ALFAGTV6.COM

[Sporttunergtv6]

Hey guys,
I would like to buy a nice set of cams for my 3l 24v 164 motor and I do not know where to start. I would ultimately like to supercharge the motor, so maybe Greg can give me some advice so as not to go too wild with cam profile . I will definately be running some form of aftermarket fuel and spark control. Other than that I must be clear that although I want this motor to be fast, i want it to be enjoyable/drivable. When it does go on the track, it will only be for non competative track days.
I was looking at the C&B cams and I was wondering what you guys thought of this spec:
AR24.ST1
Road max:
10.4
9.2
260°/274°
112°/110°
20°-68°/67°-27°
1.2/1.7 I.T.
What else is out there?
Thanks,
Vittorio

[rz]

hi vittorio,
if you choose to supercharge the engine it is not advisable to put hotter cams in it!
the fuel will be blown right through you exhaustpipe
you will notice hot cams, but it is never enough.....supercharging however WILL be satisfying

[Jim K]

Marc is right; and you know what? Sell the 24v engine to some techno-nerd, buy a good used 12v, rebuild it (just a rebuild, nothing extravagant) and stuff a GG kit on it! Think about it, has to be the most cost-effective performance mod for a V6!You should be able to make money in the 24v/12v swap, plus you'll save more than $1000 by not buying the 24v cams...Hell, you'll never get that kick-in-the-back SC feeling even with an expensive na job!!
Jim K.

[Greg Gordon]

I will post my thoughts on cams for supercharging this weekend. The short version is this. It´s far more cost effective to put the money for cams into something else when supercharging, like an intercooler, modern injection etc.

[Barry]

Just for that crappy smell on the beach here...
My experience with TURBOCHARGING and the 12 V engine is that the 12 v engine can do with a mild cam upgrade when turbocharged.
I would suggest an upgrade but with altered LCA`s for less overlap..

Look at what the experienced boys have done and use..Porsche use a negative overlap cam in the turbos...

I suspect that the multivalve engine will be a different kettle of fish though..

Vittorio,The 24v is lovely to play with when it comes to LCA`s on the cams..Id look at the GTA intake with the std exhaust cam,different lCA.experiment with this ,Im sure you will find that sweet spot..
Also follow the practice of slightly bigger exhaust valves for turbo,supercharging....Ive not played with this specificlly yet as Ive always gone for bigger valves on both sides..

Got your mail,btw..thanks.

[Greg Gordon]

The school of thought with valves seems to be that supercharged engines benifit from exhaust valves about 90% the size of the intakes. That's quite a bit larger than we usually see on hot n.a. motors.

The ideal cam profiles for supercharged engines and turbocharged engines are probably different. This is because on a supercharged engine the pressure on the intake side is much higher than the exhaust side enabling the intake air to purge all the exhaust from the cylinders during the overlap period. This also allows the supercharger to pack the entire volume of the cylinder and combustion chamber with air. If you do the math you will find that results in about 10% more space to cram air into as compared with a n.a. motor with a volumetric efficiency of 100%. Of course too much overlap and an excessive amount of boost will be lost out the exhaust valve.

With a turbocharged motor the opposite is true. The pressure on the exhaust side (between the cylinder and the turbo) is usually higher than the intake side and even in a best case scenario it will be equal to the intake side. Clearly this will create different issues with valve timing especially in the overlap period.

The way I see it the bottom line is this. Cams for these engines are really expensive. So expensive that it's almost prohibative to try multiple sets of cams to try and find an ideal combination. With the stock cams you can make a lot of power. The $1000 you could spend on cams might increase power, but spend it on an intercooler, water/meth, SDS or Gotech etc. and it WILL increase power.

[Sporttunergtv6]

Thanks guys for all your comments. I hear ya loud and clear. I got the motor out of the crate last week and I am going to send the plenum and valve covers out for the required welding soon. While those are in the shop I am going to bring the block and z t ransmission to the guy who is making the adaptor plate .
victor