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Another High comp + Boost thread

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    Another High comp + Boost thread

    I'm brainstorming an f23 bottom end bored to 88mm, sleeved, 11.5:1-12:1, 7500-8000 redline.

    f22a top end with the combustion chamber matched to the bottom end. Would it help to get oversized valves and a P&P? I have read some places that it helps and other places where it doesn't play a large part in forced induction applications.

    A Bisi lvl 1.2 or 2.4 cam, I want to have decent off boost response.

    Turbo that kicks in at around 3500-4000 at 5-10 psi, maybe a gt35 or similar
    Air to water intercooler

    e85 fuel is a thought

    300-400whp goal for now, not looking for peak power but a wide powerband and quick response.

    This is a hypothetical build with and infinite budget. I believe it is possible, why? Because, race car...but seriously the k series are doing it easily so why can't the f series?
    Last edited by sonikaccord; 08-22-2013, 10:32 AM.

    YouTube Clicky!!

    #2
    Compression seems too high.

    The infinite budget sounds like a cover your ass statement. Inifinite budget and I can have a 1200HP CB7. It's unreasonable unless you hit the powerball a week or two ago.

    Comment


      #3
      That's why I said hypothetical. Yes and it's to cover my ass from people that want to say "Hey bro...that's going to be expensive." I'm looking for facts about the engine and it's components not what my wallet looks like

      Why do you feel compression is too high?

      YouTube Clicky!!

      Comment


        #4
        Boost bumps compression so starting so high isn't always advisable, not saying it can't be done but that high comp is typically seen in an N/A application. It would have to run a low amount of boost which means no real room to up the boost.

        Comment


          #5
          Exactly! there isn't much discussion about high compression and boost here other than it's not safe or it's typically not done, but hell people are boosting stock f20c's and their compression ratio isn't that far off...

          Not looking to really up the boost. With the high comp it should be extremely sensitive to boost changes which means I don't need a ton of boost to get the power I'm looking for, I'm not looking for alot of boost either. Maybe 15 psi max and that's a strong maybe.

          My main concern is detonation. I know that e85 cools the intake charge a bit as well as has a higher octane. A water to air intercooler should cool the intake even more.

          YouTube Clicky!!

          Comment


            #6
            Originally posted by sonikaccord View Post
            I'm brainstorming an f23 bottom end bored to 88mm, sleeved, 11.5:1-12:1, 7500-8000 redline.

            How are you going to make that F23A rev to 8,000rpm?

            f22a top end with the combustion chamber matched to the bottom end. Would it help to get oversized valves and a P&P? I have read some places that it helps and other places where it doesn't play a large part in forced induction applications.

            What are your reasons for swapping heads?

            A Bisi lvl 1.2 or 2.4 cam, I want to have decent off boost response.

            Talk to Bisi; if this is a daily you may want to stay 1.2

            Turbo that kicks in at around 3500-4000 at 5-10 psi, maybe a gt35 or similar
            Air to water intercooler

            Depending on which one, you might want to rethink turbo choice.

            You rarely see air-to-water these days, have you found one that will work for our cars given the space constraints?

            e85 fuel is a thought

            My thought is do you have a capable tuner and enough gas stations to support it.

            300-400whp goal for now, not looking for peak power but a wide powerband and quick response.


            This is a hypothetical build with and infinite budget. I believe it is possible, why? Because, race car...but seriously the k series are doing it easily so why can't the f series?

            I'm going to say it anyways....it's going to be expensive. Why? Because Race Car.
            '94 JDM H22A: 178whp 146wtq

            Originally posted by deevergote
            If you say double dutch rudder, i'm banning you...

            Comment


              #7
              Originally posted by Joey GT-R View Post
              H-Beam rods, forged pistons and proper clearances. It's not a necessity to go to 8k esp. because I plan on keeping the f22 tranny w/lsd of course.

              I don't want nor need the sohc vtec head, and from what I've read the f22a head has the potential to have better flow and I think it has better aftermarket support, I'll have to look that up.

              Indeed I will contact Bisi.

              I had crunched the numbers for a properly sized turbo, but this was a while ago. I may just have to start over with that.

              Garrett has pretty small ones that fit nicely where an air-air would

              Plenty of gas stations here in Atlanta. Finding a tuner would be the hardest part about this design.

              If this came to fruition, it would be a 2-3 year build unless I won the lottery.

              YouTube Clicky!!

              Comment


                #8
                Valve overlap and managing cylinder pressure become the challenge. F20C has a valve train built to accomodate this. Our dinosaur f22a platform has nothing of the sort. So, you get one cam profile and thats it.

                I chose f22b1 because of this. Variable valve timing = manageable high compression+turbo. Shorter stroke means you can actually rev to 8 grand safely.

                Piston speeds will become an issue for you. The engine won't explode, but it wont WANT to rev that high either. It will be hard on the engine, it will shorten shelf life.

                Why?


                Because. Racecar
                Originally posted by wed3k
                im a douchebag to people and i don't even own a lambo. whats your point? we, douchbags, come in all sorts of shapes and colours.

                Comment


                  #9
                  Thank you toycar!

                  My limit should be determined by when my car stops making power right? And if I design it to where it keeps making power beyond where the engine is capable of still being reliable then I designed it wrong.

