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  • restricting power

    So I got to drive my brothers 240sx in hpde event which has a stock ka24de. I enjoyed it way more than my ls1 that I was thinking about swapping back my old ka24de for a season.

    all I need to drop my old ka is new oe style pistons & rings $150, bearings $100, clutch kit (exedy stage 2 $500), harness ($100) and misc fluids ($100)to drop it in. over estimating itll be a total of $1000.

    but ive been also searching at ways to reduce my ls1 power and I cant really find much info on. I don't want to reduce my pedal travel. I could restrict the exhaust with a 3-2.5 reducer at the tail pipe. I read in places people putting a rectrictor in their intake but I have no success of finding a place to purchase one.

  • #2
    the easiest way is a simple flat plate restrictor behind the throttle body, or in the intake tube somewhere. it's pretty common in race classes to limit power this way. They do it in everything from Corvettes to spec miata.
    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
      Pedal stop is even easier. WOT on my LS1 is 79% and it makes 300whp. Much more fun than stock KA24DE! And the sounds is way better.

      August Mid-OH event - https://vimeo.com/180610525
      NASA Time Trials TT3


      BTW I work for Garrett

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      • #4
        Yea, a restrictor plate is common, but I don't think it's going to reduce power THAT much.

        You can just really short shift things and carry higher gears to get the same effect as quite a bit less power. It's also easier on the engine if you're shifting at 5k RPM vs. 6.5k RPM.

        What about a stockish SR swap? I always thought that was a fun amount of power, and you'll have great aftermarket support. Although it was pretty fun doing an event with a siezed up GT2871R. It was making about 90 rwhp (only able to pull about 80 kPa MAP at WOT due to sucking through the turbo and intercooler), as 1.6 Miatas were slowly walking me on straights.

        But you definitely lose throttle modulation skill when you almost can't spin them up no matter what you do, so keep that in mind. Momentum driving is a skill, but so is driving a higher HP car fast around a track.

        The cool thing with a turbo is you can vary the power level quite a bit on track. Running 7 psi vs. 14 psi feels very different, almost like a different car.
        '18 Chevrolet Volt - Electric fun hatch for DD duty!


        DefSport Koni Sleeve and Spring Perch Buy!!!
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        • #5
          originally all i found on ls1-tech was this which says asa on it


          and i couldn't find anywhere that sold something like that. that person bought his on ebay

          but after searching for the spec Miata restrictor plate, i found this



          that seems very simple to make for the ls1 and create few with different size holes trying that out.

          i want to try to avoid an sr swap since that would cost a whole lot upfront when i only want to do it for 1 season. the ka i already have my old blown swap with cracked ringlands.

          i hated being part throttle here and there, slowly bringing it back to WOT, but with the stock ka i was straight to the floor for a lot of it lol. but you are right def, I never thought about the whole throttle modulation being a skill until you mentioned it.

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          • #6
            6mm bolt/nut and some washers and you can make a pedal stop with varying whp output. Doesn't get any easier!
            NASA Time Trials TT3


            BTW I work for Garrett

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            • #7
              Originally posted by clotuning View Post
              So I got to drive my brothers 240sx in hpde event which has a stock ka24de. I enjoyed it way more than my ls1 that I was thinking about swapping back my old ka24de for a season.

              all I need to drop my old ka is new oe style pistons & rings $150, bearings $100, clutch kit (exedy stage 2 $500), harness ($100) and misc fluids ($100)to drop it in. over estimating itll be a total of $1000.

              but ive been also searching at ways to reduce my ls1 power and I cant really find much info on. I don't want to reduce my pedal travel. I could restrict the exhaust with a 3-2.5 reducer at the tail pipe. I read in places people putting a rectrictor in their intake but I have no success of finding a place to purchase one.
              This is a bit OT, but if you do do this, an Exedy stage 2 clutch kit is totally unnecessary on a stockish NA KA for road racing. All endurance guys just run an OE replacement kit and they last awhile. Just get a quality one and make sure your clutch pedal adjustment is good. As a matter of fact, I don't understand why anyone puts higher capacity clutches on NA cars that are near-ish factory power/torque levels and are road raced. I have an ACT unsprung 4 puck disc and HD pressure plate on my S14 VQ from the previous owner and I want to bludgeon it with a viking battle axe whenever I'm maneuvering in the pit, paddock, garage, trailer, etc. If the motor was making a good deal more torque, sure, but it's not. Save your money.

              Back on topic:
              It's one thing holding back to slow down and another to feel like you're going all out, but going slow down the straight because of power and torque limitations. The latter is much more satisfying because you're still wringing the snot out of the car. I can understand your desire to do this.

              But, Def makes a good point about modulation skill. I HPDE'd a GD STi (305-350whp and spoiled with AWD) for almost a decade then started wheel-to-wheeling in lower powered RWD cars (Alfa Romeo Milano then my S13 with KA24DE). That transition was simple and super enjoyable. Going from such an easy and very fast car to drive fast to those was still very rewarding.

              Now I have an S14 VQ and compared to my friend (very fast) who's been driving and tracking E36 M3's, I'm a spaz, as can be seen in this comparison vid (I'm top):
              https://youtu.be/bATszqztrko

              Regardless, that's a lot of effort to slow down after having an already amazing setup it seems. If you're always going with your bro to HPDE's, just swap a session or two with him? Otherwise, I think putting a pedal stop is by far the cheapest and quickest solution as mentioned here.

