ALFAGTV6.COM

[75evo]

Or you could try one of those O2 sensor non fouler pipe. It just moves the O2 sensor further away from the exhaust gas stream . Seems to work for some people.

[Saabretooth]

Thanks.

I'll be speaking with the Tuner to see if he can normalize the mixture at the lower RPMs.
If not I'll try out that O2 Sensor Non-Fouler Pipe.

Car is running great, Pulls very hard, and keeping up with a Swedish V6 Turbo which I believe is Stock, is not an issue all the way from 150 km/h to 220s

[Tim0172]

Saabretooth, just a quick other question;
You said that you had the heads skimmed 1,2mm are you sure that they skimmed it this much?
and did they cc'd the heads after they skimmed it?
I think that 1,2mm is a bit to much.
It would bring your compression up to aprox 13.5:1 maby a bit more.

Tim

[Jim K]

Am I happy today! Spent ~3hrs at the grinder's shop and we really exhausted the 24v cam discussion. We sat checking different profiles on the Cam-Doctor, analyzing all kinds of available parameters. We finally agreed on a hydraulic non-sinusoidal lobe, 10.3mm lift and ~226*@1.25mm. This spec doesn't say much by itself as the very important part is the increased 'area under the curve'. We settled for moderate acceleration and minimal jerk, very close to the std cam values. A serious departure from Alfa standards will be the suggested timing; more on this later ...much later!
While there, I measured a set of 'gta1' profiles from S.A. Was I disappointed! I can't believe those people are selling cams... The lobes have so much evident jerk there were signs of impending wear (I can imagine the followers too). The funniest -and least professional- part, is their lobe is a mixture of two separate profiles with the transition point clearly defined even visually...As for the profile itself, it was wrongly designed especially at the ramps and otherwise very-very close to the std gta lines -I would hardly call it a performance profile. Damn, someone wanted 300€ for these and I was thinking about it... These cams are a bad joke. Since some people have had good results with them (I can't see how) I can't wait to see what our own profile will do! Rats, I've got to start on that 3.2 thing!
Jim K.

[Saabretooth]

Hi Tim.
Yup my instructions to the machine shop was 1.2mm.
The reading that I did was a maximum of 1.3mm before something would knock.
I just chose 0.1mm buffer for tolerance.

How did you come up with the 13.5:1 figure?

I'm not sure what you mean by cc 'd.

Performance is really good. I'm not looking for anymore power unless it's reliable.
At best I would explore with great ratios final drive from a 2.0, 1.8 or 1.6.

Cheap and cheerful. Direct application of usable power.


Jim, If you could come up with a set of cam locks or a cam setting template. ... I would explore re setting the cams.

The other way with adjustable sprockets is a bit more expensive. And time consuming.

[75evo]

cc is just the term people use for measuring the volume of the combustion chamber before and after skimming or re-shaping. cc or ccm just means cubic centimeter i,e, the GTA is like 31XX ccm.

I'll measure mine, but it has been skimmed. not too much. Maybe like 0.5mm or something, I forgot. I think mine will be close to 11:1.

[Tim0172]

I just wondered how you came up with the 1,2mm.
if you skim the head the compression chamber wich is in the head gets smaller thus giving higher compression ratio.
Mine is now 46cc leading to a compression ratio of 12,5:1 this is with a skim of 0,8mm.
with your skim it is probably north of 13:1 but i dont know for sure because i dont know your chamber cc's.
what octane number is your fuel you are running? To avoid knock it should be high, atleast above 100 Ron.
if its not i recommend you to use a octane booster. The standard ecu is capable of detecting knock you also have 2 knock sensors on the block.
When knock is detected your ignition is retarded wich leads in powerloss but will save your engine.
you do not want to be staring down in the sump thru one of your pistons....

Tim

[Saabretooth]

Hi Tim,

I can't recall exactly, but I believe I got the info from one of the South African Guys who maxed out his 3.2 V6.

Again I can't recall if its on AO forum or 156.net.

Have put in 15,000 km on it, and pulled to 7000+rpms several times already. engine runs well and feels urgent to respond.

I change out to 50wt oil every 7000km.

[75evo]

Sabretooth,

When is your GTA due for scrap? Do they check the engine serial when they scrap it?

[Saabretooth]

Sabretooth,

When is your GTA due for scrap? Do they check the engine serial when they scrap it?

I CAN SMELL A VULTURE!






its an 07 car. so its got at least 3 more years. I am hoping to keep it longer if the cost of ownership here makes sense....

Yes they do check how carefully, I don't know.. but they're supposed to check

[75evo]

He he!

[kevin]

Hmmm , Jim you got me worried as I have the gta 2 profile from the same era that this BMW tuning shop was making all theses cams for the Alfa boys . . I did hear of a few cases that these cams were wearing quickly but I thought it was due to the hardening process or lack off .
Are your cams gonna be from billet ?

[Jim K]

Kevin, I asked about the possibility to make billet sets and they will not be cheap! However, the characteristics of the profile can guarantee there will be no lobe wear so regrinds will be entirely safe. We double-checked it with the Cam Doctor software and the critical values are equal to or better than the std cams!
I haven't seen or checked 'gta2' cams, but if they are of similar 'qualities' to the gta1's...
I would be very interested to measure a set... get to know the competition
Jim K.

[75evo]

JimK,

So even your most aggressive 24v regrind profile, after having a 3-hour mental orgy with your cam grinder, will wear less than the stock GTA cams? Quite remarkable.


BTW I got my rods & the rod seller from Hong Kong is a really cool seller! Very responsive!

[Jim K]

To be entirely safe, we based the design on a 32mm diameter follower -the 24v ones are 33mm so we're sailing. 10.3mm lift means we don't have to worry about valve springs or guides, as the std parts will take a max safe lift of 10.7mm. The reason for not going over 10.3mm is I don't want the followers to overextend. If they do, the obvious cure is to use Maserati 7mm valve shims ~1.5-2mm thick between the valve and the follower.
You got Maxspeeding rods? Yes, they are very quick and professional people to deal with.
Jim K.