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Thread: Duratec 2.5 question

  1. #1
    Join Date
    Feb 2017
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    36

    Default Duratec 2.5 question

    O.K. building Birkin with Duratec 2.5 power. There is a treaded plug in the side of the block, right side near rear. I think you can use a block heater in the hole. What size is it? I need to use it for the coolant temp sensor probably with a 1/8 npt or 3/8 npt single wire sensor for the coolant temperature gage.

  2. #2
    Join Date
    Feb 2009
    Location
    The Frozen Northeast
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    366

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    Pm me your e-mail I have some manuals for the engine
    Right/left?? Intake or exhaust? Holes for the egr are at the back, intake side

    P.

  3. #3
    Join Date
    Feb 2017
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    Got the EGR blocked off with plate from Massive. Threaded plug is on exhaust/passenger side. PM sent.

  4. #4
    Join Date
    Dec 2014
    Posts
    104

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    It's "-18. You can get an adapter from Earls or Summit that allows you to use a NPT sender. In my case, I use this for the coolant temp sender for the electric coolant pump controller.

  5. #5
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    Feb 2017
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    Thanks!

  6. #6
    Join Date
    Jun 2017
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    waltermitty
    what if any mods are you doing to the internals of the engine?
    If you upgrade the crankshaft and the rods + pistons you could do huge HP and torque.

    Seeing as the engine has more torque than your normal 2.0 engines, are you going to use a higher ratio differential . I know the caterhams with 2.3L engine used those higher diff ratios(lower number).. some even suggest 3.14. That would allow you to rev the engine higher at lower rpm.
    have you made any decision on that?

    Anyone driven a 2.5 duratec AND a 2.0 Duratec... ..... what differences does one feel at the wheel?
    regards
    Peter
    Last edited by peterk; 06-15-2017 at 09:35 AM.

  7. #7
    Join Date
    Apr 2012
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    113

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    Quote Originally Posted by peterk View Post
    I know the caterhams with 2.3L engine used those higher diff ratios(lower number).. some even suggest 3.14. That would allow you to rev the engine higher at lower rpm.
    If you are revving the engine higher, how can you simultaneously be at a lower rpm?

  8. #8
    Join Date
    Oct 2006
    Location
    Cincinnati
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    3,270

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    Gotta be "go faster at lower rpm's"? Or, get more top speed out of each gear?
    '97 Caterham Super Sprint, 1700 Crossflow-sold
    '09 Birkin S3, Duratec-sold
    '03 Caterham Zetec track car

  9. #9
    Join Date
    Feb 2009
    Location
    Eagle, Colorado
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    100

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    I have driven both, my demo with a 2.0 all stock bottom end with Crower stage 2 .389/.373 lift cams, Jenvey throttle bodies. The 2.5 is a recently completed customer's car with 11.5:1 pistons forged rods 4.10 lift cams and AT Power throttle bodies. Dyno results, converted to sea level from 6500', (where we are located) 260 hp on 91 octane pump gas. At 6500' the 2.0 pulls strong to the rev limit of 7000 and most of the time you can go to full throttle at will without undue tire spin. With the 2.5 it pulls very strong to 7000 and seems to rev as quickly as the 2.0. You must "apply throttle" to avoid undue tire spin. Driving the 2.0 a couple of weeks ago in Austin at COTA the 2.0 felt like the 2.5 at 6500'. I have not driven the 2.5 at lower elevation but I can safely say it will be a rocket with huge amounts of torque and seemingly not revving slower that the shorter stroke 2.0. Both cars are XS (wide body) Birkins with the same tires and gearing.
    Tom
    Birkin Direct-USA

  10. #10
    Join Date
    Jun 2017
    Posts
    4

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    yes, i should have chosen my words better.
    It should read "rev the engine higher at a lower speed"

    If the car is a road car, speed limits where i am at 110kph would get you to 3rd gear, but a little more refinement with the differential would allow you to hit 4th gear at 110kmph.
    I guess it depends on whether you count the "music of the engine gear changes" a part of the fun of having a birkin 7.
    Some people install 2.0 duratecs as they say it allows them to rev higher , which is more fun.
    But colin chapmans philosophy in designing the car never really mentioned that the engine should "rev" easy, so its not part of a lotus 7 design feature.
    Here in AUstralia, everyone uses the 2.0 duratec, seldom the 2.3. which are being phased out, and no one i know of has a 2.5........ yet

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