Best after market exhaust for 3.2

[Ascari32]

Paris5garage for me, and the Wizard, which is very Ferrari - like.

But more than one or two, seem to generate more racket from under the bonnet than the exhaust - like someone threw a load of nuts and bolts into the engines - awful! All that spitting and backfiring too -  must be "Hooked on timing chain slap!"

And at least one has chronic asthma! And I bet none of them get much more than five or six extra horses from them. Not much of a return for the expense.

Come on! How can anyone do this to such a fabulous coupe'? A fantastic platform for something really - really special.

It will be "Go - Faster Stripes" next!

Mind you, I can't say too much given the grief I am suffering. But hey! Anyone who owns an Alfa has chronic masochistic tendencies!

Guilty, but I love them.

[Ascari32]

If I've learned anything reading this thread its that aftermarket exhaust install on the 3.2 is a black hole of effort and money 

"Round, like a circle in a spiral, like a wheel within a wheel.

Never ending, or beginning, on a ever spinning ----------- ad infinitum.  https://youtu.be/qKV9bK-CBXo

So a couple or three days later, still a standing code/alarm - presumption it is Lambda/MAF related and I abandoned the car due to bitter weather.

Spent some time trying to get my head around what is going on and in particular, what the hell the ECU has to do with all this! A couple of really good articles read, authored by company that does stand alone ECU's for racers. Not really interested in exactly what they do, more the reason why they do it!

The particular area I was interested in was Wideband Lambdas fitted into the headers - Pre - cat Lambdas. The post cat lambdas can only act upon what the exhaust gases contain, after catalytic conversion. Of particular interest is the closed loop action of the manifold lambdas. Several re-reads persuaded me the MAF element I bought was providing an output voltage which resulted in the ECU setting a Fuel figure, beyond the range at which the wideband lambdas could enable the ECU to "Trim the Fuel" to within the "Lambda Tolerance/AFR" and thus the code/alarm.

And bitter conditions meant the engine was barely getting up to temperature, thus a very heavy smell of petrol from the exhaust - extra fuel injected below operating temp to help get the cats up to temperature. This was in the supermarket car park, on tick-over, whilst my wife was shopping.

This latest code/alarm occurred within a few, miles of the garage technician interrogating the ECU for historical faults/codes and having found no recent ones, reset the ECU, although standing alarms had been present when he did so.

As I understand it, the ECU is continually monitoring the AFR and storing any changes - slowly adjusting the fuel trim over a substantial period - "Standard Deviation", or long time averaging. Clearly, the mismatch was too great for the ECU to stay within bounds.

The MAF element fitted was 280 - 218 - 008. So clearly there is a problem with it's Transfer Characteristic. However, given the alarm appeared after very few short miles, I reasoned the ECU would not have had sufficient "Drive - Time" to store/average/modify the mean fuel injection quantities, before the failure occurred.

More in desperation than faith, I decided to refit the Porsche MAF Sensor. 280 - 218 - 055: AKA, 98660612501. The difference between 008 and 055, aside from the obvious is, with my 3.2 JTS there is an output from the MAF on tick - over with 008, whereas with 055 there is not; confirming my belief that it is relatively insensitive, which ties in with the fact that the Porsche 911, 3.8L is Turbo-ed. Meaning, one can remove the MAF plug with the 055 and the engine does not respond to the disconnection - no change in basal output voltage. If however, one disconnects the 008, the engine does respond with the "Weight" dropping out of the exhaust sound - less powerful although still rock steady at 750 rpm. And it's output voltage drops to it's basal figure when the MAF element is disconnected.

Importantly, with the 055 the exhaust system is considerably more sedate and the engine revs cleanly. I am hoping my initial judgement on the 055 was clouded due to the ECU having; prior to fitting last time, had an extensive history file of lambda adjustment/averaging and thus it went out of bounds when the 055 was initially changed.

The engine still had not come up to temperature after refitting 055 and the conditions were still pretty bitter, although it was not dark. So cold, I decided I would go sit in the car while it came up to temperature. But, after a short period, and the engine still quite cold, the differences became obvious and I got out of the car to have further listen at the back of the car. She was just a little uneven at tick-over but nothing that I would not be content with.

I am talking of less than ten minutes after the MAF had been changed. Realizing the A/C was on full blast, I looked through the rear screen and the engine management failure had cleared. I had to go sit in the car, just to get my head around this and in doing so, switched the A/C off. The engine settled immediately to a gentle purr. Got out the car, walked to the rear and the exhaust note was nothing like anything I have experienced during all my travails.

