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Differences in two E30's

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    Differences in two E30's

    So last year I purchased a 1990 325i track car with a SpecE30 legal roll cage and stripped interior. The car drives awesome, sounds awesome, and has GC coilovers, camber plates and some other suspension bits so it handles awesome as well. Only problem is it doesn't have any interior fans in it, much less air-con...it's leaky when it rains, and you have to drive with the windows down or it fogs up. It's also a pain in the ass to get in and out of when you just want to go get some groceries. There aren't any sunvisors even, so you have to drive around like Ari Vatanen in Climb Dance.

    My solution was to buy a second 1990 325is. Now it's luxurious, comfortable, and smooth. It has some bilstein shocks and lowered springs, and a nice stereo.

    The only problem now is that the new car is just waaay too tame. The exhaust appears stock, and is way too quiet. Also the engine is lethargic and unresponsive compared to the track car. When I blip the throttle on the track car it just sings and spins up freely. On the new car there is a half-second hesitation and then it begrudgingly spins up.

    The only major differences between the two are as follows:
    1. Track car has AC delete
    2. Track car has rusty, loud exhaust and, presumably, high-flow cats - it still passes smog.
    3. Track car has 4.10 LSD, I think the new car has a 3.73 or something...not quite sure yet.
    4. Track car is significantly lighter and has little to no insulation.
    5. Windage tray and oil-pan baffle in track car.
    6. Track car dyno'd at 149whp - 150ft/lbs

    I don't think the track car has anything special in the form of a light weight flywheel, we had a replacement engine dropped in it and the tech told me the flywheel was stock, "Heavy as sh!t" to quote him.

    So what should I do to spice up the new car?

    Option 1. Strip all the fun stuff off the track car and see if that helps.
    -Good: If it works then I will have a spicy, easy to live with 325is that is just a total hoot to drive around.
    -Bad: If it doesn't quite solve the problem then I have two shitty cars instead of one great one and one meadiocre one. It also detracts from the whole point of having a track car...why put a lame exhaust and sh!tty suspension on something with a roll cage?

    Option 2. Start buying stuff to upgrade the new car.
    -Good: It's always fun spending money. I'm thinking IE Exhaust and maybe Miller PSIK MAF conversion, high-flo cat. As far as suspension goes, possibly switch to GC coilovers and camber plates or throw in some Bilstein Sport shocks (I think it has the HD ones it it now) and some vorshlag plates or something. Stiffer springs too?
    -Bad: Wow I just described about 3000$ worth of stuff to put on a car I just bought ( and spent all my spare money on). I have this money where???

    Option 3. Quit complaining and shutup, I wish I had problems like yours.
    -Good: It gets quieter when I close my mouth, and I save money and effort by doing nothing.
    -Bad: Nothing changes

    What do you guys think? I think for me option 2 is the most fun, but it will take alot of time and detract from other things I want to do in life, like eat.

    EDIT: I put this in the engine forum because I want the new car to be as responsive as the track car. Does deleting the AC make that much of a difference or is there something wrong with the new car?
    Last edited by MrPedals; 08-17-2012, 08:16 AM.

    #2
    Do basic maintenance, maybe upgrade the paper filter to a K&N, and then option 3.
    Ben
    Thelma-Louise, the '88is Chump Car - back to M20 power!

    2014 ChumpCar Season Schedule!
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    October 4 PittRace Sprints: 2nd in C-class
    October 18-19 NCM, Bowling Green KY: 2nd, 1st!
    Nov 1-2 Watkins Glen - Chumpionship - 1st car to exit the race with significant body damage :(

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      #3
      Option 4

      Sell car to Gus because he needs a DD and would love to have these "problems"

      Comment


        #4
        Originally posted by NigelStu View Post
        Do basic maintenance, maybe upgrade the paper filter to a K&N, and then option 3.
        Car came with a K&N filter in it, I actually dumped it...the tech who installed the engine in the track car (and this is a shop that resides at Thunderhill raceway in Willows, CA) told me the paper ones make more horsepower anyway. I figured he would know cause he had dyno'd the whole field of SpecE30 cars last year to get a baseline and make sure people weren't cheating. Track car also has a paper filter, so that shouldn't be causing the big difference in engine response. Both cars have the same Turner/Conforti chip in the computer as well.

        I also, very first thing, replaced the distributor cap and rotor, spark plugs, spark cables, air filter, ignition coil, and did an oil change. The car drives much smoother and idles better, but the engine response is still lethargic when compared to the track car. The car barely passed smog, so that is what instigated the tune-up in the first place.

        Maybe a vaccum leak or something is wrong with AFM? I'm thinking of trying to clean everything up that involves intake and maybe getting a valve job done. The new car has 180,000+ miles on the original engine. It has good recods and shows that whoever owned it in the past was pretty good about maintenance.
        Last edited by MrPedals; 08-17-2012, 09:48 AM.

        Comment


          #5
          The hesitation off idle sounds like intake leaks. A smoke test will tell.

          If the track car has 4.10 vs a 3.73 in the DD, that will make a noticeable difference in acceleration. Couple that with difference in weight and the cars will behave very differently. But, the car barely passing smog suggests that the engine isn't running right and/or the catalytic converters are bad.

