Announcement

Collapse
No announcement yet.

7a block stroker

Collapse
X
  • Filter
  • Time
  • Show
Clear All
new posts

  • #16
    Originally posted by A80Avant View Post
    What's the best comp ratio to go for , for such an engine. Boost no.more than 2bar
    Depends on what fuel you can get in Greece, who is going to map it and how confident you are of your knock control.
    sigpic
    1991 Audi S2 3B - 2.5 Stroker engine
    1997 A6 2.5TDi quattro avant - C4
    1976 RD250E / 350LC cafe racer

    Comment


    • #17
      I'm mapping it, vems will have knock control and fuel can't get more than shell 100 racing which should be around 98 at best.

      I was told to go for 8.0:1 from rosten due to my 'small turbo' hahaha

      Comment


      • #18
        My 92.8 stroker uses 159mm rods and 8.1:1 compression pistons, for what it's worth. I bought it as a package deal, would have opted for 9.3:1 myself, but it's enough to get a guy started haha.
        Find me on Instagram @pry4sno
        2010 Golf Sportwagen TDI /// Wifey Mobile
        1992 80q 20v /// Eventual AAN'd Winter Sled
        1990 Cq /// Project: Because Racecar

        Comment


        • #19
          I'm not sure as to how high the compression should be, but I like a torquey engine. But I don't have the experience as to how.it should be

          Comment


          • #20
            when you have a low cr you can drive with a lot off boost but the engine will have more lag so if you want a torquey engine a would not go to low with the cr,origional the cr is 9.3:1,mine is 8.0:1 so maybe you can choose around 8.5-9.0 .this is only my opinion,i'm not an expert on this :-)
            audi coupe quattro b2 2.2 20vt project (573hp-626nm)
            TWINCHARGED power,zero lag
            AEM W/M injection

            Comment


            • #21
              How many people are running 2bar boost on a standard engine with just rods? Loads I would guess. If you're only planning to run 2bar and you're confident of your knock control, why lower the CR?
              sigpic
              1991 Audi S2 3B - 2.5 Stroker engine
              1997 A6 2.5TDi quattro avant - C4
              1976 RD250E / 350LC cafe racer

              Comment


              • #22
                It's what people who sell these pistons recommend. As the stroke is larger on this engine, timing is becoming lower.

                Rosten suggests that 8:1 compression which by a bit of decking may end up close to 8.3:1 may allow similar advance timing as the stock 9.3:1 normal 2.2 engine.

                What is the translation in this? I suspect most people think that since the turbo you are using will be awakened from 3000rpm or so the car will be lively anyway so why compromise extra boost if it may become knock limited?

                I just want to get it right from the start

                Comment


                • #23
                  its how far up the rpm range the boost is developed that makes the difference. low cr means more timing is possible up top to aid in boost up the rpm range. and lower egt

                  knock control I wouldn't rely on saving my motor.



                  Comment


                  • #24
                    As engines like this will not run more than 7000rpm I'd say that I'd lean towards a a 8.5:1 to get somewhere in the middle with timing

                    Sent from my SM-P550 using Tapatalk

                    Comment


                    • #25
                      gotta be for a wide powerband. still if you do 2bar at 7k then its still quite high. needs good breathing at that to keep it cool.

                      tbh not sure what mine is with skimmed pistons. ive been trying to gauge the hassle/benefit for stroker on these engines. still cannot decide if its worth it

                      Comment


                      • #26
                        To me it would be great fun to be able to have a k24 spool on a 3071 gen 2 power turbo from such engine. So far the 2.2 is still laggy for me and as I don't really rev that high, I figured this would be nice

                        Comment


                        • #27
                          If you're thinking of the 3071 mk2, the EFR 7163 and Xona Rotor has some really nice turbos to consider, as well.

                          Originally posted by A80Avant View Post
                          As engines like this will not run more than 7000rpm
                          Will not, or cannot? I have every intention to rev mine to 8000 rpm.

                          Granted mine is a 92.8 crank, but I know that 034 didn't mind revving theirs out with the 95.5 crank (among others).

                          Everything just has to be zero balanced and you can't skimp on the hardware.
                          Find me on Instagram @pry4sno
                          2010 Golf Sportwagen TDI /// Wifey Mobile
                          1992 80q 20v /// Eventual AAN'd Winter Sled
                          1990 Cq /// Project: Because Racecar

                          Comment


                          • #28
                            It's good to know, just tired of engine rebuilds. Too much money. If I still have the car till the stroker is ready I'll use it. Otherwise if everything sells ill go for something newer

                            Comment


                            • #29
                              Originally posted by GazzaG60 View Post
                              gotta be for a wide powerband. still if you do 2bar at 7k then its still quite high. needs good breathing at that to keep it cool.

                              tbh not sure what mine is with skimmed pistons. ive been trying to gauge the hassle/benefit for stroker on these engines. still cannot decide if its worth it

                              I couldn't justify the extra cost and hassle of building a stroker for my goals (max 500hp).
                              I also chose to drop my CR to 8.4:1 as a compromise between driveability / boost response and higher rpm timing/boost capability. Higher CR produces more exhaust energy so boost response is faster, lower CR gives you a bigger volume of charge to exploit and puts less heat into it during compresssion stoke. Avoiding knock is the name of the game, also boost is only useful if you can keep the charge temps down. Low IATs are paramount. Everything is a balancing act / compromise!
                              Panthero Coupé quattro 20vt
                              Indigo ABY coupé
                              Imola B6 S4 Avant

                              Comment


                              • #30
                                gotta say the flywheel work with the skimmed piston and weight matched revs picks up pretty well especially in the lighter b3 saloon.

                                never had an issue with charge temps and egt. even at higher hp levels im not sure. pub/forum points yes. real world gains not sure.

                                Comment

                                Working...
                                X