Rear silencer for tuned vauxhall

[Guest]

I have tuned vauhall HPC. It has standard 4 into 1 exhaust with 5 inch silencer with 2 inch bore. I am told this could be strangling breathing and 2.5 bore silencer would be better. Does anyone know who supplies this. Presumably JPE had bigger bore.

[Mavic82]

Not sure if they still being made but Raceco converted my collector to have a 2.5 or 2.7 inch outlet and new silencer with bore to match. Kept the headers as I rather like them.

[k.russell]

There were at least 3 different side exit manifolds from the factory, early cars had small diameter header pipes 1 5/8" diameter and a 2" silencer. The later cars used the race headers that were 1 7/8" and more equal in length and think still fed a 2" silencer, albeit a larger diameter. I would think this is what you have. The jpe was a special and had very long primaries, the 4 into 1 collector was part of the silencer that was 2 1/2" diameter with not a great diameter silencer, it was very loud. Had all of these on my car. Went along with a better 4-2-1 design as the engine was updated . And use a large long silencer. Most of the manufacturers BTB etc will supply these and as mavic has suggested this might need the collector modifying.

[k.russell]

Search Vx silencer In the archives, quite a bit in there.

[Birkin S3 ZA.]

I am busy building a set of headers for a Chevron race car with a 280 hp 2.0 Opel motor.

They are 50mm headers into a 4:1 and a short 3" tail pipe I will post a picture later, I am sure its not what your looking for as it will be about 115 db.

header size in most cases is worked out on HP, up to 240hp is 1'3/4 up to 260hp 1"7/8 260hp and over 2".

This is just for guidance for a four cylinder, port size should be 3 to 4mm smaller than the header id

and 2" 1/2 silencer would work well.

Chris.

[Birkin S3 ZA.]

Almost finished a bit of grinding and polishing here and here

its a pain to keep them the same length in a confined space due to the frame.