1 2 3 ... 5
Grtechguy
Grtechguy SuperDork
2/25/11 12:00 p.m.

From a guy who's never owned a forced induction vehicle.

what are the "criteria" to "safely" turbocharge a NA engine?

What is needed?

Obviously

a) the Turbo

b) turbo manifold

Lets a assume a generic 4-cylinder setup.

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/25/11 12:02 p.m.

Fuel/ignition tuning. Usually need quite a bit more fuel than stock system.

Some may suggest that you can get by without an intercooler, i wouldn't even bother trying. Get an intercooler setup.

Stronger clutch.

Something to tune. Depending on the power goals/engine, you may get by with FMU, stock ignition maps, and high octane fuel. If you want to go further, megasquirt or something is VERY beneficial.

Dr. Hess
Dr. Hess SuperDork
2/25/11 12:03 p.m.

Generic Fuel Management. Either you need to go with a stand alone computer or some type of piggy back system. Many of the details are worked out these days, if you look on teh w3bz, y0. Some people have "got by" with a rising rate fuel pressure regulator, but it's all hack at that point.

bigbens6
bigbens6 New Reader
2/25/11 12:16 p.m.

Thats like asking what the rules for beer are, or steak, its too nebulous...

Turbo Boost control custom spark and ignition exhaust intercooler Good gas

But if we knew just a LITTLE more we could give ALOT more help...

What are your goals, mid range, or top end Budget, r u buying a used turbo or brand new, greatly changes options What mods are already done What the CR of the motor WHats the fuling system like, room to expand? Can the transmission handle any more power/TQ etc.. etc...etc...

Raze
Raze Dork
2/25/11 12:17 p.m.

All depends on how much boost you're running, size your turbo, you'll need to modify your exhaust besides just hooking up a manifold and turbo, oil to/from lines, potentially coolant to/from lines, PCV modification for when you pressurize your crank case, size your pistons for lower compression ratio, don't go running a boosted 12:1 motor and expect it to live long, upgraded rods, rod bolts, crank if necessary, as has been mentioned, fuel management which includes sensor on how you want to run air flow metering, MAP is the easiest by far but requires extra sensor and $, and may not be compatible with stock engine management, i.e. might have to go standalone (see MegaSquirt), larger injectors, larger fuel pump, upgraded or adjustable fuel pressure regulator, wastegate for the turbo, either internal or externally gated, but choice affects exhaust design, upgraded driveline components (if necessary, i.e. transmission, diff, LSD, halfshafts). Goodluck.

Grtechguy
Grtechguy SuperDork
2/25/11 12:18 p.m.

I have nothing specific in mind, just thirst for knowledge.

Ran you run mild boost on cast pistons, or is forged the only way to go?

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/25/11 12:19 p.m.

You can boost cast pistons. The forged pistons usually come with the territory of HIGH power applications. Lots of factory turbo cars without forged pistons. My MX6 has hyperpeutic cast pistons.

The point where "HIGH" power applies varies motor per motor.

NickF40
NickF40 Reader
2/25/11 12:44 p.m.

Supposedly don't do it to a Paseo

4cylndrfury
4cylndrfury SuperDork
2/25/11 12:55 p.m.

I know people getting away with ~7psi on stock internals, fuel, and ECU in SR20DE motors running tiny baby little turbos and FMIC, but high octane fuel and retarded spark timing are necessary.puts down an extra 15-20 or so ponies at the wheels, which is pretty decent considering the overall cash investment isnt that bad (can be done at the pull and pay yards). The biggest cash draw is usually the exhaust manifold and downpipe etc since those vehicle specific parts.

Ive recently been toying with the mathematics involved with a centrifugal supercharger at low boost. theres a lot of options, but theyre more expensive in most cases.

bigbens6
bigbens6 New Reader
2/25/11 1:07 p.m.

In reply to 4cylndrfury:

Problem with centrigugal is the complete lack of boost in the first 70% of the revband... though it if is for a track car thats acceptable i suppose...

Streetwiseguy
Streetwiseguy Dork
2/25/11 1:10 p.m.

Add boost until little bits of piston start to stick to the spark plugs, then back it off a bit.

Conquest351
Conquest351 Reader
2/25/11 1:24 p.m.

Usually, the way we would set up turbo motors is as follows... (Using a Mustang as an example)

9-9.5:1 compression for off boost power, AT LEAST 42 lb injectors (stock is 19 lb), 255 lph fuel pump (stock was 150+/-), Upgraded clutch, Programmer, Intercooler setup (Now if you don't have room, you can always add a little shot of nitrous or additional injector for ethanol to help with the intake charge temp)

Basically you want to keep your compression low, but not too low. Keep your fuel in check and it's OK to run her a little rich. Start with boost kinda low and turn it up until you're happy (which will be never). Keep an ear out for detonation. Just set it up pretty conservitive and play with it and you'll be OK.

Remember, atmospheric pressure is 14.7 psi. Every additional 14.7 psi of boost (1 BAR) will double your NA hp.

novaderrik
novaderrik HalfDork
2/25/11 2:59 p.m.

a couple of extra short blocks are also handy to have around as you learn your way around a turbocharged engine..

1988RedT2
1988RedT2 Dork
2/25/11 3:08 p.m.

Three little words: Don't go lean.

93EXCivic
93EXCivic SuperDork
2/25/11 3:10 p.m.
1988RedT2 wrote: Three little words: Don't go lean.

