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Building an LS all-motor monster

Discussion in 'General Tech Articles' started by pissedoffsol, Feb 12, 2004.

  1. pissedoffsol

    pissedoffsol RETIRED

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    Sep 28, 2002
    Retirement Home
    Just because you don't have VTEC doesn't mean you can't romp on others who do. In fact, the LS motor is a very good starting point for building a good-power, streetable motor.

    Let's take it in 2 steps- head and block.

    The LS Head

    As we all know, the LS head has horrible flow ratings in comparison to a VTEC head. No problem. With some machine work, a port and polish job can up the flow a good amount.

    The intake manifold is also highly restrictive. A simple bolt-on upgrade to a Skunk2 unit will help get some power in there as well.

    Cams: how big do you want to go?
    Crower makes some good cams for a reasonable price. at nearly half the cost of VTEC cams, LS cams can be had, and still have a budget left over for the much-needed valvesprings and retainers. If you don't plan to upgrade the springs/retainers, I would not recommend taking this motor above the stock redline. Valve float IS an issue in the ls motors after redline with stock springs/retainers.

    For a street car, the crower 403's are an awesome cam. they still idel smooth, and yet, the lobes are taller than a jdm ITR's VTEC lobe. Hows that for some top end power? Now- you're probably wondering about torque. Sure- its going to "hurt" some low end by not having a small non-vtec lobe to use, and also, its going to eat some more gas.... but hey- this article is about making power- not how to drive 50 mpg. There is no reason why you still can't hit 20 mpg around town on a 403 cam.

    That takes care of the head- we have a good set of cams, and a breathing package.

    The Block

    "There is no replacement for displacement," says the V8 head. Well, while this is true- there are some other options to consider before you go around talking about boring and stroking.

    Honda cars have a vast array of parts available to them. The aftermarket is huge. But, there's also the oem Honda equipment.

    If you plan to keep the stock 81mm bore, there is a plethora of pistons availble to bump up your compression- thus, giving you tons more torque, and making your larger cam profile useable.

    JDM b16A P30 pistons are the weapon of choice for the all motor LS bottom end. Not only do they give you a good compression ration- they are cheap. They can be had for about $100 used. It will yelid a higer compression than Integra type R pistons do, and they fit fine- even with the 403 cams. The JDM p30's have a 6.93cc Piston Dome Displacement (PDD) per piston and will give 11:1 compression on a stock head (stock gasket thickness, stock mill, stock combustion chamber cc)

    By now, you're probably asking, why not the type R pistons? There are two reasons for this. Number one, frankly, all but the CTR are smaller.

    USDM P73 itr pistons have a 3.64cc PDD yielding 10.3:1 compression.
    JDM P73 itr pistons have a 5.96cc PDD, yielding 10.8:1 compression.

    The JDM PCT Civic type R pistons have the highest oem PDD at 8.63cc and will net you 11.4:1 compression. I can't say for sure if these will clear the 403 cam or not though, so make sure you clay the motor properly for clearences.

    Secondly, and most important, the ITR and CTR pistons will NOT fit on a stock LS rod. The B16 pistons, do. LS and B16 rods are much wider at the top than a gsr/itr/ctr. The opposite is also true: putting a gsr/itr/ctr piston on an ls/b16 rod will yield undesireable results.


    Well, wildbillhatchbac ran this exact setup before selling out for a bmw :)


    ported head, crower valve train
    crower 403 cams, stock cam gears
    jdm p30 pistons
    stock lS rods
    stock LS computer - no vafc or anything else of any kind
    stock header
    shit short ram intake
    hacked dc sports integra exahust to fit a hatch.



    which gave this dyno:


    and this a/f ratio for that pull:


    As you can see, it runs pretty rich from the mid range all the way up.

    And that was good enough for 150 whp. That's just behind gsr territory.

    With tuning, there is easily a 5-10 hp gain.
    With cam gears (which crower reccommends a degree tune), there is probably another 5-10 hp gain.
    with an aftermarket header and a real intake, probably another 2-5
    with more rpms from a tuned computer, theres a bunch of top end left. remember, this was the stock b18b1 ecu. (cams are said to be good for 8500)

    and after all that, on the dyno- bill had a bad pcv valve, which was making him suck in oil and smoke like a mo'fo :) So I'm sure that was robbing him some power.

    For under $2000 for the full swap, build, and parts, bill put together a hatch that walked HARD on b16 SiR powered hatches - on the stock ls tranny - and could easily hang with modded GSR's.

    Roughly, 160-170 wheel horsepower is obtainable with this setup and a couple bolt ons, runs on premium octane gas, and will suprise a hell of a lot of people when they ask you what you got- and you tell them, "LS". "What??!?!?!? no Veeetechk y0!?" "nope."

    Happy building :)

    Attached Files:

  2. wildbillhatchbac

    wildbillhatchbac the OG VIP

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    Sep 28, 2002
    thanks bro, awesome write up. i seriously couldn't have done better myself.

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