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okay i was just thinking, and i always see people ask on here the best way to get a lot of power from a NA 900. could you just get a manifold off a turbo model and go from there? is the NA 900 strong enough internally to be turboed? i mean most cars can handle a few extra psi anyway, right? if this is commonly done and i am a moron, any popular sites?
 

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thanks guys, and good info s900snt. im not on the verge of doing this, i was just ponerding becasue i hadnt seen too much talk about it...but then again, i dont look too hard i guess. im content with power on it right now, ( for speed i drive the 310 horse subaroo.) the saab is stock and i drive it once or twice a week. its fun for rallying and being able to hammer the throttle in the twisties and wrestle it through. if i go to college and buy it from my parents i would most likely free up some exhaust but pay more attention to handling....
i asked b/c my ffiedn has a very tired 89 turbo that could be taken for pennies and present oppurtunities....again, thanks for the help.
 

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s900snt said:
The only problem is that the engines are build for boost at 8:1 compression
Stock compression ratio on the B202 turbo engine is 9:1.

s900snt said:
The 2.1 Cylinder head is significantly improved over the 2.0
Group9 flow tested B202 (2.0L) and B212/B234 (2.1L/2.3L) heads, and found that the B212/B234 heads flowed only 5% more.
http://www.saabcentral.com/forums/showthread.php?t=22813

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This comes up a lot... But it's still a good debate.

Some people say you can do it and everything will be great. I am from the other school of thought that says you can do it - but why bother with the hassle if your not going to do it right. If you leave the 10:1 compression ratio you will get more detonation, knock, pinking, pre-det, ect, ect... to counter-act this fundamental issue you have to pay more attention to things like the mixture, ignition quality and timing, charge cooling, coolant temperature, octane rating.



Even with the stock compression ratio of 9:1 you end up suffering from det. at the traffic lights and on hot days. Better charge-cooling helps stop this on the stock setup but you shouldn't really be looking to tip the balance in favour of knock. 9:1 is a high compression ratio for a turbo engine 10:1 is crazy.



Sometimes racing turbo engines use a high compression ratio but they use race fuel, water injection and all sorts of other extreme methods - sometimes they even run with a little bit of knock - all this is open to debate of course
 

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Matthew said:
Stock compression ratio on the B202 turbo engine is 9:1.
Okay, my mistake.


Matthew said:
Group9 flow tested B202 (2.0L) and B212/B234 (2.1L/2.3L) heads, and found that the B212/B234 heads flowed only 5% more.
http://www.saabcentral.com/forums/showthread.php?t=22813
But that alleged 5% difference accounts for 12HP on the N/A engine and I belive it would have a larger impact in a forced induction engine.
 

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s900snt said:
Okay, my mistake.




But that alleged 5% difference accounts for 12HP on the N/A engine and I belive it would have a larger impact in a forced induction engine.

ummm. it's not the 5% efficiency gain in the flow of the head. as ejenner noted, it's the extra 100 cc's of displacement.

also, it is impossible to put turbo pistons in a 2.1 engine. The 2.1 block is bored out to gain the extra displacement. 2.0 pistons are too small.

additionally, good luck keeping a headgasket together, the 2.1 has enough trouble without the turbo.
 

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wow, yeah. It really is a bigger piston in the 2.1

At first upon reading the replies in the post I was heated up about the bigger bore talk....now I've confirmed it.


;oops:

I haven't had a head gasket problem yet.
 

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that's not to say you wouldn't be able to get pistons for a 2.1 block. Wheather you want them for a 2.0 or 2.1 and you are looking to get modified / forged pistons makes no difference to availability. Obviously for a 2.0 you can get the standard Saab pistons - but the price would be the same if they wern't Saab ones.

Other way to do it is to increase the size of the combustion chamber by sticking a spacer in between two head gasketts. But once again - if your going to go to that much trouble (i.e. getting a spacer acuratly machined to the correct size from the right material) you may as well just rebuild the engine anyway.
 
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