High compression B18 + cam choice

Discussion in 'Engine' started by Steve M, Sep 6, 2018.


  1. Steve M

    Steve M Active Member

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    Hi guys

    I'm planning on doing a high compression build on my B18 over the winter, aiming to keep it as a road engine mainly, with some trackdays thrown in too.

    Seen so many different setups and opinions so struggling to make a decision on what parts and setup I want.

    I've been offered a set of Rocket Motorsports M24xx cams with Golden Eagle cam gears which I'm interested in. In my head I'm thinking of this setup at the moment

    Rocket M24xx cams
    Titanium springs + retainers (BC possibly)
    Titanium valves
    OEM valve guides + stem seals
    OEM head gasket
    Weisco 12:1 pistons
    Manley or Carrillo rods
    Standard crank + bearings

    Does this sound like a good setup to the more experienced guys here? And will this be a good streetable setup?
    Any advice appreciated, thanks!
     

  2. Vtec6000

    Vtec6000 Super Moderator Staff Member Donator

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    Go 12.5:1 on the pistons for those cams.
     
  3. Pete180

    Pete180 Lost in dreams..

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    Decent setup that! from all I've researched and learnt so far. That should get some good power for an N/A b series. Gone for a mild high comp myself. Not cheap though trying to squeeze power N/A! soon adds up :( lol not surprised a lot of people are going turbo these days, I'm having thoughts of it too. I swear those Rocket cams idle lumpy and sound meatyyy if they're the one I'm thinking of!

    Don't forget injectors and fuel pump if you haven't done so already :)
     
  4. Steve M

    Steve M Active Member

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    Thanks for the input guys! The seller said clearance was tight with his set up which is why he'd said 12:1 would be best as he ran that, that was on a B20 though.
    He's also said he had a decent idle with them too, I'd prefer not to have a really lumpy idle if I can help it!
    It is a reallly expensive way to go it seems, understand the k-swap/turbo route attraction now, but I'm going to rebuild it anyway as it's using a bit of oil and is quite smokey now, don't see the point spending a lot doing a standard rebuild, may aswell spend a bit more and make more power!
    Ahh forgot to mention those! It'll get a walbro 255 pump and OEM K20 injectors, unless I'll need a bit more capacity than those?
     
  5. Pete180

    Pete180 Lost in dreams..

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    Could also consider a head skim or different head gasket to alter compression ratio too.
    A buddy in the states had these exact cams too, they sounded lumpy like a hot rod lol but after adjusting the timing with the cam gears he said they idled much better, almost like stock actually.

    Thats a fair point! I did the same thing. I only went for a mild high comp at 11.8:1. The turbo youtube videos are swaying me though lol
    Pretty sure 255 fuel pump will be sufficient! Injectors my friend either went for 340cc or 410cc, if you find a set at a good price to grab. To have that extra room to play with. I think OEM K20 are 310? I would've thought that'd be sufficient too, maybe a tuner can advise
     
  6. Steve M

    Steve M Active Member

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    Wasn't too sure if I'd have much room to play with when it comes to skimming the head, I'll get the surfaces cleaned up and was thinking a standard thickness gasket.
    Yeah the seller said he got it idling pretty well, stable around 900rpm which would be fine.
    I've considered force induction but love an n/a b series!
    I'll have a look about and see what other people have run with this setup, are K24 injectors a larger capacity?
     
  7. Vtec6000

    Vtec6000 Super Moderator Staff Member Donator

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    I've setup 24XX cams on a b18c with Wiseco 12.5:1 pistons and there was no issues with clearance. Providing the cams are degreed correctly and Ecu tuned correctly it will idle nice and smooth.
     
  8. Steve M

    Steve M Active Member

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    Ahh that's excellent! I was actually going to see whether I'd be able to get you to map the car on one of your visits to Scotland!
     
  9. Pete180

    Pete180 Lost in dreams..

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    Spoke with my buddy running these cams. He's on 12.5:1 compression also + other mods, he made around 250hp 170lbs (in the US though)

    K24 injectors, umm I'm not too sure but I saw on google someone saying they're 310cc also
     
  10. Steve M

    Steve M Active Member

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    That's good power! What other mods did he have done? Just bolt ons or was there head work involved too?
    I'll have a look online and see what I can find, k series injectors would be a cheaper option, but would rather keep the duty cycle down with a larger injector if they'll be running near max duty
     
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  11. Pete180

    Pete180 Lost in dreams..

