Weird Exhaust Blow

[bassmaster23]

I have a strange exhaust blow from my downpipe, where the join to the rest of the system is, it only blows randomly, more so at higher RPM, i fitted a new O gasket but its still the same, also tried aload of gob in there but its still the same. Im just confused because it doesnt blow all the time, sometimes its fine for a few hours then it blows for a few hours and so on. Any help would be mucho appreciated. Ad.

[BertieG]

i seem to have a very similar problem at the moment, new gasket didnt help, overwhelming amount of exhaust paste didnt help, rinsing the bolts up tight didnt help. id be interested in suggestions too

[bassmaster23]

i seem to have a very similar problem at the moment, new gasket didnt help, overwhelming amount of exhaust paste didnt help, rinsing the bolts up tight didnt help. id be interested in suggestions too

Yeah i tried doing the bolts up tight aswell to no avail, im inclined to think that its something to do with heat or the gasket repostioning or something, or the engine pulling away from the exhaust, but its doing my head in so need help! Is yours an aftermarket or standard exhaust?

[Prickle]

Standard backboxs on these are a tad noisy over standard imo.

[BertieG]

Yeah i tried doing the bolts up tight aswell to no avail, im inclined to think that its something to do with heat or the gasket repostioning or something, or the engine pulling away from the exhaust, but its doing my head in so need help! Is yours an aftermarket or standard exhaust?

aftermarket manifold and decat pipe. have a solid lower engine mount and changed the bolts to solid ones with no spring so there should be no movement in the join at all but it still does it

[Manu]

Standard backboxs on these are a tad noisy over standard imo.


:clapping:

[Prickle]

:clapping:

Arnt they though haha. The amount of 1.1s vt' etc ive heard with oem backboxes have been noisy then your average car with oem exhausts lol.

[nichollsvts]

They all sound like there slightly blowing, but when you check there's nothing doing.

[bassmaster23]

Mine is an aftermarket system aswell, and when i say blow i mean really blow, like its not connected atall, then after letting it sit a couple of hours its fine again. hmmm.

[huricane]

i had a blow from the down pipe thought it was the gasket between the mani and engine but it turn out to be a crack around the neck of the downpipe just something for you to check

[nichollsvts]

^^^^

As above, metal expands under heat and retracts when cooling down. If you have a crack in the manifold/exhuast somewhere when you first start your car it will sound like its blowing, then as the system heats up the metal expands to the point where its almost "seals" the crack.

That sounds unlikely but its the only thing i can think of where your exhust sounds like its blowing at first then isnt.

[bassmaster23]

^^^^

As above, metal expands under heat and retracts when cooling down. If you have a crack in the manifold/exhuast somewhere when you first start your car it will sound like its blowing, then as the system heats up the metal expands to the point where its almost "seals" the crack.

That sounds unlikely but its the only thing i can think of where your exhust sounds like its blowing at first then isnt.

Its the other way round though mate, it doesnt blow atall from when i first start the car but then after a while it was just start to blow, then i turn it off for say 20 mins and it stop blowing again.

[bassmaster23]

Anybody got any ideas.

[bassmaster23]

heeeeeeeeeeeeeeellllpppppp