This thread is to cover the basics and what is needed to go BT and other high performance parts.
HOW TURBOS WORK
First, for anyone not sure how turbos or turbo cars work,
please go here and read first.
TURBO PARTS AND SIZING.
Please read the following info from garrett
GARRETT turbo tech 101
GARRETT turbo tech 102
GARRETT turbo tech 103
Please get very familure with mainly 101 and 102. 103 is more advanced than most will need to be. But if you can understand 102, you are ahead of the curve and will be able to handle turbo talk on the forums.
1.8t ENGINE BLOCK PARTS AND STRENGTH
The 1.8t came built extremely strong. The block itself doesnt need sleeved like in other brands engines. The pistons are forged and made by Mahle and have seen over 700hp on an engine dyno. The cranks are forged also and have yet to break due to power. The only week part of the engine is the rods. They are good for 310-330wtq depending on 19mm or 20mm wrist pins and turbo used.
Basically to make big power on a 1.8t, you basically only need to swap rods with aftermarket H-beam or X-beam rods. This will allow you to make over 500whp depending on turbo and other mods.
AEB/ATC/AMU/BEA rods - SCAT H beam - PAUTER X beam
GOALS and SIZING
To properly size a turbo, you need to have some idea on what your goals are and how much work you plan on doing. Do you want a fast spooling turbo? Do you want to change rods? ETC.
STOCK TURBOS (ALL IN FWHP)
KO3(S) - 200-220WHP 230-250WTQ
KO4-001 - 220-240WHP 240-280WTQ
KO4-20/22/23 - 230-260WHP 200-220AWHP 260-300WTQ
These are more of a tq producing turbo. Great for low end power (2500-6000rpms), but they suffer major power drop off at 5500-6k rpms.
GT TURBOS
GT turbos are DBB (dual ball bearing) if they end with a R. If not, they are journal bearings and have gt style wheels. DBB turbosspool up 15% faster and consume less than 1/2 the power than journal bearings turbos. This means faster spools ups and more over all power than journal bearing turbos.
As you should of learned in TURBO TECH 102, all GT turbos are put in families (GT25, GT28, GT30 etc aka shared turbine wheels) and the last 2 numbers are the size of the exducers.
TURBO NAME - POWER LEVEL - EXPECTED SPOOL (based on most popular housings).
GT28R /GT2560R - 270-300whp - 3000rpms
GT28RS /GT2860R - 290-330whp - 3200rpms
*GT2871R -325-360whp - ~3400rpms
*GT2876R - AVOID THIS TURBO, BAD MATCH FOR THE 1.8T
*GT3071R - 360-425WHP - ~3800rpms
*GT3076R - 380 - 500whp - ~3900rpms**
*GT3082R/GT3040R - 440-550whp - ~4200rpms**
*GT35R/GT3582R/GT3540R - 450-600whp - ~4700rpms**
All housings are based on .64 T25 housings for the GT28 family and .63 T3 housing for GT30/GT35 turbos. These work out for the fastest spool with the good flow.
* Denotes that to use these turbos to their full potential you will need to do rods so you dont blow your engine. Also you will start to see significant gains by changing out other parts like intake manifolds, cams, and either port or move to a AEM big port head.
** Denotes turbos would also benifit from an increase in housing to .82 T3. Expect 500rpm increase for an increase in housing size. You will however increase the top end greatly at the sacrifice of some low end power.
T - SERIES TURBOS
These turbos are all journal/thrust bearing turbos unless the chra (center cartrage) is changed to aDBB unit. They are often just oil cooled unless again, upgraded. You can also get the T series turbo in two versions, 270 or 360 thrust bearings. The 360's oil far better and since the T series turbos use more oil, it is a good idea to get the $50 upgrade. If it doesnt say 360, it is a 270 thrust bearing. Pagparts.com is the only place off the top of my head that i know of that sells both. As stated before, journal bearings spool slower which isnt always a negative. A t3t4 turbo can make more power on the stock rods than a faster spooling GT turbo. Not to mention that since they use older tech, they are about 1/2 the cost of a GT turbo. You can however decrease lag on a T series with a smaller housing (using a .48 instead of a .63).
