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amaz'in · May 21st, 2021, 19:50

Hi Doug,

I have a 69 131 so a B20A and a very late 70 133 so a B20B, the latter I aim to bring to Southwold unless the rain is utterly torrential.

Derek, are you going? I attended the last one in my Mid Blue 131 and you were there.

Doug 142 bhp (flywheel) is a very impressive figure if the Dyno was accurate, and it would take a certain approach to arrive at a figure such as this for example:

A very healthy B20 (somewhat below 50-60k miles) and preferably a recently re-built or very fresh motor to begin with. 142 bhp so likely an SAE figure? Volvo achieved 118 bhp from a B20b as it left the factory.

So a certain route needs to be followed, actually at this point I'm going to convert to DIN as I can compute these more easily. 118 is 100 DIN, actually 101 by the Green book, but let's stick with 100 bhp for now.

You would need rid of the original B20b strangling dual butterfly emissions manifold, but likely you never had this if a 131 converted to 133 spec, either the earlier alloy inlet manifold along with the E/Injection exhaust manifold as fitted to the 1800E/140GL, or a tubular exhaust manifold from the likes of Simons, along with the rest of the free flowing exhaust would get you to around 107/8 Ish.

Head and cam next, you would need to up the compression ratio from 9.3:1 to it least 10.0:1 then, port+ polishing inlet and exhaust manifolds and also the head along with careful gas flowing and with 44 mm inlet valves and careful chamber cc'ing would get you to 135-137 Ish, next up cam choice, changing a B cam (standard B20b) to a D/K cam might get you to 140+...just but only with around 100 octane and the appropriate advance which lower octane unleaded won't allow.

D cam will achieve a tiny amount more power Top end but not as tractable as a K, if you have a D cam it will really pick up as rpm goes over 3500 rpm but will be quite lumpy below 1500-2000 rpm.

D/K cam need to idle around 900 rpm B cam 800. F cam (next up from D/K will idle around 1000 so these figures may give clues to cam type but wouldn't recommend F/R/S/U for road use and local trips to the supermarket etc.

James.

May 21st, 2021, 19:50	#14
amaz'in Senior Member Last Online: Aug 2nd, 2022 10:46 Join Date: Nov 2006 Location: Norwich	Hi Doug, I have a 69 131 so a B20A and a very late 70 133 so a B20B, the latter I aim to bring to Southwold unless the rain is utterly torrential. Derek, are you going? I attended the last one in my Mid Blue 131 and you were there. Doug 142 bhp (flywheel) is a very impressive figure if the Dyno was accurate, and it would take a certain approach to arrive at a figure such as this for example: A very healthy B20 (somewhat below 50-60k miles) and preferably a recently re-built or very fresh motor to begin with. 142 bhp so likely an SAE figure? Volvo achieved 118 bhp from a B20b as it left the factory. So a certain route needs to be followed, actually at this point I'm going to convert to DIN as I can compute these more easily. 118 is 100 DIN, actually 101 by the Green book, but let's stick with 100 bhp for now. You would need rid of the original B20b strangling dual butterfly emissions manifold, but likely you never had this if a 131 converted to 133 spec, either the earlier alloy inlet manifold along with the E/Injection exhaust manifold as fitted to the 1800E/140GL, or a tubular exhaust manifold from the likes of Simons, along with the rest of the free flowing exhaust would get you to around 107/8 Ish. Head and cam next, you would need to up the compression ratio from 9.3:1 to it least 10.0:1 then, port+ polishing inlet and exhaust manifolds and also the head along with careful gas flowing and with 44 mm inlet valves and careful chamber cc'ing would get you to 135-137 Ish, next up cam choice, changing a B cam (standard B20b) to a D/K cam might get you to 140+...just but only with around 100 octane and the appropriate advance which lower octane unleaded won't allow. D cam will achieve a tiny amount more power Top end but not as tractable as a K, if you have a D cam it will really pick up as rpm goes over 3500 rpm but will be quite lumpy below 1500-2000 rpm. D/K cam need to idle around 900 rpm B cam 800. F cam (next up from D/K will idle around 1000 so these figures may give clues to cam type but wouldn't recommend F/R/S/U for road use and local trips to the supermarket etc. James.