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Discussion Starter · #21 ·
Do you have the 'wheels' figures as well as the calculated flywheel figures?
The losses through the AWD are very similar to the Aussie giving a figure of 34.05% and 38.27% respectively for the first and second run with the Aussie at 35.38%. With the second run being the higher figure, perhaps there is an issue with temperature - in the gearbox and diffs. I will have to put some temperature sensors on them to see which is responsible for the greatest losses.

However, it seems the losses are in the right ball park and the transmission clunk, which can be avoided does indeed seem to be a normal characteristic. With so much "Slack" in the system, it seems logical that it is most definitely the rear diff that bears the brunt, given the rear wheel bias of the AWD system. It has been particularly noticeable these last few days as I have been driving in "Heavy Walking Shoes". Just as my GTV is better driven in slippers or plimsolls, the Q4 also seems prefers it. With light foot wear, she can be driven virtually "Clunk Free".
 

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I've found that if you only push the clutch half way in whilst changing from 1st to 2nd the change is the smoothest you will get from the Q4 drivetrain. The clutch is fairly light, so the sole of the shoe does help with what's going on with the peddles


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Discussion Starter · #23 ·
I've found that if you only push the clutch half way in whilst changing from 1st to 2nd the change is the smoothest you will get from the Q4 drivetrain. The clutch is fairly light, so the sole of the shoe does help with what's going on with the peddles


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Thanks for the tip.:beer:
 

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And so it proved to be. 17 to 23 mpg was no where near what Alfa quote; drinking oil like a fish, pinking like an old series "B" engined Austin Metropolitan that I once owned and what seemed to be days for the engine to respond to the throttle. Plus that god damned awful tick-over: rock solid, but if I didn't get the revs up smartish, the bloody thing would leave me red-faced at traffic lights and junctions by stalling on me.

I now have to find the money for a; my standard cams to be re-profiled by Colombo Bariani - one or two extra horse but a decent lift again on torque, or b; a set of full blown C.B. cams at 2 grand.
My previous Brera didn't drink oil, only fuel, only pinked at low rpm when the cam timing was playing up and I never had any problem with it stalling, or having a slow throttle response. Those last three symptoms could be attributed to a weak MAF sensor signal - they are identical to what happens on a diesel with a weak one.
Ian
PS yes Sizewell, I am digging out all your old 3.2 posts and trying so far in vain to find some feedback from anyone on cam change or reprofile.
 

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You can buy MACE camshafts instead of C&B ones that claim to gain 40hp more with a tune. They're much cheaper than C&B's too, for the alloytec engine. They're available on eBay


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For the full perusal by those interested Parties.
I hope someone will be able to provide results of a similar test to this with an unmodified unit. Should be very interesting. I have the FWD and it is standing at 68000km. No issues with oil consumption whatsoever, and coming from a 3.2 Brera (got it at 92000km with one chain replacement done) which only had the normal service interval applied, I can say that frequent oil changes are a must. Engine noise still basically the same as when new, so I am hopeful.

The engine heat issue is also interesting. I wonder what benefit will be gained by replacing the manifolds for cat-less branches in this sense?

Thanks for the post Sizewell.
 

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You can buy MACE camshafts instead of C&B ones that claim to gain 40hp more with a tune. They're much cheaper than C&B's too, for the alloytec engine. They're available on eBay
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Thanks, have emailed them. Their prices are a lot more affordable.

Holden Captiva 3.2 presumably? I wonder if they work with the Alfa's vvt okay?
Mind you, if the vvt is disabled, it wouldn't matter provided the now fixed timing is correct.

They also have tool to hold the cams on one bank whilst changing the other bank's.
 

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Discussion Starter · #28 ·
My previous Brera didn't drink oil, only fuel, only pinked at low rpm when the cam timing was playing up and I never had any problem with it stalling, or having a slow throttle response. Those last three symptoms could be attributed to a weak MAF sensor signal - they are identical to what happens on a diesel with a weak one.
Ian
PS yes Sizewell, I am digging out all your old 3.2 posts and trying so far in vain to find some feedback from anyone on cam change or reprofile.
I'm sticking with Colombo Bariani. They worked a treat on my Berlina, Giulietta's and my Alfetta GTV6. Thing is, I am not going to remove the manifold cats and the Mace cams have an even higher lift. My theory is, the manifold cats are being saturated by the volume of exhaust gas when the valves open - hence the god damned awful roar from the front. A bit akin to pointing a fire hose at a wall with a 20mm hole.

