1. This site uses cookies. By continuing to use this site, you are agreeing to our use of cookies. Learn More.

ls vtec build question

Discussion in 'Engine Building' started by vtecsir1, May 24, 2005.

  1. vtecsir1

    vtecsir1 Senior Member

    Messages:
    3,313
    Likes Received:
    17
    Joined:
    Dec 5, 2002
    Location:
    Orlando, FL
    im in the process of an ls vtec build, i have a b18b and a gsr head. my question is would you guys think 11.6:1 is a safe comp ratio for daily driving and longevity? i want to run 11.0:1 but its easier to find jdm pistons for a more resonable price. tuning will be minimal and most likely be a chipped p28.

    i plan to put jdm r pistons or usdm r pistons in the setup with a 3 layer head gasket.

    just looking for some input since i know some of you have done this before.

    thanks
     
  2. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    :yes:

    I'd use an SCE copper head gasket though. You can adjust your cr by the thickness you order. 11.8:1 is a totally fine cr for everyday driving but a .040 head gasket will net you 11.5:1.

    Use this
     
  3. vtecsir1

    vtecsir1 Senior Member

    Messages:
    3,313
    Likes Received:
    17
    Joined:
    Dec 5, 2002
    Location:
    Orlando, FL
    yeah i used c speed racing and got 11.57:1 using a stock gasket and p73 pistons, i will go that way then if its easily handled.
     
  4. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    You will run into trouble trying to fit the ITR pistons onto the LS rods, and an aftermarket rod will not work.

    The LS rods will have to be machined to fit those ITR pistons on them, you are much better off going with the P30 pistons and a .040 head gasket. The p30s will fit on those LS rods with no machining. The LS rods are the weakeast point to begin with, and shaving them down doesn't exactly add to their stength.

    LS and B16 rods will take the LS and the B16 pistons with no modification

    Gsr/itr/ctr rods will take GSR/CTR/ITR pistons with no mods.

    You are stuck using the LS rods in that motor. The Gsr/itr/ctr rods will not work, which in turn limits your piston choices. Unless you go forged like I did. :D Then the posibilites are endless.
     
  5. hybrid89

    hybrid89 thistownsucks...

    Messages:
    1,821
    Likes Received:
    1
    Joined:
    Jan 8, 2003
    Location:
    SoCal



    I couldn't have said it better myself. iwent through the same deal and ended up going with a forged piston and rod setup.
     
  6. vtecsir1

    vtecsir1 Senior Member

    Messages:
    3,313
    Likes Received:
    17
    Joined:
    Dec 5, 2002
    Location:
    Orlando, FL
    why wont the itr rods work? rod stroke? i did not know this, and yes i know about the machining to make the itr pistons fit on the ls rods.
     
  7. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    Correct. The ITR/GSR rods are too long, they will put your cr in the 15s. (I actually always read they were too short but Scat and Eagle say they are longer)

    The problem with the machining of the LS rods is that the cost of getting them shaved and shot-peened works out to damn close to the price of a set of forged h-beams. Well, maybe half, but your talking about a piece of shit stock LS rod that has been made structually weaker, VS a forged H-beam rod. There is no comparrison.

    Herein lies the problem. Forged aftrmarket rods and pistons use a floating wrist pin, while stock rods and pistons use a clip-type wrist pin. To my knowledge there is no way to use a stock piston with an aftermarket rod, or vice versa.

    So now you are either spending $300-400 on rods and $450-$550 on pistons to go forged,

    OR

    you can run the stock LS rods with P30 pistons and use your headgsket to adjust your compression. It's all up to your budget and ultimate goals for the car.

    Personally, I want my SI to run low 12s so I knew that forged internals with nitrous was going to be needed. LS rods are just shit past 250 hp IMO. If you just are building a healthy daily driver than say fuck it, and go with oem shit.
     
  8. vtecsir1

    vtecsir1 Senior Member

    Messages:
    3,313
    Likes Received:
    17
    Joined:
    Dec 5, 2002
    Location:
    Orlando, FL
    well im looking for close to 200hp to start and after that will depend on how happy i am. maybe i will just go with ls rods and pistons.
     
