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S14 Radiator ducting

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  • S14 Radiator ducting

    My VQ swaped s14 runs really hot @ the track. I think I need to improve the radiator ducting currently I have none. I don't have a lot of time before my next track day so I'm not looking for a solution that requires a crazy amount of fab.

    I still have the stock core support and and bumper beam, I'm not prepared @ this point to cut out the core support and build some complicated tube structure out front. I am OK with doing some cutting and notching though. I need a solution I can tackle in a weekend

    Anyone have pictures of what they have done?
    Here is the car in question




  • #2
    Oh no I posted in the wrong section. Moderators please move to the 240sx section.

    Comment


    • #3
      Take the hood spacers out and make sure the back of the hood is sealed to the firewall. Do you have an undertray? Are there any gaps around the side of the radiator, like where the AC condensor used to be? A lip and splitter would force more air through the radiator as well.

      Comment


      • #4
        as long as you're not posting crap FS in the non-classified sections, nobody's really going to bust your ballz on where it is. I just click 'view new posts' when I come, so I don't even know what section 95% of the threads are in..

        Anyway, ducting shouldn't be too bad.

        First.. drop the rear of the hood if you can. having the rear end jacked up like that doesn't help cooling at all- the area at the base of the windshield is a high pressure zone at speed and air gets shoved into the engine bay there, not drawn out. That raised rear works fine and looks cool for waxers and dyno queens, but is wrong for a track car.

        second.. you already have a decent guide up top. Just get you some flexible plastic sheeting and large-head rivets, then go to town behind the bumper and around the core support opening. It's fairly easy to see what needs to go where in order to block airflow between the bumper openings and the radiator.

        After that, you need a bigger radiator. fans won't really help on track unless it's a low speed (below 40mph) track. After that speed, there's enough air going in the front end of the grill that a radiator fan isn't going to help much.

        Hope that helps.
        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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        • #5
          Yeah, I just realized you probably can't put the rear of the hood down because of the VQ IM. However you do it, blocking that opening should be the priority. It only raises the pressure under the hood and makes the radiator less effective. Does the front vent sit behind the radiator? how much space from the lower portion to the front of the engine?

          Originally posted by Matt93SE View Post
          as long as you're not posting crap FS in the non-classified sections, nobody's really going to bust your ballz on where it is. I just click 'view new posts' when I come, so I don't even know what section 95% of the threads are in..
          I'm the same way, I had to check which section it was in and it's not really "wrong" where it is.

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          • #6
            I've been having an issue too the last couple track days with water temp slowly climbing, having to pull back into the pits or do a couple cooler higher gear laps.

            I have a Koyo radiator, stock shroud/fan, stock thermostat AFAIK. I actually think it's partially an exhaust leak in the engine bay, but I definitely don't have anything directing air and I'm sure having the condensor in still doesn't help air flow any.

            This thread seems to imply that vented hoods cause more harm than good? I have a non-vented and have though about putting a vent in somewhere before the hot side.

            Anyone use additives, like DEI radiator fluid?
            97 Kouki SR 240

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            • #7
              It depends where the vent is. Some areas on the hood are low pressure (generally front, except the vertical leading edge) and will let air out. Some areas are high pressure (back half) and let air in, raising the pressure underhood and lowering the pressure differential that forces air through the radiator.

              In the case of Arp's car, the front vent is probably quite effective, the raised rear is counter productive.

              Comment


              • #8
                Thanks for all the input. Unfortunately I can't drop the back of the hood it is literally resting on my intake manifold.

                I am running the stock undertray but am hoping I will have a splitter that runs back to the crossmember by the time I go out again.

                I will work on sealing the back of the hood the best I can though.

                The hood vent is behind the radiator but not really that far behind. I will add another further back to improve cooling.

                Plenty of space between the engine and radiator

                Comment


                • #9
                  You didn't mention if you have an oil cooler or not? Not sure if those nylon braided lines are for one in the picture above. I've found an oil cooler to be a big factor in holding steady/stable temperatures while lapping.

                  Adding ducting will help of course. Like mentioned by Matt, it's pretty obvious where ducting should be whenever you get the front bumper off.

                  If you need more flow, then I would suggest maybe cutting the front bumper and beam. I did this when I needed more air to pass through the intercooler and radiator.

                  My old S13


                  IG: l_fitzhenry

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                  • #10
                    Splitters that run to the back of the cross member stop air from being able to escape beneath the car after going through the radiator, and kind of seal up the engine bay with hot air... At least on more than a couple Honda's I've seen at the track, they ran into overheating problems directly after installing a splitter that went back to the front crossmember. Their solution was to do the hood vent thing that you've already got.

                    I'd personally make sure things are sealed up on the tops and sides of the radiator, and put a number of 1/8" holes in the thermostat if you haven't already.
                    '95 240sx

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                    • #11
                      I'd be concerned with the flow from that lower radiator hose. Maybe it's just the photo, but it looks tiny and a little kinked.

                      If you have the room, I'd make that vent deeper, rather than add another one. As in, cut the hood farther back toward the engine and curve the hood section farther down into the space between the engine and radiator.

                      Is that oil cooler in front of the radiator? You could move it to a side opening, since the heat released by that heat exchanger just goes right through the radiator.

                      Comment


                      • #12
                        The lower hose is 1 3/8" just like the in and out on the radiator the picture makes it look small. The near kink however is real. I might put one of those anti-collapse springs in it just in case.

                        Comment


                        • #13
                          Originally posted by LanceKA-T View Post
                          If you need more flow, then I would suggest maybe cutting the front bumper and beam. I did this when I needed more air to pass through the intercooler and radiator.

                          My old S13
                          Any pictures of how much you cut out of the bumper beam?

                          Yes those lines are for an oil cooler. Ill have to investigate how difficult relocating it will be.

                          Comment


                          • #14
                            Griffin radiator

                            I designed a new radiator for my 240. It has a internal oil cooler and is a double pass. I run a surge tank at the rear of engine compartment to keep the radiator full of water. If you like they will put radiator cap on top of rad. 240sxTTC is running one, you can see how his is doing.

                            griffin part # 9D-28912-01

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                            • #15
                              Originally posted by rioredstang View Post
                              If you like they will put radiator cap on top of rad. 240sxTTC is running one, you can see how his is doing.

                              griffin part # 9D-28912-01
                              After talking with Griffin in length about my application, they recommended not running a rad with an integrated oil cooler. My oil temp would not be reduced enough. KA engines at the high RPM I run generate a lot of heat. Instead I upgraded to a LARGE separate oil cooler, which I put in front of my KOYO. Oil temp was reduced from 270F (w/ Setrab 619) to 230F (w/ Setrab 934) but coolant temp increased 10F to 205F (I like coolant temp to be 190-200F). Ambient temp was 92F and track temp ~120F. To address the coolant temp I ordered a Griffin race rad, which has about 2x more cooling capacity than the KOYO. Also adding more ducting and switching from dual Altima fans to single SPAL 12" fan. Ducting is critical and for track only cars dual fans block too much air exiting the rad. Most race cars don't run any fans but I occasionally get stuck going to tech and want at least a smaller single fan.
                              Last edited by 240sxTTC; 07-07-2013, 09:53 AM.
                              NASA Time Trials TT3


                              BTW I work for Garrett

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