Turbo specifications explained

Beneith is the tecnical terms that is found on the turbo product pages explained. However before you dick into reading all the explainations, please be informed that we have already selected the correct turbos for you in the racing programme. You only have to choose your desired hp-range and turbine inlet flange to select your new Racing Turbo.
Having said that, for those with own skills, It is important that all terms are well understood when discussing, comparing and selecting a turbo charger. Many fail to correctly understand e.g the difference between inducer and exducer when looking on both compressor and turbine wheels as they "flip". Another well know fault is the misunderstanding of A/R as being linary with backpressure and spool-up characteristics instead of the correct use of Area (cm2) as correct factor. Read beneith to understand why things often are misunderstood, how they should be used and what the technical terms mean.


HP Range


The HP range is the recommended power (hp) range. If 250-650 hp is listed, then it means that the turbo operates best within this area, however it will still delivery boost and power beneith 250 hp and it will still provide more power than 650hp. When analyzing the compressor map the maximum air volume, i.e. power, can be more deeply analyzed. All compressor maps are found on each product page.


Low inertial bearings


The new racing turbos all have the new double low inertial bearings. The new double low inertial bearings spools up appr. 15% faster than normal 360 degree trust bearings.


Billet Compressor Wheel


The racing turbos all have the new forced billet compressor wheels. It starts with a solid forced aluminium block and from here milled out to the specific profile. The benefit of the billet wheels are:

1) much more agreessive pitch and innovative design possible
2) more strenth
3) less mass/weight than normal casted aluminium

Lightweight Inconel Turbine Wheel


All turbos has the new lightweight inconel turbine wheels. The benefits are:

1) Higher durability
2) Less mass - less weight
3) more efficient design

Oil inlet/outlet


When oil inlet reads M10x1.0 it means oil inlet has a threaded inlet with the M10x1.0 theat. All selected racing turbos also have possibility to use an inlet flange as two threaded M8x1.25 holes are positioned beside the e.g. M10x1.0 oil inlet hole (see flange #7). Meaning it is optional whether to use the threaded oil inlet e.g. using AN fittins or simply buy the flange #7 for oil inlet. Oil outlet is always a flange on our selected racing turbos. It is numbered by the flange # as found beneith. Amost all of the racing turbos e.g. MPR59XX - MPR65XX turbos has the flange #8 as oil outlet flange. All flanges can be purchased - see the section "Related parts" to order flanges.

Generel it is recommended that the bearing housing is not tilted more than 20 degree for correct oil flow (see image under next section for watercooling).


Watercooling - Inlet/Outlet

Those of the smaller to medium sized racing turbos that runs with high shaft rpm all have water cooling (small compressors requires higher shaft rpm than bigger compressors). The water cooling system comes standard plugged with two bolts when delivered. It is thereby optional whether you want to use it. However it is STRONGLY recommended to use watercooling for best possible durability, specially if the turbo is used for high output racing or drifting. We have race teams that both run our racing turbo with and without the use of watercooling,.however if not utilizing the watercooling then it is highly recommeded that idling (cooling) before engine shot down is carried out for 2 minutes minimum. A turbotimer has the function hereoff. Note the image below too see why watercooling is such a strong feature on high shaft rpm running turbos.
This picture shows the strong impact from watercooled bearing housing - it clearly shows how powerfull watercooling when utilized before engine is shot down.
Notice how small the "bump" in oil/bearing temperature is after engine shutdown when using water cooling (the blue line)

Compressor - Antisurge


Antisurge or Reflow ore Recirculation as it is also named is the function that allows the compressed air to recirculate if the engine is "blocked" or limited in consuming the outcomming air. The antisurge feature allows us to pair big compressors on small turbines and hence getting really fast spool-up and still operate in all areas without "compressor stall" on small engine displacement.


Compressor/Turbine - Inducer

Understanding the term "Inducer" on compressor vs. turbine is very important. Inducer is very often misunderstood and mixed up between compressor and turbine as it flips when "inlet" is outside on the compressor and inside on the turbine. So, remember that inducer is the small inlet side on the compressor side, whereas inducer is opporsite the tall end on the turbine wheel as this is the inlet point.

