Geddes Automotive Auckland are specialists in performance, Bigbore, Cat Back exhausts & mufflers, bolt on or tailor made exhaust systems. We supply & fit extractors (also known as headers).


Geddes Automotive Ltd have been building custom performance big bore and catback exhaust systems since the late 1960's. Our systems have won Australasian awards, helped win race championships and helped win many drag speed records with our own and customers vehicles.

Geddes Automotive carry stocks of Bigbore exhaust mufflers, exhausts pipes, exhausts catalytic converters (cats) and high flow cats. We have all the equipment required to build your tailor made performance big bore and catback exhausts system: bender, welders, db readers and technicians that can fit bolt on exhausts systems for you or tailor make the big bore system for you.

If you have a preconceived idea of the sound you are attempting to create we can build a mock up system and trial combinations of exhausts mufflers for you.

We also carry a large range of exhausts tips, chrome exhaust tips and stainless exhaust tips for you to choose from. We can show you what they look like in place on your vehicle.

Give us a call and arrange a suitable time. We have courtesy cars available. Refer to conditions.


Car manufacturers design their exhaust systems to comply with emission, noise and manufacturing laws. They design them to be as quiet as they need to cover the largest number of potential customers. Sometimes they make their exhaust systems with restriction points that you cannot see.

An exhaust system is only as good as the smallest restriction point. Some manufactured big bore systems look good but in effect are not that much better than a standard system.


An extractor (Header) is the exhaust manifold taking the exhaust gasses from the head of an engine and grouping the cylinders so that they end in a twin outlet or single outlet. On a 4 cylinder engine there would normally be 4 pipes off the head flange and joining into 4:2:1 or 4:1 configuration. A 6 cylinder engine would be 6:2:1 but almost never 6:1. V8 are usually 4:2:1 or 4:1 on each side.

An extractor (Header) works through design, where the pipes meet they go into a collector, as one cylinder fires and the exhaust gasses go down that extractor pipe and go past the extractors pipes junction, it creates a vacuum into the other pipes. When the next cylinder fires there is already a vacuum in the other extractor pipes so the vacuum helps to suck the exhaust gasses from the other cylinders and so on.

Engine timing and cam design also play a part. Most extractors/headers begin to increase engine performance once the engine is above 2,500 RPMS, and the higher the revs the more performance can be gained.

There are many designs of extractors: length of pipes, the shape of the pipes off the head and at the joins, anti revision cones, pipe size etc. Custom made extractors and exhausts can give large gains to performance.

Geddes is a family owned automotive repair garage. We have the equipment & know how to provide all automotive mechanical, auto electrical repairs, taylor made exhausts, fitting of bolt on exhausts, and an automotive service on cars, vans and trucks.

Our workshop is in Onehunga Auckland, close to Hillsborough, Penrose, Otahuhu and Mangere.

Stocks of mufflers
Stocks of mufflers
Stocks of Chrome & stainless tips
Display of some tips stocked
Tailor made big bore exhaust
Tailor made Big Bore System
Tailor made Big Bore Exhaust
Tailor Made Big Bore System
Exhaust system mount
Properly mounted exhaust system
Tailor made twin exhaust system
Tailor made twin system
Tailor made Twin into single system with Stainless tip
Tailor made Big Bore System with Stainless Tip

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Geddes Automotive Performance Exhausts & Mufflers Auckland