No announcement yet.

SR20 build options

  • Filter
  • Time
  • Show
Clear All
new posts

  • SR20 build options

    I have been driving and doing events with my S13 240sx with a stock turbo ~250whp sr20 for a few years now and decided its time to upgrade the power.

    I am kinda split between what direction to go in with the build so wanted to see if I could get some opinions since folks on this forum have probably tried both options I am considering.

    Option 1:
    Rebuild engine: (current engine is low on compression so needs rebuild), do a full EFR 7163 kit AEM ECU, injectors etc. Good for around 400whp

    Option 2:
    Rebuild engine: (current engine is low on compression so needs rebuild), do a GTX2867 turbo on stock mainfold, upgrade injectors, cams and tune. Good for ~ 350whp. Tune using current Nistune setup.

    Is the EFR+AEM significantly better for a 350-400whp setup? There is a step cost increase (Almost double) and I am looking at this purely as $$ vs. enjoyment.

    Once I priced everything out, seems like the EFR + AEM is nearing LS1 territory which is also tempting... That would be "easier" horsepower but not sure if it would be as much fun. I don't wan't to start another SR vs. LS1 discussion, IMO they both have their pros and cons, for me I really want to experience rebuilding an engine and the SR20 seems like a good platform to get the experience. If I really wanted an LS track car a C5 z06 would probably be a more cost effective option.

    A 3rd option could be EFR setup but keep the Nistune. Are there significant benefits to going with the AEM in a car that sees 80-85% street driving?

    -Goal for this car is to have a fun track car that is enjoyable on the street.
    -Minimize time working on the car/ setting it up to maximize time driving it and reliability.

    I have an AP2 s2000 as the "daily driver" but I find my self driving the 240 more often because its more fun and so far just a reliable. Being able to enjoy the car on a daily basis is definitely high on the priority list!

    Last edited by ZainRacer; 11-30-2017, 06:13 PM.

  • #2
    Option (C)

    EFR on bottom mount manifold (6758 is a little more than 1K out the door). Convert to V band downpipe and profit. 6758 is good for 400WHP with a good chunk of headroom remaining. It also fits on a stock manifold (however, a Tomei will fit better or if you can find a used FR, even better)

    At this point, unless you are shooting for "all of it" a GTX would be a close second

    This is strictly from a $$$ standpoint. I am 100% in the EFR camp, however, I also realize the realities of life, and double the price for only 50 WHP in a non competitive environment may not be worth the expenditure.

    However, the GTX simply does not compare to the EFR apart from peak output.

    P.S GTX is good for 400WHP as well.


    • #3
      Thanks for the feedback!

      For ECU turning, would AEM offer significant benefits over Nistune? E85 is not readily available near me so I would be sticking to 93 octane pump gas for what ever setup I end up with.

      I know the GTX can do 400whp but would that be feasible on 80-90 degree track day running pump gas? With either turbo I wanted to keep it in a very safe zone for track use.

      I would rather have 350whp and just focus on driving and enjoy that vs. push things closer to the limit with a smaller margin of error.


      • #4
        AEM (infinity) is without a doubt an much more capable ECU than the Nistune. Will you use all the features and failsafes?? That is up to you to decide.

        GTX will do 400 on pump. Billet wheel is impressive. Lots of heat however from the turbine side if you are running anything that favors spool vs outright power.

        350WHP, stick with NIstune and be done. GTX or bottom mount EFR, lots of fuel, profit.

        It is very easy to go down the rabbit hole of "while I am there" when talking about the EFR. Stock based manifold, properly support (due to pulled out studs), inconel hardware, run stock based piping, and profit. Watch for heat, back pressure.


        • #5
          Honestly, the biggest problem with the stock ECU is I've never seen a ROM tune that didn't go pig rich for a second on a SHARP throttle input (like 0-100% TPS within say 0.1 sec) and large injectors. Maybe Nistune has fixed that by now, but every ROM tuned car I've seen did this.

          But if yours works really well for track usage, I'd personally go FR twin scroll top mount + EFR 7163 and keep your Nistune. The twin scroll manifold and housing DOES help response, and the 7163 has very low inertia and great response low end on an SR. It being top mount generally makes working on the turbo much easier, which is key for a track car. I had to weld my turbo to my manifold when driving hard. All the turbo 4 cyl guys that drive hard in TX have the same issue (Miata, SRs, Mazdaspeed guys etc.). Top mount T4 completely eliminates the issue and you can work on the turbo as quick as you can pop open the hood and grab a tool.

