10-11-2023, 10:37 AM
Hi Ruairidh
Here's some background information from the makers, before the days of the trades description act !
Extracts from the Sixth Printing of the “A7 Textbook” by The Sporting Motorist’s Agency Limited, suppliers of DANTE speed equipment for the Austin Seven.
AUTHOR’S NOTE.
The A7 Textbook has gone from strength to strength and more than 1,000 copies have been sold since it was first introduced in May 1956. This booklet is now accepted as a standard work on the fascinating subject of Austin Seven “Special” Building, and we have pleasure in introducing yet another printing for distribution to enthusiasts wherever they may be, at home or abroad.
We are also gratified to find that there are other booklets dealing with the improvement and modification of the A7, for imitation is the sincerest form of flattery. However, the original should not be confused with its imitators, so look for the name “THE SPORTING MOTORIST’S AGENCY, LIMITED.”
D.A.S. FEBRUARY 1957.
6) Carburation, etc.
One of the first steps towards boosting the performance (speed and economy ) of the car is to improve the “breathing” qualities of the engine. This is most simply achieved by fitting one or two downdraught carburettor(s) on a special inlet manifold; a step which will be found to give an immediate improvement in performance. A double carburettor gives better power but is naturally a little more complex to tune, etc. Suitable carburettors include the Ford 8, Solex type 26 A.I.C., Zenith V.I.G 30mm. The special inlet manifold should be used in conjunction with either the DANTE exhaust manifold or the pre-1932 standard exhaust manifold, which can be supplied by The Sporting Motorist’s Agency Limited, if required. If your car has a scuttle tank, an S.U. electric fuel pump should be used to assist fuel feed to the downdraught carburettor(s). Further improvement in performance whilst retaining the standard exhaust manifold, will result from the use of a silencing system as described in Section 7 below.
All flanges and ports must fit perfectly and there must be no sharp edges or protrusions to impede the gas flow anywhere at all. Internal polishing of the manifold and ports is only of secondary importance to this.
7) Exhaust System.
You may perhaps have regarded with horror the tortuous path taken by the exhaust gases of a standard A7 engine when escaping to the open air. A great improvement in performance is given by fitting the DANTE cast alloy “bunch of bananas” type exhaust manifold which combines the advantage of low weight with free gas flow to the silencer and tailpipe. The benefits of good manifolding are not fully realised, however, until a “straight-through” exhaust system has been fitted, and a motor cycle silencer devoid of baffles, with narrow-bore tail pipe (7/8” or 1” internal diameter) will give good gas extraction.
Here's some background information from the makers, before the days of the trades description act !
Extracts from the Sixth Printing of the “A7 Textbook” by The Sporting Motorist’s Agency Limited, suppliers of DANTE speed equipment for the Austin Seven.
AUTHOR’S NOTE.
The A7 Textbook has gone from strength to strength and more than 1,000 copies have been sold since it was first introduced in May 1956. This booklet is now accepted as a standard work on the fascinating subject of Austin Seven “Special” Building, and we have pleasure in introducing yet another printing for distribution to enthusiasts wherever they may be, at home or abroad.
We are also gratified to find that there are other booklets dealing with the improvement and modification of the A7, for imitation is the sincerest form of flattery. However, the original should not be confused with its imitators, so look for the name “THE SPORTING MOTORIST’S AGENCY, LIMITED.”
D.A.S. FEBRUARY 1957.
6) Carburation, etc.
One of the first steps towards boosting the performance (speed and economy ) of the car is to improve the “breathing” qualities of the engine. This is most simply achieved by fitting one or two downdraught carburettor(s) on a special inlet manifold; a step which will be found to give an immediate improvement in performance. A double carburettor gives better power but is naturally a little more complex to tune, etc. Suitable carburettors include the Ford 8, Solex type 26 A.I.C., Zenith V.I.G 30mm. The special inlet manifold should be used in conjunction with either the DANTE exhaust manifold or the pre-1932 standard exhaust manifold, which can be supplied by The Sporting Motorist’s Agency Limited, if required. If your car has a scuttle tank, an S.U. electric fuel pump should be used to assist fuel feed to the downdraught carburettor(s). Further improvement in performance whilst retaining the standard exhaust manifold, will result from the use of a silencing system as described in Section 7 below.
All flanges and ports must fit perfectly and there must be no sharp edges or protrusions to impede the gas flow anywhere at all. Internal polishing of the manifold and ports is only of secondary importance to this.
7) Exhaust System.
You may perhaps have regarded with horror the tortuous path taken by the exhaust gases of a standard A7 engine when escaping to the open air. A great improvement in performance is given by fitting the DANTE cast alloy “bunch of bananas” type exhaust manifold which combines the advantage of low weight with free gas flow to the silencer and tailpipe. The benefits of good manifolding are not fully realised, however, until a “straight-through” exhaust system has been fitted, and a motor cycle silencer devoid of baffles, with narrow-bore tail pipe (7/8” or 1” internal diameter) will give good gas extraction.