One of the modifications which would need doing before the engine mods was a new exhaust. This is due to the fact that the standard Caterham 4-1 exhaust manifold is completely the wrong length for good torque in the mid range. I could have bought a caterham 4-2-1 exhaust system but they cost about £800. The other alternative was to have a custom exhaust built. I asked Dave Andrews for recommendations of exhaust companies and he said that Powerspeed in Ashford and Exhaust By Design (EBD) were both good. Rob Day had had nis caterham exhaust modifield bu EBD to use a new manifold but retain a modified Caterham catalyst silencer. Mick Smith had had a complete 4-2-1 system built by Powerspeed which had given him very good results on the rolling toad. In the end I decided upon the Powerspeed system since it did away with the Catalyst and was a repackable system.

Exhaust by Design Manifold

This is Rob Day's custom manifold by Exhaust By Design (EBD), it utilises the standard Cat exhaust with the Lambda sensor relocated in the front of the Cat.

Rob Day Exhaust 1 Rob Day Exhaust 2

Powerspeed 4-2-1 manifold and repackable non-cat silencer

This is Mick Smith's custom repackable silencer and 4-2-1 manifold with long primaries and secondaries.

Mick Smith Exhaust 3 Mick Smith Exhaust 1 Mick Smith Exhaust 2


Exhaust 1 Exhaust 2 Exhaust 3 My Exhaust 1 My Exhaust 2 My Exhaust 3 My Exhaust 4 My Exhaust 5 My Exhaust 6 My Exhaust 7 My Exhaust 8 My Exhaust 9 My Exhaust 10




These photos show both cars side by side to highlight the overall differences in the exhausts.

Both exhausts


These photos show a closer view of the complete exhausts on both cars. The main differences are the way the primaries come out of the engine bay, the slightly different collectors on the secondaries and the length of the silencer.

My Exhaust 11 Mick Exhaust 1


These photos show the arrangement of the primaries on both cars. The primaries on my car cross over in the engine bay with No1 primary going underneath and behind the other three, while Mick's primaries cross over as they come out the engine bay. The primaries on mine are also slightly longer.

My Exhaust 12 Mick Exhaust 2
My Exhaust 13 Mick Exhaust 3


These photos show both cars side by side to highlight the overall differences in the exhausts. The primaries on my car cross over in the engine bay with No1 primary going underneath and behind the other three, while Mick's primaries cross over as they come out the engine bay. The primaries on mine are also slightly longer.

My Exhaust 14 Mick Exhaust 4
Mick the mapper