EA engines custom intake manifolds?

[Dan. S]

for those that may be interested I have new specs for the standard EA81 inlet manifold design.

The previous specs were incorrect as I enttered a wrong camshaft parameter into the calculator. The new specs have been triple or more checked and I know they are good and what I will now use.

16.5 inches length on the intake runners from the back of the valve face to the bottom of the plenum with a 1.5 inch inside diameter.

Plenum volume is 578 cc or otherwise known as 578 mls

Now to make it:)

[steptoe]

Are those calcs for fuel injection or carby? A rough guide has been for efi - match intake volume total to engine capacity , so 1800cc.

The safari twin carb set up were basically downdraught manifold with carb sitting directly above the ports. I'd reckon the alternator needed a sideways step.

[Dan. S]

Are those calcs for fuel injection or carby? A rough guide has been for efi - match intake volume total to engine capacity , so 1800cc.

The safari twin carb set up were basically downdraught manifold with carb sitting directly above the ports. I'd reckon the alternator needed a sideways step.

The calcs I have made in my last post are for a stock standard EA81 with the common siamese port heads (one intake runner per head) and using a carburettor. I figure the hole at the top of the plenum can be made the same as the hole on the stock standard manifold that the stock standard carby bolts onto.

The beauty of using a stock standard engine to rebuild is not spending loads of cash on it and determinig things like the size of the hole where the carby sits over the plenum on the intake is easy because I will use the stock standard dimension from the original spec. Just improve the rest of the intake system below it.