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XC90 T6 Swap for Volvo S90 Executive

Old 08-25-2018, 04:32 PM
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Location: Barbados, West Indies
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Default XC90 T6 Swap for Volvo S90 Executive

Hi, everyone

Before I go any further, while this is an engine swap post, I'm not looking for anything insanely fast. I like turbos because of all the talk of volumetric efficiency, and given the size and weight of my car, I feel as though 180 horsepower is unfair, and 275+ would be a better suit. I just need some advice on what to watch for while swapping the engine.

A few years ago I bought a 1998 S90 Executive, which I blew up while driving on an oil leak (wasn't seeing any oil puddle thanks to the splash guard under the engine, and the oil light wasn't consistently on, so I didn't know anything was wrong until the engine started making noise).

After sitting for three years and trying to figure out what engine to drop into the car (I wanted back another Volvo 6 cylinder) I finally decided to buy a T6 engine from a 2004 XC90, as my research said the block would bolt up, and externally everything looked just like the original B6304 engine I blew up, just that the head and manifolds are different.

I'm currently awaiting the engine's arrival into the country (living in Barbados, engine sourced from Ireland). Now I know there will be some modding to do, but I just want to be clear as the research I did was a little cloudy (not many people have dropped a T6 into an S90/960)

Can I keep the harness that might be coming with the XC90 engine, or should I transfer my B6304 harness over so it can plug up to the ECU?

I understand there's a weird CVVT solenoid connector on the exhaust camshaft that's intended to control emissions during cold start. My S90 already has a smog pump. I've seen some threads saying to just run some connection to the cam solenoid so it can run, but it's not necessary, I'm curious - can I run the connection from the smog pump to the solenoid and just ditch the smog pump altogether (I'll miss that growl the engine made when smog pumping - maybe I could have my cake and eat it too?)?

The reason why I'm wondering about ditching the smog pump is because I need to make room for the turbos. The car is RHD, so I've already got the smog pump AND the Brake Master Cylinder in the way, among a few other possible parts. Then, because of how the engine is mounted, I've got the driver's side engine mount to worry about, so I know I already have to fabricate manifolds and downpipes to give the turbos clearance from the manifolds.

I want to keep the T6 turbos, give the internals a refresh if possible (engine had 97,000 miles when pulled), but what about boost control? Was there ever a need for the XC90 ECU to control boost pressure, or was it stock wastegate pressure keeping her going?

Basically I want to give this car the in-line 6 engine it should have had, but got cheated of due to timing.

Also, the car is automatic. Anything to watch for there? I know everybody's in favour of stick-shifts, but I have no patience for the clutch pedal and I like the smooth sound of automatic gear changes. I've not hear of any trouble with the AW30-40 transmissions (why should I? It's a Toyota transmission, isn't it?). What about the rest of the drivetrain?

Listening out for some helpful advice here. I know I've probably skipped a few details. Let me know if further info is needed.
Old 09-05-2018, 06:02 PM
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I'd like to buy two tickets to watch the show.
Old 09-06-2018, 06:32 AM
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Location: Kingsport, TN
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In engine swaps of this type, if you don't have some guru around that creates new ECU programming, you need to make the engine think it's still in an XC90. Pursuant to that, you need a donor car to make it easier. You don't have that. I am not sure how much wiring harness you'll get, but you'll need to use an XC90 wiring harness if you are going to run the original engine controls. They used computer-control on the boost. It has throttle-by-wire. I think it also has a bunch of VIN-coded computers that won't work unless they think they're in the original car and oh they also have to think they haven't been stolen, even if they are in the original car. You probably could get a "ECU tune" that removes some of the difficulties.

The XC90 used an electronically controlled transmission, and there would be data linked between the engine and transmission controls. That is the only way it can be done. A reasonable person could probably pull the swap off, with a donor car, but I am not sure how you would deal with using the S90's transmission if it was also electronically shifted. I never had an S90 so I am not sure about that part of it.

Last edited by firebirdparts; 09-06-2018 at 06:35 AM.
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