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Thread: Duratec 2.5 question

  1. #11
    Join Date
    Jun 2017
    Posts
    4

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    Tom
    Which car do you prefer, the 2.0 or 2.5 birkin for the road given your experience in them.? I understand the 2 engines are basically the same weight, so it woint effect performance (power/weight ratio), the 2.5 a tad higher in height.
    Seems the 2.0 is a much cheaper option money wise, just change the cams. People often say its best to upgrade the internals on the 2.5 as its a stroker version of the 2.0 .\
    regards
    Peter

  2. #12
    Join Date
    Feb 2009
    Location
    Eagle, Colorado
    Posts
    97

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    They have different personalities, the 2.0 needs to be run harder but doesn't complain, I run it to 7000 all the time. The 2.0 with just adding the Crower cams is a very reasonable cost the only other things you need to do are change to a Receline wet sump, add throttle bodies and sort out how you want to handle the water pump and alternator belt routing.
    The 2.5 requires less effort, as far as how hard you need to push the engine, to do what you can do with the 2.0. The 2.5 requires more modification than the 2.0, remove the balance shaft (19 lbs, much is rotating mass), change to the Raceline wet sump, change to a low profile cam cover, AT Power throttle bodies (only company I have found with the shorter direct to head throttle bodies for the 2.5 that will fit under the bonnet, very nice but more expensive than Jenvey) and then sort your belt routing.
    A note on the low profile cam cover, our cam cover was made for the 2.0 and 2.3, which don't have variable cam timing, the 2.5 has variable intake cam timing which is part of the front camshaft bearing cap, it is one piece that bridges both the intake and exhaust cams. To use the cam cover (needed for bonnet clearance) there is extra machining needed to the head to make everything fit. This is another additional cost on the 2.5.
    I might have driven the 2.5 50 miles, I have many thousands of miles in a 2.0 and like them both for different reasons. If you like momentum driving over brute force the 2.0 is for you and it makes plenty of power for a 1285 lb car.

    Tom

  3. #13
    Join Date
    Jun 2017
    Posts
    4

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    Tom
    yes i see your point, the 2.0 is much easier to go with in time and money. I do like the idea of buying a new engine and just doing the cam work upgrades, will just take a day. Surprisingly the 2.0 and 2.5 cost the same new from the factory.

    In regards to your own 2.0 car, what HP and torque increase do you get with the crower camshafts jenvey ITB.? I havnt seen any figures stated anywhere.

    For the OP, I understand the same camshafts can also be used on the 2.5. More power to you on your build, i have built complete engines and know how it is when you get into it all.
    Peter

  4. #14
    Join Date
    Feb 2017
    Posts
    33

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    The 2.5 is rated 170 hp in the '12 Ford Focus. With the ATPower throttle bodies designed for the 2.5, Crower street cams, and the Birkin 4 into 1 headers I can't see how it will make less tha 200 hp. I will be running the Subaru 3.70 rear which gives about 140 mph at redline in 5th with the T9 transmission. Not real sure how launch will feel with T9 with just tall 1st. 2nd. The biggest pain with the 2.5 has been pulling head to get it modified for low profile cam cover.

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