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Discussion Starter · #1 ·
I'm thinking of rebuilding my non turbo 900 2.3 into a 900 turbo. I know it is a lot of work and you need a donor car with all the wiring etc. so that is the part we don't have to discuss.

My options are:

Finding a 900 2.0 turbo and build the complete 2.0 engine into my car or finding a 900 2.0 turbo and rebuild my car into a 2.3 turbo (using the cylinder head of the 2.0 turbo (same bore)). The last option is in my opinion the better one. At the moment there a a couple of problems i can think of.

1. The pistons of a non turbo, are they the same as the pistons of a turbo version?

2. A 900 2.0 turbo has a garret tb25, will this turbo be big enough for a 2.3 engine

3. The ecu of a fpt 2.0 isn't programmed for a 2.3l engine. Which trionic (from which car)can i take combining the 2.3 with the garret tb25. Or is it possible to take the 2.0 fpt trionic, (it might be possible that the trionic itself will adapt to the bigger engine)

I hope someone can give me some answers
 

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1. The pistons of a non turbo, are they the same as the pistons of a turbo version?

Pretty sure they are not. The non turbo is considerably higher compression. You'd be looking for the pistons from a 9000 2.3T Aero, as they are forged.

2. A 900 2.0 turbo has a garret tb25, will this turbo be big enough for a 2.3 engine.

That depends on how much boost you run. Really you should be looking to set the engine up like an Aero, in which case you'd want the TD04HL-15T either 06cm like the Aero, or 05cm like the Viggen.

3. The ecu of a fpt 2.0 isn't programmed for a 2.3l engine. Which trionic (from which car)can i take combining the 2.3 with the garret tb25. Or is it possible to take the 2.0 fpt trionic, (it might be possible that the trionic itself will adapt to the bigger engine)

Idealy you'll want a custom programmed T5 setup. That would allow you to use any turbocharger you wish, or any you happen to have handy.

Finding a 900 2.0 turbo and build the complete 2.0 engine into my car or finding a 900 2.0 turbo and rebuild my car into a 2.3 turbo (using the cylinder head of the 2.0 turbo (same bore)).

Not 100% sure on this, but I believe all of the T5 cars, and the 2.3L non turbo, used the same head. Also the camshafts in your 2.3L naturally aspirated engine are VERY nice ... if you aren't using them I can think of a few people who would love to have them. They are one of the few differences between the various heads. But I suggest you keep them as they flow quite well. If you do keep them make sure you tell the person who re-programs your ECU that you have the N/A camshafts.

Sounds like an interesting project ... I would approach it from this angle:

Find 9000 Aero pistons and turbo. Get custom programmed ECU to take advantage of the 300 hp potential of that turbo. Keep your stock intake manifold (it makes heaps of torque), keep your stock camshafts (they help make good hp), and keep your stock cyllinder head. (though I would consider porting and polishing it)

I'd also reccomend getting the pistons coated with a ceramic top, and anti-friction coating on the skirts to prevent wear and galling. And the exhaust valves coated to reduce heat fatigue and increase the life of the valves. Not to mention keeping the valves cool, which helps reduce the chances of detonation.

Here is an example of a place that sells internal coatings (but you'll want to find somewhere closer to you, as this site is on the west coast of the USA by me): http://www.performancecoatings.com/enginecoatings.html

Good luck on the project and make sure to keep us all updated!


Dubbya~
 

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Dubbya is right about the pistons. The 2.3 atmo engine has a higher compression ratio than the turbo version therefore has different pistons.

Another option is to use a 9000 2.3LPT as a donor. You won't be able to tune it to the same level as an Aero engine but the supply of LPT's is more plentiful. If you have the ECU re-programmed you can turn it into a 2.3FPT very easily . I'm not sure whether the 9000 engine will go straight in to a 900 - if not the job will be a little more complicated. Perhaps someone could enlighten us?

Good luck with the project - it sounds very interesting!
 

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Discussion Starter · #4 ·
Originally posted by Adrian W:
[QB] "1. The pistons of a non turbo, are they the same as the pistons of a turbo version?"

Pretty sure they are not. The non turbo is considerably higher compression. You'd be looking for the pistons from a 9000 2.3T Aero, as they are forged.
Are you sure the difference is in the pistons and not in the cylinderhead. I've heard somewhere that the engines were the same except for the cylinderhead.
 

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Basically between turbo and non-turbo as far as I know it comes down to pistons (higher compression ratio) and camshafts (a little more aggresive to make the power on the non-turbo).

The camshafts will work fine with the turbo engine, should even be worth a few extra hp. The pistons however will not. I reccomend 9000 Aero forged units as they are much stronger than most, and if you ever end up tuning the car aggresively they're good to 400+ hp.

I'm pretty sure Saab did not change the cyllinder head, other than the afformentioned camshafts. This is because when buying parts for a GM900 not only are the part numbers the same for turbo and non turbo, but even from 2.0 and 2.3.

See here: http://www.thesaabsite.com/900new/ng900engineparts.htm

Pretty sure if that, since there wasn't a 2.3L turbo for the NG900, that the head is off a 9000 2.3L (later engine) and bolts straight up into the 2.0 and 2.3 GM900's. I'm betting The Saab Site just didn't bother to re-label that part.

Also I've heard that, *with some modification*, the Viggen's head can be put even onto the C900 block. So Saab heads are very interchangeable.

And it would be expensive for Saab to make two different heads for the same engine block. When they can make two different pistons. It would cost them much less for just the pistons.

Dubbya~
 

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Discussion Starter · #8 ·
Not yet, it's very hard to find a nice donor car. The first step i want to take is finding a donor car with AC, leather and off coarse a turbo engine. I'm looking for a car which had a rear or side collision, for a reasonable price. I found one a couple of day's ago, but sadly i found out that this car ran on gas (lpg), that, for me is an "no go".

I'm still looking for people who have done the conversion, and can tell me about all the difficulties i can expect. I still dont know how the engine wiring is connected to the car wiring.

My car is allready equiped with koni/eibach suspension, this was a real improvement.
 

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I would probably be thinking about a programable ECU. With this you would be able to get the setup right pretty quickly.
 

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Other benefits would be control over detonation meaning you could probably keep your existing pistons. The Motec I'm about to install can control the fuel and spark for each cylinder individually and can also adjust the mixture based on wide-band lambda readings so it should be pretty accurate.
 

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Other benefits would be control over detonation meaning you could probably keep your existing pistons. The Motec I'm about to install can control the fuel and spark for each cylinder individually and can also adjust the mixture based on wide-band lambda readings so it should be pretty accurate.
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But will it be possible to run FPT with the existing Pistons????
 
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