2.0 vs 1.8, what's the difference?

[zandrew]

I asked this on the b5 section and got no love so I am asking here.it seems this upgrade is done more in the b6 then the b5. I have a 2001 avant and am thinking about this upgrade coupled to a 6758efr or 7163 efr (choices choices, makes it harder it when your sitting on both)and I would really like to know what the gains are, specifically.

I know it makes more hp at less psi, better spool, etc. How much though or is there a clear cut comparison of the 2?

[diagnosticator]

More hp at lower boost with a larger turbo is a myth. Developing the same hp, the boost will be the same for both turbos. The only difference is that the larger turbo will be running at a lower RPM for the same boost.

[Tiluleshpingen]

More hp at lower boost with a larger turbo is a myth. Developing the same hp, the boost will be the same for both turbos. The only difference is that the larger turbo will be running at a lower RPM for the same boost.

did you mean the smaller turbo?

[zandrew]

More hp at lower boost with a larger turbo is a myth. Developing the same hp, the boost will be the same for both turbos. The only difference is that the larger turbo will be running at a lower RPM for the same boost.

??? I am saying that a bigger engine will require less boost to make the same hp with the same turbo, that's a benefit.

I was hoping to see a good dyno comparison between the 2 but have yet to find one.

[diagnosticator]

No, the larger turbo will be spinning slower at the same boost.

[zandrew]

Can you explain? Everything I have read is contradictory to this statement. A larger engines moves more air at a lower RPM then the smaller engine. That in turn increases spool. If you think of a 2 liter bottle being filled by a compressor that same sample of air being stuffed into a 1.8 liter bottle will have a higher psi to hold the same mass of air.

I am interested in this greatly.

[thetikm]

You guys are talking about two completely different things. Diagnosticator is talking about turbo size. You are asking about engine displacement

[zandrew]

That's what I thought. He needs to pass that to the rest of us....

[MoparFreak69]

Depends on what version of the 2.0 you are talking about. The 2.0t in the B7's are Direct Injected, but still shares a lot of similarities to the 1.8t.

[thetikm]

Are you talking about a stroker build.

[zandrew]

Yes, I am b5 which is strictly 1.8t but I am 06A. I am trying to use my budget the best I can and on the fence of what will get me the best overall results. I am going to use the 6758 efr (though I also have a 7163 efr) and I am thinking 2.0 Stroker over built and cam'd head. I can always upgrade the head later but is the extra displacement going to pay that much dividends with this turbo setup?

[diagnosticator]

You guys are talking about two completely different things. Diagnosticator is talking about turbo size. You are asking about engine displacement

Yeah, I misunderstood the comment by the OP, "I know it makes more hp at less psi, better spool, etc.", where guys often incorrectly think a larger turbo makes more power at lower boost.

The power difference between a 1.8l and a 2.0l displacement engine with all else equal is only a small difference.

Compared to a 1.8l engine a 2.0l with the same size turbo will spool slightly sooner due to the small increase in exhaust gas flow rate with the 2.0l displacement. Stated another way, compared to a 1.8l displacement engine, a 2.0l engine will develop the same boost at a slightly lower RPM with the same sized turbo.