  9. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    Bah, fuck that. The LS pistons won't get you anywhere near 200 hp. The JDM B16 P30 pistons fit on the LS rods with no mods and net @ 11.8:1 in a stock deck LS/VTEC. Add a good valvetrain and some nice cams and you'll easilly be at 200 wheel hp. :thumbsup:
     
  10. noobvang

    noobvang Senior Member

    Messages:
    382
    Likes Received:
    0
    Joined:
    Apr 30, 2003
    Location:
    Twincities, MN
    Just use my sig for reference if you need an idea to start with. Have'nt dyno the bish yet but pretty close tho. Just built the head up, you'll get to 200 hp no problems. Beating GSR hatches like nothing in my 4dr.

    Hope this helps in your choices, and make sure you've got good gas to run with. 93 is the best choice, 90 is pusshing it tho.
     
  11. vtecsir1

    vtecsir1 Senior Member

    Messages:
    3,313
    Likes Received:
    17
    Joined:
    Dec 5, 2002
    Location:
    Orlando, FL



    the compression is what is going to help with the power not the name of the piston in this case. i can make decent power off the ls pistons to start, i dont feel like dumping tons of money into a bottom end that is fairly new still. i dont plan on pulling this motor past 8 ever and will be daily driven and occasionaly autox so i dont see the need in building up the block. i would like to just run a 2 layer head gasket which would put me at 9.9:1 which is almost at what a stock gsr is at.

    anyone know of a good 2 layer gasket for an ls?

    setup will be a

    98 b18b block
    00 gsr head
    etc mods.

    i may possibly even just get a gsr block instead still debating though.
     
  12. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    :shrug:

    I'm just trying to help. The LS pistons have no relief for the valves. If you run any sort of cam what-so-ever then you are going to smack your valves with those LS pistons.

    Also, you don't want a 2 layer headgasket. Spend the 60 bux and buy a copper headgasket. You will be glad you did later.
     
  13. formby

    formby learning in progress

    Messages:
    5,735
    Likes Received:
    23
    Joined:
    Feb 19, 2003
    i have pr4 .020 over cast pistons in my lsv...and its quick.....14.2@98.6mph and i suck at launching (faster than gsr crx) and i plan on using an 80 shot of juice..on 93octaine... and i did a comp test and it was 210 all across the board
     
  14. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
  15. formby

    formby learning in progress

    Messages:
    5,735
    Likes Received:
    23
    Joined:
    Feb 19, 2003

    lol..i just wanted you to see that you were wrong
     
  16. formby

    formby learning in progress

    Messages:
    5,735
    Likes Received:
    23
    Joined:
    Feb 19, 2003

    reading it againg i would've said the same thing,,,,but youre still wrong :p
     
  17. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    Bah, you aren't running any cams. Slap some Jun 3s in there and tell me if you smack a valve. :)
     
  18. formby

    formby learning in progress

    Messages:
    5,735
    Likes Received:
    23
    Joined:
    Feb 19, 2003
    sure i can accept that...but you said

    If you run any sort of cam what-so-ever then you are going to smack your valves with those LS pistons.
     
  19. sohcslammer

    sohcslammer Senior Member

    Messages:
    2,193
    Likes Received:
    0
    Joined:
    Apr 11, 2003
    Location:
    Bay Area
    <_<

    I meant, any kind of cam what-so-ever, MORE than stock. And no, what I said is not entirely true. You could probably get away with the CTR or ITR cams, but any more than that and it's piston smacking time. :(
     
  20. formby

    formby learning in progress

    Messages:
    5,735
    Likes Received:
    23
    Joined:
    Feb 19, 2003
    yeah.. but by looking ls pistons for hours at a time i think ls pistons are fine... because you can switch to agrassive cams in a stock ls...however my friends gsr improves dramatically by switching to ctr cams and pistons.....i plan on doing the same....best bang for buck.imho
     
Verification:
Draft saved Draft deleted

Share This Page