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Question on max boost with a stock rb26dett

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  • Question on max boost with a stock rb26dett

    I just have a question on what kind of boost could you run with a rb26dett. If I had a goal of getting around 500-600 hp. While still running the dual turbo set-up. I have heard the stock turbos should not be pushed passed .7 bar....

    Is the stock long block capable of this(obviously I would upgrade the oil pump)?

    By going to larger turbos-what would recommend? or definately not use?

    as well- an idea on injector size...750cc?

    thanx for your help

  • #2
    I'll try and share what I've learned over the past few months since no one else has responded and hope the gear heads don't flame me too much.. First - do your reading - that's the fun part! Stock r32 turbos can't go past .7 because the ceramic wheels disintegrate and make a big mess. The stock internals, provided everything tests OK (compression, leakdown) have been known to hold 600hp, but I'm not taking mine that high. I am doing a build right now with Garrett 2860r-5 turbos, from what I've read they are about the best match for 500-600hp. I am using 1000cc hks injectors and an appropriately sized fuel rail (hks) and pump (sard) but each cc is approximately equivalent to one HP, so 600cc injectors would be fine. I am also upgrading to Tomei Poncam Bs and replacing the exhaust manifold (Tomei Expreme), downpipes (Tomei), coils (Splitfire - my r32 coils weren't generating spark at boost higher than .7) and ignition (hks twin power), and an rps max clutch and flywheel (because the stock one won't hold the torque) to complete the picture.. Good luck!

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    • #3
      Stock turbos can go well over 7psi. A certain person on here was dyno'd at 487whp? with stock turbos.

      1990 Pearl White GTR

      Comment


      • #4
        You can bump the boost a bit up but its best to keep it at under 1.0 bar cause anything higher than 14 psi, you risk shortening the life of the stock turbos. If you want to run more boost, you have to upgrade the turbos. If you plan to run high hp, its recommended you do a compression test to find out how strong your motor is and whether or not a rebuild is in order.

        Comment


        • #5
          Yup, 27psi IIRC. Water/Meth can work wonders. It popped at 27 but Andrew ran 22 psi for a very long time with Water/Meth. Ran 11.70's at 122mph IIRC. Stock turbos can produce the goods.




          Jon.
          Why don't you come over to MySpace and Twitter my Yahoo untill I Google all over your Facebook.

          1990 GTR Drag Special T88H34D 11.24 @ 127.55mph at only 1.2bar...... officially. SOLD

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          • #6
            Originally posted by Dragon Humper View Post
            Yup, 27psi IIRC. Water/Meth can work wonders. It popped at 27 but Andrew ran 22 psi for a very long time with Water/Meth. Ran 11.70's at 122mph IIRC. Stock turbos can produce the goods.




            Jon.
            Yeah I guess that works too, just make sure you get a good kit that has a boost safe system should the tank runs out or fail to inject the mixture.

            Comment


            • #7
              Turbo's can fail due to high oiltemps when running higher boost levels. Air to air engine oilcooler is a must have mod. Also higher exhaust temps (engine running lean) is another cause of ceramic turbo failure. Upgraded fuel system, Z32AFM x 2, 600cc injectors, fuelpump upgrade, retuned ECU or aftermarket ECU is a must have when boosting engine up with stock turbo's. Also ECU tune must produce no knock if you want engine to last. Also need a boost controller. Also add full exhaust, podfilters.

              Should be able to extract around 430ps with a basic boost up on R32 GTR with stock turbo's and the above mods.

              For 460hp with stock bottomend -

              Tomei Poncams Type B (260 duration)
              Tomei valve springs (depends on engine km)
              2x Z32 AFM + 2x Z32 plugs
              Apexi airfilters
              Boost controller
              Full exhaust (from turbo's, which includes dumpipes).
              Apexi Podfilters x 2
              Nismo 600cc injectors
              Nismo fuelpump
              ARP headbolts, ARP grease
              Tomei metal gasket kit (includes metal intake gaskets, metal headgasket, etc)
              RB26 repair gasket kit (new valveseals, etc)
              Tomei oilrestrictors
              N1 turbo's (or rebuilt stock turbo's)
              Nismo baffle plate (sump)
              Stock ECU retune or aftermarket ECU
              Twin plate clutch + upgraded slave cylinder, braided clutch hose.

