magnex - strange bangs

[jimblive]

i got a cat back magnex system for my 172 and have noticed some strange bangs when on full throttle (mainly in 2nd), it does not do it all the time though?

anyone else had a similar noise?

is it running rich and burning off the un-burnt fuel?

 

[RobFenn]

That would be when you lay off the throttle, so something else i guess.

 

[jimblive]

thats what i though but was unsure?

no idea what else it could be though, does not sound good!

 

[Paul Freemantle]

Have you chacked all the mountings? Tried moving the system see if there is any play in it.

 

[jimblive]

yeh i tried that and it does not catch/hit anything.

it almost sounds like the rev limiter cutting in but the acceleration is still smooth.

another thing i have noticed is that it does not seem as frantic now when it gets to 5k, seems smooth all the way which has a effect of making it feel slower. anyone else found this?

 

[telford_mike]

I get a few bangs when I floor it away from the lights - think its something to do with giving it loads after its been idling for a few minutes.

 

[jimblive]

mine does it even if ive been travelling for a while. eg going along on a dual carriage way go into a roundabout, floor it out the otherside and it does it?

 

[Flying Scotsman]

I get a slight knocking noise from mine during acceleration when the system has heated up, but no banging. Had a look at it under the pit and reckon the bend over the rear suspension beam is fouling slightly (only about 10mm gap when stationary. Probably worse for me since I lowered the car by 40mm at the same time. I think the short stub pipe between the CAT interface and the system needs to be shortened, moving the whole system forwards by about10mm. This will give more space for movement of the swinging rear beam. Also reckon that the rear exhaust mounts (especially the square spoked mount) are not stiff enough to support the heavier Magnex, so more movement than normal.

Neil

BTW Mike, the system fitted on the MK2 without any mods as you said. My Magnex dealer is going to take this up with them directly to get their listing updated. Loads of room between valance and twin pipes.

http://www.fifegallery.co.uk/domains/cliosport/exhaust_magnex02.jpg

 

[jimblive]

cheers for the advice. i dont think its coming from the zorst though, the more it does it the more it sounds like the limiter kicking in. it only does it in 1st and 2nd from about 5.5k onwards????

with regrds to putting my magnex on a my mkI they had to adjust the brackets and said it was a right pain, took them nearly 2 hrs!