BVH/1341cc Bottom end vs standard spec

[benh999]

Right folks,

I'm just about to pick up my g40, with roughly the following spec:

R1 charger(jabba heatshield)
toothed pulleys (65mm)
Gt inlet manifold
green 250cc injectors
ppp exhaust manifold
bastuck exhaust
Mocal thermostatic oil cooler
FMIC

Before the FMIC she was producing a healthly 151bhp


Long term if I were to have the head flowed with big valves and had the 1341cc forged bottom end, besides for greater strength etc what difference would a BVH and 1341 bottom end make on the above listed spec?

Just thinking as and when the engine finally needs a rebuild whether it would be better for a standard rebuild or the latter option.

Regards

Ben

[breadman]

Ben, a properly ported big valve head will make you more power, but you'll need a cam and definately a remap to get the best out of it.
The 1341 conversion will increase torque rather than power. The forged pistons do make the bottom end very strong too, so well worth it if you are doing a bottom end rebuild. 

[Yoof]

A good comparison for you with turbo'd G40s at 20psi (K03) other mods very similar:

Stock 1272cc & Stock Head circa 180bhp

Stock 1272cc & BV Head circa 194bhp

1341cc & Stock Head circa 194bhp (but held 10bhp more than the above combination until peak power- very similar peak torque)

1341cc & BV Head 203bhp

I'd say (very roughly) a 1341cc conversion was worth 10bhp over a 1272cc- a big valve head approximately the same when added to either 1272cc or 1341cc.

Obviously this is for turbocharged G40s, so won't be quite the same for G-Laders, but won't be a million miles away.