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Thread: Opinions to build a good Xflow.

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    Opinions to build a good Xflow.

    Hi,



    Hi, I have a 1600 Xflow which I would like to rebuild to get as much power as possible for street use (I am willing to lose some comfort for the benefit of power),
    the car will be used in rallies and rallies of classics.
    I had thought: large valves Inlet 41.3 and 34.5, Ported head, inlet 34 mm and Exhaust 33mm, Cams 244, Webber 45, pistons +0.90 (I do not know if it is possible to increase more safely) crankshaft and flywheel balanced and lightened . What power could be achieved ?, 150 hp?.


    Thanks.

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    Re: Opinions to build a good Xflow.

    you might see 150 bhp, most engines wont do that much on a 244 cam, unless you do something pretty special more like 140-145 bhp

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    Re: Opinions to build a good Xflow.

    Iv got virtualy same spec in my mexico and it makes just shy of 140bhp 124lbft which as graham says is prob limit on 244.you would need 254 or above to see those figures but your going up in rev range.

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    Re: Opinions to build a good Xflow.

    Thanks guys,

    My idea is to use the car on the street too, so I think Cam254 would be too much.
    What do you think about the porting measures for these valves?
    Is there any specification / configuration for twins 45 in this engine? I've seen it increase to 1740cc, is that safe?
    What would be the optimal RC?

    Thanks

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    Re: Opinions to build a good Xflow.

    254 is way over the top for street use.

    the bigger the engine the better torque wise, and the better it will cope with 45's which are really too big other than for the most highly strung engines.

    as for whether 1740 is safe or not it depends on your luck but usually not!

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    Re: Opinions to build a good Xflow.

    Iv got stage 4 race head and found twin 40s better with 244 than 45s in fact it only made 1bhp more at very top end with 45s i think you will find for street use 244 is limit really.your prob better off staying 1700cc and use forged pistons as lighter less friction etc and at v least arp rod bolts and steel rocker gear

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    Re: Opinions to build a good Xflow.

    Quote Originally Posted by Graham View Post
    254 is way over the top for street use.

    the bigger the engine the better torque wise, and the better it will cope with 45's which are really too big other than for the most highly strung engines.

    as for whether 1740 is safe or not it depends on your luck but usually not!


    Thanks Graham,

    Which do you think is a max. for the increase of CC in the pistons?

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    Re: Opinions to build a good Xflow.

    Quote Originally Posted by Theyellowmex View Post
    Iv got stage 4 race head and found twin 40s better with 244 than 45s in fact it only made 1bhp more at very top end with 45s i think you will find for street use 244 is limit really.your prob better off staying 1700cc and use forged pistons as lighter less friction etc and at v least arp rod bolts and steel rocker gear
    Thanks

    I will keep it in mind.

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    Re: Opinions to build a good Xflow.

    the car will really use it very little, and in classic events and some mountain route, very few km a year but those few km I would like to feel a good powerful engine, with good range of Rev. and reliable.

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    Re: Opinions to build a good Xflow.

    You already are nearly 1700cc you will gain very little more by trying to stretch the cc further

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    Re: Opinions to build a good Xflow.

    Piper 391 is something to think about

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    Re: Opinions to build a good Xflow.

    Hello everyone,

    I have advanced in the construction of the engine, the head is finished with larger valves and Stage 3 specifications. Now I will buy the pistons, but ... I have thought Accralite forged piston 83.5mm with them Compression Ratio is obtained: 12.0: 1 (approx), can this be too much ?, you think it will be necessary to use reinforced parts (pushrod, roller rocker, Conrod ...)


    Thank you

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    Re: Opinions to build a good Xflow.

    12.1 is too much for all but the most extreme race engines

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    Re: Opinions to build a good Xflow.

    Other than a forged piston, what other piston options are available ?

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    Re: Opinions to build a good Xflow.

    Quote Originally Posted by Shauns View Post
    Other than a forged piston, what other piston options are available ?
    to build a good engine takes more then buying off the self parts and bolting then together!

    the answer is use the forged pistons but machine them to suit your needs

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    Re: Opinions to build a good Xflow.

    Quote Originally Posted by Graham View Post
    to build a good engine takes more then buying off the self parts and bolting then together!

    the answer is use the forged pistons but machine them to suit your needs
    Very seldom are the piston manufacturers compression ratios correct, they are only a guide as we all know each engine is different anyway. Not the case with a X Flow but most makers leave the intruder on the large size to be machined down to the desired compression but they don't tell everyone so anyone unsuspecting builds the engine only to find the compression sky high.

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    Re: Opinions to build a good Xflow.

    HI,

    Thanks Graham, Yes, I think that's too much too, what would the maximum be for you?

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    Re: Opinions to build a good Xflow.

    HI,

    Thanks Graham, Yes, I think that's too much too, what would the maximum be for you?

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