InfamousRS

Im having trouble understanding all of the turbo lingo. I understand the T3, T4, T04 stuff I think. I dont understand the T04E, T04B or what ever the letter at the end is. Also what is the .57, .54, .48 trim apply too? Pretty much just about any thing to do with tubor sizeing, and how do you figure out what size is best for your engine?

I don't expect you guys to try to explainall this stuff to me, unless you want too. Is the any really informative sites out there the will though?

Thanks for any help or info!

Seraph0

I can't believe I'm going to say this but:

Do a search. There's been MUCHO talk explaining what all those numbers mean. I bet you will learn a lot.

Rob03Pro5

Well, I'll answer your questions since I have nothing to do after my finals!

Differences between T04E and T04B

<u>Blades</u>
The T04E and T04B are different T4 families. One "generally" has a quicker spoolup characteristic and the other has higher flow. The T04E has 6 main blades with 12 sub-blades... these blades are rather large, so they move alot of air. The T04B has 7 main blades and 14 sub-blades.. these blades are a little smaller than the T04E's so they spool quicker but dont generally move as much air.

T04Bs are actually a little more dynamic than T04Es. You can find small T04B's that push just enough for 330hp and others that push over 550hp! The major's of a T04B can range from a 1.9" to a 2.44"! The largest major a T04E has is a 2.29".

Understanding Trims

Those numbers you referred to are Trim levels. They dont really have a dot before them ".54, .50, etc." They are just numbers that represent the wheels in that particular turbo. For instance: A T04E 54 trim means that it's a T4-E family with a 54 wheel package.. which is a 2.17" inducer and a 2.95" major. Every trim has different wheels. Go to http://www.turbocharged.com and click on Catalog.. then to Turbonetics' logo. You can see all the different trims and their respective wheel sizes.

Understanding Exhaust Housing A/R

The .48 you mentioned was an exhaust housing A/R for a T3. T3's usually offer .36, .48, .63, and .82 A/R exhaust housings. The differences between them is basically the volume.. how much air can go through it. A larger exhaust housing will produce better top-end HP but also create more lag.

To figure out which turbo is best for you, you need to read some compressor maps and do some number crunching. If you look at a compressor map, you'll notice the Y-axis is for Pressure Ratio and the X-axis is for Air Flow in lb/min.

First, you need to figure out what your max psi is that you want to run.. and sort of guesstimate at what psi you will be at each jump in RPM. (like 2psi at 2k, 5 at 3k, 9 at 4k to redline) Then you need to find out what those Pressure Ratios are for each of those PSI's. This is how:

Boost PSI + 14.7
------------------- = Pressure Ratio
14.7

Once you've got that figured out.. make a little table:

PR-----RPM-----CFM

and fill in each PR for each RPM.. dont worry about CFM cuz we're getting to that.

Next, you'll need to figure out your car's CFM output at those given boost numbers. Here's the equation:

Engine CI (cubic inch) x RPM x 0.5 x 0.90
-----------------------------------------------
1728

That would be your CFM at that rpm.. then you would multiply by your Pressure Ratio to find the CFM with the turbo at that psi.

Then you take all those numbers you put on the chart, and plot them on the compressor map.. and draw a line going through them. Do this for a few turbos that you have in mind and you'll see which turbo is best for you. Generally you want the line going *near* the surge line and run straigh to the right, through the most efficient part of the compressor map.

Hope some of this helps.

InfamousRS

Thanks Rob, for taking the time to explain that all to me. No I just need to sort through it and figure it all out.

Seraph0

Another good post for the archives.

freakie

erm how do u ge tthe maps rob? also, the Engine CI ..that sorta gets me, does it mean like a b18c will be 1.8 and H22a will be 2.2 or what?

Rob03Pro5

You can find the turbo maps at http://www.turbocharged.com. Click on the "compressor map" link. CI = Cubic Inches. A B18 is 1798cc (or so) which is around 109.7-110ci. Use that for the equation.

Here's some CI's so you dont have to do the math (no that its hard.. this is just easier for u!):

2.3L = 2258cc ~ 137.8ci
2.2L = 2157cc ~ 131.6ci
1.8L = 1798cc ~ 110ci
1.6L = 1595cc ~ 97.3ci
1.5L = 1493cc ~ 91.1ci

BlueShadow

to convert Liters to Cubic Inches Displacement just multiply the number of Liters by 61

2.157 L x 61 = 131.577 CID

BlueShadow

you only have to map 3 RPM points at the minimum
-Redline (at full bost)
-RPM at which the compressor will reach full boost (usually 50-70% of redline)
-Idle with no boost.

you can do more RPM points too if you want to see what the airflow rate is at those different RPM's. and these might even be useful for when your doing fuel.