The Camaro Club (UK)

I used Thrush mufflers on mine, sound OK to me....

They were about £35 each from WASP. Give Mark a call there and he'll sort you out...

He ships weekly from the USA and can get anything from Summit, Jegs, Rock Auto, NPD etc.

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My '80 progress thread - hugger orange! Now with LQ9 power - forged pistons, LS2 rods, 236/242, .621/.612, flowed and milled 317 heads. MS3X

4L80e, 12 bolt, 4.11, Moroso brute strength posi, steel shafts.

Subframe connectors, g-braces, solid body bushes, carbon hood and front bumper, custom door cards, Autometer gauges.

Well I finally managed to measure my exhaust system, its a 2.25" system with the offsets I imagine we mostly have. So I assume a pair of these are required

http://m.summitracing.com/parts/flo-942448

Well I finally managed to get my Flow Master Super 44's fitted and it certainly sounds a lot better. Still seems pretty quiet compared to some but does mean I can actually talk to others in the car

Excellent news, glad to hear it's sorted Good that it's got enough volume to be pleasing but still possible to hold a conversation. If you do get the itch down the line for a louder exhaust you can always add some cut outs for an open exhaust sound, whilst still retaining a decent cabin volume when running it closed.

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Yeah if I do replace my entire exhaust system I would like to add some electronically operated cut outs. But before that a more aggressive cam is required I think

Following the fitment of my new mufflers I have noticed a new ‘challenge’ that needs to be overcome. I am now getting a lot of ‘backfiring’ if that’s what it can be called.

If I accelerate hard and ease of the throttle it pops and bangs – but this is what I would expect. However it also pops and bangs on light or moderate throttle while accelerating – this is not what I expect!

The pops and bangs are frequent, many dozens of times over a journey, and from the drivers seat at least sound like they are coming from driver side about mid way down the car – of course this is unverified and might just be cos that’s where I sit.

So I am thinking it might be caused by one or more of the following:

1. My manifold gaskets are blowing a little on both sides
2. The new mufflers do not have air-tight seals
3. The installation has loosened another part of the exhaust system which is now blowing
4. The new mufflers are causing significantly less back-pressure and the carb needs re-jetting etc

Of course it might be none of these things, I just wanted to pick the brains of others of what to look at first!

I could be wrong here but most of the time backfire is from overfuelling / not burning all the fuel or a bit of both. Maybe it just needs a quick tune to run a leaner mixture which can be done without rejetting if it's only slightly off. This should take care of the issue if it's caused by overfuelling.
The other cause could be from not burning all of the fuel, which could be down to ignition system. Could be something small like taking out the plugs and gapping and cleaning them, to new wires (if old) maybe even a weak coil.
I can't remember if you have headers on yours? One quick way to check cylinder performance is to run the engine for a few minutes and the drop some water droplets onto each header pipe. Each one should cause a nice bit of steam. If you get a to a header pipe that doesn't really steam up and is much cooler if you put your hand near it, compared to the others, then it's a sign of non combustion / incomplete burn and that could be throwing fuel into the exhaust which is igniting on its journey down the exhaust.
If you have a timing light and a vacuum gauge you can get a pretty quick overview of how the engine is running and then work through the steps. Could even be the timing is slightly out. Maybe you've already done some of these recently?

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How to post pics: When writing a message, scroll down and use the "attach file" option. Where possible, a photo sharing service can be used such as Flickr, Imgur etc. The image location (usually ending in .jpg) can be copy and pasted between the ][ brackets that appear when you click the 'Img' button (you can find this button at the top of the message box).

How to post youtube vids: Click on the 'youtubeHD' button at the top of the message box and in the middle of the ][ brackets that just appeared, copy and paste everything from the youtube web address that appears after the = sign i.e if this is the url: https://www.youtube.com/watch?v=K2cNqaPSHv0 just copy "K2cNqaPSHv0").

I'd go option 4 of the ones you state.

I've had options 1 - 3 and didn't effect in the way you say (just lots of other blowey rattly noise) ... Overfilling will as 78Camaro points out..

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“You only live once, but if you do it right, once is enough.”

Well I am not 100% sure it is backfiring, but this is the best description I can think of and is honestly what i think it is.

Could well be needing a quick tune, but surprised there would be such a difference from just changing the mufflers. I do think it is the next part of the puzzle to look at, thanks guys!

Well the have the problem fixed

The manifolds are now sealed and not blowing, so too is the rest of the exhaust system.

That didn't fix it however, so checked the plugs, leads and cap etc. They were all pretty worn, a couple of the leads were even burnt through. So I replaced the lot and now it is running really sweet

I must say, that as good as it now sounds it's still pretty quiet, at least inside the car! Wonder how many others would say Flowmaster Super 44's are quiet!!