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  • ka cam question

    First off sorry if this has been answered. searched and have read many threads.

    Refreshed ka and put bc 264/264 in with plans for turbo. that never happened and plans changed. started autox 2 years ago and its obvious my low/mid is lacking. The courses here tend to be pretty fast, quite a few having to go into 3rd. Through all the threads I have read I'm finding mixed reviews on doing the 248/232 combo. So my question is what would be the best option? keep 264/264, hot cam 248/232, back to stock 240/248?

    s13 with 14 ka. still have the swirl valves, obx 4-2-1 header, and 3" catback.

    tl:dr - n/a ka - keep 264/264, switch to 248/232, or stock 240/248 for fairly fast autox courses.

    Thanks

  • #2
    I run 248/248 in my car. power doesn't pick up until above about 4500, then it pulls to rev limit at 6700.

    Where you located? I haven't seen any 240s AutoXing around Houston in a while. would be happy to swap around and play with cams if you want to try them.. for your case, best thing to do would be to collect some run data and log RPM/gear/speed. then look at some dynos with various cams and see which ones have the most area under the curve for the speeds you're running.
    Originally posted by SoSideways
    I don't care what color they are as long as they are LONG AND HARD.
    '04 G35 Sedan 6MT- The DD
    '96 240SX- The Track Toy

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    • #3
      I'm in Memphis so unfortunately cant take you up on that offer hah. There havent been any 240s out here doing autox either. I have tried looking for dynos a few times but all the threads I find come up with broken links to the dyno sheets. As far as my current 264/264 i can find zero dyno/info with them on a n/a engine, only minimal ka-t, and always lead to just doing the hot cam. I do have a set of 13 and 14 cams laying around so i could try a couple different combos. only one I cant do is 248/248 unless I go find another 248. I will do the rpm/gear/speed but will have to wait till next month when it finally warms up some around here. If you have any tips on what I could search that I might now have tried that would be great.

      thanks again

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      • #4
        I did the hot cam swap and autocrossed my car all last year in NNJR and NEPA scca. S14 engine in S13, no emissions or swirl valves. Car made 140hp 160tq and the response on course is good except when coming out of hairpins where I don't like downshifting.

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        • #5
          Just as a talking point, there's a corner at my local track that I can take in 2nd or 3rd gear that opens to a long straight where I run to redline in 4th.

          I've come out of that corner in 2nd and 3rd gear dozens of times, and I still have to shift to 4th in the exact same spot on track- within 10 ft at 80mph.. That tells me that even when I feel like it's off the cam in 3rd, it's not worth the effort to downshift to 2nd and "waste time" with the shifting. it's also a lot easier on the transmission not having to downshift to 2nd at 5500rpm and then right back to 3rd.

          just something to think about when you're discussing power bands and 2nd/3rd gear turns. for autoX, it's a bit more of the opposite end though-- 3rd gear is the exception vs. the rule whereas road racing spends more time in 3rd than 2nd.
          Originally posted by SoSideways
          I don't care what color they are as long as they are LONG AND HARD.
          '04 G35 Sedan 6MT- The DD
          '96 240SX- The Track Toy

          Comment


          • #6
            Originally posted by Matt93SE View Post
            Just as a talking point, there's a corner at my local track that I can take in 2nd or 3rd gear that opens to a long straight where I run to redline in 4th.

            I've come out of that corner in 2nd and 3rd gear dozens of times, and I still have to shift to 4th in the exact same spot on track- within 10 ft at 80mph.. That tells me that even when I feel like it's off the cam in 3rd, it's not worth the effort to downshift to 2nd and "waste time" with the shifting. it's also a lot easier on the transmission not having to downshift to 2nd at 5500rpm and then right back to 3rd.

            just something to think about when you're discussing power bands and 2nd/3rd gear turns. for autoX, it's a bit more of the opposite end though-- 3rd gear is the exception vs. the rule whereas road racing spends more time in 3rd than 2nd.
            That's my experience too, even lugging 3rd in an SR where I'm off boost at the apex. The STACK dash agrees that it's no faster, and in many cases you are a bit slower unless you're brutal on the transmission to speed shift it.
            '18 Chevrolet Volt - Electric fun hatch for DD duty!


            DefSport Koni Sleeve and Spring Perch Buy!!!
            http://www.nissanroadracing.com/showthread.php?t=5902

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            • #7
              matt on your 248/248 did you do adjustable gears or just the 4 tooth way?

              Have you ever tried doing the 240/232? I was reading DjPantsSpecR thread on nico, and there was tloof who explained exactly why each combo worked/didnt work. He kept referring to 240/232 being best for low and mid range while still not falling on its face at 5kish. While djpants said he always went back to 248/232 and the 240/232 was 2nd. Any input on that?

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              • #8
                No gears here. Just offset the teeth by whatever it took to align everything at TDC.

                I installed a 248 on the intake first, stock exhaust. It was more peppy than the stock s14 cams, but it really livened up on the top end with the second 248 cam. I'm not worried about performance below 4500rpm since I'm never below that while on track. If I am, then its time to downshift.

                And no, no dynos of this setup. Never bothered.
                Originally posted by SoSideways
                I don't care what color they are as long as they are LONG AND HARD.
                '04 G35 Sedan 6MT- The DD
                '96 240SX- The Track Toy

                Comment


                • #9
                  well I went with the 240/232 and had an autox today, which ended up being the fastest layout I've been on, getting up into 4th. Can definitely tell the torque is back in the low and mid range, and its falls on its face at 6k. Going to keep it for a few more events that are hopfully not as fast. Thanks again for the help.

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                  • #10
                    I don't Road Race or Auto-X due to no Track, but FWIW I had the 240/232 Setup in my 14 and it did give a nice bump in the mid range while making the top end very slightly stronger but still falling on its face after 5600~.

                    In my Fastback I have now with a 14 KA running 248/248 Cams @ 4 Teeth + 7.5* Estimated Drilling my own Gear Using a Print out/Over lay of the JWT Gear. It's like Matt said, Low/Mid is about the same as a 240/248 Setup, but really comes Alive above 4500 and rips all the way to 7100 on a Stock S13 ECU with no hesitation. Power doesn't seen to fall till early/mid 6000 which is perfect to be shifting near 7 to put you back in the sweet spot.

                    Cars down right now due to a Blown Clutch but am looking forward to getting it Power Checked so hopefully have some solid info later.

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