1994 Volvo 850 - N/A to Turbo conversion

mmd94 · Post by **mmd94** » 02 Jan 2015, 12:06

I am currently in the process of converting a N/A setup to turbo. I am hoping to find some information on the oil lines for the turbo, and what I will need to add to convert it. I already have the Turbocharger, Intake manifold, and exhaust manifold for the turbo.

Post by **precopster** » 02 Jan 2015, 12:22

Turbo and exhaust manifold are the easy part. Lots more to do.

You need all the coolant and oil feed lines for the turbo to have a source of supply. At the rear of the block you need the fittings which share coolant off the rear block drain tap and also the coolant pipe at the rear of the block will need to be replaced with a turbo one.

The oil feed for the turbo will need to be tapped into the block (there's a blank space to accomodate it) however location of this will need to be determined by looking at a turbo block.

Of course you need an intercooler and intercooler hoses. The intake manifold can be retained if you tap some more vacuum ports into it. You also need a early style TCV and a turbo ECU as well as a turbo engine loom.

Also you need an emgine oil cooler. You can use a 1999 style cooler which is plumbed into the sump directly or replace the radiator with a turbo unit which has an extra cooling tank.

Have you fitted lower compression pistons?

Are you sure you want to do this? It's such a headache to do when you can just buy a turbo car that needs some TLC

Post by **erikv11** » 02 Jan 2015, 12:47

precopster wrote:... You also need a early style TCV and a turbo ECU as well as a turbo engine loom. ...

As in, the entire engine wiring harness must be swapped out for a turbo one.

Post by **Ozark Lee** » 02 Jan 2015, 17:52

Ugh.

Add to the list that the '94 N/A is likely a Jetronic LH 3.2 ECU system (2 module ECU) that will need to convert to a Motronic (single module ECU). This also changes some of the wiring harness into the cabin for things like the climate unit. The Jetronic was an OBD-I system and the Motronic is OBD-2 so the list of changes marches on. What would really be special is if the N/A is a VVIS model.

Good luck.

...Lee

Post by **E Showell** » 02 Jan 2015, 19:05

Madness unless you have lots of time and patience for endless troubleshooting.

Post by **precopster** » 02 Jan 2015, 23:00

Yeah after buying a 98 V70R recently and rebuilding the head and seeing the countless differences between it and my non turbo cars I would never dream of it unless I bought a damaged turbo car to syphon parts from unless you like doing endless trips to wrecking yards.

Blockpartie · Post by **Blockpartie** » 03 Jan 2015, 03:54

Ozark Lee wrote: [...]
The Jetronic was an OBD-I system and the Motronic is OBD-2 so the list of changes marches on.
[...]

That's incorrect. Motronic 4.3 is OBD I with the exception of some specific versions. No Motronic 4.X fully comforms to the OBD II standard in any case.

mmd94 · Post by **mmd94** » 06 Jan 2015, 23:49

Thanks for all the information! I would like to get some clarification on the engine harness and ECU, is it truly necessary to convert the ECU and harness over? This is a pre-ob2 system, and I was curious if it's needed seeing how I will have it tuned regardless. Also, are lower compression pistons necessary? I haven't heard of that needing done before. Thanks again!

Post by **Ozark Lee** » 07 Jan 2015, 00:55

From your pictures you have the Jetronic engine control system and there is no turbo version of that system. You are pretty much on your own with this one. There may be some aftermarket products to provide boost control but it won't be anything stock. The other option is to buy the entire wiring harness and ECU from a turbo car and replace essentially all of the under hood wiring including the ECU box and sockets.

The compression ratio on the N/A engines is extraordinarily high at 10.5 to 1. The turbo engine is 8.5 to 1. If you try to boost the 10.5 to 1 engine you will blow it up. You can't just swap in the stock turbo pistons either. The non turbo stock bore (83 mm) is 2 mm larger than the turbo engine (81 mm). To the best of my knowledge Volvo doesn't offer 2 mm over pistons, I think all they have are 0.5 mm over and 1 mm over.

The turbo exhaust valve are also different between the N/A and the turbo.

I'm not saying that this cannot be done. With enough time and money just about anything can be accomplished but this is an extraordinarily difficult model year to even try on. By the time you are done you will have invested much more money than you would have by just buying a factory turbo and it will be a Frankenstein.

...Lee

Post by **tryingbe** » 07 Jan 2015, 07:01

Being a Frankenstein, you'll be stuck with unique problems that no one will be able to answer.