Discussion
Thought I'd look to see if I could find the exhaust rattle and blow I heard when using the car earlier this week. Did the usual check rear muffler/box hangers not bad, so i thought I'd check to see why I was unable to stop the NS pipe moving around do much as it was obviously rattling against the chassis.
Then I came across this
A bit more detail if it's not obvious...
The weld on the cherry bomb decat has failed....
Then I came across this
A bit more detail if it's not obvious...
The weld on the cherry bomb decat has failed....
Byker28i said:
Lots of popping and banging means you have an air leak in the exhaust. It will quieten down without the crack.
Cats quieten the exhaust between 8-10db over straight through pipes, but I found put a lot of heat soak into the cabin, gearbox and clutch, which is why mine are removed.
Unless it's the ACT decat sport pipe. Which means it's working just as it should Cats quieten the exhaust between 8-10db over straight through pipes, but I found put a lot of heat soak into the cabin, gearbox and clutch, which is why mine are removed.
Incognegro said:
Byker28i said:
Lots of popping and banging means you have an air leak in the exhaust. It will quieten down without the crack.
Cats quieten the exhaust between 8-10db over straight through pipes, but I found put a lot of heat soak into the cabin, gearbox and clutch, which is why mine are removed.
Unless it's the ACT decat sport pipe. Which means it's working just as it should Cats quieten the exhaust between 8-10db over straight through pipes, but I found put a lot of heat soak into the cabin, gearbox and clutch, which is why mine are removed.
Interesting point about the heat soak, I'll take it for a good blat today to see how it is doing. Tbh 10db off the noise would be nice at least I can commute in it more often without waking everyone up!!
Mines the 2.5" quiet ACT system, full with with stainless manifolds. It's been fitted for the last 7 years.
Tailpipes have extra silencing in, as do the two long centre pipes. I have straight through decat pipes.
Maximum noise I can make it do (Neil Garners noise test at the open day) was 116db, full revs and making it pop and bang. at 4.5K revs it's 106db, which comes down to 96-98db with the trackday cans on. Put the cats in as well and I lose a little power but get it down to 87/88db, which got me onto a Thruxton trackday once.
They didn't do the cherry bomb decats when I got mine. How much do they quieten by?
Tailpipes have extra silencing in, as do the two long centre pipes. I have straight through decat pipes.
Maximum noise I can make it do (Neil Garners noise test at the open day) was 116db, full revs and making it pop and bang. at 4.5K revs it's 106db, which comes down to 96-98db with the trackday cans on. Put the cats in as well and I lose a little power but get it down to 87/88db, which got me onto a Thruxton trackday once.
They didn't do the cherry bomb decats when I got mine. How much do they quieten by?
Nice to see, I seem to recall recommending to Tim at the time about putting cherry bombs in the centre section. Mines not 2.5 though, I got mine made up in 2.25 pipes as it kept the gas speed up better whilst not actually being a restriction, again from memory.
I actually wanted to get a large subdivided single centre big box section made up. I did all the calls from exhaust port through headers to the box on paper it would work but never got around to getting it made up. I did the calculations along with the header sizes which were actually bit smaller bore than some were proffering at the time, can't remember what it was though.
The decat cherry bombs don't knock that much off the noise tbh, I suspect no more than 5db.
Well I've been for blat, no more noticeable heat tbh, a lot quieter, more muted pops and bangs but still there. The car seems a bit blunted, don't know if that's Psychosomatic or not. At least when it was louder you knew you were pushing on, now it's a lot quieter it's strange to be going faster and not know it though!
I actually wanted to get a large subdivided single centre big box section made up. I did all the calls from exhaust port through headers to the box on paper it would work but never got around to getting it made up. I did the calculations along with the header sizes which were actually bit smaller bore than some were proffering at the time, can't remember what it was though.
The decat cherry bombs don't knock that much off the noise tbh, I suspect no more than 5db.
Well I've been for blat, no more noticeable heat tbh, a lot quieter, more muted pops and bangs but still there. The car seems a bit blunted, don't know if that's Psychosomatic or not. At least when it was louder you knew you were pushing on, now it's a lot quieter it's strange to be going faster and not know it though!
Umm, went for blat today and decided to venture into southsea to see no1 son and watch the arsenal game (that's another story, s
te doesn't cover it). Got stuck in the beach traffic for about 40 minutes, crawling at less than walking pace, my that was interesting, slight smoking from underneath as the cats bed in their surroundings 
but no overheating as such fans cutting in nicely keeping it below 95. However whilst sat in the traffic I've now got a slight misfire, can't make out if it's ignition or if the BP ultimate I put in yesterday as my usual Shell station us being refurbished, it normally only drinks V Power as I have had misfires on other stuff before now......but it started when very hot and gave erratic idle 
. Came back after the match and gave it an Italian tune up on the motorway, but not happy at tick over and rough light throttle running. Thoughts?
te doesn't cover it). Got stuck in the beach traffic for about 40 minutes, crawling at less than walking pace, my that was interesting, slight smoking from underneath as the cats bed in their surroundings but no overheating as such fans cutting in nicely keeping it below 95. However whilst sat in the traffic I've now got a slight misfire, can't make out if it's ignition or if the BP ultimate I put in yesterday as my usual Shell station us being refurbished, it normally only drinks V Power as I have had misfires on other stuff before now......but it started when very hot and gave erratic idle . Came back after the match and gave it an Italian tune up on the motorway, but not happy at tick over and rough light throttle running. Thoughts?HarryW said:
Umm, went for blat today and decided to venture into southsea to see no1 son and watch the arsenal game (that's another story, ste doesn't cover it). Got stuck in the beach traffic for about 40 minutes, crawling at less than walking pace, my that was interesting, slight smoking from underneath as the cats bed in their surroundings but no overheating as such fans cutting in nicely keeping it below 95. However whilst sat in the traffic I've now got a slight misfire, can't make out if it's ignition or if the BP ultimate I put in yesterday as my usual Shell station us being refurbished, it normally only drinks V Power as I have had misfires on other stuff before now......but it started when very hot and gave erratic idle . Came back after the match and gave it an Italian tune up on the motorway, but not happy at tick over and rough light throttle running. Thoughts?
Mine's mapped for V Power and did the same as yours the only time I put ultimate in (had to cos I was nearly empty and no Shell station for miles around). My guess is it's nothing to worry about - but get it filled up with V Power soon as! te doesn't cover it). Got stuck in the beach traffic for about 40 minutes, crawling at less than walking pace, my that was interesting, slight smoking from underneath as the cats bed in their surroundings but no overheating as such fans cutting in nicely keeping it below 95. However whilst sat in the traffic I've now got a slight misfire, can't make out if it's ignition or if the BP ultimate I put in yesterday as my usual Shell station us being refurbished, it normally only drinks V Power as I have had misfires on other stuff before now......but it started when very hot and gave erratic idle . Came back after the match and gave it an Italian tune up on the motorway, but not happy at tick over and rough light throttle running. Thoughts?I think most of the really rough running last week must have been down to the glowing exhaust and fuel rails being really hot too, my aircon is not working at present so no fuel cooling...........
Whilst the car is rougher on different super UL fuels is definately sweeter on V power, lets put it this way, with the high compressions the lump is running I wouldn't try running it on regular unleaded.
I brimmed it at the weekend with Shells finest and all good, although it might need topping up again..........
Whilst the car is rougher on different super UL fuels is definately sweeter on V power, lets put it this way, with the high compressions the lump is running I wouldn't try running it on regular unleaded.
I brimmed it at the weekend with Shells finest and all good, although it might need topping up again..........
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