LT3/C20GET vs C20NE Engine Questions - Second Generation Forum

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LT3/C20GET vs C20NE Engine Questions
Thursday, May 22, 2014 8:08 AM
Hi folks - hoping to gather some advice on the above engines.

The long and the short of it is, I'm posting from the UK where we didn't get the LT3 engine (also called the C20GET engine, which came in the '87-'90 Sunbird.) One of our equivalent cars (Vauxhall Calibra) came with the C20NE engine, which is pretty much the same, but with no turbo:

I'm trying to get together the info needed to turn a C20NE engine into a C20GET/LT3 engine.

As far as I know, and I'm hoping someone can confirm, the differences are:

- Both manifolds.
- Turbo ofc.
- Loom.
- ECU.
- Pistons (forged on C20GET, unsure about rods.)
- Air intake routing is different. Might go without saying as it's got a turbo ofc.
- Oil routing for turbo.
- Unsure on injectors.
- FPR.

Is anyone with expertise reading this so far and spotting anything I've missed?

More importantly, I'll need a rough costing of these bits going forward. Does anyone know where I might find them either new or used or set about getting them (once I find out what they actually are of course) and mailing them to the UK?

Thanks for reading this far, and hugely grateful for any and all advice on the issue!

Re: LT3/C20GET vs C20NE Engine Questions
Monday, July 21, 2014 7:01 AM
This may be a little late, but ... I've been interested in the differences between the US and UK versions of these engines for a while and have done some research - I've been looking into the 20SEH more, which we didn't get here in the US. Anyway, I'll go in order here and this is just to the best of my knowledge, I have not owned an LT3, so it's all secondhand info more or less. There are people who know a lot more about these than I do, but I'll give you a general idea hopefully.

Yes, both intake and exhaust manifolds are different. However, we have a version of the 2.0 here which is called the LE4 - it is very similar to a C20NE, and its intake supposedly flows better than the turbo intake and has a larger throttle body, although I can't remember the sizes offhand. You can get a new exhaust manifold from if you search under a 1990 Sunbird 2.0L turbo.

Obviously, the turbo.

Wiring harness/loom and ECU, yes are different - I believe all the UK versions are Motronic, but not here. Not sure if this may be something where it would be easier for you to go aftermarket like a Megasquirt or something, I have heard that the factory tunes are not too great to begin with. Depends on if you intend to keep it stock I guess.

Pistons are forged and are lower compression than the C20NE. I don't believe the rods are forged, but I have heard they are possibly stronger than the LE4/C20NE, but I have nothing to back that up.

Intake routing is different, yes obviously. One (probably irrelevant) thing to note about that is I think the C20NE came with a flatter cam/rocker cover than we got here in the US, so the intake piping routes over the top of it. Shouldn't have a problem retaining C20NE cover. If you look up images of an LT3 you'll see what I mean.

The block is tapped on the C20GET for the oil return, it's not tapped on the LE4 and I doubt it would be on the C20NE. I think the oil feed just taps into a block where the oil pressure sender is on US cars. I'm not totally sure how the C20NE is set up.

The injectors are larger for the turbo. The turbo injectors are 30lb/hr or 315cc/min, and I believe the LE4 are 16lb/hr. Not sure what the C20NE is, but I'm guessing closer to the LE4. Another thing to note is the turbo injectors are low impedance, not high like the LE4. These can also be found on rockauto.

I have no idea about the fuel pressure regulator. Again, can be found on rockauto.

One more thing, I don't know anything about them really but I'm guessing that the distributor is different between the two. The C20NE distributor doesn't look the same, and I assume it's a different system due to the different engine managments they use between the US and UK.

For one I'm assuming you can order off rockauto there since I've done the reverse and ordered UK-only parts (shipping of course is pretty expensive) and for two, anything you can't find on there like the intake, turbo, etc. I'm not really sure where you can easily source them from.

86 Skyhawk wagon 1.8SOHC 93 Sunbird two door 2.0SOHC 93 Sunbird four door 2.0SOHC
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