              Then add cooling mods like thicker radiator, lowtemp thermostat, N1 waterpump, engine oilcooler with built in thermostat.

              That's the full on boost up list for stock RB26 bottomend.

              Then next stage can be a 700hp (at engine) capable bottomend on the cheap (without N1 shortblock) -

              Forged pistons
              ARP rod bolts
              N1 oilpump
              ACL bearings or Nismo bearings

              Note: Make sure you check for cracks on top (deck) of stock shortblock.

              Not on the cheap bottomend -

              Forged pistons
              Forged H beam conrods (includes ARP rod bolts)
              JUN oilpump
              ACL bearings or Nismo bearings
              N1 shortblock

              Probably be looking at a triple plate clutch, ATI pully upgrade, HKS 25/30 turbo's (or similar), etc.

              But in my opinion, it's better to rebuild the whole engine and do it all in one go.
              RESPONSE MONSTER

              The most epic signature ever "epic".

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              • #8
                Both my GTRs run stock turbines at 1bar. One has seen nearly 30,000km in my hands (the way it's meant to be driven) and the other only 2000km so far. Anyways .7bar is less than the .8 factory boost setpoint which I don't even think your stock actuators could function below .8 (don't quote that). Most will say 450hp is the limit on the internals however there has been many stock blocks with razor sharp tuning to seen 800hp, Auto style's mine replica, dsport's editor R33 for example. This subject has been brought up too many times. Use the search function. I'm sure mcfly posted a 100 things about that. He has a 1000hp gtr in edmonton and seems to know a fair bit.

                The hks 2530 and nismo gt/lemans are tough competitors in the 600hp range.
                Black 1991 GTR. Serious garage stand mantle/parts car.
                Black 1990 Pulsar GTiR. Sold
                Silver 1989 GTR. Sold
                Black 2010 Subaru WRX. Weekend warrior. Sold.
                Black 2013 F-150 FX4 ecoboost. Daily driver.
                White 2012 Ford Explorer Limited. Family wagon.

                Sorry for my offensive comments, I r socially retard.

                start by having A ROLLING GTR then we talk u ******* mofo funzy little *****
                lol

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                • #9
                  Originally posted by Nismo BKK View Post
                  You can bump the boost a bit up but its best to keep it at under 1.0 bar cause anything higher than 14 psi, you risk shortening the life of the stock turbos. If you want to run more boost, you have to upgrade the turbos. If you plan to run high hp, its recommended you do a compression test to find out how strong your motor is and whether or not a rebuild is in order.
                  What would you consider acceptable for compression numbers and leakage.
                  Black 1991 GTR. Serious garage stand mantle/parts car.
                  Black 1990 Pulsar GTiR. Sold
                  Silver 1989 GTR. Sold
                  Black 2010 Subaru WRX. Weekend warrior. Sold.
                  Black 2013 F-150 FX4 ecoboost. Daily driver.
                  White 2012 Ford Explorer Limited. Family wagon.

                  Sorry for my offensive comments, I r socially retard.

                  start by having A ROLLING GTR then we talk u ******* mofo funzy little *****
                  lol

                  Comment


                  • #10
                    Originally posted by kneacsu View Post
                    Stock turbos can go well over 7psi. A certain person on here was dyno'd at 487whp? with stock turbos.
                    they have yet to show a dyno sheet so I am skeptical, and at the dyno blow up day it ran 27PSI and didn't even hit the power they claimed was hit previously on 22PSI. Not saying it didn't happen, but I would like to see a dyno sheet.



                    and he said .7 which I assume he meant BAR. That is approx 10-11PSI.... 12-13psi is what I would say is the max for the stock turbos from a reliability standpoint.