Compressor/Turbine - Exducer

Understanding the term "exducer" on compressor vs. turbine is very important. Exducer is very often misunderstood and mixed up between compressor and turbine as it flips when "exit" is inside on the compressor and outsite on the turbine. So, remember that exducer is the tall side of the compressor wheel, whereas exducer is opporsite the small size of the turbine wheel.


NOTE: Now when refering to a MPR6559 turbo - that requires that you know exactly what you are reading. Masterpower ALWAYS reads compressor indcuder + turbine exducer, meaning small end in and small end out. Those we believe are the only and most important figures to estimate power range. Precision Turbo use the same terms on their product e.g. 6262 whereas Garrett use the last two numbers for compreossor exducer GTX-XX82 and Borg Warner use the same compressor exducer on their first two numbers EFR 76XX. So be carefull to measure apples and apples when comparing turbo specifications just from the product name.



Compressor/Turbine - A/R

A/R is a calculation. It is a number between the area shown below and radius to the center of the turbine shaft. It is meant for comparing spool-up and back-pressure characteristics. Larger numbers should mean less backpressure and later spool-up and vice versa. A/R is a good reference to spool-up when comparing housing on the same turbo as long as the area from where to take the radius is perfectly round. Compressor housings is likely to be round inside, however turbine housings is never perfectly round, it vavious a lot between turbine housings. Also be aware that you can never compare A/R between turbo models that have different wheel sizes. A/R is only for comparison in between same wheel sizes. Due to the fact that the area has to be a "round" area for the A/R figures to be valid you should obviously be very much aware of the fact that A/R is the correct linary figure for selecting your turbine housing.  If not round then area and radius is no longer linary and A/R looses it purpose. Therefore only use A/R as a guide for compressor housings and not for turbine housings as turbine housings tend to have many other shapes inside than perfectly round. Always use areas cm2 instead as correct guideline for spool-up. Besides Masterpower few other manufactures such as Borg-Warner, Holset etc. also specify area on their turbine hosing for correct guidance. Many other manufactures do not. See section about "Area explained" to learn why this is so important.

Compressor/Turbine - Area

Area is the correct number to correct compare both compressor housings and turbine housings. Only area is linary with spool-up when comparing housings on same wheel sizes. Most people tend to use use A/R but Area is the correct figure to use. See beneith examples of where you can go very wrong when selelcting turbine housing based on A/R and not correctly by area instead.

Compressor inlet and outlet

The compressor inlet and outlet is simply the size of the diameter. Some of the compressor outlets have v-flance, this is mainly the racing turbos with the 76mm inducers, they have special v-flange as outlet. Those v-flanges is on stock and can be purchased in the section "Related parts". It is also possible to grind of the v-flange and use regular hose. All of the turbos have 4' inlet besides the bigger 76mm turbos that have the 5' sized inlet.
Turbine inlet/outlet
Turbine inlet flange is either a T3, T3 twin scroll, T4 or T4 twin scroll. Twin scroll means divided inlet and hence two holes in the flange. All flanges are stocked and can be purchased under the section "Related parts". Note, that when utilizing twin scroll setup the wastegate setup has to be split as well. Meaning either two wastegates with one on each "bank", or two WG-pipings going to one WG-collector with split-wall all the way up against the WG-valve from a single large WG. Each puls may not be able to enter into the other "bank", meaning no avialable routes in the WG pipings. As an example a Toyota Supra on single WG twin scroll gains 800rpm sooner spool-up when adding a split-wall up against the WG-valve. It is pure psysics and very effective both in terms of spool-up and keeping backpressure out of valve overlap.
Cylinders on Twin Scroll setup are paired with those that have the firing order most apart. On a 4 cylinder engine it is most often cylinder 1+4 in one "bank" and cylinder 2+3 in the other "bank". 6 cylinder engines differs more from firing order, but many 6-row engines are likely to be paired as 1+2+3 and 4+5+6 .