I don't think I know enough about exhaust systems to argue with the professionals. However, the CB cams have a lift reduced to 7 mm. whereas the standards are 11 mm. However, the dwell angle is much greater. This I hope will reduce the back pressure and thus the roar. But they have confirmed they will re-profile my spare cams for not much change in BHP, but a fair gain in torque. I haven't asked but I think they probably increase the dwell angle as well.

But unconventionally, I think I am going to do just the exhaust cams first. They are about 150 quid each plus carriage and tax. I am not unhappy with my power as is now, but seriously that bloody exhaust roar really grips me. And it will test another theory.

If there was an issue with the MAF, it would have shown on the AFR, yes?

Don't think you will find much feedback about cams here. The fashion is for software changes, whether they work or not.
 

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Discussion Starter · #29 ·
I hope someone will be able to provide results of a similar test to this with an unmodified unit. Should be very interesting. I have the FWD and it is standing at 68000km. No issues with oil consumption whatsoever, and coming from a 3.2 Brera (got it at 92000km with one chain replacement done) which only had the normal service interval applied, I can say that frequent oil changes are a must. Engine noise still basically the same as when new, so I am hopeful.

The engine heat issue is also interesting. I wonder what benefit will be gained by replacing the manifolds for cat-less branches in this sense?

Thanks for the post Sizewell.
A couple of guys on the Aussie site I quoted said they wouldn't touch one particular software company and another said, fitting Autodelta cat-less manifolds at 1600 quid plus tax made matters worse and power fell off. That is understandable given historically even with Alfa, the exhaust is "Tuned" for the engines characteristics which fundamentally includes valve timing. Valve timing for modern catted engines is considerably different from say for instance the Bertie's, Alfetta's and 75's. I'm afraid if it was that simple Lambo's Masers and Ferrari's would not be that expensive.
 

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I'm sticking with Colombo Bariani. They worked a treat on my Berlina, Giulietta's and my Alfetta GTV6. Thing is, I am not going to remove the manifold cats and the Mace cams have an even higher lift. My theory is, the manifold cats are being saturated by the volume of exhaust gas when the valves open - hence the god damned awful roar from the front. A bit akin to pointing a fire hose at a wall with a 20mm hole.

I don't think I know enough about exhaust systems to argue with the professionals. However, the CB cams have a lift reduced to 7 mm. whereas the standards are 11 mm. However, the dwell angle is much greater. This I hope will reduce the back pressure and thus the roar. But they have confirmed they will re-profile my spare cams for not much change in BHP, but a fair gain in torque. I haven't asked but I think they probably increase the dwell angle as well.

But unconventionally, I think I am going to do just the exhaust cams first. They are about 150 quid each plus carriage and tax. I am not unhappy with my power as is now, but seriously that bloody exhaust roar really grips me. And it will test another theory.

If there was an issue with the MAF, it would have shown on the AFR, yes?

Don't think you will find much feedback about cams here. The fashion is for software changes, whether they work or not.
I don't recognise the exhaust roar you describe. In fact the new Brera sounds quieter than the previous one, even when revved - a bit disappointing in fact, even at 5-6krpm.

The non functioning vvt on the previous one did however make it sound noticeably louder and meaner even at low rpm. So it was a case of all noise and no go - like a boy racer's 1.2 Corsa with a 3" exhaust!

So taking all your symptoms and descriptions into account, I'd say your vvt mechanism has not been operating correctly for some time, although well enough to avoid the fault codes and mil illumination.

As regards the maf and afr, I think you are getting too hung up on this. You can judge if the afr is okay by the performance, feel of the engine and throttle response as well as fuel consumption. If your engine is/was flat at low rpm and loud then this could quite easily be a combination of vvt and maf issues.