          The EFR, at least TS T4 7163 that I can speak to, changes the character of the car. I went from a T25 on stock manifold turned up to death for track usage (11 psi, IATs were not happy...). A 7163 TS on the exact same setup had a BETTER transient response, QUICKER BOOST/SPOOL THRESHOLD, and at the same 11 psi I picked up over 14 mph on the front straight of TWS (121 to 135+ mph, was running out of gear on a 4.63). It's really a wonder turbo compared to the old 80's/90's technology that most people are using on the SR. Honestly, I think a 7163 on an SR20DET with cams and a decent bottom end can do 450+ rwhp on track. The thing has flow for days...

          The GTX isn't much better. Sure, it'll put up some decent power numbers, but the experience isn't THAT different than the older GT turbos as they're still high inertia, using the same old ass turbines etc. The super new Garrett stuff promises better performance at WAY beyond EFR prices and are not drop in friendly for an SR it seems, so screw that.

          An EFR 6758 on the stock manifold fits with some work, but honestly, you need a new DP, so why not go to a nice TS top mount mani at the same time for just a bit more? To me, if I wanted 400+ rwhp on the track, it's the only option.

          Otherwise I'd just be happy with like 250-260 rwhp on the track and run an old ass T28/GT2560R.
          '18 Chevrolet Volt - Electric fun hatch for DD duty!

          DefSport Koni Sleeve and Spring Perch Buy!!!


          • #6
            I think "while I am there" is exactly how I am approaching this... it really is a rabbit hole!! lol

            The Nistune gets the job done but the bells and whistles on the Infinity are attractive. Being an engineering I think I would enjoy playing with that but it probably isn't a need right now, more of a nice to have. The failsafes would be a nice insurance on the new build motor.

            I am at a point where its getting harder to find time to work on the car so I am motivated to "future proof" it and not have to sell parts and lose $$ to upgrade stuff in 1-2 yrs...
            Decisions.. Decisions..!


            • #7
              IMO, you already have the Nistune setup, and it's something that doesn't require "extra work" to implement at a later date. Therefore I'd separate it from the "built engine/new turbo" decision.

              Either the engine and/or turbo are BIG things to change later, so make that choice now, and you can make it work with Nistune. Maybe you need later injectors to support the power - but that's not a big deal.

              If you want an Infinity in a year or two, you can do it. Don't get me wrong, it's way nicer than a ROM tune setup, but it does take some extra time to setup.
              '18 Chevrolet Volt - Electric fun hatch for DD duty!

              DefSport Koni Sleeve and Spring Perch Buy!!!


              • #8
                Thanks for the feedback. I am leaning towards that. It would be nice to "future proof" the turbo & engine. It seems like a 6758 on a stock mainfold would spool similar to a TS 7163... right? so wouldn't really be making a compromise if I only run it at ~350whp for a while.

                The main thing drawing me to the Infinity ECU is getting 20% off on it if I pair it with a wiring specialties harness. (Black Friday deal but I can cancel because they haven't started building the harness yet). I could do the bare minimum MAP + IAT (also 20%off) for now and add in the other features down the road to keep cost down on the ECU side. That would probably still be a step up from Nistune. I figure I could probably sell my current Nistune, z32 MAF and Wiring Specialties harness for ~500

                450whp possible on a S14 SR20DET with just bottom end and cams? Stock intake mainfold and head...?
                I guess I would be worried about the transmission at that point. I have heard they don't hold up well above 350whp but that's probably drift guys clutch kicking or drag racing..?

                Would a stock trans be OK at ~400whp on track?


                • #9
                  1) The 7163 will spool better than a 6758 on stock manifold (if the 7163 is T4 TS and paired with a properly designed manifold). I had a blast on my stock manifold 6758 @ 300WHP and 12-13 psi. I would step it up and go with a Tomei or similar. But as mentioned, watch out for manifold-turbo. Support the manifold/turbo like factory and just drop a few tacks. Also run inconel hardware and you are good to go.

                  2) 450WHP is doable on a cammed stock head SR, but that sounds a themonuclear bomb ready to go off (stock S14 has smaller ports than the S13 btw). Cramming all that boost down the SR20DET's throat will make even Jenna Jameson blush. I wouldn't recommend this method to make 450WHP for trackdays.

                  3) Transmissions will become a consumables like gasoline........

