Exhaust Manifold Size

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jmm25577

Original Poster:

4 posts

148 months

Thursday 29th October 2015
quotequote all
I'm having a new exhaust made for a Pinto powered Formula Ford 2000 car and have a query regarding the correct diameter and length for the primary pipes. The one I currently have is a 4-1 system, 1"5/8 OD, 26" long primary pipes with a 2" OD 27" long tail pipe through a mandatory Ford silencer which has 2" OD pipes on either side.

Taking the above into account could someone advise whether my instinct is correct having read the Vizard book, that 1"5/8 primary pipes are too large and what size would be preferable to work with the 2" OD tail pipe. At this juncture I'm considering 1" 1/2 OD 26" lengths which seems more suitable to the HP of 125/130BHP for these engines which are 2 litre, dry sump, standard internal components and cam, ported head with weber 32/36 DGV5A carb on standard manifold.

Pumaracing

2,089 posts

208 months