400i Exhaust Question

For 400 gt and 400i the systems for left and right are different; 412 has similar central mufflers.

 

I've installed OEM correct center mufflers (2 inlets, 3 mufflers, 2 outlets). Boy are they heavy! I see nothing about them that is different. They should work on either side. The brackets for the hangers are the same on each side. The inlets and outlets are centered. The header flanges are the same.

Al

 

Tony,

On the exhaust system I recently installed on my car (400i GT) the left and right center sections are identical.

regards, Jan
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Kliko, is there a crossover pipe that connects between the two pipes on the left side and a crossover between the two pipes on the right side? I'm not asking if there is crossover that goes all the way across the entire car, just a short one on each side. Thanks.

 

Jim
There are three crossover pipes on each side; they are called mufflers. If any balancing of flow and pressure is going to occur it will happen there.
Ken

 

Jim,

No, there are no crossover pipes between the two pipes in each individual system apart from the mufflers. I concur fully with Ken.

My car used to have a pipe which connected the left and right system, it was part of an emission control system. A pump used to blow fresh air via a single pipe, then via a Y-pipe into both left and the right exhaust system.

I removed all the emission control components including the cathalic convertors (see pictures below) and installed the new system. The new system does not have a connection between the left and right exhausts and the engine runs a lot smoother with the new system. It makes a big difference.

Jan
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Oldcoin,

Just out of curiosity; did you paint the exhaust system black or did you keep the stainless steel look?

Jan

 

I may have a spare brand spanking new Stebro system if anyone is interested. PM me if you'd like.

Sebastien

 

All those pics make me want to scream for straight pipes. Yikes. Any reason for all those mufflers?

 

+1
Is the noise intolerable?
Would the neighbours know exactly what times I come & go? (no late night rendez-vous)

Think Dave mentioned he had straight pipes...

 

Yes, lots of mufflers and also weight! My current setup has one set of double mufflers on each side going into the Ferrari factory resonator/tailpipes at the back. Currently I have "test pipes" installed ahead of the double mufflers with the catalytic converters residing comfortably in my garage as my 1983 400i is exempt from emissions testing in CT. The noise with the test pipes is pretty sporty and not intrusive for longer drives according to people who have been in the car, especially with the windows up. The car is significantly quieter, too quiet imo, with the cats installed.

The stock setup of three stages of mufflers PLUS the resonator/tailpipes stage is overkill to me.

John

 

I just went to the garage and took these pix. Between the first and second muffler there is a crossover pipe. These are ANSA OEM mufflers. Also, anyone have a clue what the small pipe from the header around the flanges and connects in front of the first muffler is for?? Besides creating opportunities for exhaust leaks!

Al
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my understanding, and please correct me if i'm wrong (Rifledriver), is that the bypass pipes are there to aid in sound (volume) reduction.

...but i have that from a custom muffler guy, not the Factory. to me it seems that it could also have advantages where back pressure is concerned.

but hey, whadda i know ?

 

Most likely emissions, hotter air from headers helps burn off any hydro-carbons (unburnt fuel) in exhaust. Hence cleaner exhaust gasses

 

but it's the same on the 365GT4 2+2 and the 400...neither of which gave much thought to emissions control.

i really couldn't say for sure...

 

Would also heat the cats up quicker; but again why 365 & 400?

 

Mordalo
My car and several others have two straight pipes from the collectors back to resonator/mufflers behind the rear wheels. My mufflers appear to be ANSA and are polished stainless or chrome. Dave Stacey uses a US sourced muffler in the same location and more easily replace then mine would be.

As for sound, I have been told from those driving behind me (FCA members) and one person cycling along the road that the car sounds fantastic. It gives some noise in the car but on long trips it is never an issue and if I had the right neighbors they would love to know I was going out for a ride.
Ken

 

re: the crossover pipes...at least in theory, these should help performance. The 400 pipes are small (only 1.75" each) to thread thru the suspension in the rear. The theory is that the crossover would allow any firing cylinder to evacuate thru either of the 2 pipes. One on hand, its a surprise that Stebro did not put in the x-over, oto my bet is that the sharp 90' angle is not really great for flow...

The 400 exhaust is really not much more than a long glass-pack; there are no baffles or chambers in the exhaust, they are straight flow-thru from end to end.

My factory exhaust had rusted in places, but strangely the front 2 mufflers (the ones that are usually replaced with cats during federalization--my car obviously came in by an exemption) seemed to be completely coated along the insides and were non-functional as mufflers...I found a set of stainless take-offs (perfect condition first-2 mufflers taken off for someone else's EPA certificate, I'm sure.) but will actually go back with 3.5x7" Magnaflow mufflers. The Magnaflow are smaller bodies than the original 3.5x9" 400 mufflers, but the good news is that the 2-to-1 (part number 11148) is basically a Y-pipe and muffler in one...So 2 each on each side (2 to 1, then reverse 1 to 2 before going to the rear mufflers) should work. Making the straps to hold as original and bending pipes will be the bigger challenge...Lee

 

Btw, I weighed the muffler set; each side (not including the rear mufflers and pipes) is 60 lb. I cut open the front muffler;
- each muffler is basically (2) parallel mufflers wrapped together. The outer shell is ~16 gauge, with an asbestos-looking wrap over the pair of mufflers. The inner mufflers are even thicker steel, probably 14 gauge.
- the 20mm header bypass pipe doesn't flow thru ! The front half of the first muffler only provides a chamber 20mm header pipe, at least on this 1983 muffler the main pipe only flows thru. You can see the main pipe (sorry, the lead is cut off the front) is solid on the front half, however I have another (undetermined year) where the main pipe is perforated for the length inside the muffler. But as my car shipped, there only the rear half of the fronts have any stainless packing.
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Gentleman, for further insite to mufflers, please go to the "vintage" catagory, and read about the 365 GTB/4 Ansa thread.
Gary Bobileff