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Discussion Starter #1
Right, there's been lots of debate on this and many other sites for some time now about the merits of the std. V6 cams, the possible gains of swapping for GTA cams etc.

Always keen to improve the performance a little, this is something I've been looking to do lately but wanted the facts before putting any money anywhere. So through much internet trawling, reading of manuals and talking with a few of the industry experts, I've collated the information in the attached pic. This gives the full specs for the std 2.5 and 3.0 camshafts as well as the GTA cams and some popular alternatives.

Now without going too techy in the thread, duration and lift are the two things that generally produce performance. Open a valve for longer and higher and more gas flows. There are obvious downsides if this goes too far but that's the bones of it. So, as a little experiment I've calculated the % increases for both duration and lift for each option over the std cams, taken the avg of this and used it to estimate the performance increase. The percentage that come out are fairly believable and in line with trypical expectations of cam gains if you look at websites such as Puma Racing.

As a final twist, I've also included a couple of basic specs for the E36 M3 engine which is often used as a performance comparison given it produces nr. 95BHP/L in non evo spec (remember though that engine also runs throttle bodies and high compression which are also a major factor).

Summary

  • The std cams are very tame timing wise. The duration is quite short and there is little to no overlap. This is great for smoothness but doesn't equate to big HP.
  • The GTA inlet cam isn't much different, it has slightly more duration - though not much - and some useful extra lift. Even so the likely gains are only 6-8HP.
  • AHM's offering are pretty serious and great if you want to build a really powerful engine, but the bottom end may suffer without increased compression / throttle bodies.
  • Piper and Newman offer near identifcal spec cams that would seem to offer a good power potential without pushing things too far.
  • Non std cams will need to be set with dial guages and a timing wheel making the fitting a little more complicated.
  • The std M3 cam is a similar spec to the Newman and goes some of the way to explaining the 'peakier' nature of the engine.

So... I'm very tempted with the Piper grinds. They're pretty cheap because they re-profile your existing cams. Downside, they re-profile your cams so the engine will be in bits for a week or so. The Newman are billets so are very good value... not sure if that is plus VAT though.

When I last had the car on the rollers I was only at 208BHP due I think to slightly off cam timing and at the time a totally knackered exhaust front to back. Could be quite fun to go from 208HP to 250HP in one swoop as for any of these options, a full custome re-map will be in order as well!

Chris

Note - out of respect for Aide's insider info I haven't published all of the AHM specs and don't intend to - but there's enough above to see they're serious cams.
 

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Thanks Chris!

As someone mentioned on another thread the shape (ramp) is important, but it's great to have some finite lift and duration figures.

Cheers for sharing. :thumbs:
 

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Hello,

This thread is very interesting. I have some practical experience with V6 (SOHC) cam selection for my 3.0 12V. The progression I went was:

75 3.0 V6 with JE forged pistons: std -> QV -> C&B SM1 -> RJR 590/85a
155 2.5 V6 standard 10:1 pistons: std -> RJR 570

I have the EXACT data on lobe shape for all the above cams (we put them on a profiling machine).

The RJR cams were superior to the C&B cams. After I replaced the C&B with the RJR 590/85a cams I had to remap my ECU (Autronic SMC) lean out the fuel table. The RJR 796 cam has a faster ramp, without being too hard on the lifters, and has less early duration. The lobe angle separation is also customized for track use. The result was very similar if not better, idle, sub 2500 rpm performance and increased top end performance. You seldom see SOHC 12V engines which still make power past 6500 rpm. Mine makes power (~195 rear wheel bhp, that is 225 bhp in my books) all the way to almost 7000 rpm. The 75 has almost stock cylinder heads.

Imagine what a proper set of cams, high compression pistons (11-11.5:1) and 164 exhaust manifolds would do to a 156 GTA? 300 bhp is not a problem.

It also passes the stringent California bi-annual emissions test (I have exact figures for Hydrocarbon, Carbon Monoxide, Oxygen, Carbon Dioxide, Nitrogen Oxide) . I can get roughly 27-29 mpg UK Imperial gallon on the highway at 70 mph.

