a new fuel pump. They have some kind of flow rating (usually Liters-per-hour) and if you order online, they will usually tell you how much horsepower it will support. For a well-done turbo install, expect to be making about 100 more horsepower. Next, you will need a new fuel pressure regulator, preferrably rising-rate and adjustable. After that, you will want some fuel injectors. I have posted an article on how to size your injector. Use it wisely. Generally, you can't get too big of an injector. If you want to turn up the boost later on, then injectors is one less thing you will have to replace again.

Make sure you fill up with high-octane gas before you tune the car for the first time. 87-octane will make your car very unhappy with its newfound ability to add more air.

Next up: electrons. As smart as computers are, they are really stupid. For example, your ECU can't tell that you are now throwing in a lot more air and fuel. So at this point you will need an ECU retune. This is where it would be nice to buy a programmable EMS, go to a dyno and ask the tuner there to tune your car. Once he's seen the color green, he (or she) will be more than happy to make sure your motor does not go boom. Before this though, you will want a few more parts. Colder spark plugs will be extremely helpful. If you are doing a K-Series turbo, you will probably need a new MAF or a way to fool the MAF in to thinking there is less air then there is (older Hondas used MAP which is a little more forgiving for turbo power). As far as new gauges, oil pressure and temperature, coolant temperature (the stock gauge does not count), air/fuel ratio, and boost are good ones to start with. Fuel pressure too. Wire these up (hehe enjoy) and you will instantly know when you are about to be SOL.

Turbo timers are a nice luxury to have, but it's mostly not worth the cost. Just sit around for a minute to let the oil cool off. Although if you have just been driving around normally and not like a meth-head, then you won't need to let the oil cool.

The next thing is all the little nit-picky things that will make this a lot harder than you would think. All turbos have some kind of oil line and many also have collant lines. These need to be plumbed. An inlet and outlet bung will needed to be added to your oil pan. Where exactly is up to your motor. Ask someone who can actually see your car and give you the right answer, not me. You will also want a good clutch so that your burnouts are actually from your tires and not from your transmission. You will also want an LSD so that both of your tires will spin. And you will want better tires so that you can actually drive the car when you are done tearing up some parking lot pavement. At this point, you probably won't need driveshafts, but if you want to put them in, go ahead. You will probably want new brake pads and coilovers won't hurt, either. Neither are needed to make car run, but both will help tame this new beast.

Turbos add lots of heat (heat=power, sad fact of life), so you may want a new radiator and cooling fans. This depends on where you live and what car you have. A Civic will need a radiator. A Prelude probably won't. Drive around and decide for yourself. As for the intercooler, make sure you don't block your entire radiator with it. Intercoolers come rated with how much power they can support. Don't go too big, as an intercooler that's excessively large will contribute to turbo lag. You may also need to increase the airflow into your engine bay for cooling. More grille area, cooling ducts, and vented hoods are all good solutions.

Tips: Most people boost the H, D, and B-Series of Honda's engine family. All three of these will run fine on 9 psi of boost if you have good tuning and your parts support it. Unless you really skimped out somewhere, your parts will hold up fine, so it really depneds on who is doing the tuning. You can boost the K, but it has a higher compression ratio and is not as boost-frinedly. I would say 7 psi max, but since I have no experience with the K personally, I don't know. Best to err on the safe side. If you want to boost anything other than these four, 7 psi is also about as high as you want to go on stock internals. 8 psi might work, but remember each psi is doubling the amount of air your engine sucks in normally. 1 is a huge number here. If you want to throw the money at it, Hondas best can easily withstand more. But doubling your horsepower will make most people plenty happy.

Speaking of doubling your horsepower, learn to drive this thing before you do any more to it. That much power can get you in a lot of trouble (and I don't mean with Johnny Law. Newton has a wrath all his own). So drive it carefully at first until you get a feel for what you car can now do. Then by all means beat the ish out of it.

The last thing to remember is that you can avoid all this by just buying a prefabbed turbo kit. But where's the fun in that?

By popular request, here is a summation of everything you should, or will need.
Mandatory:
-Turbo (duh)
-Turbo exhaust manifold
-Turbo piping
-Boost Controller
-Intercooler (possible to turbo without it, but you're going to be slow)
-ECU tune
-Fuel injectors
-Fuel pump
-Blow-off Valve (BOV) or Bypass valve (much harder to plumb, but more efficient)
-Oil temperature, water temperature, boost, air/fuel, and fuel pressure gauges
-Cooling fans and/or radiator
-Colder spark plugs (1 or 2 heat ranges colder than stock)

Helpful Parts:
-Adjustable Fuel Pressure Regulator
-New tires
-Bigger exhaust
-Coilovers
-New brake pads
-Vented hood
-Oil Cooler
-Stage 1 Clutch
-LSD
-Driveshafts

DISCLAIMER: The contents of this article are not necessarily the official views of, nor endorsed by, the owner of HondaClub(com).

[Tomas]

Great article Beaters.

[PrimeTimeV6]

What do you have on a waste gate? What spring sizes would be best with different boost ratings on the blow off. Also another cheap way to cool your engine more efficiently would be to put a lower temperature thermostat.
*Note: You would NOT want to remove your thermostat completely since your engine will take a LONG time to warm up and you don't want to run a cold engine hard.*

[8695Beaters]

Your boost controller will override the wastegate. Basically the boost controller interrrupts the air going to the turbo wastegate and fools it into thinking there is less boost than there is. So if a wastegate is designed to let out at 7 psi and the boost controller holds until 15, the boost controller will hold boost until it reaches 15 psi and then let the air go to the wastgate (which will then let go). So you can boost as high as the turbo will flow (and how storng your engine is). Those are the limiting factors to power.

[dre5491]

Note: You can get up to a rough estimate of about 12 LBS of boost on a correctly built motor. This includes everthing beaters mentioned plus pistons, piston rings, ect... So don't think just because you have a Honda you can't run decent amounts of boosts just you will need to rebuild the engine internally to get the maximum amount of boost out of your car.

[8695Beaters]

I hope I made it clear that 9 psi is the maximum you can run on STOCK internals. A well-built Honda OEM block can support 500 horsepower before without worry. Past that, you need a Dart block and way more money. Plus you have to deal with reliability and an engine like that borders on being unstreetable (or unlegal), making it out of the league of most enthusiasts. And to be honest, even 400 horsepower is overkill in anything but drag racing. 300 is about the max for a road race FWD car anyway.

[dre5491]

You made that very clear. I was just adding a note for people that they can get more boost if they added internals.. On a 4 cyl engine (except evo or sti) I would never run more than 15 lbs. If you have stock internals specially on a Honda motor and run more than 9 psi you won't have a motor for long.

[PrimeTimeV6]

I have got a friend that has a 99 SI with a built motor running 12 PSI low and 24 PSI high. His is an every day driver.

[dre5491]

Hes not running 24 PSI all the time is he? If he is on pretty much any car thats torture.

Edit: Ehh lol not to contridict myself but I guess it isn't if your cars built right my youth group leader is running 22 LBS of boost on a farely stock Cobalt SS. Hes got Meth injection and a good tune but thats about it. So I guess it can be done of DD 4 bangers.

[PrimeTimeV6]

No no...lol. His low boost setting is 12 for everyday and his high boost is 24 for track days. Thats how his boost controller is set.