Today I drove in heavy rain, visibility was very poor. The exhaust completely changed note, it sounded louder at first but then more like a motorbike exhaust, the performance dropped and there was some vibration. I've noticed this twice before but again, only in heavy rain.

Any ideas what this could be caused by? I've got a Revolution cat-back exhaust on with the 'sleeve fit'. Could it be anything to do with that? If so then why?

Has anyone experienced similar?

 

Sounds like your getting water where your not suppose to be getting water what car and what mods (including things like removing the bonnet vents off classics)

Tony

 

I've an 04 WRX that's just had a full 50k service and otherwise drives better than ever.
The only mods that could be playing a part are the exhaust and a K&N panel filter. The other things i've changed are the brakes, 18's, and adding a front splitter.

 

I had a lack of power in my wrx once in heavy rain last October over the Peak District tops on my way to Old Trafford - I think rain was getting in through the bonnet vent as I was going uphill head on into the rain when I noticed the hesitation. It's never happened since but I've heard of others suffering in heavy rain. Didn't notice any change in the exhaust note but then I've not got an overly loud exhaust. I've only noticed it the one time though and it's been fine since.

 

Did you notice any vibration underfoot?

 

Strange... I was going to post a similar thread this morning.

I experirenced the same thing, my exhaust note changed to a more tappy kinda sound (De-Cat Afterburner Vortex) which is usually very deep. I was concerned it was my bottom end knocking it was that noticeable!

Seems ok this morning, seems to have settled down a bit.

 

My CTR does the same occasionally in very very heavy rain (lots of standing water). Car is stock and it only happens once in a blue moon so I just ignore it.

 

Mine settled down as soon as the heavy rain stopped. It's just un-nerving and I think my wife would be worried if it happened whilst she was driving it late one night. I suppose the easy answer would be to just not give her the keys!

 

Going on the description it sounds like water is getting in the HT side of the ignition system, making it drop a cylinder or two.

Check the condition of the boots over the spark plugs, coil packs for any cracks in the housing and if its a model that also has HT leads, make sure the boots are sound, the HT connectors aren't corroded (clean metal not full of blue oxide powder) and the leads themselves aren't chaffed or damaged anywhere.

Having said that I've never had a problem with my Impreza vs water. And I've driven mine through some impressive floods (as well as crossing streams and rivers ) in its time. Not to mention the regular (yet cautious) steam cleaning of the engine bay.

 

Thanks for that Ali, i'll get my head under the bonnet.