I also have a 3.0 24V waiting to go into the 75. It will have 11:1 or 11.5:1 forged pistons and will be designed to run upto 7200 rpm. I cannot go more as I am using standard rods, bearings, oil pump and most importantly the hydraulic lifters.

I was told by the author of the Alfa tuning book that the profile to use was the Renault Clio 182 Williams, as it is an emission friendly cam with good power characteristics.

Most likely I will use the service of webcamshafts.com to re-weld my standard cams.

BTW, do you know how much the VANOS in the M3 advances the cams? Does the M3 3.0 have twin or single VANOS and when is it triggered? Is it run advanced then retarded at low rpms or is it the other way around?
 

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Discussion Starter #4
Imagine what a proper set of cams, high compression pistons (11-11.5:1) and 164 exhaust manifolds would do to a 156 GTA? 300 bhp is not a problem.
The general consensus that I reached when speaking to a few people was that if you knock the compression up to about that kind of figure and fit some nice cams then good numbers are attainable, but there could be questions on the low end smoothness without going down the throttle body conversion route. I think the std. throttle body is also starting to reach it's flow limit at that stage as well which is another reason it gets easier with that re-worked - and why a lot of big engine conversions swap for bigger items. AHM say they see a pretty solid 300BHP out of the 3l with that route, and thats without any major re-working to the internals (i.e. same bottom end and std valves). So on the GTA, with an extra couple of hundred cc, something in that ball park should be possible even on std manifolds, I think the cats hurt the torque more so than top end HP.

It also passes the stringent California bi-annual emissions test (I have exact figures for Hydrocarbon, Carbon Monoxide, Oxygen, Carbon Dioxide, Nitrogen Oxide)
Thats good to hear, thats my one only slight concern as our Euro3 regs basically mean emmission must be pretty much zero at idle now!

BTW, do you know how much the VANOS in the M3 advances the cams? Does the M3 3.0 have twin or single VANOS and when is it triggered? Is it run advanced then retarded at low rpms or is it the other way around?
3L M3 had single vanus which advanced the cam based on RPM, very similar to the variator in the Twin Spark I think, so it kicks at given RPMs. Not sure by how much though but I would guess maybe as much as 15deg. The 260 figure I put was at the higher end of the avg for that one, I couldn't find any difinitive specs / didn't search as hard either so I suspect that's the 'all in' figure.

The 3.2L has twin vanus which as I understand is triggered by the throttle which means you get extra power whereever you are in the rev range when you floor it, and better economy when you're off gas everywhere. All adds up to how they got 320HP in a production engine - because in reality it's way more sophisticated than the Busso... those are both the 'rest of world spec' engines mind, I think you got the raw deal in the US with a somewhat less sophisticated, lower power model that met your regs!


I think I'll be going for the std. Piper re-grinds, Piper state they're good to go without other mods and as they're not too agressive I'm hoping I'll be nice and safe on idle and keep most of the low end grunt which I love in the GTV. Should still be good for some good extra power at the top though! Don't think I can justify pulling the heads for a skim, I know if I did that I'd want to port the heads too and my brain knows it's simply wasted money on an already powerful road car. Hopefully the cam change will give a nice dose of power and liven up the slightly dosile power delivery.

Be keen to get your thoughts on that?
 

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Discussion Starter #6
Have you looked at these?

Pro-Alfa Serious Alfa Romeo tuning and motorsport preparation

Found their website the other day, I'm also considering my options for more power out of my 3.0. The engine will be coming out this year for a cambelt & clutch anyway..
Interesting find, reads well but pretty nasty website, doesn't even give an address all though I eventually found they are based in the midlands.

Cam specs looks fairly interesting, lots of lift with modest duration on the inlet which should equal good power, would be interested to know the rest of the timing to see the overlap etc. Best part of £100 more than Piper though...

Anyone know any more about them - they look like they should have a motorsport pedigree?
 

