H-pipe

[TwiLighTBluEGT]

I recently had a MAC h-pipe with hi-flow cats professionally installed, and since then, my car sounds better and I think I picked up a couple of highway horses, but sometimes when Iam driving at a constant speed, I can hear rattling from under the car, and when I first start the car and put it in drive and hit the gas to accelerate, it sometimes makes this weird popping sound for the first 1-2 seconds that sounds like it is coming from the engine compartment. I've had the H-pipe on for a good 3 months now, and my car seems to be fine, except for the noises. Just wanted to know if anyone has experienced this with an aftermarket H-pipe.

[Unit 5302]

As far as the popping noise, I'd have to guess your engine is running lean, and that's causing a backfire. Perhaps your fuel injectors are a little weak or need a cleaning.

The rattle is most likely the smog pipe that connects to the air pump being loose.

[25thmustang]

I don't know about the ratteling, but my car has the same Mac H-pipe, and I was told that the popping is merely the expanding and contracting of the exhaust. It happens after you let off the throttle, and when I first start my car in the morning it happens. I was told that this is normal, and was okay. Oh ya, mine also did this when I had the stock H-ipie and Flowmaster cat-back.

[explicitone]

I also have the mac h-pipe but I have the off road pipe and mine only does it when I let off the go peddle

[drtbiker]

i actual heard, i am just quoteing that it is called infire, from the differances in pressure and temps of inside the exaust system and the out side air, i am not sure if that is true but that is what i heard

-rl

[ChunkFunky]

I'll just add to the list... I used to get the POPPING in the exhaust when I let off the gas on my olds. I am to understand it's actualy your exhaust igniting as it gets fresh oxygen from the outside air. I used to get it bad when I had a leaky header seal... once I fixed it it went away.. I dont think it's BAD for anything so much.. I thought it sounded kinda neat actualy.. it was a nice grumble when I let off the gas...

-as

[TwiLighTBluEGT]

It get the same sound when I let go off the throttle, but the popping sound I am talking about happens when I first press down the throttle, not let off of it. And it sounds like it comes from under the hood, not from the exhaust. I know it is the H-pipe because it happened right after I drove it for the first time after I put the h-pipe on. Another thing, it seems to only do it in really humid weather. When the air is warm and clear, it is fine.

[89 Cobra LX]

My stock h-pipe used to rattle. It was the metal-cover that goes over the catalatyc converter. Get under the car and bang around on the h-pipe to find the rattle.

After I installed my offroad h-pipe I had a problem with the smog-pipe bouncing around on the h-pipe. I shortened the tube and used a rubber tube with some clamps to hold it in place better. Another option would be to wrap the pipe with heat-wrap.

[drtbiker]

If i actual ride the rpms and then shift it is weird i get the pop when i accelerate. Well i found out what that was when my friend was following me one day it shot a 2ft flame out each pipe. I figured it was maybe the motor running a little to rich. maybe way to rich i have no idea why it does that but who knows lol


-rl