Sound after removing pre cats.

[Pink_Floyd]

Not the sound from the end of the exhaust but the sound in the engine bay. For those that have removed their pre cats but stil have the main cat did you notice any difference in the sound of the engine in the engine bay.

[Simon says]

Yes, its more ringy you will get used to it + when they carbon up a bit where they didnt carbon up before it should mute them a tad

[Pink_Floyd]

Simon says said:

Yes, its more ringy

That is what I get and just wanted to confirm that it was the removal of the pre cats that was causing it.

[Zippee]

I didn't have any difference, though I opted for the ACT manifolds as replacements for the OEMs, they don't have pre-cats in as standard but there was zero difference.

[SSPPGG]

the cats can quieten down some of the "valve noise i think, it seems to resonate more without a cat

[Nosh]

Has anyone got a picture of a Clive Y piece and an ACT one (preferably in situ)?

Thanks
Nosh

[Simon says]

Ok ACT Clive F

[Nosh]

Simon says said:

Ok ACT Clive F

Mr Says

The top one is ACT, yes?

[Simon says]

Nosh said:

Simon says said:

Ok ACT Clive F

Mr Says

The top one is ACT, yes?

Hi Phil yes ACT /Left & Clive F /Right

[Nosh]

Simon says said:

i Phil yes ACT /Left & Clive F /Right

Mmmmmm

Food for thought - decided to go for the plunge and just hope it ain't too loud.....

....just need to find a good deal now

Ta mate.

[Kitchski]

A bit more resonation within the header which sounds like a minor manifold leak under load, but nothing more than that. Doesn't really make the car any louder.

Enjoy the cooler under bonnet temps though

[Simon says]

Kitchski said:

A bit more resonation within the header which sounds like a minor manifold leak under load, but nothing more than that. Doesn't really make the car any louder.

Enjoy the cooler under bonnet temps though

This.

[VictorMeldrew]

It's worse when the main cat comes out as well, sounds like a spanner was left in the engine somewhere. Anti reversal cones in the main cat chamber can help apparently. I don't think the ACT or Clives Y pieces suffer the same issue, it's a product of gas expansion into the now cavernously empty cat chambers. Kind of like a 2 stroke expansion chamber, except no power boosting effects, just a ringy ding noise.

[Simon says]

VictorMeldrew said:

It's worse when the main cat comes out as well, sounds like a spanner was left in the engine somewhere. Anti reversal cones in the main cat chamber can help apparently. I don't think the ACT or Clives Y pieces suffer the same issue, it's a product of gas expansion into the now cavernously empty cat chambers. Kind of like a 2 stroke expansion chamber, except no power boosting effects, just a ringy ding noise.

I reckon so too most not Tivvers 1st reaction when you open the bonnet and they see the exhaust pipework is ...... WTF

[SILICONEKID340HP]

VictorMeldrew said:

It's worse when the main cat comes out as well, sounds like a spanner was left in the engine somewhere. Anti reversal cones in the main cat chamber can help apparently. I don't think the ACT or Clives Y pieces suffer the same issue, it's a product of gas expansion into the now cavernously empty cat chambers. Kind of like a 2 stroke expansion chamber, except no power boosting effects, just a ringy ding noise.

The ACT and Clives Y piece get better over time ! Wanted to remove mine straight after fitting it but i gave it some time ,im very happy with it .

[Nosh]

SILICONEKID340HP said:

The ACT and Clives Y piece get better over time ! Wanted to remove mine straight after fitting it but i gave it some time ,im very happy with it .

Which one do you have Daz?

[SILICONEKID340HP]

Nosh said:

SILICONEKID340HP said:

The ACT and Clives Y piece get better over time ! Wanted to remove mine straight after fitting it but i gave it some time ,im very happy with it .

Which one do you have Daz?

ACT but my choice would be clives Y piece ..
Got a dood deal on my Y piece..