I had fitted a Quicksilver Cat Back Sports (not Supersports which is straight through) exhaust which has brought the exhaust noise to a good level (punchy and bassy but not antisocial).

If I add free flowing Cats (something like the Nameless) will the noise be affected? if so in what way.

TIA

Mark

 

Anything that increases flow from the exhaust does so because of reduced resistance and that will always increase the noise, simple physics. In fact any mod that increases power will increase the noise, if it doesn't, then I'd want to see the dyno chart

 

Changing to a less restrictive catalyst will absolutely make the car louder.

If you go to a high flow cat then I'd suggest starting out with a completely stock exhaust, the cats are very effective mufflers.

 

I had the un-resonated Miltek exhaust fitted to my XKR and always felt there was something missing when pushing on a bit, like something was holding the car back. I later got the 200 cell cats and these finished it all off nicely, the car felt happier (so did the driver) and the exhaust note was rounded out nicely (opinions from neighbours early in the morning may vary).

 

Ok thanks for the info.

The noise with the new exhaust is pretty good. Food for thought. The thought is that I would go to somewhere in the uk plus remap

like here

//www.tomlenthall.co.uk/performance/tl-exhaust-upgrades

to ensure the Quicksilver and new cats are in harmony.

I can take more bass and a few more DB's but don't want to end up like guy a few doors down who has a straight-through system on his Porsche which sounds so loud it's ridiculous and he pussyfoots the car around the neighbourhood.

I guess all I'm enquiring is does changing the CATS give a big noise step change. Perhaps I'll call the above and discuss.

 

Tom has a very good reputation amongst XK owners and is known for his helpful attitude.
Give him a call (he also does twin screw superchargers and limited slip diffs if you're feeling flush)

 

I'm now in dialogue with Tom. His normal 200 cats won't fit but he can try another. I will put the car in so they can look. Will report back in few weeks.

 

Ok so booked in for modded pulley on s/charger, new 200 cats to fit the Quicksilver new exhaust and a remap.

Only bad thing is it's not booked in till 29th!

 

Remap? I thought these ECUs could not be remapped?

 

They can, but you have to pull the ECU out of the car, open the housing, and flash directly to the processor on the PCB, then put it all back together again...

My ex-JLR contact is the only guy in the world who can load custom tunes over the OBD port i.e. no need to remove the ECU from the car, everyone else is doing it the hard way...

 

What cats are you looking to get and from where?

 

Tom Lenthall in the UK can get 200 cats which will fit the Quicksilver exhaust. Not sure of the make but as he is a Jag specialist (and races them) I'm assumning they will be decent.

 

Nice! I wonder if they'd fit a Mina exhaust system. I have that on my car

 

I have the Nameless Cats and a custom made 2 1/2" exhaust system. She does turn heads when she fires up, but then it settles down. She sounds nice when just cruising, but as soon as you start opening the throttle, she lets you know who's the boss. On the highway it's kinda like sitting on thunder. I can hear the exhaust if I listen for it. Overall, quite a nice system.

 

All done. Cats, s/charger pulley, airfilter and remap.

The car goes like stink now and sounds great (thoatier and slightly bassier than with just the sports exhaust). So much so that the heater has to be on full cos I can't bear to wind up the windows.

Orange light came on before it went in and was traced to a air bypass component on s/charger leaking which was also fixed by insertion of 2nd hand part off another car.

 

Sounds like you're reasonably pleased with the changes!

 

You bet!

 

Anyone know roughly how much power gain 200 cats, sports exhaust, modded s/charger pulley, K+N filter and perf remap should give?

 

I don't know what the car in you .sig (XLR-S) is but let's guess XKR. 20HP maybe. Ditch the K&N.

 

ops fat fingers. Corrected sig.

Ok ta K+N no good then?