308 Magnaflow

Guys,
I'm getting ready to do a Magnaflow based exhaust for my 77 308 GTB and I have two questions for those who've done it before.
1) What size, model number of the Magnaflow muffler do I need to use? Stainless preferred if available.
2) Is an external crossover pipe necessary or does the internal routing of the Magnaflow unit make it redundant?
I look forward to answers and comments.
thanks

 

i have fabbed up a few s/steel mufflers 308 2V using a 5" x 8" oval and also muffler for a QV using larger style 5" x11" oval both with great results we don't run cats here so i just plummed it striaght on the extractors
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Hi Rizzo,

Looks really clean. Are your tips resonator style or straight. Do you have to wear ear plugs on trips??

I found that with the Flowmaster, (basically an open baffled chamber), that it was too loud without resonator type tips. Even with the resonator type tips, my wife still wears ear plugs ;-)

The stainless looks better than my painted can. Maybe next time...

hth,
chris

 

tips on both exhaust are straight through mate the 2V was a bit loud rumbly at idle so combat the rumbles i upped the idle a touch all good now the QV is no where near as bad so a may go to the larger QV style muffler soon i will have a spare muffler for sale if anyone is in need

 

Hi Riggio

What (original QV?) spare muffler will you have for sale soon?

Cheers
Urs

 

I have magnaflow and love it, you can usually get a used one on ebay or cragislist. I wanted a valid warranty so I got it here. Magnaflow 14568. Also some of the forum sponsors selling magnaflow*usually have a sale going on. Either way its a great cat, sounds great, and very easy to install.

 

What do you mean "it's a great cat"? Since my car is a '77 it is a non-catalyst car so I have no need, nor do I intend, to retrofit cats. Maybe I just missunderstood you.
So, did you order the unit yourself and then take it to a muffler shop or did you do it all yourself? The price on the website you posted is really great. I should think that a custom muffler shop would mark it up plus, of course, tack on $200-300 for labor. Am I close? I'm also curious as to whether they could do it in a day, an afternoon or how long it would take? Does anyone know of a good muffler shop in the Longmont, CO area, by the way?

 

i have the factory muffler off my euro GTB QV. $100.00 + shipping and its gone. i also added a Magnaflow to the car as soon as it was delivered. the shop fabbed the tubes and brackets, the car was not modified.
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I just did a Magnaflow setup using 11378 http://www.magnaflow.com/02product/shopexd.asp?zone=main&id=8010. This is a 2.25" dual in/dual out 11" muffler. This muffler has a straight thru design where the perforated tubes go straigh across. I was told all the longer mufflers have a "X" design internally. So in the pix of the above exhaust the exhaust flow will meet somewhat head on. Not sure what kind of backpressure this creates, but looking at it geometrically, the longer the muffler the more the flows will meet head on. Hope you guys know what I mean.

I'll try and post up some pix of mine soon so that you can see what I did.

Henry

 

Guys,

Any Magnaflow suggestion for a 2V FI car (1981) w/2 cats (someday test pipes)?


I cannot justify $2.5K for gold pipes in the house let alone polished "tin cans" in a car.


Thanx.

 

Hi carreaper
Any loose parts/rattles in your original QV muffler?
Would you consider shipping it to Hong Kong?
Regards
Urs

 

Thank you all who've chimmed in. Lots of very useful information gleaned from your responses, perhaps the most important that i don't have to spend $2-3K on an aftermarket unit, but also important to me that Magnaflow is 1) light weight compared to my original fatso muffler by 20 or so lbs. and that 2)the sound is probably mellower and deeper (basso profundo?).
So, now can we get down to specifics? For a 1977 2-valve, carburated, non catalyst, 308GTB which Magnaflow (NOT Flowmaster--too loud by several reports) part number should I use? Is it #14568 or #11378? Or is there yet another # that someone else has already used? Can we have measurements (inlet, outlet) and inside configuration (straight through, crossed internals).
Let's (ahem!) hear your response(S).

 

true dual exhaust on my euro 308 gts. fabbed up for a mere $600 by my muffler guy. it has lasted 8 years so far - what a sound - let them pupies breathe.
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Here's what mine looks like...
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Carreaper,
Your exhaust won't fit a de-catted 2v will it?
B.

 

I see that you guys who are running this setup are doing it sans the muffler cover. Will the muffler cover fit over the magnaflow muffler?

 

my car is a euro spec - no muffler cover from the factory..

 

Mine will. I just prefer the look without the "diaper".

 

To sum up:
1) since HANKNUM's 308 has a catalytic converter, the one to use for those cars so equipped is Magnaflow #11378
2) RICHKMO'S 308 appears not to have cats, therefore use Magnaflow #14568
3) CARRREAPER's car, a later 308 but a Euro car (and therefore no cat?), ses Magnaflow, but no part number is provided--can we get you to pipe-in with a number?
4) Am I on the mark with my assumptions?
let's hear it.
thanks

 

My car is now in the process of going the Magnaflow route as well. It is a '79 US car sans cats. Upon inspection from underneath by the muffler shop they suggested to go with 2 resonators mated up the Magnaflow part #11385.

I have a couple questions though from re-reading this thread. First, are the resonators needed on a non-cat car? I don't mind the car being louder, but don't want wake up the neighbors type load. Would I be better off going with the resonator type tips? I was going to re-use the tips from the original exhaust wanting to have everything still fit under the exhaust cover and look somewhat original.

Second, I was also curious about what Hanknum was referencing per the cross over routed 14" muffler that my shop suggests versus the straight through design of the 11" muffler. Any Magnaflow gurus out there that can comment on difference in performance with these two mufflers.

 

I am having a Magnaflow installed as we speak. We went with the 14" model (dual 2.5 in and out) and removing CATS/Straightpipes alltogether, so my new straightpipes will be for sale here on Fchat shortly if anyone wants them...pictures to follow next week. I like the dual tips so we are going with a new set of double-walled ones...

 

Henry, indeed they do. The 14" model I am having installed has the "X" design internally, but you can see it cleary with a flashlight and there shouldn't be too much backflow as there is PLENTY of room for the exhaust to flow out so there shouldn't be too much of an issue as they are so free-flowing compared to the stock lump...will let you guys know and supply at least pics and hopefully some video, but no promises there as it is getting to be winter here.

 

Does anybody have sound clips of their magnaflow set up?

Jim

 

That is the same muffler I am going with. So are you not going with any type of resonator at all, or are the tips resonated?

 

I have a muffler setup i want to sell it's a magna 2.5 in/out s/steel pm me
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