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Discussion Starter #1
Hi

Not sure if this is the right forum for this so please feel free to move to a more suitable place.

I'm about to replace, or at least the garage is about to replace, my 2.5L V6 with a 3.0L unit from a 9000 (cambelt failure at 80 killed the 2.5 )and would like to know what the potential problems are e.g will the management system in the 2.5 be able to cope with the 3.0.

If anyone has any experience of doing this swap I'd be most grateful to hear from them.

Regards


Ian
 

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There's a guy in The Netherlands who says he's got one of five 1994 900 V6's that were part of the original press fleet and had a 3.0 litre in there. He was at Speed 2003 - maybe someone has a pic of that car online. He had the engine bay fitted out with Opel '3.0' badges, but otherwise the car looked stock to me (aprt from the wheels, the big fr*gg*n' stereo in the boot, etc., that is).
He was the only Saab to try the drag strip there, but his time wasn't really conclusive about whether it was any faster than a 2.5 would've been IIRC.
Can't really say whether his claims of it being a 3.0 were justified, then. It just might.

Anyways, the swap has been done before in a Calibra, and in that car it was only the block as the 3.0 MV6 heads would not clear the bonnet. Remember the Opel/Saab 9000 3.0 litre unit came with a variable intake manifold system that would be hard to incorporate in the 900, too.

So going from the assumption that, if anything, it would have to be a 3.0 short engine/2.5 heads and manifolds hybrid, neither the original ECU nor the 3.0 one would be a perfect match. I would expect the (9000) 3.0 ECU to be closer, though, and it's not like OE manufacturers (especially smaller ones) haven't done this kind of stuff already to avoid having to reprogram for any kind of small variation in spec. As long as the volumetric efficiency of both engines is within a few percent over the operating range, the engine management system, especialy if it's based on an air mass meter (don't know what the Opel/Saab Motronic on the V6 has), will be able to adapt to the variations.
 

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Discussion Starter #4
This is where I start to get a little concerned as the garage have told me that the engines are identical and the 3L would just be a straight swap. I asked about the engine management and they can sort it out. By the way I'd like to make it clear that these guys are not a bunch of backstreet cowboys but their not Saab specialists either.
 

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Discussion Starter #5
Was typing my reply as Leon was posting his so thread is a little out of order. Now feeling NOT so concerned.

Anyone fancy guestimating what it'll do for the performance?
 

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Well - if they manage to drop in the whole engine instead of mating the short block to the existing heads (which in your case would have meant swapping a couple of bent valves, I guess), the 3.0 lump does clear the bonnet and intake/exhaust systems meet the manifold in the correct places, then, you're set.

Half a litre extra capacity won't exactly hurt performance - the 3.0 litre was rated at 210 hp versus 170 for the 2.5. Torque was about 300 Nm for the 9000 V6 IIRC...
 

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Discussion Starter #8
More than a couple of bent valves! Apparently the tensioner seized and shredded the belt. I finished up with one snapped cam, one bent cam and a number of valves smashed through the followers. Basically the heads are scrap metal. Got a good deal on the 3L lump though - 63000 miles (warranted mileage)for £750.00 + VAT plus fitting.
 

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Discussion Starter #9
Well the 3.0L lump arrives today so hopefully I'll be able to let you all know how it went in a day or so.
 

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Discussion Starter #10
Well, got the car back today and what a difference with the 3.0L lump under the bonnet. It pulls like a steam train all the way through the range
and fuel consumption seems to be better
than with the 2.5L (probably due to the fairly large hike in torque.) Begs the question why the hell Saab never produced a 3.0L option, especially as the 2.5L always felt slightly underpowered to me. Next step is to get the ecu tweaked but that's going to have to wait until after Christmas.
 

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Nice one


Let us have some more impressions when you've got used to it, it sounds like an interesting conversion
 
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