Originally posted by Ye Ol Ripper
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Hi Adrian
1) Your engine is a 1275cc A series, not a 1798. B series.
2) Your engine is a single carb set up & not a twin carb set up.
The twin TR7 carbs being of larger size , according to Peter Burgess book give less low down torque on a standard 1798 B series engine than the twin 1. 1/2 SU's. It is for that reason they weren't usrd as standard on MGB's.
However if the cylinder head has tripple valve seats, been ported and gas flowed with a long cente branch manifold & a cam such as a piper 270 . Then the TR7 carbs will improve matters.
So my point is it really depends on whether the B series is standard spec or not.
I have rolling road tested many engines. Both the A series & B series engines gave between 2 & 5 hp with water injection.
The key thing here is to get as much cold air into the intake, being drawn from the front of the car, ideally with a large bell ram pipe on the grill end of the hose.
In the future instead of my current pancake filters. I plan to use an area on the offside to mount an airbox with filter, possibly using the cylinder head studs to attach some bespoke brackets. The cold intake from the front enters the airbox , which might be from a puma 1.7. then the large outlet goes to something similar to GGrum's stainless steel fabricated unit on his Alfa engine.
However the air feed to the air filter box (originally from the puma 1.7or Fiesta Mk4),will have to travel either over the engine or at the back of the engine between the cylinder head to bulkhead space and then feed into the carb fabricated air box at the rear or on the top of it. The limiting factor to the routing is that the Puma 1.7 intake hose diameter is very large and it therefore might not fit under the Bonnet/ Rocker cover space , as there needs to be some clearance also there too from the hot engine below it. It is therefore likely to need to have an air entry point into the fabricated carb box at the rear,rather than the top.
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