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Thread: High Comp stuff

  1. #1
    Forum User Wobba's Avatar
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    High Comp stuff

    Best cams for 12.5:1 block with ITB's and breathed on Meg head? Need to retain a reasonably broad torque range if possible...

    Also...typical power gain for a 11.2:1 block over OE compression?

    Any advantages or disadvantages to be considered?

  2. #2
    What cams are you using?
    I think the gains are around 5-10%, however i think your relatively low power (were see saturday!) may be down to worn b/e (what else could it be, the rest is all new?) so i would expect if you went high come your b/e your be in the 200's.

  3. #3
    Forum User Wobba's Avatar
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    225's at the moment which may not really be ideal for a high compression bottom end.

    We will see on Saturdays RR. I will be scratching my head if it is lower than 180 still...

  4. #4
    12.5 for comp only now worth it for a road car.

    11.5 with your spec should add about 10hp, combination for inc cr plus fresh BE. I have only all built up ready to go...!!!

  5. #5
    Forum User Wobba's Avatar
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    Quote Originally Posted by Evogone
    12.5 for comp only now worth it for a road car.

    11.5 with your spec should add about 10hp, combination for inc cr plus fresh BE. I have only all built up ready to go...!!!
    Lol Evo, you been drinking or just get your words in a twist? Not sure if I am reading you right

    You have a 12.5 ready to go?

  6. #6
    Was told by craig its approx 3% increase in power per compression unit raised.

  7. #7
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    Higher the compression = higher engine braking, engine will run hotter, reduced ignition advance and over compressing an engine can be a disadvantage. Run 12.5:1 and the engine will probably become a bit flat below 3,000rpm as a result of lower levels of ignition

  8. #8
    Forum User Wobba's Avatar
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    I guess risk of detonation is increased due to the compression and engine needs to be more finely tuned? With a tougher block you could however run it at theoretically much higher revs and with the right setup still produce power up there too.

    I take your point about the lower rev range though. Food for thought.

  9. #9
    Quote Originally Posted by Wobba
    Quote Originally Posted by Evogone
    12.5 for comp only now worth it for a road car.

    11.5 with your spec should add about 10hp, combination for inc cr plus fresh BE. I have only all built up ready to go...!!!
    Lol Evo, you been drinking or just get your words in a twist? Not sure if I am reading you right

    You have a 12.5 ready to go?
    LOL but yes i have one 11.5cr.....ready and waiting company should be all set to go at the end of the year. Off to Barbados for a couple of weeks before christmas and then will be sorted. Got a new job so its a bit manic the last few weeks.!!!

  10. #10
    high compression is a good thing and essential for high overlab cams and will enable the use of a much more lairy cam without the loss of low down grunt.


 

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