Exhaust Question

[1988mgm]

Hey guys, I got a 1988 Grand Marquis 5.0 sefi and I was wondering if leaving the h pipe unbolted and removed will cause any problems cause I've been driving it like that for about two months and was wanting to know cause it just started making a popping noise when I let out of the gas to slow down

[t65neon5]

kind of a burbling popping grumbling sound?.....if so...thats what my coupe did when i let off the gas with no muffler due to lack of back pressure.....id imagine that its not "good"....but if everything else engine wise is in good shape and you refrain from full on to full off throttle,then it will "probably" be ok

[1988mgm]

Yep that's exactly what it sounds like so I need to get some muffs huh?

[sly]

other than the heat belching out on the bottom of the car... I don't see anything that could be bad about it. The lack of pipes just allows for that popping noise more and makes things louder (drone). The stock cats are plenty for mufflers though. I'd put an H pipe on with free-flow muffs just so I could move the noise out the back of the car and not vibrate my ass/feet running down the road.

[1988mgm]

Well I'm planning on getting the h pipe and some thrush welded (flowmaster knock-offs) to muffle it some

[sly]

sounds like a plan.

[88Vic]

The stock manifolds and cats make more backpressure alone than what you need. I have duals with no mufflers at all, just pipe and it's still choked up due to manifolds and cats. My exhaust also isn't loud at all except when I step on it but I hardly ever do since it sounds terrible due to my big exhaust leak, I can't stand that ticking sound. But anyways my plan is Mustang headers and no cats, that'll finally let this thing breathe like it should.

[1988mgm]

Well I was gonna get some thrush welded muffs, but I went with the thrush turbo muffs instead. the way I'm gonna do it is I cut the flanges off my y pipe and I'm gonna weld the new muffs to them then ill bolt it in there. Anything I should be worried about? The reason I didn't go with the h pipe yet cause I can't afford it yet.

[88Vic]

Maybe i'm not getting it, but you're going to put the mufflers on just after the cats?

[1988mgm]

Yes where the cats bolt to the hpipe

[sxcpotatoes]

I have some mustang headers with 2.5" h-pipe exhaust and no mufflers or cats at all. As long as you take the pipes all the way over the rear axle, all the noise is out back. I have absolutely no drone, but if I'd gone smaller on the pipes it could have possibly been annoying.

http://www.youtube.com/watch?v=5sSYq37EIOI&feature=plcp

And before I had my Oxygen sensors hooked up.

http://www.youtube.com/watch?v=rquI2zzH_zk&feature=plcp

If you want more examples, go to the official exhaust video thread on here: http://www.grandmarq.net/vb/showthre...ficial+exhaust

[90ltd]

What makes this popping sound? Its the intake charge being drawn thru exhaust valve during valve overlap(both intake and exhaust valves are open) and explodes in exhaust port collector area instead of being contained and burning smoothly in combustion chamber. What this means is that you need cam with less overlap in order to get rid of popping sound when using less restrictive exhaust. The camshaft will probably have to be custom made.

[1988mgm]

Well got the muffs welded on yesterday and it sounds a lot better it has a good rumble up to around 2 grand then it it goes quiet all you you hear is the engine. Also it gave me a lot more low end power.