More cushion for the pushing. Oh wait what are we talking about?

miatame
miatame Reader
2/25/11 3:11 p.m.

I thought rule #1 was "Strap a turbo on and see how she does, and if it holds the power turn the boost up"

no?

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/25/11 3:13 p.m.
miatame wrote: I thought rule #1 was "Strap a turbo on and see how she does, and if it holds the power turn the boost up" no?

That's how i operate. If it holds, that means that either 1) Your turbo isn't big enough and/or 2) You aren't pushing enough boost.

bigbens6
bigbens6 New Reader
2/25/11 3:26 p.m.
Conquest351 wrote: Remember, atmospheric pressure is 14.7 psi. Every additional 14.7 psi of boost (1 BAR) will double your NA hp.

I would argue that in most cases it will not quite be double your N/A power unless you can get your BAT's down to ambient which most air IC setups cannot do, i guess if you used H2o you prolly could but you will always have to contend with backpressure, and the laws of thermodynamics...

NickF40
NickF40 Reader
2/25/11 3:31 p.m.
miatame wrote: I thought rule #1 was "Strap a turbo on and see how she does, and if it holds the power turn the boost up" no?

Yup, that's it! I always thought that as well.......

Merc
Merc New Reader
2/25/11 3:37 p.m.

Something to control: Fuel spark boost timing

That's usually is it.

High octane helps against knock.

A lower compression will help to widen the margin or error with tuning.

Proper heat range plugs will help to save plug life.

A larger fuel pump for more fuel and to prevent engine from starving.

Larger injectors for more fuel.

An intercooler will help reduce air temps to reduce knock and detonation.

A blow off valve or bypass valve will help blow-by in the engine and seals.

A proper sized turbo will create a good amount of hp and tq. Too large and it will feel sluggish in lower rpms, too small and it will be torquey and have little or no high end power.

Plumbing for oil to the turbo.

Plumbing for oil from turbo to oil pan.

Plumbing for coolant to turbo (if available)

Plumbing from turbo to(intercooler,) throttle body

Plumbing from exhaust to turbo

Plumbing from turbo to exhaust.

I think that is it. Most engines should be able to handle around 6psi of boost safely. Although it doesn't seem like much, it is a huge difference over stock.

Here is a recommended read for someone who want to know more about boosting. It is a beginners/intermediate read. I got a copy for reference:

Forced Induction

92CelicaHalfTrac
92CelicaHalfTrac SuperDork
2/25/11 3:38 p.m.
bigbens6 wrote:
Conquest351 wrote: Remember, atmospheric pressure is 14.7 psi. Every additional 14.7 psi of boost (1 BAR) will double your NA hp.

I would argue that in most cases it will not quite be double your N/A power unless you can get your BAT's down to ambient which most air IC setups cannot do, i guess if you used H2o you prolly could but you will always have to contend with backpressure, and the laws of thermodynamics...

Pressure doesn't mean a whole lot. It's more about flow than pressure.

14.7psi on a T25 =! 14.7psi on a Holset HX40.

mndsm
mndsm SuperDork
2/25/11 3:58 p.m.

^ What he said. Now let's say for the sake of arguement that you are displacing 2l/air at atmosphere. If you can manage to shove a whole 'other 2l of air in it, and flow the according fuel, and control temps so that you don't suffer power loss due to heat... THEN you might be looking at doubling power. Only problem is, unless you're running like a T-88 or some giant nonsense, you're going to be running a E36 M3load more than 14.7psi. I guarantee you, the K04 on my ms3 running 15lbs/boost is NOT flowing 2.3l air/revolution.

bigbens6
bigbens6 New Reader
2/25/11 4:09 p.m.
mndsm wrote: ^ What he said. Now let's say for the sake of arguement that you are displacing 2l/air at atmosphere. If you can manage to shove a whole 'other 2l of air in it, and flow the according fuel, and control temps so that you don't suffer power loss due to heat... THEN you might be looking at doubling power. Only problem is, unless you're running like a T-88 or some giant nonsense, you're going to be running a E36 M3load more than 14.7psi. I guarantee you, the K04 on my ms3 running 15lbs/boost is NOT flowing 2.3l air/revolution.

That was kinda my point about BAT's...

mndsm
mndsm SuperDork
2/25/11 4:11 p.m.

Also, I forgot one thing. compression. But yeah, you get the idea. It's late.

Twin_Cam
Twin_Cam SuperDork
2/25/11 4:44 p.m.

Well, bare minimum: turbo, manifold, intercooler, fuel delivery of some kind (preferably MegaSquirt, don't use one of those mechanical FPRs, they make your pistons cry), wastegate (if not internal), BOV or recirc valve, oil lines, bung for the oil pan, downpipe to mate to your existing header flange, intercooler tubes. That's the bare minimum. Along with silly little stuff, like a breather for your PCV valve, because boost-pressurized engine oil likes to ruin gaskets.

In a perfect world, you would also have a stonger clutch, a sweet larger-diameter freer-flowing exhaust system, better tires and an LSD, an electronic boost controller, forged pistons and con-rods, thicker head gasket (depending on the car), ported head, etc etc.

1 2 3 ... 5
Our Preferred Partners
iPNX5cSOpY3wOHUM7fabRoJzrL8VK2FwebRX4uU5TAvKdflEtPDk0sUz3IYFrCxt