Ok so im looking at doing a turbo build here in the quick future. Its a 2.5l inline 6. Ive found alot of the parts that i would need but the biggest issue now is what turbo? Im looking to make between 3-400WHP. I have no idea what all the numbers are for the turbos im looking at tho.... I dont understand the different trim codes or sizing? The compressors? its all foreign to me, so if someone can help me get a grasp on this i'd appreciate it.



The turbo im looking at is from TurboChargingDynamics.com. Couldnt seem to get the attachment so heres the link, TCD Stage 3 Turbo - Turbo Charging Dynamics. Exert from website: "This T4 frame turbo happily support 250-480 HP and provides great spool up. Compressor wheel is 60 trim. Turbine can be ordered with P Trim or S5 trim. .58 exhaust housing is what we recommend for these power levels. This turbo comes with an on center housing for use with all TCD manifolds. 4 bolt housing is standard. V band housing is a $95 option. Ceramic coating available for $85. Polished compressor housing available for $50."

Now i understand what ceramic coating and polish jobs do and why there used, but i dont understand the type of housing option?

 

i'm guessing this is going on the m20. check out bimmerforums f/i section there are tons of guys in there that have done it and have great in detail write ups.

also i'll see if i can find any of my old spec sheets on my build that might be of use to you

 

look at holset turbos i run a hx40 with a 16 cm ex. housing and i start boosting at 2200 full boost (1.6 bar) by 37-3800 good to about 480ish i have a friend running a 19 cm housing and making close to 600whp with a stock rb25 with 272 cams and stock head gasket

 

Well 1st off, your turbocharger selection would greatly increase if you ran a different manifold, as the TDC manifold is set up to run a T4 flange(which is the hot side of the turbo) There are a hand full of T3/T4(which use a T3 flange) turbo's out there that can do what you want and then some. Since you are running a larger displacment motor like the 2.5L you will have the pleasure of being able to spool most of the turbo's you can get, fairly quick. so the big question is this. What are you using the car for? weekend drag strip? Weekend track car? or just a fast daily driver? these questions will he us determin weather or not a turbo is right for you, and as most know, not every turbo works for everyone else. Let us know what your setup is looking like, and then a turbo choice and be narrowed down much easier for you.

BTW:
compressor- is the cold side of the turbo

Turbine- is the hot side.

Center Section- is the cartrige that holds the bearings and cooling sections.

A/R- is the Area/Radius of the wheel and the housing, in terms the Area is the Area/Size of the inlet(the whole), and the radius is the measurement from the center of the wheel to the center of the exhaust inlet, you divide these numbers and you get the A/R. the larger the numbers the bigger the wheels, bigger wheels make power at higher RPMS smaller wheels make power lower in the RPM's

Custom turbo's tend to run larger compressor wheels and smaller turbine wheels which make them hybrids. You dont want to choose a turbine wheel to small because if you do you wont be able to make alot of horsepower. And to big will make the turbo very hard to spin(laggy) Compressor sizing is somewhat the same. you need to find a median where your flow ratings from the compressor side match the flow rating and spool-up rates of the turbine side.. Give us that info and we can help more

here are a few links to follow and read up on as well. enjoy !!

Turbo Selection: A Guide to Understanding Flow Maps - Automotive Articles .com Magazine
Turbochargers: Design and Related Parts - Automotive Articles .com Magazine

 

Ok. First off im building a DD that i will run at the strip and light to light occasionally. I will also mess around with drifting a little here and there. I plan on doing a stroker kit, probably 2.8 to 3.0 liters. A reground 272 cam. Intake exhaust, ignition, im going to slowly change evrything. I like getting the most out of my cars, and i like turning my own wrenches. So the T4 is the hot side, and most Turbos are set up for the T3 side to mount to the manifold? And you want to match the flow rates for the cool and hot sides as best you can?

 

Correct, there is just a larger choice of T3/T4 turbo's in the market that will better suit your needs then a large frame T4 turbo. T3/T4 turbos can noramlly reape the benefits of great spool-up rates and maximum CFM flow rating(more HP) Large T3/T4 turbo's can even support uppwards of 700HP in some trims. In your case a GT3040 would be a great turbo for what you need/want. I have been able to spool up a GT3040 as fast as 3200RPM's on a S200 motor which is only a 2.0L-2.2L With your 2.5L you will have minimal lage and they support in upwards of 580WHP, so in the future they will have a turbo that will still suppor your needs, but will still get down in the form you are runnnin at now. This is just 1 choice, I will give you a few other options and sizing choices later, as I have to leave for some work.