A kid in town that I know jsut totalled a 2004 Jetta GLI by hitting a telephone pole head on at about 55mph. Once I found out he was okay, I checked out the car and found that like most front wheel drives, the turbo was tucked safely back near the firewall, and seemed to be unharmed. I assume this turbo is too small to be getting any ideas about taking it out of the car and swapping onto a 12a, but I figured you guys could set me straight for sure.

 

Yep, way too small.

 

Yeah man that's way too small. Start with a stock Turbo II turbo and work up from there

 

yeah, get a stock T2 Hitachi.

 

Out of curiousity, does anyone know what size the Turbo II turbo is? Also, my friends describe turbos as being T38's or a T56, what do the numbers mean?

 

Hitachi HT-18


-Ted

 

first you have to understadn that with the proliferation of turbo assemblers (not manufactures) assemblers that there is currently no ryme or reason to naming of a turbo.

the manufactures have one set of names for the various components that they produce, and then the assemblers tag it with there own names to try and sell it.

so for the basics: such as for older journal bearing style turbos:

T25, T3, t4 and t6 are all denoting the size of the exhaust flange. t25 is very small usuually a small OEM turbine size for anything from a 1.6~2.6 litre engines. they are often found as twins on engines above 2 liters think silvia , skylines and skyline gtr's

Toyota's use heavily modified turbine housings that resemble a t3 in regards to flow but thats as close as the resemblance comes.

Mazda uses a hitachi HT-18 which is a cross bastardised version of a flange that sits somewhere between a t3, and a t4 its physically closer to a t4 than a t3 however its wheel size is slightly smaller than a garret "O" trim wheel and the a/r of the houseing itself is 1.0

thing to remember the physicall size of the houseing changes radically depending upon the flange design. A T3 1.0 houseing is smaller than a T4 1.0 housing. All else being similiar the T4 flows substantially more than the T3.

garret gt series:

suffice to say the starting size is the gt35r, now if you go with a T4 flanged version or a t3 flanged version is up to you, but please remember this: in the past 99% of the members on the forum, including the larger tuners would have said that a T-3 houseing is to small and would cause restriction and damage to the cartridge...... now that everybody has bought into the T3 flanged version of the gt35r thing think about it, the majority of them are having problems with he cartridges overheating, and the seals and bearings going kaput. This has happened with several of my friends cars, and I would reccomend the T4 flange version as a result. yeah the T3 flanged model of the GT35r gives great spool, but if the turbo goes boom in less than 5 k miles average, than what good is it?

something to think about.

kenn