There is of course the possibility of defective O2 sensors - these don't last forever and if under fuelling when the ecu is operating closed loop / part throttle can also cause poor performance but better mpg. (not to mention a hotter running engine)

May you should do a plug cut - this is the best way to check mixture on the road.

I really do hope your cam experiments pay off and I agree that software tuning is a quick and dirty answer for many.

40 odd years ago you had no choice but to do it mechanically with hotter cams, gas flowed cylinder heads, tubular exhaust manifolds and bigger or multiple carbs. Sadly many have forgotten how relevant these mods are and that software should only be used to optimise the results (as Mace make clear).
 

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Thanks, have emailed them. Their prices are a lot more affordable.



Holden Captiva 3.2 presumably? I wonder if they work with the Alfa's vvt okay?

Mind you, if the vvt is disabled, it wouldn't matter provided the now fixed timing is correct.



They also have tool to hold the cams on one bank whilst changing the other bank's.


I can't see them not working, it'd be great if they do at the price. Would changing the crank pulls really make a difference? I've heard they do, but not really convicted on this engine...



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A couple of guys on the Aussie site I quoted said they wouldn't touch one particular software company and another said, fitting Autodelta cat-less manifolds at 1600 quid plus tax made matters worse and power fell off. That is understandable given historically even with Alfa, the exhaust is "Tuned" for the engines characteristics which fundamentally includes valve timing. Valve timing for modern catted engines is considerably different from say for instance the Bertie's, Alfetta's and 75's. I'm afraid if it was that simple Lambo's Masers and Ferrari's would not be that expensive.
Its very easy to lose torque with an incorrectly designed manifold, both in terms of diameter and tuned length.

Petrol motors need some back pressure so although you can tune the runner lengths, this will only work correctly at one rpm, every where else the pulses will cause worse exhaust flow and torque loss.

It was the case last century that for stage 1/2 tuning on a 4pot motor, 4 into 2 into 1 manifolds gave a wider spread of torque, whereas for racing, where max possible bhp is needed, a 4 into 1 worked best.

I doubt the knowledge and skills exist today and its just not good enough to think the absence of the cat will guarantee a result.
 

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Discussion Starter · #34 ·
I don't recognise the exhaust roar you describe. In fact the new Brera sounds quieter than the previous one, even when revved - a bit disappointing in fact, even at 5-6krpm.

The non functioning vvt on the previous one did however make it sound noticeably louder and meaner even at low rpm. So it was a case of all noise and no go - like a boy racer's 1.2 Corsa with a 3" exhaust!

So taking all your symptoms and descriptions into account, I'd say your vvt mechanism has not been operating correctly for some time, although well enough to avoid the fault codes and mil illumination.

As regards the maf and afr, I think you are getting too hung up on this. You can judge if the afr is okay by the performance, feel of the engine and throttle response as well as fuel consumption. If your engine is/was flat at low rpm and loud then this could quite easily be a combination of vvt and maf issues.

There is of course the possibility of defective O2 sensors - these don't last forever and if under fuelling when the ecu is operating closed loop / part throttle can also cause poor performance but better mpg. (not to mention a hotter running engine)

May you should do a plug cut - this is the best way to check mixture on the road.

I really do hope your cam experiments pay off and I agree that software tuning is a quick and dirty answer for many.

40 odd years ago you had no choice but to do it mechanically with hotter cams, gas flowed cylinder heads, tubular exhaust manifolds and bigger or multiple carbs. Sadly many have forgotten how relevant these mods are and that software should only be used to optimise the results (as Mace make clear).
The engine is really sweet in lower gears and acceleration is turbine like with a lovely mechanical sound from the engine. And there is absolutely no need to rush the next gear, the torque just keeps on and on. But this car is supposed to be a luxury sports saloon and with a decent torque curve, cruising at seventy there should be no drama. But, I can only think, the pressure on the cats when accelerating from cruising speed, causes it to be so crude, it ruins the impression. Get her out of the mid two thousand and up to four and it goes deathly quiet, pure silk.

I can only think that with the shortening of valve operating times, the pulse rate is too short to exacerbate manifold cat resonance. So with a lower valve lift and an extended dwell time, the amplitude will be too low to cause the cats to resonate.
 

