Bolt-on Engine Air Filters

Post by **minor_hickup** » Wed Aug 13, 2008 9:59 pm

You wouldn't want more than a 292 on a street motor, if the whole engine isn't spot on it'll idle like crap, luckily his doesn't and is pretty sweet. I think the ideal length may be slightly longer than 8.5" but the inner wing is in the way! As for a big motor it's only a 2 litre!

I think that the very long pipes probably works well because of each cylinder breathing through an individual 40mm barrel, hopefully 45mm soon! Soon to remove the choke butterflies soon and re dyno with high compression pistons. It would be interesting to play about like this with an a series, I doubt such long pipes would be needed on a single, what with higher intake speed and inertial ramming effect from breathing through a single barrel for all four cylinders. Just got to sort out some fuelling issues after a rebuild, run it in and see if we can break 160bhp on the rollers.

Post by **bmcecosse** » Wed Aug 13, 2008 10:25 pm

Trouble with A series engine - is the shared inlet ports and the firing order 2134 - so there are two sucking pulses through the first port - then two through the second port and meantime the gases in the first port are hanging about waiting for their turn again! So - inertial ramming has little chance of working. This is why an 8 port head makes a very worthwhile difference to the A series, used with 4 x Amals or 2 x 40 DCOE or of course FI - it gives each inlet a chance to run properly with reflective waves in the port and a chance of some ramming effect. The extra torque from an 8 port A series even running a 310 cam is unbelievable.

Post by **minor_hickup** » Wed Aug 13, 2008 10:29 pm

Yeah I see what you mean. But the 8 port seems a very expensive way to go. I see where picky was coming from just forcing the air in! I've often had thought of sticking an MGB engine in, heavy but you start with as much power as you'd be tuning up to with a 1098 or even a 1275 and its a period option.

Post by **bmcecosse** » Wed Aug 13, 2008 11:10 pm

Indeed - the Wolseley/Riley versions had that engine (early version) in the same basic chassis so it shouldn't be that hard to do. But i fear for the fuel consumption. Is there room for the B gearbox with overdrive I wonder ??

Post by **minor_hickup** » Thu Aug 14, 2008 8:32 am

Overdrive would be a nice period alternative to a 5 speed. I don't remember the type 9 being a particularly pleasant box in the sierra!

Post by **bmcecosse** » Thu Aug 14, 2008 8:26 pm

Well - it's not a specially large gearbox, and would fit straight on any B series motor - but it is quite long when fitted with the overdrive. May even find an MGB prop shaft would fit the diff! Could be quite a simple 5 speed conversion.

Post by **minor_hickup** » Thu Aug 14, 2008 9:56 pm

I'm sure it would make a cracking car for touring and motorway work too!

Post by **bmcecosse** » Thu Aug 14, 2008 10:06 pm

So - why don't people do it ? Is the fuel economy poor ?

Post by **minor_hickup** » Fri Aug 15, 2008 8:51 am

I imagine it isnt great, MGBs are good for 25mpg average from what I've heard. But I believe plastic orange had an MGB powered moggy.

Post by **bmcecosse** » Fri Aug 15, 2008 9:01 am

Oh yes there are some around - but don't see crowds of people flocking that way! Yet many are prepared to pay huge amounts of money to fit Ford 5 speed boxes! My mate has a spare MGB o/d gearbox lying around - must compare it with an A series backplate to see how much it differs!