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-   -   AC MK IV Exhaust system questions... (http://www.clubcobra.com/forums/ac-mkiv/134817-ac-mk-iv-exhaust-system-questions.html)

griffbl 10-05-2015 04:30 PM
AC MK IV Exhaust system questions...
 
I have a 1985 AC MK IV..it has the dual exiting exhaust pipe tips on the driver's side, and it is in reality, a single exhaust, all be it a rather free-flowing one. It has headers, which Y pipe into a single glass pack type muffler, and then the single exhaust goes over the axle and into a Resonator? box and it then splits into the dual tips. Can this resonator, which is a large odd shaped box on the inside of the passenger side rear wheel, be removed and simply replaced with pipe? what purpose does this serve?

Thanks!

Griffbl

rodneym 10-05-2015 04:45 PM
Certainly different than the MkIV I had.
Can you post a pic?

Mark IV 10-05-2015 05:41 PM
The carb'ed MK IVs had the "cheater duals" that exited via twin pipes, this was because we piggybacked on the Mustang 5.0 certification and that had a similar system. When we went to EFI engines the exhaust went to the full dual system with four catalytic convertors, again cribbed form the Mustang. So a MK IV with factory carb has twin outlets on one side, EFI cars have a single on each side.

The resonator changes the tone of the exhaust. You can remove it but may not like the raspy sound.

griffbl 10-05-2015 05:55 PM
Quote:
Originally Posted by Mark IV (Post 1365807)
The carb'ed MK IVs had the "cheater duals" that exited via twin pipes, this was because we piggybacked on the Mustang 5.0 certification and that had a similar system. When we went to EFI engines the exhaust went to the full dual system with four catalytic convertors, again cribbed form the Mustang. So a MK IV with factory carb has twin outlets on one side, EFI cars have a single on each side.

The resonator changes the tone of the exhaust. You can remove it but may not like the raspy sound.
Thanks much for the quick responses....So the box inside of the passenger side rear wheel is indeed the resonator? I do not have as much ground clearance as I would like with the 4" round glass pack style muffler.....i think i am going to go to spintechmufflers.com and have a flat style muffler built that will not extend below the frame rails..i could even have one built with two inlets and two exhausts for pure duals.... Even now with no catalytic converter, but with headers, even while exiting the muffler through one large pipe (until it splits into two after the resonator) actually seems to flow rather openly....i do not mind it somewhat loud....but not too loud. Given my car is carbureted, a relatively open exhaust does help the little 302 run better....and certainly if the motor gets any other modifications. What would you do? You are the expert as to MK IV's!!

Best,

Brad

DanEC 10-05-2015 07:07 PM
I have Spintechs on my ERA and although they have a nice rumble they are not especially loud until I really open up the throttle. Then they have a pretty good bark, but not nearly like large diameter side pipes. There is link in my signature to a video of my car idling.

griffbl 10-07-2015 11:48 PM
Quote:
Originally Posted by DanEC (Post 1365814)
I have Spintechs on my ERA and although they have a nice rumble they are not especially loud until I really open up the throttle. Then they have a pretty good bark, but not nearly like large diameter side pipes. There is link in my signature to a video of my car idling.
Those Spintechs sound great! I have considered them, as they make a low profile muffler perfect for low ground clearance applications. Which Of there mufflers do you have? Are you running resonators also, or mufflers only?

Thanks!

1Bigfish 03-28-2018 10:56 AM
I have a 1986 AC MKIV with single exhaust. No Cats, no resonator just one muffler midship.

Mark IV 03-28-2018 11:57 AM
Quote:
Originally Posted by 1Bigfish (Post 1441435)
I have a 1986 AC MKIV with single exhaust. No Cats, no resonator just one muffler midship.
86 was a "split" year, early cars were carbed single exhaust, later cars were EFI and duals.

With no cats and no resonator your car was modified. Autokraft did not ship non-compliant cars other than some rollers.

monster7 03-28-2018 01:59 PM
go in contact with "Westcott cobra", he have the same car and did what you are asking for...

monster7 03-28-2018 02:04 PM
Go in contact with "westcott cobra", he did what you are looking for on his MKIV

Old Phart 03-28-2018 09:48 PM
"Autokraft did not ship non-compliant cars other than some rollers." Actually, they did with #185, the last of the carburated AC MKIV's. The original owner called the UK and
requested Autokraft to not install the required side marker lights for the U.S. regulations. It actually made it through U.S. customs.

Back to the original post: I installed a 2 inch diameter exhaust pipe with 18 inch Thrush glass packs similar to a 1965 Cobra or 65 Shelby GT350 and it sounds great! Reminds me of CSX2252

427Larry 03-29-2018 03:07 AM
I had the only Factory Built (No Roller) AC MarkIV 427 Built, #1055, no side marker lights, etc., It had headers with the under car exhaust, just mufflers, no catalytic converter. The original owner new Brian Angliss and had the car built special, and had Brian to photograph the build every step of the way. I sold the car to Bob Gaines in the mid 90's, and he just sold it a 3 or 4 years ago. I have no idea who bought it, if I known it was for sale I would bought it back, I think he sold it for $85,000.00, to cheap in my opinion. I talked to Brian Angliss personally and he confirmed that it was the only factory built 427 MarkIV he ever built.

Old Phart 03-29-2018 01:38 PM
I remember that 427 AC MKIV. Very nice and next buyer got a good deal.

427Larry 03-29-2018 05:13 PM
Old Phart, Yes it was a very nice car, I sold it to buy a 1966' 427 Cobra, which I sold not to many years ago when I felt it got be to valuable to drive on the track anymore, so I bought some Kirkhams. You don't happen to know who owns it now do you ?

Old Phart 03-29-2018 08:39 PM
Quote:
Originally Posted by 427Larry (Post 1441507)
Old Phart, Yes it was a very nice car, I sold it to buy a 1966' 427 Cobra, which I sold not to many years ago when I felt it got be to valuable to drive on the track anymore, so I bought some Kirkhams. You don't happen to know who owns it now do you ?
Wish I knew where it was, 427Larry. Maybe email the MKIV registrar?


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