Of course, all this will change again, no doubt. But, it came as a huge surprise, particularly how civilised the exhaust sounded. And it reassures me - if it is like this now, then regardless of what other issues pop up amongst the general malaise, it can be like this again. And if I can make it thus - I'll be very - very happy.

However - let's see what tomorrow brings!     

Still bitterly cold and a degree of nervousness made me reluctant to venture out, plus my wife's concern, given the prevalence of this new strain of Covid - 19. However, I persuaded her I was just going to put some fuel in the car and would pay at the pump - no human interaction. And I was really keen to find out if the absence of the engine management fault was going remain so. Plus, I was going to fill up with 99 instead of 95, just to provoke things a little.

A made a conscious decision to follow the Alfa Handbook and immediately drive off, not waiting for the engine to come up to temperature, but I showed some respect keeping the revs down and not pulling tall gears.

Before I launch into a terribly long and boring analysis of what I expected, let me just simply say, after forty minutes the car remained free of engine management alarms. Not only that, progression was really good but less willing to pull higher gears at low-ish revs. Assumed the AFR was less rich at low revs but not so low as to believe it to be wrong. Good acceleration but I was driving more "Granny - like" than usual. Engine really quiet and exhaust drone - free. But gases loading the rear boxes so they were growling a little. Cruise control at 70 was remarkably quiet - this is not the same car that droned incessantly around 2500 rpm. But the sound is more sporty and it is entirely from the Alfa rear boxes. The exhaust system; up to them, is incredibly quiet!

At tick - over; warm engine, the tail pipes are amazingly silky and quiet. A lot less meaty than hitherto and I am really quite chuffed about them. So much so, the Ascaris will have to be tried again to be absolutely fair to them.

It seems such a long time ago, since the Alfa Cat was replaced with the Supersprint Sports Cat and boxes were on an off, more times than my socks. I am hopeful, this has been a lesson I shall not forget. Things started to come together after the Coil Packs were all changed.

I devoted a lot of time, testing the MAF with various inserts after concluding the proper Alfa MAF element was no longer suitable when I made so many changes, particularly the Camshafts.

A 2.0 & 3.0 GTV MAF was tried and not being able to find a Porsche insert at a sensible price, I bought a 280 - 218 - 008 which has a higher Kg./Hr. range than the 3.0, but not as high as the Porsche Turbo 911. It was better than the 3.0 GTV's, but still not as good as I would have expected.

The important thing to remember is, I did not have the ECU reset or the standing alarms cleared. Secondly, and this I realise now was an important factor, the three elements were not so far apart: characteristic - wise, to persuade me they were totally unsuitable.

So, finally I found a 98660612501, AKA 280 - 218 - 055 which I tried, not having reset the ECU. It failed badly. engine running but certainly undrivable to any great degree and gutless. So the 008 element was refitted and that I believed was as much as I could do for the time being.

It was at this point I asked the garage to check the code alarms and reset the ECU. Possibly 6 - 10 miles further and a engine management code returned. Bloody nightmare!!!!!!!!!   

About three days later, in sheer desperation, I decide to try 98660612501 again, after, reading an excellent article on stand - alone ECU's for racers. And I might add, discovering 98660612501, AKA 280 - 218 - 055 is the correct insert for a Porsche 3.8/4.0 Turbo 911; and a Ferrari 599 GT. And the 3.2 JTS engine! Cost £41-00p. 008 cost £32-00p.

Although all the changes to my exhaust system were planned, for a considerable amount of time I believed something was seriously amiss. When in truth what was complicating matters enormously was; unappreciated by me, a) either the original MAF element was faulty, or b) it was not the correct element. I believe it was (b).

Why? Well, I did not appreciate the mechanics of the ECU properly at that time. Closed loop lambda control functions in cruise mode. When one is accelerating hard, it goes into open - loop. The 3.2 JTS also goes into open - loop when one lifts off the throttle, the vvt solenoids returning the camshafts to their "exhaust advanced/inlet retard" positions, albeit under the control of the ECU. And importantly for me, I now realise, the output voltage from the MAF returns to the figure stated for the device in Bosch Data Sheets. The fact, I now realise, I could adjust the output voltage of the MAF, at tick - over should clearly not have been possible.

The output of the MAF falling to it's Transfer Characteristic Minimum indicates to the ECU, airflow is stymied by the throttle being closed and the ECU then switches to "OPEN - LOOP" and ignores the lambda signals. It does not utilise the lambda signals at tick - over!!!! Because the ECU hitherto had been seeing a voltage above the figure stated in the data sheets, and probably embedded in the ECU's memory, it was still reading the lambda signals and adjusting the fuel flow from the injectors - hence the powerful Tick - over.

