No announcement yet.

How many miles can we expect out of a 2.5?

  • Filter
  • Time
  • Show
Clear All
new posts

  • How many miles can we expect out of a 2.5?

    After reading a bit about on how alot people have over 150K miles on their cars on original engines, how many miles can a 2.5L produce before needing some type of re-ring etc?

    I have around 20-25k miles on my 2.5 and I've only redlined maybe 10 times total since then, I do like spirited driving though, in between the 4500-6k rpm at times, never held there just passing through the gears. I've only used premium synthetics (Neo Synthetic) and oil changes have come at around 5k on original filters, mostly the dealer Mahle's.

    I know I'm just being paranoid as these engines are sturdy built lumps, but I know increased power means decreased reliability especially when you punch out a US spec 2.3 to accept 2.5l slugs, not to mention the 11:25 to 1 compression on the cat-pee we call gasoline in California, luckily I have always run rich from a screwy AFM, but soon the MAXX goes in and it will be tuned accordingly.

    Engine builders speak up

    Maybe Mr. McHenry can chime in on this one.

    The Chuck giveth, and the Chuck taketh away

  • #2
    Hard to say but with the stroke only being 3mm longer, I see no reason why a 2.5 wouldn't last as long as a 2.3. I think the real issue is whether it's detonating and at what RPM's it's at the most. With hotter cams the engine will probably see the upper RPM range more often so there's more wear and tear.



    • #3

      I'd agree that a 2.5 probably sees more stress than a 2.3 but I think the bigger factors are going to be proper maintance and strict avoidance of detonation. Detonation will ruin ANY S14 in very short order. I'm convinced that my 2.5 will be more durable than my 2.3, despite the increased power, given stronger-than-stock internals. Wishfull thinking? Perhaps - but don't burst my bubble! ;^)



      • #4
        let me point out the irony in that a member named highrever redlines his car once every 2 thousand miles.


        • #5
          Cilinder volume is not the limited factor on durality, unless your cilinderwalls are to thin.
          Horse powers end especialy RPM`s are the limited factors.

          If you look at the tuning program of KK-Automobile in germany,, you can see the harder you tune your engine, the less
          kilometers it goes.

          Stage 1 ca. 240 ps. - Unlimited
          Stage 2 ca. 270 ps. - Unlimited
          Stage 3 ca. 300 ps. - Depends on how u use it
          Stage 4 ca. 320 ps. - ca. 10000 KM
          Stage 5 ca. 350 ps. - ca. 4500 KM
          Stage 6 ca. 370 ps. - ca. 1500 KM

          I hope I made a good point here. Correct me If I`m wrong.


          • #6
            I am a highrever! I'm just not a redlinerever!.. redline is bad mmkay?

            The Chuck giveth, and the Chuck taketh away


            • #7
              well, FWIW I had the car out today and
              hit over 8200 rpm on a lot of my shifts, perhaps
              50 times? or 100 times? and then I short shifted it
              perhaps another 100 times at 7000-7500.

              I was out playing with the CR/4.10 gear combo

              I think Ive got my full throttle AFR down pretty good now.

              one problem I have still is that in 5th gear at full
              throttle when you lift it keeps going for a little
              before it starts to decelerate.

              anyway, dont think you have much to worry about.
              accelerating thru the rpms is good. I try not to
              keep the engine at over 8000+ rpm for very long periods
              of time, but it is built to handle the revs.
              the stock engine you can rev at 7000 all day long.

              those KM numbers given for those KK engines are not
              the mileage, its by when they are supposed to see a
              scheduled revision.



              • #8
                Well at lot of it has to do with the build specs, was it built tight or loose? How good was the block when it was bored? Was it properly broken in?

                I fell since most of our 2.5's are either mostly stock BMW parts or Motorsports parts they should be as good as OEM motors.

                IMHO, my 2.5 should last longer, why?
                I change oil a LOT more
                I keep the engine in perfect tune all the time (have a shelf full of plugs, wires, cap & rotor, O2, shims, TB, sync tool, etc..)
                I got a massive baffled oil pan, and my engine takes almost 8qts of oil now.

                Since I have a TON of low end power, I don't have to rev it up to 8K to make it go, most of my street driving even "FUN" driving is done, 2-5k RPM's When the car can pull at 2000 RPM's it's a LOT more fun!

                Most of the newer parts are better quality and much better metallurgy then 1980's stuff, the tuning that can be done now is also better then stock, it's really easy for me to control detonation with the MAXX.

                Just have fun and don't worry about it, I hope to get about 10 years out of my motor!

                Do not click
                At least it's German