esde

I've been searching around here and some other sites looking for info that explains how the numbers show what components are in a turbo. I read people calling a turbo a 64, or a 62, and then a 64/71/.80, or a 62/71, and then an s300... what do all of the numbers mean? My truck runs a stock HX35, and is a bit of a dog till it builds some boost. To get it to spool sooner, would I want a smaller exhaust housing, a bigger compressor, and which numbers are those? Sorry for my ignorance, I'm just trying to understand how this all works and the pro's/ con's of the different options.

JonnyLightning

the 62 and 64 and 66 is the diameter of the wheel on the intake side of the turbo, witch is known as the "compressor" wheel. A larger wheel will flow more air and be capable of more boost, but it's not as easy as saying x will flow y more than z.

The other larger (middle) number is the diameter of the turbine wheel. The turbine wheel is on the exhaust side of the turbo. The compressor wheel and the turbine wheel are connected via a shaft through the middle of the turbo. The turbine wheel is driven, which turns the shaft, which drives the compressor side of the turbo to build the boost.

The third number, usually between 12cm and 16cm is the housing diameter. In general a larger housing will spool slower but have more power capability. Same thing for the compressor wheel.

Larger diameter turbine wheels characteristics are they surge less, have lower drive pressure (the pressurized air inside the exhaust manifold, and more top end power.

In the end, all other things being equal, a larger compressor wheel for the most part determines the horsepower capability. The tradeoff to larger numbers is their slower to respond because theres more rotating mass to spin.

I copy and pasted it from another CF thread. Don't know how to do links of that stuff but thus should help



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JonnyLightning

S300 is the turbo frame size.

It took me 2 years of reading these forums and I'm still learning everyday. One thing I do notice is people don't like answering questions that have been answered hundreds of times so I would use the search button and you'll find most of questions already answered


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esde

Thanks for your reply. I've read and read, but had yet to find an answer as clear as you gave. For reference, what are the sizes of my stock HX35? And when you say the last number is housing, are you referring to the compressor or exhaust housing? Thanks again.

DC199512V87

hx35 is a 54/58/12. iv heard that it can also b a 56/58/12? but not sure....anyways the 12 is the exhaust housing size i think. gurus will b quick to correct me . cant imagine ur tiny turbo being a dog to spool unless u have stock or less than stock fueling?? i know my stock turbo right now (plenty of fuel) goes from 10psi at cruising to 35psi in under a second. obviously there will b no boost build below 1250rpm so i dont drive there, buit im sure u knew that...... while i dont always like the search function on this forum, google works wonders too

DodgenIt

Unless you have a fueling problem, I'd say the stock turbo's spool quick. I for sure wouldn't go any smaller then your hx. It's a really good all around turbo.

jbm5309

Go to this website and you can download anything from service manuals to troubleshooting info.

http://www.holset.co.uk/mainsite/fil...%20Manuals.php