What TD04 do i need for my Saab 9-3  ('98-'02) of 9-5 ('97-'10)?

The standard Saab TD04 as used on a 9-3 Aero ('01-'02), Viggen and a 9-5 Aero is the TD04HL-15T#5.

What can i dissect out of that name?

 
TD04 is the turbo name.
HL is the turbine wheel.
15T is the compressor wheel.
#5 is the turbine housing.

What Trionic 7 engines use the TD04?

B205R

B235L

B235R

What is the difference between the standard TD04HL-15T#5 as mounted on T7 Saab's and the TD04HL-15T#6 listed in our shop?

 
The difference is in the size of the turbine housing. That is the part of the turbo where the exhaust gasses flow trough. Trough the exhaust manifold hot gasses flow trough the turbine housing where they power the turbine wheel.

The opening where the exhaust gasses pass trough is smaller on the #5 housing compared to the #6 housing. When the gasses are compressed trough a smaller opening the flow will be relatively high. This lets the #5 housing spool up quicker. The larger opening on the #6 housing lets gasses flow a little less fast, but allows for more capacity. With this less restrictive turbine housing a little more top end power can be given before the limit of the turbo is reached.

What turbine housings did Saab install on their cars?

 
All of Saab's T7 engines for the top end models were equipped with the TD04HL-15T#5. De manual transmission 9000 Aero was equipped with the TD04HL-15T#6. The automatic transmission 9000 Aero was equipped with the smaller Garrett T25 to save the automatic transmission from too much torque.

How can you distinguish the TD04HL-15T#5 from the TD04HL-15T#6?

 
The most obvious difference is the entrance shape of the turbine housing. On a #5 housing this is a round hole, on the #6 the hole is oval.
The location of the wastegate in relation with the turbine flange also differs. This explains the need for a curved wastegate rod on a TD04HL-15T#6 for a T7 mounted TD04,  on a TD04HL-15T#5 the wastegate rod is straight.

Is a TD04HL-15T#6 from a 9000 Aero a bot on match for my 9-3 of 9-5?

 
The 9000 turbo does not bolt on a Trionic 7 engine without a slight modification. The compressor and turbine housing have a different angle apposed to each other. The connecting flange on the turbine / exhaust manifold also differs. 

Will a "King Cobra" fit on any TD04 turbo?

 
The air intake pipe mounted on the compressor housing restricts air flow on high power Saab's, especially on the first series of 9-5 Saab's the air intake pipe had a rather small diameter. 9-5's from a few years later had a larger diameter air intake pipe allowing the engine to take in more air.

In the year '06 Saab introduced 9-5 Aero's with 260 hp. Saab fitted the larger air inlet pipe with a less restrictive lower curve towards the turbo. On the different Saab enthusiasts internet forums this air intake pipe has gotten the name "King Cobra".

Space is a limiting factor surrounding the turbo. To fit the King Cobra in this limited space a different compressor housing was needed. The compressor housing on '06 and onward 9-5's is 15 mm shorter.

I's possible to switch a pre '06 compressor housing with a new smaller housing to fit the King Cobra. All other parts of the turbo are exactly similar. You only need to change the compressor housing.

original picture by DrBoost.

Volvo uses a even bigger turbine housing. Will this fit a Saab?

 
You can find a volvo TD04 with a #07 turbine housing. To mount this on your 9-3 or 9-5 a T25 flange is needed on the turbo. Volvo uses the T3 flange on its exhaust manifold and turbo.

You could use a exhaust manifold from the first models Saab 9000. These manifolds have the T3 flange. When unaltered this manifold mounts the turbo approximately 4 cm higher compared the the original T25 manifold, to compensate you will need to use a adapter of some sort.

Most of the #7 Volvo turbine housings have a angled connection to the downpipe. These housings are least restrictive but need an alteration to the standard Saab downpipe. On the early 850's the turbine housing was a conical downpipe fitting almost similar to Saab's. This turbine housing opening is a bit smaller in diameter compared to the angled version resulting is a reduction in top end power.

Volvo uses a larger compressor wheel on some of its models. Will this compressor wheel fit my Saab turbo?

 
It is possible to mount the Volvo bigger compressor wheel on your Saab's turbo. The 19T compressor wheel is 4 mm larger in diameter and has a 2 mm bigger exducer. The compressor housing has to be altered to accommodate the larger compressor wheel.

We recommend mounting a #6 or a #7 turbine housing in combination with a 19T compressor wheel. When you force a lot of air into your engine this has to come out trough the turbine housing. A restrictive turbine housing will amount to high exhaust gas temperatures.

15T, 16T, 18T, 19T, what is the difference between these compressor wheels?

The difference is the size of the compressor wheels. This can be measured on different locations. The exducer (1) size, the inducer (2) size, the compressor wheel height (3), and the height of the exducer blades (4).

Cold filtered air enters the front of the compressor wheel in the inducer (1), the compressed air exits the compressor trough the exducer (2) trough the intercooler to the engine. 

Hot exhaust gasses leave the engine trough the exhaust manifold and enter the turbo trough the side of the turbine wheel (5) trough the inducer (7) and exit the turbo trough the exducer (6) in to the downpipe.

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