                  4) Yep, selling those items and going infinity is not a bad idea. I would keep the 300ZX MAF to get you up and running quicker. You could probably get more if patient, but not much as Nistune is up against likes of Nismotronic, Power FC (not sure why the hell anyone would use such an archaic device....., etc)


                  • #10
                    I never dyno'd it at the power level, but I'm pretty sure my car made at or over 400 rwhp at various times on the same SR trans the whole time. It made 300 rwhp on the dyno on a GT2560R... and then made way more than that with bigger turbos and a sweet VE head on a built bottom end.

                    A 7163 will do 450 rwhp on an S14 SR with some decently big cams and a GReddy intake plenum. Keep in mind something like a Full-Race T4 manifold + a 7163 will breathe WAY better than a GTX anything on a stock SR manifold. Like I said, exact same boost on the EXACT same engine my car picked up 14+ mph on the front straight of a track and was basically on the rev limiter on stock S15 SR cams at 7.2k RPM. It picked up probably 60-70 rwhp at the same boost due to the better flowing turbine manifold and way bigger turbine wheel with the bigger twin scroll turbine housing.

                    400 rwhp on a GTX2867R or something like that? Absolute time bomb on the track. 400 rwhp on a 7163 T4 setup? No sweat, probably has plenty more to give.

                    EVO and STi guys push them well over 500+ AWHP in time attack mode, so 450 rwhp on an SR is not pushing it hard at all given it has like 5-8% less drivetrain loss. That's like 420 awhp on an EVO, which they consider stock turbo at 30 psi territory almost... hahah

                    But seriously, no reason to be overly conservative on the power level. The 7163 lowers the knock threshold by letting the exhaust breathe way better, so having to run low boost because you've got a restrictively small turbo on a crappy stock manifold (in comparison) does not really apply.
                    '18 Chevrolet Volt - Electric fun hatch for DD duty!

                    DefSport Koni Sleeve and Spring Perch Buy!!!


                    • #11
                      Wanted to updated this thread incase someone else is considering a similar setup. Also looking for feedback on cams!

                      I ended up going with the 7163 TS setup from fullrace.
                      I don't think there is really a "wrong" choice here, and mostly comes down to personal preference.

                      My thought process was to get a turbo setup that I would never really want to upgrade. This seemed like a good 350whp option that is 500whp capable if I want to do that.

                      It also seems like it will be the most responsive compare to the T25 6758 or
                      GTX2867. This is important to me on a fun street/track car.
                      It will also be the easiest to install (all bolt in!) and probably be very reliable.

                      I went with the AEM setup for the ecu for the added fail safes and because it will be fun playing with the bells and whistles that the Infinity offers. Nistune would have probably been fine but this was just personal preference.

                      Plan is to get the ecu and turbo on my current motor and get everything setup/running properly at a conservative boost level (12-14psi) then when I want more power I can do the motor build on the side (possibly go with a VE head) Due to time constraints I don't think I will be able to do the build until mid/end of next year.

                      What would be a good cam for this setup on an other size stock S14 SR20 (stock intake mainfold/throttle body)?
                      I have narrowed it down to Tomie Pon cam, JWT S3HL (thats what JWT recommended), or JWT S4.

                      Here is duration/lift info. for a few cams for reference.

                      Cam - Duration - Lift (in) - Lift (mm)
                      JWT S4 HL - 266 - 0.484 - 12.3
                      JWT S3 HL - 260 - 0.457 - 11.6
                      JWT S3 - 260 - 0.442 - 11.2
                      JWT S4 - 266 - 0.464 - 11.8
                      Tomie Pon - 256 - 0.453 - 11.5
                      JWT C1 - 264 - 0.476 - 12.1
                      JWT C2 - 275 - 0.5 - 12.7
                      OEM - 240 - 0.362 - 9.2


                      • #12
                        S4 all the way. Although I heard good things on the C1 but havent personally tested (but require springs and retainers)


                        • #13
                          IMO, the JWT stuff doesn't buy you enough of a benefit over the Tomei stuff for the power.

                          If you want drop in, a 256/256 Poncam will give you a good balanced low end to mid/upper RPM boost. A 260 Procam will give you a bit more up top. I think my rough pricing is like $360ish for Tomei SR cams last I checked, which is like $200ish less than JWT cams.

                          If you want more flow, just go VE head with the extra money IMO.
                          '18 Chevrolet Volt - Electric fun hatch for DD duty!

                          DefSport Koni Sleeve and Spring Perch Buy!!!