Contour Enthusiasts Group Archives Forums Modifications 3.0L Duratec Be afraid, be very afraid...

Now, I'm far from an expert in this field, so my next question might sound pretty stupid...

Aside from the seat sizes, you're pretty much saying the 2.5L heads have the same sized intake ports as the 3.0L heads? Why then would the 3L have bigger valves? I do find that hard to believe, but what do I know...

Anybody that knows what they're talking about wanna chime in an edumacate me?

John

As far as the "ports" go in the heads. We are using 2.5L SVT heads for the higher-comp ratio. I do not deny that 3L heads have larger ports than a 2.5L head but they do not have the compression ratio that we desired. My comment was directed at installing 3L valves into 2.5L heads.

As to the engine management question...that solution will be posted shortly.

Thanks for the interest gents!

QWIK,

I'm in complete disagreement about the size of the valves seats and the ports. I have measured almost everything you can think of and that is an area that I paid special attention to. The valve seat inside diameter is the important part of the measurements. The 3L heads use the SAME valve seat as the 2.5L heads...Same outside diameter, but the inside is cut out more and they are over 1mm LARGER on the inside diameter. Not to mention that the intake port/runner in the head is wider overall by several milimeters.
If you look closely at the 3L heads and the 2.5L heads side by side, you can tell that they use the same geometry regarding valve placement, and that they use the same basic valve seat. As I already said, the 3L is cut wider on the inside to compensate for the larger port. The valve seat is actually thinner than the 2.5L because of it.

Doing a simple calculation will show that even a 1-1.5 mm increase in that diameter results in about 6 - 10 % increase in cross sectional area. THAT is a significant improvement.

A good port/polish up to the seat will help, but the seat is still the restrictor.
When I did mine, I had widened the whole intake port/runner in the heads including the 'bowl' under the valve seat. I decreased the angle that the air would have to flow into the chamber past the seat as well. THEN I took the heads to the shop and had them re-cut the seats to fit the 3L valves. I also told them what inside diameter that I desired the seats to be and they cut them to that new diameter. THEN I took them home again and matched the intake passage to the newly cut seats and polished everything.

All said and done I put a lot of time into this step and it was definitely worth it.

warmonger

Thanks for clearing that up Warmonger...

-J

Just so you guys know, they've been experimenting with the 3 liter ECU. The car has run on it in the past, not sure if anything has changed since then. Bypassing the PATs is a non issue, only taking a few simple jumpers in the underhood fuse box (so says my friendly car alarm/starter install shop I used to work for). Or, your original keys can be programmed at your dealer once the new ECU is installed. The 3 liter ECU is already programmed for the 24# injectors, but not the compression jump or the SVT cams, so a custom chip/Apexi/Greddy would still be better.

I've been following that project with great excitement to see what it puts down with the 3L UIM in place...

BTW, what Warmonger did with the bigger valves is standard proceedure for installing larger valves, not to take anything away from what he did. I too was confused by their decision to not use the larger valves in their 2.5 heads, or use the 3 liter heads instead for that matter since boost plans have roamed about under the lid of this project. Boost on 11:1 compression? 3-4 pounds at most maybe which = 30 HP or so on this engine... to many secrets to judge properly at this point. I can't wait to see it dyno when it's complete though after all of the time in it.

So a small valve, high CR turbo? Ahhhhh, OK.
Custom cardoc exhaust....Ahhh OK
No AFC-controller...Ahhhh OK

Not an engine expert but my curiosity is now tweaked.

How about forged rods & pistons..Yeah, Neah?

Forged rods and pistons aren't going to help that much unless the pistons are also there to lower CR. Why spend the extra money on that when they could have used the 3L heads which flow better anyways... secrets secrets.....

R

How much power/pressure do YOU think the powdered metal rods will stand up to? Remember, the 3L rods are same as 2.5L rods.....

Mercury Maurader Supercharger project 4.6L (described in C&D) powder metal rods failed at about 350 HP. Strongest 2.5L S/C cars are at 350 HP now. Now this is a 3L with turbo. 450 HP maybe.. (actually the 2.5L project turbo of Ken Dutweiller made that-- with forged internals). 500 HP?? You do not think it a bit crazy to invest all the time and money in a 3L turbo that will make at least 400-500 HP when tuning complete and not beef the internals??

So, did he do this??

No Im saying is start out right. Hell yes beef up the internals. But why the heck would you use the 2.5 heads unless you wanted the bump in CR?
Remeber the 3L heads flow better. Use the 3L heads and then upgrade your rods and pistons. But don't start with poor flowing heads and high CR and expect to just throw some forged rods in there and everything will be ok....

R