                  So I'm changing my redline to 7500 officially. Valve overlap is determined by the cam and limits my powerband, I'm not really worried about that part since I don't have too many choices in that category.

                  I do want to talk about cylinder pressures though. What differentiates a low compression, high boost engine and a high comp low boost engine in this regard?

                  And can anyone recommend any books on engine building and tuning?

                  YouTube Clicky!!

                  Comment


                    #10
                    Here's my mentality...

                    a. you either go high compression + boost, have to run conservative timing on the planned fuel, and deal with what might be disappointing results until you run race gas.

                    b. lower compression, less chance of detonation, run MORE timing with same fuel, make more power on the planned fuel and have more fun with it street driving. Not to mention race fuel is still an option for even higher boost or just more timing, which both = more hp.


                    THEN: 1993 Accord 10th Ann. Ed.---------------------- NOW: 1996 Accord EX
                    My Ride thread
                    Flickr
                    Originally posted by d112crzy
                    And it can only get better. That's the best part.
                    All I gotta really say is:
                    People of cb7tuner, this AUTO is NOT a joke. It has impressed ME, the hater of auto's.

                    Comment


                      #11
                      Originally posted by sonikaccord View Post
                      Thank you toycar!

                      My limit should be determined by when my car stops making power right? And if I design it to where it keeps making power beyond where the engine is capable of still being reliable then I designed it wrong.

                      So I'm changing my redline to 7500 officially. Valve overlap is determined by the cam and limits my powerband, I'm not really worried about that part since I don't have too many choices in that category.

                      I do want to talk about cylinder pressures though. What differentiates a low compression, high boost engine and a high comp low boost engine in this regard?

                      And can anyone recommend any books on engine building and tuning?
                      Corkey bell has some good literature out there


                      High comp + boost is using a higher compression ratio piston to compress already compressed air.


                      Low comp + high boost is less compression ratio piston applied to already compressed air.

                      At 10:1 compression, you compress air at a rate of 10:1 basically. If you compress air that is already compressed, there is a compounding affect.

                      Either way, even at low compression you still compress air that's already been compressed when you run anything forced induction. Less compression happening in the cylinder is easier to manage, generates less heat and is safer overall for detonation issues.

                      Let the turbo generate the pressure basically. That's why people favor low compression for turbo.

                      But with fuels available like e85 and meth kits becoming so much more affordable and useable, higher compression + boost has been gaining traction because managing detonation is getting easier
                      Last edited by toycar; 08-24-2013, 12:09 PM.
                      Originally posted by wed3k
                      im a douchebag to people and i don't even own a lambo. whats your point? we, douchbags, come in all sorts of shapes and colours.

                      Comment


                        #12
                        Originally posted by prNonVtec4u View Post
                        Here's my mentality...

                        a. you either go high compression + boost, have to run conservative timing on the planned fuel, and deal with what might be disappointing results until you run race gas.

                        b. lower compression, less chance of detonation, run MORE timing with same fuel, make more power on the planned fuel and have more fun with it street driving. Not to mention race fuel is still an option for even higher boost or just more timing, which both = more hp.

                        thank you. if it was up to me, id run a flat top (10:1?). best mixture and flame front.
                        I <3 G60.

                        0.5mm Oversized Stainless valves and bronze guides available. Pm me please.

                        Comment


                          #13
                          My own personal experience and opinion, I wouldn't go above 10:0:1 compression with a mild boost level.
                          The term psi takes in more than a number of 15.
                          15psi in a straw is not a lot of air, 15psi in a 10" pipe is a ton of air. The term people use for saying how much boost they will run is incorrect.
                          Go more by airflow numbers. Like what I ran was 48lbs a min. Pushing a relatively small tdo6 20g ported at 32psi through a large intercooler and 4" piping, and a 72mm tb, with a ported head cut valves 264/265 web cams, and a full 6" exhaust from the tubular manifold back to reach that airflow, the meire fact I had mahle pistons 9:5:1 compression and no skid side coating had nothing to do with how much airflow the turbo produced at a given psi.

                          Every turbo has a different efficiency range, and mine was slightly outside of it's due to being highly ported.
                          I suggest you get this infinit fund supply before you start building though.
                          "Self Renewed"

                          Comment


                            #14
                            Originally posted by KeeleDesign View Post
                            My own personal experience and opinion, I wouldn't go above 10:0:1 compression with a mild boost level.
                            The term psi takes in more than a number of 15.
                            15psi in a straw is not a lot of air, 15psi in a 10" pipe is a ton of air. The term people use for saying how much boost they will run is incorrect.
                            Go more by airflow numbers. Like what I ran was 48lbs a min. Pushing a relatively small tdo6 20g ported at 32psi through a large intercooler and 4" piping, and a 72mm tb, with a ported head cut valves 264/265 web cams, and a full 6" exhaust from the tubular manifold back to reach that airflow, the meire fact I had mahle pistons 9:5:1 compression and no skid side coating had nothing to do with how much airflow the turbo produced at a given psi.

                            Every turbo has a different efficiency range, and mine was slightly outside of it's due to being highly ported.
                            I suggest you get this infinit fund supply before you start building though.
                            your kidding 6" exhaust!?!?

                            Comment


                              #15
                              Typo, I meant 4" turbo back I was going to go 6" out the side of the front bumper and never did.
                              "Self Renewed"

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