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Just to give you an idea

My 12V cams:
Exhaust: 10.05mm 244 degrees
Intake: 11.1mm 272degree
Lobe centers and ramp profile are proprietary
Tests are done on a rolling road dyno (loaded test) no idle and fast idle test. We did away with those in the late 90's.

Result:
15 mph HC: 32 ppm (parts per million) CO : 0.01%
25 mph HC: 20 ppm CO : 0.01%

I'm going to increase the compression of my 2-valve engine to almost 11:1 within the next few months. This will increase NOx but will unlikely increase HC or CO. The latter 2 will mostly be affected by A/F mixture/cam overlap. I won't be changing my cams anymore, 11mm is about the MAX I would want to use.

I just checked the MoT tests, looks like for vehicles earlier than 2002 HC is 200ppm and CO is 0.3% ? Can this be correct??? You can have 12:1 compression and 12mm cams and still pass!!!!
 

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Discussion Starter #8
I just checked the MoT tests, looks like for vehicles earlier than 2002 HC is 200ppm and CO is 0.3% ? Can this be correct??? You can have 12:1 compression and 12mm cams and still pass!!!!
For most modern cars the limit is set for the individual vehicle I think. For my GTV (first registered 30th Sept 2002 - dragging it into the newest category by 30 days) the limits are:

(my last test in brackets)

Fast Idle @ 2500-3000RPM
CO 0.2% (0.157)
HC 200ppm (0ppm)
Lambda 1.030 (1.007)

Natural Idle
CO 0.3% (0.059)

So if that's what you get with a small overlap of 18deg, what impact do you think moving to c.40deg would have?

Also, how do you think that would idle on the std. plenum (what are you running?)?

Cheers...
 

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300 bhp is on a 3.0 24vs with throttle bodies,our cams,high comp and and std 3.0 exhaust manifolds
with a good ex system no cats std heads etc

We have just done a 147 3.2 GTA std eng std cams etc
just on our Throttle bodies,BTB exhaust system no cats std manifolds and Motec ecu
gave 300 bhp :)
 
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Sounds awesome, but the only problem with ITB is that the car will no longer be any good for daily use. OK, a bigger TB like the F360 one, that will work, but ITBs....only for track.
 

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Sounds awesome, but the only problem with ITB is that the car will no longer be any good for daily use. OK, a bigger TB like the F360 one, that will work, but ITBs....only for track.
Why? Huge cost?
My mates Civic has ITB's and all sportsbikes have ITBs and they're perfectly tame in traffic etc

I'm actually surprised at how cheap the piper regrinds are, I'm starting to thing a 3.0 V6 engine swop will be a good idea.
 

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Chris,

You will see some increase in HC with the increase in overlap, but not by much at all. One other thing my cam builder told me is, even if on paper the maximum overlap is more than stock, but depending on the lobe's ramp at the early stages of intake open/exhaust close, the effect of the overlap may not be as bad as you think.

All you need to do is the cams are setup perfectly. Well with aftermarket cams, there is no other way to do it other than using dial gauges and following the spec sheet. The cam locks won't work anymore. Then remap to make sure the mixture is spot on.

I just checked my exhaust manifold for my 75 (modified from a 24V 164). The flanges are welded to the pipes on the INSIDE. So the welds are slightly impeding the flow of the exhaust out of the head's exhaust port. Pretty sure there are some gains to be had if you cleanuo out the welds. Just make sure it doesn't leak afterward.

For the plenum, when I do the conversion, it will have the GTV6 plenum, modified intake runners to adapt it to the 24V injector spacers. The Throttle is standard GTV6/75 throttle which is quite big as it is. The plenum is just slightly modified to increase flow.


Adie,

Good to hear that 300 bhp is possible. I'm aiming for 270-280 with no ITB, 10mm cams, 11:1 pistons, cleaned up (but unported) heads, and Autronic ecu.


