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Discussion Starter · #1 ·
On Ebay recently there is a Saab Turbo engine for sale with balance shafts removed.

I was curious about this and emailed the seller for an explanation.

He explained that it was a spare engine prepared for his mk2 escort racing car. The balance shafts in his opinion slow the response of the engine, increase stress and are not necessary.

I had not thought of this before but I assume the balance shafts purpose is to improve the refinement of the engine at low rpm; not something a racing car needs. Removing them would also save weight. Not sure how this is achieved? Is there a chain drive?

Anyway this is another step that may be included in my Zero budget trackday car.

any thoughts welcome here.

Rory
 

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It's not so much the saving in weight that matters but the reduction in rotational inertia, which makes for a more responsive engine. IIRC if you remove them you need to block of the oilways so many folk just disconnect the chain drive.
 

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Hi

Early GM 900s were without balance shafts, I understand. The 2.0 n/a was quoted at 140bhp then about a year later they were added and bhp dropped to 130 quoted. Same for the 2.3 n/a - 155 then 150bhp. I read this somewhere but where! Why can I remember this and not peoples' names crazy: :crazy:

Al
 

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The 2.3 N/A had balancer shafts right from it's first introduction in MY90- hence the B234 notation

The 2.0 went from B202 to B204, gaining balance shafts in the process from MY94 onwards, which is all 4 cyl GM900s.
 

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Didn't realise that re the 2.3. I could have sworn that early GM900s 2.0 (L and early M plates) were without balance shafts? They wouldn't be B202 would they but B204?

Al
 

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I might not be going mad after all? :)

Al
 

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It would appear not :) it took a lot of digging but I did finally find a reference to a B206, which is indeed a B204 minus the double balance shafts. Never heard of that before- sorry for misleading you.
 

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I think my source was a Parkers guide from 1997 but I can't find it amongst about 300 car mags hanging around...well, you never know when you might need them! BHP dropped by 10 or so with the shafts. Was this just on the 2.o or 2.3 as well according to your source?

Al
 
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