          I'd suggest that you focus your efforts on making the DD run right to start with. My guess is that it needs the head and injectors rebuilt and probably needs new catalytic converters. The first thing I'd do would be to get compression (dry & wet) and leak down numbers (on a hot engine). I'd also want to see what hot oil pressure looks like at idle and above 5k. It would make little sense to spend a bunch of time and money on the head if the engine is badly worn.

          Oh yeah, it is almost impossible to improve on the stock airbox.
          The car makes it possible, but the driver makes it happen.
          Jim Levie, Huntsville, AL

          Comment


            #6
            Originally posted by jlevie View Post
            The hesitation off idle sounds like intake leaks. A smoke test will tell.

            If the track car has 4.10 vs a 3.73 in the DD, that will make a noticeable difference in acceleration. Couple that with difference in weight and the cars will behave very differently. But, the car barely passing smog suggests that the engine isn't running right and/or the catalytic converters are bad.

            I'd suggest that you focus your efforts on making the DD run right to start with. My guess is that it needs the head and injectors rebuilt and probably needs new catalytic converters. The first thing I'd do would be to get compression (dry & wet) and leak down numbers (on a hot engine). I'd also want to see what hot oil pressure looks like at idle and above 5k. It would make little sense to spend a bunch of time and money on the head if the engine is badly worn.

            Oh yeah, it is almost impossible to improve on the stock airbox.
            Looks like it's going to be Baloney and cheese sandwiches for the next couple months. What's your opinion on the MAF conversion?

            I will go get the engine checked out. I did a compression test myself while I had the spark plugs out. I will post the actual numbers later when I can find the piece of paper I wrote them on. I don't claim to know how to do a compression test so take it with a grain of salt. If I rember correctly it was something like this:
            < back of car -----BMW----- front of car >
            168psi 155psi 170psi 166psi 160psi 170psi

            I don't think the engine was particularly "hot" since I was touching it and not burning myself.

            The lethargic engine is mostly noticed when you try to heal toe on a downshift. It is noteably more difficult to time it correctly because of the delay in throttle response. To be fair, the track car is easier to do this in than any other car I ever driven, even my E46 M3. I think that's why I'm wondering if it's because of the AC.

            Comment


              #7
              Those would be decent compression results. A leak down test will tell more.

              It really sounds like there are intake leaks and I think that if you get those fixed the hesitation off idle will go away. And when it does down shifting won't be a problem. Find a shop that can do a smoke test.

              The Miller MAF kit is good, but do you really need it on daily driver?
              The car makes it possible, but the driver makes it happen.
              Jim Levie, Huntsville, AL

              Comment


                #8
                check your c191 connector (fuel rail harness) for corrosion. Spray it with some cleaner. Some of those wires are direct to your fuel rail and will cause hesitation along with start up issues if its dirty.

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                  #9
                  So I'm back...
                  Checked the C191 harness connector on the white DD car and it seems ok. Drove the car to work today for the first time and it really doesn't drive that bad. I think that most of the problems stem from comparing it to the other track car more than anything that's really wrong with it. I'd have to say that the throttle response "hesitation" I'm experiencing is more akin to driving with a very large marshmellow underneath the gas pedal. I have to physically press the pedal down harder and sooner than I'm used to in the other car, and I translate that as a lack of throttle response.

                  Now for some pictures...there are some curious differences between the two cars engine bay:

                  First off, Track car the first week we (GF and I) bought it:


                  Engine bay of the track car:

                  *notice the cruise control delete

                  Engine bay of the new White 325is:

                  *If you look at the vacuum line on the brake booster it is significantly different than the track car. Why? No idea.

                  This part comes out quite easy, is that bad??

                  Comment


                    #10
                    Originally posted by MrPedals View Post

                    This part comes out quite easy, is that bad??
                    Don't have an answer for the other questions, but this was the same on my car, slid right out. Not sure if it is suppose to, I just put a small amount of adhesive silicon on there to hold it in place a get rid of any leaks.
                    sigpic

                    Comment


                      #11
                      JB weld that sucker to eliminate your vacuum leak.

                      Comment


                        #12
                        Originally posted by jlevie View Post
                        The Miller MAF kit is good, but do you really need it on daily driver?
                        I LOOOOVVVVEEEE it on mine.


                        Leave Me Transaction Feedback

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                          #13
                          Yes please jb weld that.

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                            #14
                            That loose elbow is one intake leak and I'll bet on there being others. Have a smoke test run.

                            Clean the nipple and socket with acetone or lacquer thinner then apply JBweld. Let the car sit for 12 hours for the epoxy to set up.
                            The car makes it possible, but the driver makes it happen.
                            Jim Levie, Huntsville, AL

                            Comment


                              #15
                              Originally posted by jlevie View Post
                              That loose elbow is one intake leak and I'll bet on there being others. Have a smoke test run.

                              Clean the nipple and socket with acetone or lacquer thinner then apply JBweld. Let the car sit for 12 hours for the epoxy to set up.
                              Well I had the timing belt, and other accesory belts, water pump, and camshaft seal all replaced yesterday. My buddy did all the work and he appears to have put some sealant on that loose elbow. The car drives much better now, and revs up a lot easier. Next thing is a smoke test and save up for exhaust and MAF conversion.

                              Thanks for all the advice guys. I will keep you posted if I find anything interseting.

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