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Discussion Starter · #35 · (Edited)
The engine is really sweet in lower gears and acceleration is turbine like with a lovely mechanical sound from the engine. And there is absolutely no need to rush the next gear, the torque just keeps on and on. But this car is supposed to be a luxury sports saloon and with a decent torque curve, cruising at seventy there should be no drama. But, I can only think, the pressure on the cats when accelerating from cruising speed, causes it to be so crude, it ruins the impression. Get her out of the mid two thousand and up to four and it goes deathly quiet, pure silk.

I can only think that with the shortening of valve operating times, the pulse rate is too short to exacerbate manifold cat resonance. So with a lower valve lift and an extended dwell time, the amplitude will be too low to cause the cats to resonate.
August in Italy is when they take their annual holiday. I shall be speaking to their agent when he gets back from his. But when I wrote the article you refer to, I had not yet had the car on the Dynamometer. I am also wiser by a couple of thousand miles of increased economy and much increased engine performance. I shall still pursue the issue. However, I am now coming to accept the idea of a lower lift and greater dwell angle as the answer to my exhaust problem.

Only one issue concerns me in this regard and I am loath to mention it really. However, it is the issue of perhaps more heat on the exhaust valves - possibly burning them! But the current back pressure suggests they are already running hot and indeed, may be causing greater cylinder head temperatures than necessary, leading to greater thermal losses. So with a "Figuratively speaking", slower cylinder discharge, allowing smoother flow through the cats, perhaps the temperature may indeed be reduced quicker. But I won't get a response on that until September.

I'll copy this to the other thread as Radical sees this thread as his personal property.
 

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Discussion Starter · #36 ·
I don't recognise the exhaust roar you describe. In fact the new Brera sounds quieter than the previous one, even when revved - a bit disappointing in fact, even at 5-6krpm.

The non functioning vvt on the previous one did however make it sound noticeably louder and meaner even at low rpm. So it was a case of all noise and no go - like a boy racer's 1.2 Corsa with a 3" exhaust!

So taking all your symptoms and descriptions into account, I'd say your vvt mechanism has not been operating correctly for some time, although well enough to avoid the fault codes and mil illumination.

As regards the maf and afr, I think you are getting too hung up on this. You can judge if the afr is okay by the performance, feel of the engine and throttle response as well as fuel consumption. If your engine is/was flat at low rpm and loud then this could quite easily be a combination of vvt and maf issues.

There is of course the possibility of defective O2 sensors - these don't last forever and if under fuelling when the ecu is operating closed loop / part throttle can also cause poor performance but better mpg. (not to mention a hotter running engine)

May you should do a plug cut - this is the best way to check mixture on the road.

I really do hope your cam experiments pay off and I agree that software tuning is a quick and dirty answer for many.

40 odd years ago you had no choice but to do it mechanically with hotter cams, gas flowed cylinder heads, tubular exhaust manifolds and bigger or multiple carbs. Sadly many have forgotten how relevant these mods are and that software should only be used to optimise the results (as Mace make clear).
"So taking all your symptoms and descriptions into account, I'd say your vvt mechanism has not been operating correctly for some time, although well enough to avoid the fault codes and mil illumination."

Which brings me full circle. No! They have not been working properly at all on this engine and if the convoluted union at the centre of the "V" on my spare Brera is typical, none of them are. And this brings me back to my issue with softies. The Alfa softies will have designed in a window, wide enough for them to function, but not with any degree of accuracy. The oil pressure and flow rate in the rear bank could never ever been enough to sustain the correct tension on the lower/primary and the upper rear timing chains.

"As regards the maf and afr, I think you are getting too hung up on this. You can judge if the afr is okay by the performance, feel of the engine and throttle response as well as fuel consumption. If your engine is/was flat at low rpm and loud then this could quite easily be a combination of vvt and maf issues."

When the engine is at tick-over, the camshafts are "Locked" in the max advance - exhaust camshaft and max retard - inlet cam shaft. Inside the Phasor, is the Lock- pin which holds them in this position. It requires sufficient oil pressure to drive it out of the locked position before - repeat - before - the camshafts can start to rotate.

