Bonnet scoop VS short manifold?
We have installed several bonnet scoops with no welding. It is possible to
mark the inside of the bonnet- around the aircleaners, from the left side. I
only cut enough to clear the aircleaners- not the whole area under the scoop.
The bonnets were cut using a sabre saw- cover the paintwork first with
masking tape to prevent scratches- I also cover the base of the sabre saw.
I have mounted the scoops both with #4 nuts and bolts (about every 2") and
with flush revits- along the top flange on the scoop. Both look good, I
prefer the looks of the revits. I like to use a piece of plastic tape between
the bonnet and the scoop for a gasket. The revit heads and the bare edge of
the cut in the bonnet can be touched up with touch-up paint. A long stainless
#8 or 10 bolt is used in conjunction with a piece of brake tubing slipped
over it for a spacer- to hold the bottom/front of the scoop at the proper
distance from the bonnet.
I have also converted cars to the shorter manifold/carb to clear the bonnet
with no scoop. Yes- I am sure that there is a slight edge with the longer
manifold, however in the real world of everyday Morgan driving- I could never
tell it. The single biggest factor is in getting the SU's tuned right and now
I am convinced beyond a shadow of a doubt- that the ONLY way to get the carbs
"right on" is to use the K&N analizer.
The standard ways of adjusting SU carbs gets you close enough to drive the
car- for years with no problem. However- if you really want to get it really
right- the analizer is the ONLY way to get it right. The best tuners I know-
years and years of experience- are now believers and users.
SU tuning as practiced & preached in the manuals, is simply a matter of
tuning the idle mixture. You then depend on the fact that the needle profile
is "right" for the higher RPMs and acceleration & cruise. We have all done it
for years (fourty in my case..) and it works...
"Different is not the same"... a piece of advise that I have to tell myself
every day. There are hundreds of variables on each individual car- type of
exhaust, ring condition, CR, type of aircleaner, a protruding manifold
gasket, oil in the dashpot, on and on..... Standard tuning practice for SU's
works fine... however if you have any problems, flat spots, sooty/clean
plugs- OR... if you really want to get your car "dialed in" for max
peformance street/track/strip- buy an analizer (about $150.00)- download the
"haystack " program- and join us nuts in the great needle search.
Long or short manifold? Tune the carbs gants-ass on with either and you will
have a great running car.
Fred Sisson
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