Contour Enthusiasts Group Archives Forums Modifications Duratec Performance Cams+Heads+Intake work...

Ok i have been thinking about this a lot...i want to get some intake mods done and have a few questions for you guys...

1. is the 2001 turanus 3.0 intake the same as the svt?or am i better of having my standard(170bhp)bored and new butterflies fitted, if the latter to what size? and do sho sell the butterflies for their intake seperately?

2.Does the plastic upper intake fit as well? will i need the T/B? and do aftermarket cold air intakes still fit?

3 is there any advantage in using the plastic upper?

4.I am looking to have my standard (170bhp) heads reworked, ported gas flowed and larger 3.0 intake/exhaust valves fitted, (cannot see the point in buying svt heads just to do the same)i was going to have the heads skimmed to up the compession to somewhere near the svt (low grade fuel not an issue i run 97/98 octane), is this a problem due to the chain drive?

5. Does someone have a set of valves to sell me?

6. i am also looking into having the Cams reprofiled does anyone know of a good duration? intake and exhaust..(dave z profile?)

7 and lastly who much of a power increase should i expect with all of the above +shm headers +chip?

i dont think i missed anything i would be nice to hear some input.....get the grey mater thinking..

1. No
2. No, will require modifications to fit.
3. Yes, stays cooler.
4. Yes milling the heads is a problem. Valve to piston clearance & chains.
5. Not I
6. Only "known" upgrade is the SVT profiles.
7. Something noticeable.

Why not use the 3.0 heads to start with? They already have the big valves.

The 3.0 heads that have been gently ported with the SVT cams seems the sensable way to go.

Thanks so far guys if i used 3.0 heads would it not lower the C/R more(hmm turbo thoughts) from 9.7:1, and why are other owners using 2.5 svt heads with 3.0 valves. i take it there would be no fitting problems, i thought that the 3.0 had mor agressive exhaust cam than the svt?( anyone got a set late of 3.0 heads with waterpump drive for sale)

I would think if you doing all this head work you might just want to get a 3.0 and be done with it. You'd get the performance increase you wanted and there's no replacement for displacement. Also I thought there was a Company in Britian that made cams for the Duratec. Can't remember the post where I saw it but I do remember it. Terry probably knows.

can any 3.0 guys actually verify that if i fit 3.0 heads that it would lower the C/R more?

A 3.0 cylinder head has a chamber volume of 52.00cc, the 2.5 is 44.50cc, yes a 3.0 head will lower the CR....

Does anyone know the port diameter on the 3L?? SVT ports are 34mm with a 31mm valve seat opening & 32mm valves..To me (a non expert) that and would seem big enough to get full bang from 35mm 3L valves (since the valve seat opening is probably about 34mm)...

If the 3L ports are 34mm then the better flowing surface Extrude Honing would make SVT ports the better choice. AND although you have to remove some metal from the combustion chamber, you can give your compression a boost say 10.5 to 11 to 1.

as far as regrounding the cams, it is not advisable. What you want is more lift on the valves,and longer duration, you have to have new billets made for this, otherwise you lose lift. why not just take the 3.0 and bore it.? also 3 angle valve job,P&P, titanium springs. this will yield anywahere from 5 to 30 hp, depending on other mods. My friend has a 1995 300zx TT and he got about 35 hp from the reduced air resistance, whereas i had a 1985 300zx and it did very little,not even dyno worthy

Reground cams will give you MORE lift because you cut the base circle of the cam lobe. You can also change the duration,timing and lobe profile within reason of course.