Modifications to stock mid-pipe for sound

[9746Cobra]

I have a '96 Cobra with stock exhaust manifolds, stock H-pipe and Bassani cat back. With or without the Bassani tip inserts it's too quiet.

I've had this combo before with an o/r 2.5in H, and it was way too loud. But I LOVED the sound!

So I'm looking for something in between the two sound levels.

I've heard a stock H-pipe with the cats gutted. It basically sounded like a X-pipe, rasp city!

So I was thinking how about removing the the rear cats on the stock H pipe and having them replaced with steel 2.25in (stock dia) tubes?

It would be louder, and still having pre-cats and being 2.25in it would give a little torque saving backpressure while not being as loud as an o/r H.

If my muffler guy will do this for me I'm going to give it a try. Shouldn't cost much.

Have any of you tried this before?

9746C

 

[9746Cobra]

Well I'm probobly going to try this soon. We'll see how it sounds!

 

[98cobradan]

ya hes prolly gonna charge u just as much if not more of the cost of a new off road pipe. Becuz it takes alittle skill to weld up an exhaust the RIGHT way. I think its gonna be hard for the exhaust shop to weld new metal to an already somewhat rusted midpipe. PLus there are four cats. Plus he has to mandrel bend the pipes to fit ur car. Not as easy as u think

 

[9746Cobra]

ya hes prolly gonna charge u just as much if not more of the cost of a new off road pipe. Becuz it takes alittle skill to weld up an exhaust the RIGHT way. I think its gonna be hard for the exhaust shop to weld new metal to an already somewhat rusted midpipe. PLus there are four cats. Plus he has to mandrel bend the pipes to fit ur car. Not as easy as u think

It will be extremely easy and he won't charge me more than $20.

9746C

 

[Team Dave]

Or you can buy a hi-flow catted mid-pipe? Sure it's a bit more expensive than $20, but it's a much more correct way of doing it. I'm not gonna hack up my stock mid-pipe.

 

[Midnight_Cobra]

Or you can buy a hi-flow catted mid-pipe? Sure it's a bit more expensive than $20, but it's a much more correct way of doing it. I'm not gonna hack up my stock mid-pipe.

Word You and I need it for emissions lol.

 

[98cobradan]

It will be extremely easy and he won't charge me more than $20.

9746C

so all ur really goin for is sound over performance?? kinda strange

 

[Pale Roader]

It will be extremely easy and he won't charge me more than $20.

9746C

I can almost guarantee there will be a press-bender involved, and in that case even free wouldn't be a deal. Not judging your guy, but most exhaust shops dont know shit about actual exhaust performance. Want ads, classified here, swap-meets, etc are all good places to find really cheap O/R H's and sometimes X's.

Or if your exhaust guy can actually 'cut and paste' a 2.5" pipe in there with a mandrel elbow (as previously mentioned, harder than it sounds, or at least not a typical $20 job, unless the guy's your dad or something...), then it might be neat to replace 4 ov the 6 cats with open pipe.

Not sure, but removing 2 outta 3 cats per pipe will likely affect your emissions if you have that where you are.

So the next question: which cat do you leave in? The first one, or the last? Which has the most effect on sound? The stock midpipe does sound kinda neat. I drove around without anything after it for a while. Nice 'boom' to it...

 

[9746Cobra]

Or you can buy a hi-flow catted mid-pipe? Sure it's a bit more expensive than $20, but it's a much more correct way of doing it. I'm not gonna hack up my stock mid-pipe.

It's another $400 for one of those. Correct way? Like George Costanza says, "it's all pipes!"

 

[9746Cobra]

so all ur really goin for is sound over performance?? kinda strange

Not much performance to be had through the mid pipe on an NA 4.6L.

Maybe you gain 5hp up top and lose 5lb ft on the bottom with no cats. It's not worth fretting over, I'd rather have the sound and sound level I want then a couple more hp.

 

[9746Cobra]

I took the rear cats off today. (There are four total, the front two are called "pre-cats")

Then took the car to the muffler guy. All he needed was two lenghts of pipe cut to the proper length and then he flared the ends and welded them in. Took 20 minutes, no bending required. He charged me $20, I handed him $40 but he refused to take it and just took the $20.

Then I had the cat monitors turned off to prevent a CEL.

The car sounds good! It didn't change the pitch or tone, just made the existing sound louder. I'll bet it sounds just like an aftermarket catted H, maybe a little louder.

The idle has a nice burble to it. The car doesn't have many high sounds, just low notes and mid-range notes. There is some drone at some rpms. It's not bad and is worse with an off-road H as I've experienced.

That describes how it sounds with the Bassani cat back and tip inserts out. I'm probobly going to leave it this way and move on to getting my gears.

When I get a picture of the modded H pipe I'll post it up.

9746C

 

[98cobradan]

the midpipe is the crucial component to make a good free flowing exhaust.

 

[Red98CobraStang]

Not much performance to be had through the mid pipe on an NA 4.6L.

Are you joking? Midpipes are the most restrictive part of our exhaust...

Just swapping midpipes is good for like 10hp/tq.

 

[JohnsMyName]

Are you joking? Midpipes are the most restrictive part of our exhaust...

Just swapping midpipes is good for like 10hp/tq.

Dont we lose some torque down low and gain a little hp up top. I was also under the impression that gain/loss was moderate like 3-6. Not trying to argue, just what I have read in the past.