              When is your next track day?
              Core4 Motorsports
              CLICK HERE for Wilwood FSL6R Radial Bracket & Rear Wilwood BBK GROUP BUY
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              • #8
                pedal stop is also a very easy way to limit power and is easy to remove later if you want. I have a throttle stop on my S14 (to prevent over-extension and damaging TB/cable) and the bolt came loose on it a little-- I can use my toe to just flip a piece of metal out of the way and the throttle stop is gone.
                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
                  Honestly, I think it's better to have less power when learning, as it's less intimidating as you approach those limits. That said, lots of Miata guys think they're the bees knees in everything, that then jump into a car with power and really struggle with it. I've heard things like "it doesn't put down power well etc." "the brakes need to be better" - it's all a symptom of being used to a car that can't spin up the rear tires, and doesn't get much speed on a straight.

                  That said, you do have to learn to drive a momentum car at some point. A stock SR with a T25 isn't too far from there, which is why I mentioned it. I also think it's fun to learn to drive a turbo car balls out. The slight non-linearity of it does cause it to be a bit more of a thinking exercise on getting the most out of the car in some circumstances.
                  '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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                  • #10
                    The thing with the pedal stop is I don't want to lose any pedal travel. I don't want to end up getting used to the shorter travel and then when I remove it my muscle memory has me going 80% until I realize I have to press it down more. I like to gokart alot at pole position (electric karts) so finally I went to a legit karting track and got to use their kart that had rotax engines in them . After a few laps I realized I wasnt even giving full throttle because I was adjust to the shorter throttle pedal movement in the electric kart. That's what I want to avoid.

                    And gil I'm going to njmp Oct 15-16

                    And yea Def you're right, wit the lowered power car I was way more focused on where to turn in and track out. With my setup now, I would be so focused on figuring out my braking point that I would screw up turning in. Because my turns are sometimes sloppy my speed is different from before which now Im stuck trying to figure out my braking point again. It creates a domino effect. Don't get me wrong when my instructor tells me what to do I do fine but once he shuts up to see how I'll do on my own, im not as consistent.

                    Im going to try to reduce the power on thr intake side and see how I feel about it. I'll post up dyno results of how much each mod dropped the hp.

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                    • #11
                      Just short shift then. Shifting at 4.5 or 5k RPM is going to make the engine run cool, and you'll still get to focus on smooth power application on track out.

                      Honestly, I wouldn't be too quick to change the car up to make it easy for you to pick up as what sounds like a pretty novice student. The consistency will come with seat time, and with that confidence and speed.

                      Just don't wrap it out to redline on every shift, and if the instructor asks you what you're doing, say you're taking it easy on the engine and focusing on X, Y, and Z for the weekend, not seeing how fast you can go on the straights.


                      I've taught a lot of guys with retard-o HP setups that are common on modern cars. They do fine after they finally wrap their heads around what the car can do. It obviously takes way more seat time to work up to the limit of a new Z06 than a clapped out Miata, but I'm of the opinion that if you focus on the fundamentals and work on them, you'll get there.
                      '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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                      • #12
                        Originally posted by clotuning View Post
                        The thing with the pedal stop is I don't want to lose any pedal travel. I don't want to end up getting used to the shorter travel and then when I remove it my muscle memory has me going 80% until I realize I have to press it down more. I like to gokart alot at pole position (electric karts) so finally I went to a legit karting track and got to use their kart that had rotax engines in them . After a few laps I realized I wasnt even giving full throttle because I was adjust to the shorter throttle pedal movement in the electric kart. That's what I want to avoid.

                        And gil I'm going to njmp Oct 15-16

                        And yea Def you're right, wit the lowered power car I was way more focused on where to turn in and track out. With my setup now, I would be so focused on figuring out my braking point that I would screw up turning in. Because my turns are sometimes sloppy my speed is different from before which now Im stuck trying to figure out my braking point again. It creates a domino effect. Don't get me wrong when my instructor tells me what to do I do fine but once he shuts up to see how I'll do on my own, im not as consistent.

                        Im going to try to reduce the power on thr intake side and see how I feel about it. I'll post up dyno results of how much each mod dropped the hp.

                        Dude, I think you're over analyzing this. Because you are so worried about getting muscle memorized, it won't happen! You get how it works?? Just like an anxious person is never late for something because they're so worried about being late or screwing up. You're going to have to adapt at some level.

                        Or do what Def said with the short shift. Can you lower your rev limiter easily? Set a real limit so you basically forced to shift at a lower engine speed.
                        Core4 Motorsports
                        CLICK HERE for Wilwood FSL6R Radial Bracket & Rear Wilwood BBK GROUP BUY
                        S14 VQ AER Endurance Racing Team

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                        • #13
                          sounds like a good learning opportunity tbh, embrace the power of merica

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                          • #14
                            Originally posted by gills View Post
                            Dude, I think you're over analyzing this. Because you are so worried about getting muscle memorized, it won't happen! You get how it works?? Just like an anxious person is never late for something because they're so worried about being late or screwing up. You're going to have to adapt at some level.

                            Or do what Def said with the short shift. Can you lower your rev limiter easily? Set a real limit so you basically forced to shift at a lower engine speed.
                            I'd personally want the full rev range for passing on straights etc. People in lower HPDE groups are in general pretty bad on giving pointbys early in passing zones.
                            '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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                            • #15
                              To finish the thought - if you don't want to go fast on straights - DON'T GO FAST ON STRAIGHTS. No one is out there pushing your foot down on the gas making you wrap it out to redline.


                              Driving a slow car fast is fun, but I've never been out there thinking "I want a lower powered car," so maybe I'm a bad guy to take advice from.
                              '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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