[axeman74]

I need some opinions on this please.

The front resonator on my '74 GTV2000 resto project is rusted out due to poor storage. The engine pipes themselves are still quite good. I am having a bugger of a time sourcing a new front exhaust section here in Oz. My usual wholesale suppliers are no longer importing them into the country. I have found a NOS Ansa item that is already rusting due to poor storage, and for which the spare parts crook (sorry, retailer) wants stupid money.

I have spoken to my exhaust wiz and he has advised me to cut out the resonator altogether and replace it with a straight pipe. He claims that there shouldn't be any power loss at all by doing this. I would leave the two other mufflers/resonators as factory. I must admit that I quite like this idea.

So, has anyone here removed their from resonator altogether, and what where the results? Any power drop? I notice that Alfaholics sports system does not have the front muffler. My motor isn't quite stock- bigger cams, electronic ignition- if that makes a difference.

Any opinions appreciated.

Axeman74

 

[rogerspeed]

Have done this mod to several Berlinas and Spiders (same exhaust system as GTV). There is no downside. You do however need to retain or make some sort of heatsheilding between the pipe and the floor in the area where the resonator was as there was a heat sheild there from the factory, it does get warm

 

[euro1750]

I replaced the resonator on my spider (2000 spica stock), with a straight pipe when the resonator got a rust hole. I did not see any performance gain/loss, only that without the resonator the exhaust note became a bit "raspy" around 2500 to 3000 rpm. On my gtv, I have headers and no resonator, and this engine (2000 webers + cams) makes the same raspy noise around 2500 rpm, so I've come to the conclusion that the resonator was there just to avoid this noise. Anyone else have a similiar experience?
For what it worth, I will put a stock exhaust (with resonator) back on my spider in an effort to smooth out this noise.

 

[vintageveloce]

You may be interested in my comments here http://www.alfabb.com/bb/forums/anything-about-alfa-romeos-alfabb-com/27686-magnaflow-exhaust-systems-have-arrived-11.html#post461590
I discuss ADDING a resonator to my system. Interestingly, I found adding the front muffler eliminated some of the raspy-ness and a bit of the volume, I think.
Carl

 

[AndrewO]

Interesting.

I've had the front muffler taken out and I get a boomy note at about 3,000rpm as well. I also have a larger exhaust system which probably makes it worse. It does get annoying when travelling at exactly 3,000 but ohterwise I don't mind since it has other benefits. For a daily driver family street car I'd probably suggest against it then.

I have seen one with an after market resonator that looked like a fat sausage rather than a muffler, more like just an expansion chamber. I didn't hear it though. It was on the personal GTV of a former Alfa dealer so they might have known what they were doing.

 

[rogerspeed]

Interesting.

I've had the front muffler taken out and I get a boomy note at about 3,000rpm as well. I also have a larger exhaust system which probably makes it worse. It does get annoying when travelling at exactly 3,000 but ohterwise I don't mind since it has other benefits. For a daily driver family street car I'd probably suggest against it then.

I have seen one with an after market resonator that looked like a fat sausage rather than a muffler, more like just an expansion chamber. I didn't hear it though. It was on the personal GTV of a former Alfa dealer so they might have known what they were doing.

Pretty sure the round front resonator was a stock item on the early GTV's (1600) and/or the dealer replacement item (C.I.S.A.M. ) supplied in the seventies,

 

[rogerspeed]

Well, more faulty memory. Went to my storage today for exhaust parts for my 67GTV, Anthony (Itlalcarguy) called, the short block is done! There I found an original one piece front & center section, marked on the center muffler C.I.S.A.M. (another of those wonderful acronyms like ALFA, SPICA, FISPA, BB, etc.) The front resonator was oval, not round, on this system. Aslo in the storage was a front section with the round type resonator, it has no markings, has a slightly cruder bracket for attaching to the tranmission. As I remember back more, Super Sprint seem to be the name coming to mind.

 

[euro1750]

Just to add a little more information following AndrewO's post, my gtv also has a larger diameter exhaust (while my spider is stock), but this does not seem to contribute too much to the raspy noise at 3000, it does however make the overall exhaust note a bit more "boomy" (these are very technical terms of course, "raspy" and "boomy")
Although I've heard many people call the front section the "front muffler", it seems quite reasonable that this is a resonator (and not a muffler) with the sole purpose of damping a resonance in the exhaust system from the exhaust pulses. The location of it also (just after the 2 to 1 collector) seems reasonable also.
I've seen (heard) other Alfa's on the street, it seems pretty easy to tell if the front section (resonator/muffler) has been removed or replaced by headers because of the 3000 rpm rasp. I would imagine that when the cars were designed, this sound would not have been acceptable for a new car, hence the addition of the resonator (just my theory...)
Has anyone purchased the front section from Centerline or International? do they fit properly onto otherwise stock systems? Does Magnaflow or Stebro make this front section also, or are these systems made for headers?

 

[rogerspeed]

I was re-reading The Booklands Portfolio on the 105 Sedans last night and was struck by the common complaint of the testers, exhaust noise at or above 3000 rpm. Other than legnth it is the same system as the GTV

 

[Chsmadden]

mine's missing the front resonator. all you get is a little raspiness in the 2500 to 3000 RPM range. I think that makes it sound better.

 

[green 69 gtv]

Has anyone purchased the front section from Centerline or International? do they fit properly onto otherwise stock systems? Does Magnaflow or Stebro make this front section also, or are these systems made for headers?

I got the stock C.I.S.M.A. "one piece" system from IAP for my 69 gtv. It came as 2 pieces with a pipe clamp to hold them together. When I first tried to install it, it was too long by about 9". After some research it seemed to me that the system was designed for a Berlina, which has a longer wheel base. I talked to folks at IAP and Centerline and they both said that sometimes they receive true "one piece" systems and at other times they get the "2 piece" systems. The manufacturer seems to think they are interchangeable. so you might have to do some customizing if you order only the front-most section (I've since heard this is true of ALL replacement exhaust systems.

I wish ANSA still offered the dual end tip set-up for gtvs which are now offered again for spiders. That is what I had on prior to the C.I.S.M.A. and the sound (to me) was louder and warmer w/out the raspy quality.

 

[BlpltGTV]

I have the Alfabb Magnaflow system on my car and I don't notice any raspyness in the exhaust sound.

Will