Flatbed24v

I feel like an idiot for not knowing this. I always see turbos listed by there numbered size ex: 64mm/14mm what do these numbers represent? What are the numbers for my stocker? I was looking at htt turbos and they had some turbos that were the same numbers but different price and they were in different classes ex: street stock ss and super street ss why is this? And lastly what happens when the first and second numbers goes up or down? I am trying to find a set of twins but don't know what I am looking at. Sorry to be so wordy and thanks for the lesson in turbos.

dodgetrucker75

the 64/14... the 64mm is the size of the of the compressor wheel inducer, and the 14CM is the size of the turbine housing, stock turbos i think are around 56 or 57mm compressor wheel size, ant the turbine housings are 12cm for a manual and 9cm for the autos, on the 24valves, just a start, there is a lot more, hope this helps

Flatbed24v

that does help but how can I tell which turbos will spool fast with not much on the top end and which ones will lag early then light up at the top end and which one will be in the middle by looking at the numbers

J Lent

I've tried many different turbos, actually every turbo from HTT in 62 & 64 variants. The smaller the number means the sooner the turbo will light. A 62 turbo will light faster than a 64, but the 64 will cool better on top. That wheel is called the inducer [aka intake wheel]. The middle numbers are the exducer wheel [aka exhaust wheel] The smaller the number, sooner the spoolup, bigger means cooler up top. Although a 65 wheel may spool sooner than a 71 wheel, the 71 will hit peak boost faster [from 10psi to 50psi]. The 62 turbos are a good towing turbo, fast spoolup. The 64 & larger are more of a competition only turbo due to slow spoolup. The 3rd number is the exhaust housing sizes, again meaning bigger is cooler up top, but slower to spool.

Big Blue24

Your stock HX 35 is 54mm compressor, 58mm exhaust turbine wheel, 12cm exhaust housing. It is good for about 400 HP and will be the fastest spooling turbo due to the fact that it is small and cant support the huge HP numbers.

Many of the newer turbos have extended tip technology. This means that an equal sized wheel will push more air due to the extended tips. Essentially, ETT gives you nearly identical spoolup of non ETT older technology wheel but the flow of a larger compressor wheel.

Mike Holmen

Just to mess things up, every turbo manufacturer rates there turbine housing slightly differently. Holset uses turbine area, Garrett uses A/R. You can use the A/R in most cases. Thats the turbine housing area/radius of turbine wheel. You can also do this on the compressor side.

97 D-Tec

well if your looking for duals then wouldnt you want a turbo like a 62 to spinn up a turbo thats like a 66 and up

kammak

Why do they use a different possibly better turbo on the manual trannys over the auto's.The larger 12mm body provides more flow?If so would the manual turbo be a nice upgrade for an automatic truck without any hassles.?This is an interesting thread hope I'm not hijacking.

J Lent

I have a HX35 in the classifieds.

NoSeeUm

From the Garret site is a good description. Read under Turbo 101, Turbo 102 and Turbo 103.

Jim

Flatbed24v

thanks for all of the info guys that helps a lot

Big Blue24

FYI, Dodge put the smaller turbo on the automatics for emissions reasons. An auto trannied truck spools up a little slower thus more pollution. To combat that, they made a slightly smaller turbo for the automatics to aid in spoolup.

That said, I'm not exactly sure what is smaller on the HY35 turbos except for the well know fact that the turbine housing is 9cm. As far as compressor, cover, and turbine wheel, I have no idea.

JHew84

It should also be noted that to properly match a turbo with a specific application understanding compressor maps is very useful. Although these days so many people have tried out so many different configurations you are typically pretty safe using the "accepted" turbo for certain things.

I know there are some better write-ups on the subject but I'm in class right now and don't have the links, if I remember later I'll update my post. Here's a "how to" I found with a quick search on Google though:
http://forums.bimmerforums.com/forum...d.php?t=258035

BigErksG2

so is the 9cm housing on autos for 24v and 12v? i was under the impression that my 97 auto 12v has a 12cm housing

Destination

the 9cm housing is only found on 01 and 02 automatic trucks