QED - until tomorrow! I hope not. Finally ------------!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!     

[Ascari32]

I finally got my car in for MOT, having been delayed due to the wait for the Airbag control module and then, me cancelling after its arrival, due to heavy snow and freezing temperatures.

COVID-19 has meant customers cannot remain on the premises while their vehicles are being tested/repaired. And it would have meant a 3 - 4 mile walk home for me.

Anyway, the garage fitted the ACM, repaired a faulty passenger side windscreen jet and did the MOT.

When I arrived to pick up the car, the certificate showed an initial test failure. The figures for emissions were well out.

However, on the second test, they were even better than they had been when the car was tested after the modified engine was re-installed? I asked why?

The mech came out and explained. After the ACM was fitted and the associated dash fault alarm cleared, he quickly cleared a post cat lambda alarm, but did nothing else as no standing alarms were displayed.

However, on doing a full interrogation, he did a complete "Wipe", as he remembered I had finally settled for the "Porsche" MAF element (055), but had not had a reset done. This took a little extra time as temperatures are still pretty chill around here - hovering around zero, with snow hanging on.

Whilst I was chatting and settling the bill, my wife sat in the car which was in the external car park. On coming out and starting the car, I noticed the engine was still warm. So, by way of finding an excuse for going on a test run, I suggested we get a few bits of shopping at the next village, about 7 miles.

Well, neglecting the fact that the Ascaris still fitted, although still sounding dreadful, they seemed less so!

But going down the hill; and up again, out through a new estate with a series of roundabouts; a string of them about a mile and a half long,  the car felt lighter, flicking gracefully through the roundabouts with ease, body sweeping left then right with ease and holding her line on the throttle, more so than hitherto - or so it seemed. Flexibility seemed to have improved even more at the bottom end!!!!

There was a perceptible difference from how she performed when I took the car to the garage, and now. Boxes still breaking up, but cleaner. After the last roundabout, up onto the slip road of the 14 and away - exhaust noise climbing less unpleasant, but still unpleasant non the less. And so on to 2500 - 3000 +. Quick - quicker! Definite change to sound with the engine seemingly just coming on song sweetly. Is it me, is it illusory? Well if it is, I hope it lasts. God, I hope there is nothing more to burst my bubble - I was back in my 1983 GTV6 and just as it was then, my wife in the passenger seat, uncomplaining as the car  piled on the speed. This, I though, is how the Q4 should have always been. Just lovely!

Miserable though the weather is, I can't control just wanting to go for a drive. Hope I get to take this to Italy - Garda in the Spring!

[Stu159]

I've just changed my air filter to a sports one in my V6. The brand is BMC. I decided to grab one from the German company I bought my new disks & pads from a couple of weeks back, as it's not a big expense. It has made a significant change to the sound of my car, more so than I expected and I like it. You'll note further back in this thread I'd had my centre cats removed entirely and a high flow system added from there back. This noticeably changed my throttle response and I've since (as promised  ) had my mechanic drive it up the road for me so that I could hear it. I should add this is pre-sports filter. The sound at low revs, honestly, is OK, I wouldn't say I love it, but I don't mind it, it's here nor there, however when the revs pick up, it sounds really sweet. It's subtle still, certainly not loud but I do love it. Not sure how to describe it or what to compare it with, but its a great performance style note. The other thing I wanted to add to this thread is something I realised last night. The sports air filter seems to have fixed the droning sound inside the cabin that the high flow system had introduced. It was never obtrusive or loud enough to be annoying anyway, but it was present. Now it's gone and is replaced by the raspy sound the air filter has added. It's as though the air filter has relieved the vibration somehow? The car seems to rev a little freer, or sound like it is?

Stu

[Ascari32]

With Alfa's valve timing being what it is, anything that helps get the air into the cylinders faster has to be a welcome addition.

Also, the inlet tract is fitted with a "Helmholtz ", with the express purpose of getting rid of inlet tract resonances. So it is possible you have "shifted" any harmonics that hitherto were causing a bit of noise.

It is a difficult subject to study and understand. When I sent my Dynamometer plot to Autodelta, with a view to re - mapping, speaking to Jano later I remarked on the small dip in the upper Rev response saying the Dynamometer guy thought it may be a due to a small misfire.

One needs to understand what one is reading into issues such as these, and I didn't. However, Jano pointed out, aspects of the AFR plot in relation to the Torque/Power traces.

"It's not that", he said. "It's down to an anomaly in the inlet tract. That could change with the smallest of alterations to the plumbing".