Engine breaking with Clive y piece

[macca]

Am I imagining this? Had a good this evening and when changing down carrying a bit of speed I've alway given the throttle a little blip so as not to risk locking up. Since fitting Clive's y piece it just doesn't need it as much.

Can only put it down to less back pressure without the cat. Is this logical?

[GasMunkey]

macca said:

Am I imagining this? Had a good this evening and when changing down carrying a bit of speed I've alway given the throttle a little blip so as not to risk locking up. Since fitting Clive's y piece it just doesn't need it as much.

Can only put it down to less back pressure without the cat. Is this logical?

I'd imagine most of it is psychological

[macca]

There's definitely a difference. Just had a 12k service but don't think that would explain it

[spend]

Maybe the different sound makes you more sympathetic with the left foot instead?

[macca]

Lovely sound. Just met up with qbee, he's dumped his pre cats too; a somewhat angrier sound but not ridiculously so.

Edited by macca on Sunday 23 June 20:55

[QBee]

To be honest, I wouldn't have known yours was decatted from the sound alone. It sounded normal to me.
I should have checked the decibels while I was there.
I downloaded an app called Decibel 10th onto my iphone and checked my noise at 4500 rpm before decatting - it read 98dB at 1 metre from the tail pipes, 45 degrees out and up to the side, same as Snetterton made it in April.
So that checked the calibration of the app.
After decatting completely I did the same test in the same location and it was 99.5dB.
My best guess is that yours will be about 96db, but you will know on Thursday anyway - don't forget to ask what their reading was.