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Dyno graph inside - stock '87 325is and some E30 comparisons

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    Dyno graph inside - stock '87 325is and some E30 comparisons

    I purchased an '87 325is yesterday. It is in excellent shape for its age and has 251k miles on it. The original owner was an older lady who put 95% of the miles on it. The gentleman I purchased it from yesterday only had it for over a year. It still has the original clutch in it!

    I decided today to take it to work and dyno it to get a good solid baseline for the upcoming motor swap. The best I could get out of it was 135.5rwhp/139.9rwhp, which I didn't think was too bad for mileage on the motor.

    Next, I yanked the powersteering belt off to see how much hp/tq the pump was taking. This resulted in 137.7rwhp/143.2rwtq.

    Dyno graph - removed powersteering

    After this, I decided to see how much the silencer inside the airbox was hurting power. It didn't hurt power as much as I expected it would. Power did go up to 138.3rwhp, but peak torque did go down slightly to 143.0rwtq.

    Dyno graph - removed internal airbox silencer

    Finally, we pulled the airfilter out to make some final pulls. The filter was made by Fram and didn't have many miles on it according to the previous owner. It was clean, so I didn't anticipate much of a gain. However, this proved to be the best "mod", resulting in 141.1rwhp/146.0rwtq.

    Dyno graph - removed airfilter

    Overall, I was pretty happy with the numbers the car put down. I had heard of some other bone stock "i" motors putting down 140-143rwhp stock, so I wasn't too far off.

    Here is a graph comparing how the car came in and what some free, simple mods can do:

    Stock vs Free mods

    I definitely wouldn't recommend running without an airfilter on the street, but it is something you could remove if you did take your car to the dragstrip and were looking for a slight bump in power. :D

    Some other info:

    My friend (Jonathan 90 M3) had dynoed his previous car and current car at this dyno, so we got a good comparison of the 325is to an '87 325 and a '90 M3. The graphs were very interesting to say the least. :)

    This graph compares the 325i to the '87 325, which had a BAS chip, BMP intake, and an Ansa catback:

    Dyno graph - 1987 325i vs 1987 325

    Next, I printed out a graph comparing his 1990 M3 to the 325is. The M3 had a GIAC chip and no powersteering.

    1990 M3 vs. 1987 325is

    I figure you guys would find those graphs kinda interesting comparing the different E30s.

    I really don't have much more planned for this motor. I may add a chip, but really don't want to spend anymore money on this car. I'm saving for the motor swap. :) If anyone has a chip they would like me to try, I'll dyno it before and after, and then send it back. This goes for any other mods as well some people may have laying around. It is nice working at a shop where I can use the dyno whenever I have time. :D

    Jason

    #2
    thanks for the wealth of info, now only if e30's had a book full of mods that where ran on a dyno like the 5.0L mustangs do.

    -cam
    Cam .W '91 325is

    Spaz's 1991 Alpine White???? S52 Build Thread...

    Comment


      #3
      well, even if you factor in a 25% drivedrain loss, those are actually pretty good numbers I think.
      Michael Spiegle

      '01 Ford Escape / Daily Driver
      '99 M3 / Track Car
      '87 325is bronzit / wtf car
      '06 Daytona Triumph 675 / Daily Rider

      Comment


        #4
        That was a blast to try out some different things on the dyno. Nothing like making 13 pulls on a car the day after you buy it. :D


        Now all we need is a 318is and an m10 318i to get all the E30s for comparison. ;)

        '05 E46 M3 Imolarot/Cinnamon - CURRENT
        '98 E36 M3 Estorilblau/Dove - SOLD
        '90 E30 M3 Brilliantrot/Black - SOLD
        SRS BSNS Motorsports - 24hrs of LeMons Racer

        Comment


          #5
          Great posts!!!! Thanks!!!!

          Are you planning on removing your AC? I'd be interested to see what kinda difference it actually makes.

          I figure you can remove the AC belt first, and see if the gain is worth losing the AC for - and if so, then out comes the system to save weight.

          Comment


            #6
            Originally posted by Low Level E30
            Great posts!!!! Thanks!!!!

            Are you planning on removing your AC? I'd be interested to see what kinda difference it actually makes.

            I figure you can remove the AC belt first, and see if the gain is worth losing the AC for - and if so, then out comes the system to save weight.

            The A/C belt had been removed previously since the A/C system has a leak and does not work anyway. And yes, the whole system is going bye bye for weight savings. 8)


            We might buy a belt for it and do some with/without dynos to see if there is a gain.

            '05 E46 M3 Imolarot/Cinnamon - CURRENT
            '98 E36 M3 Estorilblau/Dove - SOLD
            '90 E30 M3 Brilliantrot/Black - SOLD
            SRS BSNS Motorsports - 24hrs of LeMons Racer

            Comment


              #7
              that makes me want to put my stock airbox back on!

              Comment


                #8
                all those #'s are on rwhp and rwt?
                '86 325

                Comment


                  #9
                  For a little more info, my M20B25 with just a JimC chip made 150rwhp and 150 rwtrq.
                  It had ~100k on it.
                  -Ted

                  Comment


                    #10
                    What exactly is the internal airbox silencer and what does it look like?
                    Jamie Webster
                    '89 325is - sold :(
                    '96 Miata - sold
                    '01 M5 - sold
                    '02 Civic Si

                    Comment


                      #11
                      i made 135 HP 130 TQ with dinan chip, hot air intake and about 60% humidity, 120k motor

                      Comment


                        #12
                        Good stuff, I was waiting for this graphs for long time.

                        :)
                        95' M3.
                        90' 325i Turboed.
                        87' 325eS Fixed.

                        Comment


                          #13
                          Originally posted by jweb
                          What exactly is the internal airbox silencer and what does it look like?
                          Could anyone tell me?
                          Jamie Webster
                          '89 325is - sold :(
                          '96 Miata - sold
                          '01 M5 - sold
                          '02 Civic Si

                          Comment


                            #14
                            If you open your airbox and look inside there a piece that is shaped like a horn. It can be unclipped and removed, but it has been debated whether removing it actually helps power or not. Athough it does look like it hurts airflow, BMW obviously put it in there for a reason. I'd leave it in.

                            Comment


                              #15
                              Would I notice a big difference in sound if I removed it?
                              Jamie Webster
                              '89 325is - sold :(
                              '96 Miata - sold
                              '01 M5 - sold
                              '02 Civic Si

                              Comment

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