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    The usual bolt ons, valvetrain supporting mods and some head port/polishing he told me. Remember every dyno is different and figures will vary everywhere so take it with a grain of salt :) just rough figures to bare in mind.
     
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  12. Steve M

    Steve M Active Member

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    Ahh right that sounds good! Sounds similar to what I'll end up running. Of course, each engine will vary slightly too, more just looking to get an idea of what I can expect to see with this setup!
     
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  13. ColbyCol

    ColbyCol B16B EK9

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    Did you get the cams in the end bud?

    Imagine you were speaking with Will? I've had a few bits off him in the past and was interested in these too but they sold so quick!

    Be interested to follow your progress anyway dude... I'm currently building a fairly mild high comp B18C too and for a while I was agonising over a proper forged bottom end for a balls out set up but end goal is to go Rotrex next year / when I can fund it so just trying to have fun with what I've got rather than building it for pure n/a and then it not cooperating with boost lol.
     
  14. Steve M

    Steve M Active Member

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    Yeah I did mate, it was Will I got them off. I'd got in touch about quite a few things but they sold really quickly!

    I'll keep updating my progress as I go, got a few other parts lined up for when I'm paid, just going to gather parts over the next few months and get it built early next year.

    Looking forward to seeing how you get on with yours too, sounds like a sensible idea so I'd think you'll get on well with it!
     
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  15. Steve M

    Steve M Active Member

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    Was having a think about this today and was looking for some more opinions on a few aspects of the build as I'm not too sure about the best way to go!

    Decided to create a list of what I have/need to buy so I can budget etc.
    Stuck on what valvetrain to go for, was thinking of super tech flat face valves with their springs and retainers, then using oem valve guides. Seen a few bad reviews of the super tech stuff but that was all 7/8 years ago, don't see many recent posts about b18s!
    Also weighing up if I'd need to buy a fuel rail and adjustable pressure regulator, or if the OEM parts will provide enough flow?
    And finally got the moment, if there's much benefit in going slightly oversize with the pistons (81.5/82mm) or if that small an oversize won't be worth the amount that the machining will cost
     
  16. Pete180

    Pete180 Lost in dreams..

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    I've heard very good things about Ferrea valvetrain but this is when it starts to add up £ :( lol I've also heard decent things about supertech and skunk2, for the most part anyway. I'll ask my buddy what he's using with those cams.

    I went with 81.5mm myself just to try and up the size n torque wherever I could while it was out but that's me. My buddys on 82mm and he's got good torque for a b18. I hear it's advisable to go 81.5mm first so that you can go 82mm as a back up if anything goes wrong. With 82 there's little room to bore out again. Personal preference :)
     
  17. Steve M

    Steve M Active Member

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    Yeah I've just been pricing Ferrea stuff up and it's expensive! If you could do that then I'd really appreciate it dude!

    I was thinking 81.5mm myself, I thought standard sleeves could go to 83mm, but now know it's 82mm, would rather leave a bit of room for any work in the future should the worst happen at any point and it needs rebored. Cant imagine 0.5mm will improve power/torque a huge amount!
     
  18. Pete180

    Pete180 Lost in dreams..

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    Ah I spoke to my mate and he said he ended up using the rocket valvetrain it came with. Yeah it's not the cheapest stuff, squeezing high power out of an N/A motor. Obviously don't want cheap rubbish stuff of course failing on you!

    Yeah that's exactly what I thought too. Tbh not sure but neither would I really lol just wanted to squeeze every bit I could
     
  19. Steve M

    Steve M Active Member

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    Ahh I see, thanks for that! I just checked on their website which only shows parts for a B18a/b, guess the fitment would be the same?
    Yeah it's definitely not cheap, not worth cutting corners though!

    That's a fair point, I'll maybe just base it on piston availability when the time comes to buy them
     
  20. Steve M

    Steve M Active Member

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    What's the general consensus on the skunk2 valvetrain? Found a new unused set of retainers for a very reasonable price online, what are the valves + springs like? Not been able to find any reviews online!
     

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