OK, I've heard several times that the Duratec is tuned down from what it could be producing, as to "not step on the Mustang's toes". How EXACTLY does Ford take the Duratec and rob it of power? I was just wondering.
i don't know why people don't get this... but most power in an engine is realized in the heads/intake manifolds.... the lower end is really only modified to allow for more strenght and life of the engine. Let's for example take a racing circuit called Nascar. All teams must use a factory block and can't be beyond 351 (or 355) ci of displacement. The carburators and ignition systems are regulated, so are a few other parts such as vavle sizes, piston and rod materials and such.... what is not regulated however is the head/intake design. This is where engine builders will keep all their secrets. With a good set of heads you can gain 50%+ out of an engine. A highly tuned non-street car can double it's horsepower with a good head work. This is also where the duratec is restricted. Funny thing is a 2.5L V6 duratec will be going in the jaguar with 220HP... same engine as we have with 50 more horses... go figure.
want more examples... a 2.5L duratec was build up buy some renowed engine builder called Duttweiler (sp?). With a turbo at 21lbs (or 26) of boost they got 450HP. stock was 200HP (they used an SVT version)... what an SVT has over us is cams, and larger intake, tb and such (head work again here)... anyhow the extra 250HP is coming from where?!?!?! well the turbo should be responsible for about 150-200HP of that and that's granting they used a real good turbo. The other 50 + 30 (the 30 is the SVT over us) comes from head/intake work... they netter 80HP from redoing the upper engine... maybe more....
Things to note... this 450HP duratec used an SVT intake, heads, cams, TB, and injectors, custom turbo (forgot the name of the make) and custom headers for the turbo. Since they were pumping so hard they also rebuilt the lower end with better rods, pistons, pins and rings - but did not bore or stroke the engine. THe valves stayed stock.... and there was extensive Duttweiler secret head porting and polishing done.
sorry for the long post but i was just discussing this with a co-worker and though i would share it with you.
Also called a cylinder head, the head sits on top of the engine block. Being a V6, the Duratec has two- One over each bank of three cylinders. It basically covers the pistons, and is where the valves, spark plug, and cams reside. Big part of the engine. The heads are responsible for getting air into the combustion chamber, igniting the mixture, and purging the exhaust gases. Any inefficiencies in this process technically rob you of horsepower. The stock Duratec is meant to be a daily driver engine, not a BTCC engine. Leo Capaldi did TONS of work to his SVT spec motor and is pushing 300 normally aspirated horsepower. Granted, this is on racing fuel and 13.0:1 compression. Port & polish, lightened flywheel, forged crank, titanium pistons & rods, custom cam grind- The works.
Heads sit on top of the cylinders and usually contain the intake/exhaust valves and such. Your lower intake manifold bolts to these for air input. Headers bolt to the exhaust ports of the heads to get rid of the exhaust produced in combustion. Unless you have a flat head engine, then the valves are in the block itself, along with the exhaust ports... Anybody see popular hot rodding magazine this weekend??!!
Edit: Geez, 2 people answered while I was typing..lol
There's a dyno plot out there of a stock 2.5L V6 before and after intake, MSDS, and BORLA. 30-35hp gain to the wheels..... There's definatelyt some elapsed time between the 2 runs (check the date)...but it still shows quite the gain.
My question about the heads, is could we take the SVT heads and put them on top of the our duratecs. If I'm not mistaken the SVT stuff that some people have done is just the upper and lower manifold? I'm wondering because I've seen pictures on DanG's webpage of some SVT stuff on his motor. That is just the SVT upper and lower manifolds, right Dan? So, if the heads from the SVT would work, what would it take to actually get them on there? I mean would you also need to then buy the SVT ECU so all the fuel mix and timing is correct? Has anyone done this mod BTW? It seems like think Purrt was saying up above that this would make us a lot of HP. I know my mustang buddies rave about ported and polished heads.
puckpuck, Terry H. over on the contour board says 10% or more hp is locked up in those precats. He says while at ford they cut a set of stock manifolds, removed the matrix, and welded them back together. He says that the 10% number was verified on an an engine dyno iirc. Either way... alot of folks dont believe that those precats muck up power, still others say that it will actually hurt perf. if you just gut them and leave the "expansion chamber" style manifold there. When a Ford engineer who was part of the devopment of the Duratec claims somthing however I listen. Several folks over at CEG have done it. Im not aware of any dynographs... I do however know that that guy with the cougar who dynoed with the CEG that day and made 180 to the wheels when svt's where putting out 173 or less had "european" as he called them... catless manifolds. HRmmm... this makes me think back to folks claiming the svt tb does nothing at all without the svt upper intake, dispite a dynograph on the CEG showing a 5hp gain. I dunno what im trying to say exactly except more inter board co-op would be nice. Each of us have our own little theorys and stupid myths (like svt tb and t/c) and stuff like that. They have already tackled alot of issues at CEG and we can learn alot over there. I would also say the taurus folks could teach us too... but the majority of people there are set on swaping out the Duratec for a vulcan crate so they can get a roots blower... jeeze Ive never seen so much ignorence as on that board. They posted a pic of a 2.5L upper manifold from a duratec(ours) and then they were like "YEH thats that new manifold that is supposed to add like 50hp to our cars!!!" I sent them a few pics of mine and other cougars & svts and made a couple of folks really mad... phew its late and im ranting.
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