Where are my precats?
Where are my precats?
Author
Discussion

alanv8

Original Poster:

88 posts

292 months

Saturday 31st July 2004
quotequote all
Thinking of changing my manifolds for the precat less ones with the reversed cones, however not sure where abouts they are. Are they in the manifolds before the lamdor sensor or are they in the arms of the Y section.
the bible shows them in the arms of the Y section but my mate claims they are in the mainifold section.
If anyone knows where they are that would be a great help,

PS what noise change can i expect from removing the above, im already running straight through at the back
thanks!

simpo two

92,700 posts

294 months

Saturday 31st July 2004
quotequote all
Look for the horizontal cylindrical sections on either side - that's where they are.

alanv8

Original Poster:

88 posts

292 months

Saturday 31st July 2004
quotequote all
Thanks
Sounds like the manifolds will have o come off then

Guillotine

5,516 posts

293 months

Saturday 31st July 2004
quotequote all
around 105db, you'll be at around 100 at the mo.

gives a much sharper sound.

GreenV8S

31,014 posts

313 months

Saturday 31st July 2004
quotequote all
If you have any sense, they will be on the floor in the corner of the workshop!

old64er

1,388 posts

267 months

Sunday 1st August 2004
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I removed mine by just taking the y piece of a destroying the precat while the manifolds were on the car.
my precats were rattling around inside the manifold and i could see evidence of them hitting the lambda sensors!!!
It took me about 2 hours to get them out from jacking the car up to droppingit back down.
I only noticed them due to the fact that i had to remove the y piece to weld it up on a split seam.

starmist

1,052 posts

271 months

Sunday 1st August 2004
quotequote all
I was running 99db with precats, empty rear silencer and ACT track day silencers, so I would reckon on about 103 without the track day silencers.

Add perhaps 4 or 5 db with the precats out. There are indeed in the manifolds, visible from the Y piece end once you've removed it. I dare say you can smash them out, but make sure you remove every piece of debris, otherwise they will damage the main cat in the Y piece.

Having reverse cones fitted in their place will prevent reverse pulses going up the primaries and increase performance. You will obviously have to remove them to get that done.

Having the manifolds and Y piece ceramic coated reduces under bonnet temperature, which reduces inlet charge temperature which again increases performance. Expect a bill for around £500 to have the decatted, reverse coned and ceramic coated through ACT.

alanv8

Original Poster:

88 posts

292 months

Sunday 1st August 2004
quotequote all
Thanks for your replies
Thinking of getting the decatted manifolds with cones from ACT just not sure wether to go for the ceramic coating.