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Thread: using angle grinder on inlet cam of 3sfe for better fuel economy

  1. #1
    Forum Member Grease Monkey
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    Default using angle grinder on inlet cam of 3sfe for better fuel economy

    Sounds wack but were I live the 1.5 tonne family townace spends most of its time
    going up hills, down hills and no more than 40-60kn hr yet torque peaks at 4200rpm
    but we never get over 2000rpm anywhere. Fuel economy is completely like politicians.

    My idea was to put in a diff ratio to raise rpm nearer the torque curve as its an auto
    with overdrive that rarely sees overdrive at all. We dont use the freeway and dont
    race anyone anywhere so the diff is one scenario but....

    The 3sge has got to have the worse economy of any toyota engine for its torque
    and power ratings for its capacity.

    I looked at tri-flow cams (unequal independent inlet duration grind) which supposedly
    increases torque everywhere on multivalve engines like the KA24de and other 16v heads
    https://www.coltcams.com/html/tri_fl...ogy/index.html


    Really hoping thats my ticket eventually however since these engines are so cheap
    was thinking of grinding one of the lobes off completely from the inlet camshaft
    so I would have only one of these small inlet valves creating a swirl effect with high
    velocity in the chamber therefore more torque like the Buick nail heads of the 1950s.

    Sure I wouldnt get the hp as I did before but this engine never sees anything close
    to the redline in anyway let alone get to its torque sweet spot area.

    I was also thinking of using a spacer for the oxygen sensor so it detects less O2
    and leans out the mixture as these old engines in Japan seem to run richer than
    in Australia for some reason and wear out rings in jp engines unlike Aussie versions.

    Am I off the wall in this or does anyone think I have a chance to get the torque
    down lower and fatter by just using one small inlet valve at high velocity?
    This is before I go an order a Tri-flow grind for it etc.

  2. #2
    Forum Member 1st year Apprentice
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    Default Re: using angle grinder on inlet cam of 3sfe for better fuel economy

    Have you had the auto serviced? The auto should downshift under high load, and use all of the RPMs of the engine. If the engine doesn't rev past 2000 rpm up a hill, all that fuel is turned into heat, both in the engine and the torque converter in the auto.
    Will the Auto manually change down when select low gears?

  3. #3
    Forum Member Grease Monkey
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    Default Re: using angle grinder on inlet cam of 3sfe for better fuel economy

    Quote Originally Posted by Liquidhandwash View Post
    Have you had the auto serviced? The auto should downshift under high load, and use all of the RPMs of the engine. If the engine doesn't rev past 2000 rpm up a hill, all that fuel is turned into heat, both in the engine and the torque converter in the auto.
    Will the Auto manually change down when select low gears?
    it does downshift well but gearing is surely for flat lands! I dont like downshifting manually but it helps to get the revs up
    Its the wives car so only I shift it manually, she drives like a butterfly which is fine with a toddler but it does my head in.

    just found out Bisimoto also supplies the same kind of staggered cams for non vtec builds and world records
    We are only after economy via lowering the torque sweet spot but might need to look for a 4.11 ratio from a 4wd petrol
    or 4.3 from the 4wd diesel version. Just rechecked torque is at 4400rpm!!! darn nasty but 11km L sounds good not 7km L

  4. #4
    Forum Member 1st year Apprentice
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    Default Re: using angle grinder on inlet cam of 3sfe for better fuel economy

    If you have a look on the ID plate it will tell you what diff it has in it and you may find something else will fit. I have A 4:3 diff in a Hilux I am parting out, the Axel code is G102. The "102" is the ratio code. Most anything with a G code is interchangable, (interdependent rear ends are an exception)
    have a look here.
    http://www.dealerquickparts.net/HPFile/AXLE%20CODES.pdf

  5. #5
    Forum Member Grease Monkey
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    Default Re: using angle grinder on inlet cam of 3sfe for better fuel economy

    will do thanks and just a note this car has 103k kms always serviced every 5k km.

  6. #6
    Junior Member Automotive Encyclopaedia
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    Default Re: using angle grinder on inlet cam of 3sfe for better fuel economy

    5sfe an option?

  7. #7
    Forum Member Grease Monkey
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    Default Re: using angle grinder on inlet cam of 3sfe for better fuel economy

    Quote Originally Posted by jonathan yee View Post
    5sfe an option?
    Was my first choice but cant get any here in Japan atm, they are rare motors now.

    Im wondering if I can change from the early injectors with few jet holes to later ones from another toyota?
    Otherwise Im sourcing another a camshaft asap but not sure whether I could run an exhaust cam with
    more lift and duration to emulate the buick nailhead v8s which used the same principle

    eg.

    It became known as the "nailhead" for the unusual vertical alignment of its small-sized valves.[1] To offset the smaller-sized valves and restrictive intake- and exhaust-port diameters, the nailhead V8 family used a camshaft with greater lift and duration. The small-diameter intake runners allowed these engines to develop high torque, with many exceeding one foot-pound per cubic inch, exceptional for the time. All of the nailhead designs have a 4.75 in (121 mm) bore spacing.
    I could probably nab a beams camshaft as there are plenty of these here but need to find out the duration information for the 3sfe and the 3sge to make sure its enough lift and duration to bother.
    Otherwise will have to reground an original which is prob going to cost more than it should since
    machine work here is overpriced.

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