ALFAGTV6.COM

[Jim K]

The methods of calculation of runner diameter and header pipe diameter are two totally different things. Some parameters may be used for both (like rpm) but that's about it.
As for why std headers are the same size, its a question of economics, just as it happened with the 2.5 and 3.0 runners. If performance doesn't suffer a lot and marketing targets are met, factory bean-counters will prevail and prevent any new design work on molds/dies/fixtures etc. If you look inside the V engine, you will find many such examples of financial concern, the biggest being the unfortunate exhaust rocker system and more recently the lobe shape of 3.2 cams, which could not have been improved without some sort of radical head redesign, allowing for larger diameter followers -or smaller base circle cam lobes.
Jim K.

[Zamani]

Hi Veglia,

Can PM me the place or specs where it got regrind? I've been looking around for cams for a while. A tuner offered cams to me but said the idle will go to hell. But it would be a fast car. It left a stock but stripped out 155 Q4 on the straight away in a very convincing manner, I think you know which video I'm talking about. Because of the idle issue I wasn't so sure about going with the cams as I need to have my car go through emissions testing every 2 years.

I asked if GTA cams were good, he say they were OK. But he said to get the best performance both intake and exhaust lobes needs modifications.

Unfortunately I sold my stock intake cams as at the time I was set on GTA intake cams, but I can find a pair of used stock cams I guess.

[Zamani]

Also, I finally got my runners. It will fit the stock GTV6 plenum, 44mm OD and 41mm ID. Only thing is I either have to grind the hell out of the stock plenum ports or custom weld new ports. I'll grind them first

[Zamani]

JimK,

What is your opinion on the 3.2 intake cams?

[Jim K]

Would you believe I haven't had a chance to graph them out yet? I only took a good look at them in a 3.2 engine. The design is very wrong as far as motion dynamics go. Flat lobes are a necessary evil in this case, the result of system shortcomings, mainly small diameter followers. The greater the flank acceleration, the bigger the follower diameter has to be, to prevent the nose of the cam 'falling off' outside of the flat follower surface. Truncating the lobe avoids this while giving the possibility to increase duration. What I would do is raise the follower out by a safe 1.5-2mm and use a conventional lobe design with smaller base circle and ~11mm lift which is optimum for these 35.6mm valves. Thse guys are fortunate the valves are light, as this type of cam lobe requires considerably higher spring pressures for high rpm operation - don't ask how high...there must be somebody out there with the proper software (they'd still have to graph out the lobe though, to determine acceleration!)
Jim K.

[MD]

Hey Freddy Feel Good, nice to see you're back although some would say your front isn't much different and besides what would a Greek sheep herder know about cams, eh??

Hey,Bazza, Hurry back will ya. I'm gonna need some help with this when he sees it. Can't seem him taking it lying down..he hee.

[Zamani]

Is Baz still in Angola?

[Zamani]

JimK,

So your 24V is going to be a 3.0 with
custom cams
Headers with 1.625" primaries
shaved 0.002" heads
Slightly ported heads
JK Rods
Modified motronic

We'll for the details in your book, but just wanted to have a rough spec of your engine.

Since the euro is down I'm tempted to go for a 3.2, but then I think again....3.0 is plenty.

[Jim K]

Z, my 3.0 24v isn't gonna be anything. It is as you say except it has the std rods (a bit reworked and properly balanced, since they had 2500km). I don't remember how much the heads were shaved but CR is 11.3:1. I will do nothing with this engine as I'm now planning to sell the 3liter car when I'm done with it (I'm going to the exhaust shop today to hopefully/finally correct big-bore problem). So, the 24v will probably be up for sale sometime soon. Pity, as I really wanted to see it in the car. Regrettably, slowly but surely all V6 stuff will have to go; I just sold a very good (std) 12v engine last month for 2000Euros. Getting rid of all V6 stuff is a way to preclude a later return/relapse to this field!
I'm concentrating on the 1.8T now, lots going on there; I believe it'll be a better overall package than any V6. For one thing, having driven both of them in the track, there's no way the V6 will take turns like an I4.
Euro/Dollar thing is bad for us , good for you now! Boy, we were happy with 1.6:1!!
Jim K.

MD: I have temporarily removed your coordinates from the targeting list for reasons you well know....DON'T PUSH IT!

[grant]

Zamani,

Can you provide details on the intake runners? I'm still looking for a reasonably priced way to increase the runner ID.

Thanks!

[Zamani]

The intake runners I got are for the 24V conversion. 12V, just get a die grinder and spend 30 mins per runner. That's what I did for my 12V runners.

[Veglia Borletti]

I'm concentrating on the 1.8T now, lots going on there; I believe it'll be a better overall package than any V6. For one thing, having driven both of them in the track, there's no way the V6 will take turns like an I4.

Hmm.. of course the turbo cars is fast.. but for me, half the fun with racing a GTV6 is the glorius V6 sound inside my car.... If I want turbo I would rather race a cossie or something like that..

[grant]

You said the runner size increase was marginal from grinding right? Still wondering if switching to a 164 style intake manifold will be beneficial for a 12V with hotter-than-S cams.

[Zamani]

Grant,

You don't need to make it super large as the 3.0 valves aren't that big either. Around 38-39mm is good enough as the stock runners are around 35mm.

[Veglia Borletti]

Back to my engine..

Have anybody milled down the heads on a 24v? I know its probably not the best way to get higher CR.. but...

Any coments..?