Updated December 13th 2009

Boost gauges and a couple of words

Here is a look and overview of boost gauge types, where a turbo boost gauge is one. So anyway, hi and welcome to this page! I have now made some updates and so it will be until next time I have some spare time over!
Boost gauges are actually vacuum/boost pressure gauges. A boost gauge measures either manifold air pressure, or supercharger or turbocharger boost pressure, in internal combustion engines. They measure in psi or bar and some of those that measure in psi, and most of those that measure in bar, also measure manifold vacuum pressure below boost.
Psi Boost gauges usually measure in the range of 0 - 30 psi, and some psi boost gauges also measure vacuum pressure, usually -30 to 0 inches of mercury (inHg).
Boost gauges that measure in bar, usually do in the range of -1 to 2 bar, read as 1 to 0 bar vacuum and 0 to 2 bar boost.

The use of measuring boost.

Measuring the boost, is the positive air pressure and usually vacuum at the intake manifold (on intercooled cars) or in supercharged and turbocharged vehicles where extra air is pushed in to "boost" the intake manifold pressure.

Prior to modifying the turbocharger system on a turbo DSM, a boost gauge is essential to have. If the turbocharger is not set up correctly, to much air will be pushed in than the engine can handle. Usually that leads to a lean fuel mixture resulting in detonation where the pistons may crack as well as apply undo stress to the rods and crank. The higher combustion temperatures causes severe engine damage since it may actually melt pistons. The top of the pistons as well as the ring lands usually melt away. This causes extreme blow by and excessive crankcase (the housing for the crankshaft) pressures which can blow seals out of the motor and the end result will be lose of oil and oil pressure.

A boost gauge is used to ensure excessive pressure is not being generated when boost pressure is being modified to levels higher than OEM standard on a production turbocharged car.

Since various boost levels affect the exhaust gas oxygen level and so the air/fuel mixture (lean or rich), an air fuel ratio gauge/meter provides additional control.

Turbochargers

Turbochargers start producing boost only above a certain exhaust mass flow rate (depending on the size of the turbo) which is determined by the rpm, engine displacement and throttle opening. Without the appropriate exhaust gas flow, air cannot be forced into the engine. The point at full throttle in which the mass flow in the exhaust is strong enough to force air into the engine is known as the boost threshold rpm. In some cases, engineers have been able to reduce the boost threshold rpm to idle speed to allow for instant response.

Turbocharger links:
How turbochargers work
Various turbocharger article links

Superchargers

A supercharger is an air compressor used for forced induction of an internal combustion engine.

Supercharger links:
Supercharging basics
Various supercharger article links

Electric vs. mechanical boost gauges.

Electric

Many go with electric gauges for several advantages. They are easier to install than mechanical that need routing of lines through the firewall. Instead, a locally mounted pressure transducer is the sender unit. Some electrical gauges have the possibility of adding a memory unit, that may store peak boost etc for later display or use. Or it can be equipped with an audible warning alarm with a variable threshold. That is useful since too much monitoring may take the sight away from the road.

Mechanical

Mechanical gauges have no sender involved, requiring the pressurized air to be sent in to the cabin. Mechanical gauges are generally cheaper so their main advantage is the price.

Further reading can be looken at;
Electric vs. mechanical gauges

Boost gauge install

Since the boost gauge install is different depending on the type (electr* or mechanical) there are different advantages for each type, the choice depends on several things. There is info to be found on the net and of course, experienced technicians can be asked too.

Electric boost gauge install

Installing a boost gauge
Installing boost gauge 2

Mechanical boost gauge install

How-To: Install A Mechanical Boost Gauge

A look at some boost gauges (scroll down)

Again some new boost gauges have been added. The Boost Gauges below are showed close to or exactly in half size when viewed at screens with the sizes 19''/1200x1024/0.294mm and 15''/1024x768/0.297mm, the two most used and with similar dot pitch.

Blitz boost gauges

MD (Mirror Drive) 60mm:

Electric

MD carbon 19450

MD white 19455

Mechanical

MD carbon 19475

MD white 19476

DC II electronic 60mm

DC II carbon 19281	DC II white 19282	DC II blue 19283
DC II carbon 19281	DC II white 19282	DC II blue 19283
DC II

Mechanical 60mm

ELV black

ELV black 19465

ELV white

ELV white 19470

SV Meter

Super Vision 19487

BLM

BLM 60mm 19320

Defi boost gauges

Racer electronic 52mm

Racer blue DF06501	Racer red DF06502	Racer white DF06503
Racer electronic 52mm - Turbo
Racer blue DF06504	Racer red DF06505	Racer white DF06506

Defi-Link Meter BF electronic 60mm

BF white DF04303	BF red DF04304
BF white DF04301	BF red DF04302	BF blue DF04305	BF series - Led appearance when led is on.	BF series - With position bezel

VDO boost gauges

Mechanical 52mm

Cockpit 150051	Cockpit 150052	Vision 150104	Cockpit white 150208
Turbo boost - mechanical 52mm
Vision 150121	Vision 150121	Cockpit white 150206	Series 1150361