Zamani
 

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I see a lot of you are going the similar way as i am :)

@ AHM

Are you Adie? My friend is Ernest Pancur, he did an 3.5 litre 12V engine for a buggy here in Slovenia.
He talks to you often over mail.
Well we hope to get 300bhp out of my 3.0 GTV with your cams, bigger throtllebody, bigger compresion etc....
Car wil be running megasquirt ecu, the newest version.
 

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300 bhp is on a 3.0 24vs with throttle bodies,our cams,high comp and and std 3.0 exhaust manifolds
with a good ex system no cats std heads etc

We have just done a 147 3.2 GTA std eng std cams etc
just on our Throttle bodies,BTB exhaust system no cats std manifolds and Motec ecu
gave 300 bhp :)
Just out of interest Adie, how well do you rate the quality of BTB's exhausts?

When you say "no cats std manifolds", do you mean no main cats and the standard GTA exhaust manifolds, or do you mean something like 164/GTV V6 CF2 manifolds?

Cheers :)
 
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Why? Huge cost?
My mates Civic has ITB's and all sportsbikes have ITBs and they're perfectly tame in traffic etc

I'm actually surprised at how cheap the piper regrinds are, I'm starting to thing a 3.0 V6 engine swop will be a good idea.
Well, I know all modern bikes have ITB, dunno about the Civic though, but my brother's E46 M3 has ITBs as well, and it's very nice to drive. But on an Alfa V6 you cannot have ITBs and a plenum, airfilter, MAF, etc. You can ether have ITBs, with a lot of modifications, or have a normal TB and a plenum, a MAF, an airfilter.
So if you opt for ITBs, you not only need a new ECU, loose drive by wire, but you also loose the airfilter. Can you drive a car w/o an airfilter daily ? Yes. But then you'll have to work on the engine every few trips or so.
 

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You can have individual air filters in each of the trumpets, a bit like individual air filters on carbs..
 

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The air going into the engine will be hot without a proper plenum.

Didn't the UK based blue 145 2.5 or 3.2 v6 have ITBs?

IMHO I think ITB is not practical for road cars. Especially if it involves a new ECU etc.
 

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Well, I know all modern bikes have ITB, dunno about the Civic though, but my brother's E46 M3 has ITBs as well, and it's very nice to drive. But on an Alfa V6 you cannot have ITBs and a plenum, airfilter, MAF, etc. You can ether have ITBs, with a lot of modifications, or have a normal TB and a plenum, a MAF, an airfilter.
So if you opt for ITBs, you not only need a new ECU, loose drive by wire, but you also loose the airfilter. Can you drive a car w/o an airfilter daily ? Yes. But then you'll have to work on the engine every few trips or so.
Thanks for the reply :thumbs:

I can see your point, having no plenium/ a home made one wouldn't be great since n/a cars are a lot more sensitive to the design of the intake system than a turbo is.
The civic doesn't have ITB's as standard, it has aftermarket ones and a cold air feed which stops just shy of them and has those wee filters that look like foam hats, I suppose it would be better if he spent more money on the intake
 

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The air going into the engine will be hot without a proper plenum.

Didn't the UK based blue 145 2.5 or 3.2 v6 have ITBs?

IMHO I think ITB is not practical for road cars. Especially if it involves a new ECU etc.
There is a relativly cheap aftermarket ECU called megasquirt which I think would be ideal for ITB's on a V6. I was doing a bit of research on this a while back and there are base setting for a numbers of engines (I can't remember if it's just the numbers or a downloadable map) and you tweak them for your car, I'm not sure if the Alfa V6 is there though.
 
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You can have individual air filters in each of the trumpets, a bit like individual air filters on carbs..
Yes, but not only the engine will suck in hot air, the foam filters on each cylinder are very restrictive.
Unfortunately, there simply is not enough room under the hood of the Alfa V6 to install ITBs and keep the other induction parts as well. ITBs with a proper plenum, which would include a filter(in the plenum), a-la M3 CSL, plus an air cold feed from outside the bonnet, that would be awesome, but w/o modding the bonnet it will be impossible, and I'm not even sure there is any amount of bonnet modding that would allow for that much space.
 
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