18 replies to this topic

[jpw1275]

Yea I've built twin hs2's on a maniflow inlet with 100mm trumpets ...... Had them running on a friends 1380 and with the vizard mods it went like stink

Cheers james

Edited by jpw1275, 19 September 2014 - 04:30 PM.

[Cooperman]

No point in going to twin SU's unless the head has been gas-flowed to allow greater flow on mixture into the cylinders.

The relatively poor head design of the A-series is what is the most limiting factor in getting more power and torque and an improvement in gas-flowing capability is the single most effective modification.

Then an improvement in carburation to maximise the head improvements can be considered and twin SU's always work well so long as, as stated above, the inlet manifold is also improved or a better one than the old BMC type is fitted.

For engines of up to 80-ish bhp the twin 1.25" ones work well, but above this figure a pair of 1.5" work best.

Think of it like water taps. There is no point in putting bigger diameter taps if the feed pipes are still too small to allow more flow volume. The matching of parts is what matters.

[minimejim]

I'm just looking at an engine online with them and was considering it, I am pretty clueless when it comes to all this talk haha it says the carbs are 1 1/4 inch ....

1275 gt engine its been fully refurbished, when I bought it the guy already had new pistons put in, and ive spent alot onit since. all new gaskets new water pump new clutch new pressure plate ive had the fly wheel re-lathed new switches new core plugs a set of 1" 1/4 twin carbs new chrome rocker cover refurbished gearbox new 75 amp alternator new fan belt new oil filter new lcb stainless steel down pipes new distributer and more it has a set of new k&n cone filters.

[minimejim]

Here it is

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