CDHB vs CABB

[chan117]

I've been looking for a replacement engine or doing a recondition of my current CDHB engine.

Is there a difference between the 2 codes and could I buy a CABB engine instead of CDHB?

The vehicle in question is a 2010 Audi A4 (B8) 1.8 TFSI.

[Smac770]

CAB and CDH are two different generations of the EA888 longitudinal 1.8T. CAB is gen 1; CDH is gen 2. The CDH changes highlights are:

– Main bearing diameter reduced from 58 to 52 mm
– Modified piston
– Modified piston rings
– Different honing process
– Ixetic vacuum pump

Also, CAB is only EU IV emissions, CDH is EU V. But that's often a reflection of the tuning in the ECM (it's the ECM tune that sets the output level, and therefore the fourth engine code character; so you're not really looking at a CABB if you're just looking at an engine and not engine+ECM). Could you use a CAB block in place of a CDH block and leave your original ECM in place? No idea; it would seem possible. The wiring diagram is the same section for B8.0 CAB and CDH.

[chan117]

Thank you for the information Sir, greatly appreciated.

I will most likely get my engine reconditioned to be on the safe side.

[A4B8 2.0tfsi]

Just buy a replacement long block from Germany, and return your broken engine when you made the swap.

[chan117]

Do you have any recommendations for where I can look to.

One of the pistons is worn out as well so it's not just the engine block that needs to be changed you see.

[A4B8 2.0tfsi]

A long block is a complete engine block, without the bolt ons, that you need to swap over, replace. https://tornau-motoren.de/de/Teilmot...etail/10008659

[chan117]

Great, thank you.

Is there a difference between CDHB and CDHA engine blocks?

I've been told by another mechanic that the engine is the same and it's actually the turbo which gives the CDHB engine the higher power rating.

Is this correct?

[Smac770]

The CAB/CDH all use the same turbo. As I've said, the fourth character reflects the tune in the ECM, not any aspect of the engine physicals.

[chan117]

I see, thank you for explaining it to me.

So I'm assuming then if I were to fit a CDHA engine into my car I will also need to get it tuned to suit?

Seem to be struggling finding a CDHB engine for a reasonable price at the moment.

[Smac770]

A CDH is a CDH. It's the exact same thing that's already in your car. Unless maybe you pick up a B8.5 version of the CDH. Same thing with the CAEB. Replace a 2009 CAEB with a 2012 CAEB, fine. Replace a 2009 CAEB with a 2013 CAEB, you're going to have to carry over the accessory bracket, the crank position sensor, etc.

[A4B8 2.0tfsi]

Since you don't even bother to read the link to the long block, or read the posts in this thread, I'm done with giving you any more help. Jesus Christ superstar, hope you ain't planning on doing the job yourself.

[chan117]

I'm new to most of this, hence the hesitations and pedantic questions...I just don't want to get anything wrong.

Thanks for the help you've given, appreciated.

[Dr-syn]

I have a 1.8tfsi engine CDHB.

I want to fit the pistons from 1.8 tfsi CABB because of the oil consumption issue.

Can I just change the pistons or do I have to change the con rods as well?

Anything else I need to consider? Obviously the rings of course.

[Smac770]

Same answer as for the 2.0T. Depends on your build date.

CAB used 21mm.
CDH used 21mm until May 30 '11 (basically >MY11)
CDH used 23mm after May 30 '11 (basically MY12>)

CAB and CDH use the same rods in the 21mm era.
CAB and CDH do not use the same pistons in the 21mm era, as CDH is Gen2 and Gen2 uses different pistons and rings from Gen1.

But when they did the rings/pistons on my 2.0T Gen2, they replaced them with pistons and rings from the 2.0T Gen1. Been fine enough since.

[Dr-syn]

Same answer as for the 2.0T. Depends on your build date.

CAB used 21mm.
CDH used 21mm until May 30 '11 (basically >MY11)
CDH used 23mm after May 30 '11 (basically MY12>)

CAB and CDH use the same rods in the 21mm era.
CAB and CDH do not use the same pistons in the 21mm era, as CDH is Gen2 and Gen2 uses different pistons and rings from Gen1.

But when they did the rings/pistons on my 2.0T Gen2, they replaced them with pistons and rings from the 2.0T Gen1. Been fine enough since.

Thank you smac

So if I understand this correctly, my build date is 2010 so I will have a 21mm con rod. I will only need a CAB 1.8 piston and rings as they are 21mm too.

in my case a 1.8tfsi CAB piston will fit my 1.8tfsi CDH rod

[Smac770]

For a some-month 2010 build, yes, it's likely the CAB components will work in your CDH.

[Dr-syn]

For a some-month 2010 build, yes, it's likely the CAB components will work in your CDH.

Thank you Smac700

I have seen on this forum site that you are very knowledgeable so I thank you for your time taken talking to me.

[Smac770]

No problem. Just remember, all I can do is speculate based on the available information. I have never put a CAB piston in a CDH, nor any piston into any engine for that matter. :-) But what you're planning to do seems to be pretty much the 1.8T version of exactly what AoA did when they replaced my 2.0T pistons/rings.

[Dr-syn]

No problem. Just remember, all I can do is speculate based on the available information. I have never put a CAB piston in a CDH, nor any piston into any engine for that matter. :-) But what you're planning to do seems to be pretty much the 1.8T version of exactly what AoA did when they replaced my 2.0T pistons/rings.

Thank you