But it is a little more complicated than that. It is only the first void in the Phasor that starts to fill, the one associated with the Lock-pin. It is not until this single void starts to fill and the phasor starts to rotate, that the inlet ports of the other phasor voids become exposed. Until that happens, they play no initial part in the rotation of the phasor from the "Locked" position.

So, there is considerable pressure required to Shift the camshaft away from the locked position and only one void - 25% of the maximum turning force - which is oil pressure derived.

The MAF plays no part in the issue at this point as the ECU has already set the petrol injection level at Ultra Lean Burn - 40/50:1. So the engine has no torque regardless of the MAF. This is the reason for my persistent. red face.

Also, the stoichiometric figure on the AFR plot is consistent with the principal of "Stoichiometric Combustion". The point at which it changes over to rich is consistent with where power is needed. "Square Law", double the speed, four times the power. Stoichiometric ratio is not enough to do that.

And finally, "What Have I done?" Nothing! Except increase the Oil flow capacity and the pressure at the rear bank! Oh! and one other little trick, which would not have worked if I had not addressed the oil issues first.
 

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Yes we have come full circle as I was commenting on one of your early threads. I can't argue with your oil supply mods but I suppose I am saying that not all vvt issues are necessarily down to oil pressure, or why does changing the chains, and possibly the variators and solenoid valves effect a cure?

The previous Brera, which had only done 37k when I bought it and 57k when I part ex'd it, and shouldn't have had vvt issues. I never got to the bottom of them and they were intermittent so maybe it was borderline oil pressure.

The current one with 99k has had the chains done and is how I remember the first one on a good day - good torque, pulls smoothly even from 1000rpm in top with no flat spots and a noticeable increase in torque above about 3500rpm accompanied by that superb howl. I've never had a stalling problem on either cars so there must be an explanation for why yours is different.

QUICK POLL.
Calling 159, Brera, & Spider owners " do you find stalling an issue if you don't use enough revs & touch of clutch slip when pulling away?"
 

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Discussion Starter · #38 ·
Yes we have come full circle as I was commenting on one of your early threads. I can't argue with your oil supply mods but I suppose I am saying that not all vvt issues are necessarily down to oil pressure, or why does changing the chains, and possibly the variators and solenoid valves effect a cure?

The previous Brera, which had only done 37k when I bought it and 57k when I part ex'd it, and shouldn't have had vvt issues. I never got to the bottom of them and they were intermittent so maybe it was borderline oil pressure.

The current one with 99k has had the chains done and is how I remember the first one on a good day - good torque, pulls smoothly even from 1000rpm in top with no flat spots and a noticeable increase in torque above about 3500rpm accompanied by that superb howl. I've never had a stalling problem on either cars so there must be an explanation for why yours is different.

QUICK POLL.
Calling 159, Brera, & Spider owners " do you find stalling an issue if you don't use enough revs & touch of clutch slip when pulling away?"
Yes we have come full circle as I was commenting on one of your early threads. I can't argue with your oil supply mods but I suppose I am saying that not all vvt issues are necessarily down to oil pressure, or why does changing the chains, and possibly the variators and solenoid valves effect a cure?

It doesn't, it just restores the "Window".

If that Brera engine in my garage is typical, this engine has always been borderline. There is no land for the gallery drillings to be properly aligned and thus there "Is" a considerable pressure reduction in the gallery to the rear bank from that union. And the flow rate is reduced hugely because of this. The timing chain - primary timing chain is the last to receive it's quota of oil and the pressure is not sufficient to maintain tension and at the same time ensure the V.V.T. response time "mirrors that of the front bank.
 

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This figure of 40-50:1 afr needs qualification. Obviously no petrol motor will run on such a high afr, so the afr in the vicinity of the plug must be fairly close to stoichometric thanks to Alfa's JTS design and it having direct injection.

Which brings me to my next question. What is it that has improved your mpg? The closed loop control should be maintaining the same afr as other 3.2 motors. So if you are using less fuel than me at a steady speed, then less fuel AND less air must be being used to maintain the same afr, i.e. the engine is generating the same torque using less air and fuel. Can this be attributed entirely to the cam timing?
 
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