                    Originally posted by Dragon Humper View Post
                    Yup, 27psi IIRC. Water/Meth can work wonders. It popped at 27 but Andrew ran 22 psi for a very long time with Water/Meth. Ran 11.70's at 122mph IIRC. Stock turbos can produce the goods.




                    Jon.
                    at 22 PSI the stock turbos are WAY out of their efficiency zone on their compressor map. All they are doing at that point is blowing hot air into your engine.

                    TROL

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                    • #11
                      I Agree, Stock turbo's don't perform past .9 bar. Not to say you can't make them spin past that point but the amount of heat generated just defeats what your trying to do.

                      On another point Water/Methanol is without a doubt a good addition to simulate a higher octane fuel.
                      " Using Fast and Honda in the same sentence is an Oxymoron "

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                      • #12
                        Thanx for all the info guys. I appreciate it. Being a mechanic by trade(18 years) I am looking forward to building up my Skyline . Just wanted to find out what were some good directions to pursue.
                        The car as it sits now-
                        1993 GT-R,
                        89,300 kms( very low KMS for a '93- about 6,000 kms a year!?)
                        HKS exhaust
                        Trust Intercooler
                        Oil cooler and filter relocation kit
                        Air Intake kit
                        Greddy timing belt and cover
                        HKS timing gears
                        HKS boost control
                        Electronic torque split
                        turbo timer
                        Apexi Power FC

                        I have done a compression test,ect. I am ivery good shape in this dept. that's why I asked.
                        I have headers, Devil's own water/ meth,Larger fuel rail,Sard fuel pump to install.....

                        I thought while I had the exhaust apart I would put Garrett GT2860R-5 turbos in

                        Comment


                        • #13
                          Originally posted by falcon View Post
                          at 22 PSI the stock turbos are WAY out of their efficiency zone on their compressor map. All they are doing at that point is blowing hot air into your engine.
                          Oh hell yea, but that doesn't mean you still can't make reliable power. Dodge guys have been running the same basic turbo (just one with WAY crappier turbines) on 2.2l and 2.5l for 20 years at 20 to 23 psi. All you need to do is control the heat with a better than stock FMI and Water/Meth. I ran my turbo at 18psi for 3 years, and boosted ALOT (with NO intercooler). Guys from Kamloops I'm sure will remember a blue Omni GLHturbo that could smoke the tires through 3 gears.

                          Andrew also had a standalone that was on the money with the tune which is most of the battle. From what I have read (and plan to test) the stock internals will hold 450 awhp reliably as long as the motor is healthy, the tune is spot on and you don't spin her much past 7500rpm.


                          Jon.
                          Why don't you come over to MySpace and Twitter my Yahoo untill I Google all over your Facebook.

                          1990 GTR Drag Special T88H34D 11.24 @ 127.55mph at only 1.2bar...... officially. SOLD

                          Comment


                          • #14
                            different engines, different flow rates, etc, same turbo on a different motor is going to require a different boost level to flow a similar amount of air.


                            Anyways, I ran ~1.3 bar most of this summer. 1.8 bar on nitrous in the fall. I had a turbo fail at 0.8 bar after all of that in the winter. So who knows what it'll stand up to. I put about 20,000KM on the car at 1.0+ bar.
                            1992 GTR - 2.7L, GT2871R's, forged bottom end, big valves, 270* cams, R34 getrag
                            2000 Honda Insight - 70+mpg daily driver
                            2003 Sierra 2500HD Diesel - Tow vehicle

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                            • #15
                              Originally posted by NismoS-tune View Post
                              What would you consider acceptable for compression numbers and leakage.
                              The r32 rb26dett compression number out of the factory is 171 psi. 140-160 psi is good for an rb26 that was never rebuilt with stock internals. I believe 117 psi is the lowest limit and I think about 14-15 psi is allowed for variances on all the cylinders. Having a strong motor is a must if you are doing a build for more hp.

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