T3s60 - 270-310whp - 3100rpms
T3T4 50trim .48 - 300-375whp - ~3800rpms
T3T4 50trim .63 - 300-400whp - ~4200rpms
T3T4 57trim - not a very efficient turbo, surges above 20psi. Avoid use.
T3T4 60trim - .63 - 320-425whp - ~4400rpms
T3/GT40 - .63 - 375-600whp ~4600rpms (GT35/40 82mm wheel with stg 3 turbine wheel)
SC61 - .63 - 375-600whp ~4800rpms (GT35/40 82mm wheel with ptrim turbine wheel)
TURBINE WHEELS
stage 1 ( 1.916 / 2.320 )
stage 2 ( 2.120 / 2.555 )
stage 3 ( 2.227 / 2.555 )
stage 4 ( ????? / ????? )
stage 5 ( 2.437 / 2.795 )
Same applies as above, to max out these turbo, you will need to rods. Also when you choose, you can upgrade the chra to a DBB unit and have faster spool and higher power potential. Take into account, if you were using a .48 housing, you need to swap to a .63 housing with it also.
BORG WARNER TURBOS
These turbos are journal bearings which spool like a dbb turbo. The reason for this is the ETT (extended tip technology). Simply put, its a taller, more efficient blade design which both improves spool ups and gives the turbo a HUGE efficiency island compared to a GT turbo and even more vs a T series. These turbos also use a much larger wheels than those on GT turbos which help reduce backpressure for even more flow and they are attached to a much thicker shaft than a GT turbo. The best part of these turbos is that they are completely rebuildable unlike a GT turbo where you are out atleast $600 for chra replacement or more for a completely new chra. The only downside to these turbos is that they are larger in size which adds weight (3-6lbs vs a gt turbo) and are only oil cooled.
S256 - 350-500whp - ~4200rpms
S258 - 350-550whp - ~4400rpms
S362 - 400-600+whp - ~4700rpms
There are others, but these are the 3 most popular. Also they come in a BW housing or a Bullseye Power SS housing in .55 and .70 housings. Theses are growing in popularity and deff a great turbo
HTA TURBOS FROM FORCED PERFORMANCE
These turbos can either be bought from FP or they can rebuild your current GT3076r or GT3582r. They remove the garrett wheel and add in there lighter billet 7 blade compressor wheel that mimics the BW ETT. These wheels will cut off a few hundred rpms of lag while increasing the lb/min rating. They recommend that you use the larger .82 housing with all versions but a .63 on a 1.8T will still be good.
HTA3076r - increases the lb/min from 54lb/min to over 57lb/min. This is good for over 30whp and 200-400rpms less lag
HTA3582r - No lb/min given but has a dramatic increase in mid range power and keeps the power increase till redline. Good for another 30-50whp in those areas
HTA3586r - This is the largest exducer that can fit in the T3 covers. Over 700awhp has been made with this turbo on evos and is most likely beyond what most will need.
ATP ELIMINATOR TURBOS
These are modified GT turbos with a ko3/4 style housings. They are a great concept but the problem with these turbos is that the flange is a huge restriction on flow. Also the housing style doesnt flow well enough for a high hp turbo. The GT2X and GT28R will be fine using a upgraded manifold and have reasonable spool. The GTRS and GT71R have a rather large increase in lag and lower power output compared to the T25 manifold and housing. Also it sounds like its a cost savings but in the end, it cost close to the same a whole kit. If money is an issue, a T series kit would be a better option.
GT2X- 240-250whp stock like spool with more psi held till redline
GT28R - 260-280whp - ~3300rpms
GTRS - 280-300whp - ~3600rpms
GT71R -290-320whp - ~3900rpms
Obviously there are 1000's of turbos and varients out there, these are just the most popular and have great tuning and parts to go with them