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    EC Tech Letter Response about E30 tuning

    ...E30 Freshening (Redux)
    I didn't realize we needed to get quite so intimate. I don't have answers to many of the questions you pose. I am looking in the first instance to get a plan together for the project. Perhaps it is best to begin with basics and then try to formulate my vision.

    I am the cars third owner and it is in excellent shape. It has 240,000km. on the clock--it is a Canadian Car and I am in Canada. It has been serviced at bmw always except for approximately 40,000 km. when in the care of the second owner. It has never been driven in the winter. I use it in the summer as a daily driver with qualifications. That is, it competes with my motorcycle and it is the only drop top in the fleet so often gets scooped by my wife or one of my children.

    That said I envision a sleeper. No modifications that do not enhance performance and as few as possible that are visible. The car has lovely lines and, at least where I am from, is much more exclusive than an E36 or 46 rag. I like to do my own work and can do most of it. I can not, however, shoehorn an M50 into it. My difficulty is that I get busy with work/family, etc., and my projects get delayed/abandoned first. I am desirous, therefore, of having a plan I can implement in stages and I can do individual stages myself or farm them out.

    The question that needs to be answered first is how much horsepower? That of course effects brakes, suspension and body work. I do not want to do brake and exhaust/intake upgrades now and find out later they are insufficient for the horsepower I end up with. I am happy to spend money but not keen to waste it. The manual says it puts out 175 ponies with 169 lb-ft of torque. It is by no means slow but can you ever have enough?. I am convinced I can get another 25 horses with intake/exhaust and chip but is that enough?

    How much can be messaged out of that engine before it looses driveability? I don't mind a lumpy idle but I still need to be able to let my daughter drive it. If we imagine more significant work like a turbo/supercharger what are my options? I did actually read in your publication about a shop that stuffs M50s in. How much can the horsepower be increased before we need to make driveline modifications? Am I limited buy the chassis' inherent lack of rigidity?

    Once I figure out how much horsepower I need, I then have some questions about the rest of the project. How much stiffer can/should the car be? Does it do any good to brace the strut towers given the lack of a roof? I don't think I want a rollcage in my car. I would like to upgrade the suspension even though the stock stuff shows no signs of wearing out. The stock wheels are in excellent shape but do look a bit dated. I am not convinced I like the look of 17-in. wheels if it will leave only wafer thin tires given the cars current configuration. I still prefer the look of some rubber, so maybe 15- or 16-in. wheels, unless of course we decide on enough horses to require bigger rubber overall. I don't think I want to start flaring fender wells at this point.

    This has been rather therapeutic. If I stick just to upgrades in the suspension, brakes and wheels and message as much as I can out of the mill what will I end up with. I am all for more fun but not at the price of additional headaches nor do I want to have to sort out a story about the car failing as the reason for my daughter being several hours late coming home.
    Thanks,
    Steve


    Initially, with 249,000 Km (149,000+ miles), we need to take into account the condition of this engine. After all, if you take your grandfather and make him run sprints he may be able to do it, but whether he'll survive it is another question. I'd recommend you do cylinder compression and leakdown testing to gauge the condition of the bottom end. If this engine has never had a valve job, I can almost guarantee it needs one now unless it has been driven very sedately. Also, basic issues like air and fuel filters, spark plugs, cap and rotor, valve adjustment, fuel injectors, water pump, timing belt, cooling system service need to be verified or addressed before any thought of increasing power on a mature engine. At this mileage, catalytic converter and oxygen sensor condition are also in question.

    The standard bolt-on modifications for the M20 engine include a chip, cone-type intake, and a performance exhaust system. I would say you're looking at bolting on a good 25 hp with these items assuming you can get fuel good enough to satisfy the chip and assuming the engine is in good condition. That's about all you're going to get without removing the engine for a complete rebuild using high-compression pistons and a Schrick camshaft, along with lightening and balancing of the reciprocating mass. There are no superchargers or turbochargers available for the M20 engine, and even when turbos were available, they requried low-compression "turbo" pistons due to this engines lack of knock sensors.

    Bear in mind the maintenance requirements of an oiled cotton gauze air filter.

    These bolt-ons will not affect driveability as long as the engine is maintained in good tune and good high-octane gasoline is used. Engine longevity depends far more on maintenance and severity of service than what performance modifications are bolted employed. Make sure you use good motor oil, BMW filters, and bear in mind that today's ultra-low-viscosity 5W-30 has no place in an E30 except during Canadian winters. The rest of the time, you should be running 20W-50.

    Yes, the M50-into-E30 is a popular conversion, but as with all conversions one should not enter into it expecting to save money over a performance engine rebuild--it'll probably cost more.

    The best speed secret for an E30 six-cylinder with a five-speed overdrive manual gearbox is a 4.10 limited-slip differential from an E30 M3. While not exactly falling off trees, especially in Canada, these components can be found on the used parts market, and it will greatly increase acceleration and top speed (due to the increased pulling power against wind resistance), at the cost of a bit more rpm at any given road speed. It is a direct bolt-in.

    As always, Red Line MTL and 75W-90 are recommended for the gearbox and differential.

    The robust E30 drivetrain and chassis is capable of handling a great deal of power, upwards of 300 hp in my opinion. There are E30s running around with M6 engines and even M60 V8s, although this makes them very nose-heavy. Nothing you can bolt-on to an M20 is going to overtax your brakes, but again at this mileage I would be concerned with the basics--condition of the hydraulics if the brake fluid was never changed, rotor and pad condition, swelled rubber brake hoses, etc. A standard rehab of these parts, good brake fluid change, and use of new rotors and performance brake pads will be all you need.

    As with any BMW, the fun quotient is best increased with suspension improvements. The E30 can be made to handle like a slot car if you are willing to put up with lower ride height and firmer ride quality. Again, we want to make sure the basics are sound--steering parts, ball joints, rear suspension carrier bushings, trailing arm bushings, etc. The hot setup is Bilstein Sport shocks, the performance coil springs of your choice--Eibach, H&R, and Racing Dynamics are popular--E30 M3 offset front control arm bushings, and a set of large sway bars with mounting reinforcements from www.turnermotorsport.com. You can also run E30 M3 aluminum front control arms for a 4.4-lb. weight savings at each side--nice especially when fitting heavier wheels and tires. A plethora of factory and aftermarket 15-inch wheels are available, on which you will want to mount 205/55-15 tires. The 225/50-15 size is also correct, but added clearance may have to be worked into the fenders and quarter panels. For your purposes with this car, 205/55-15 ultra-high performance tires such as my new favorites, the Yokohama AVS ES100, will be more tire than the car will know what to do with.

    Normally, I would say that a strut brace isn't going to function except under extremely hard cornering forces, however on a convertible I think there may be other benefits. Bear in mind that the more you firm up any convertible, the more cowl shake you will get over rough road surfaces. Unless you want to add a roll bar, that's just the way it is.

    None of these mods are going to affect reliability. If the car breaks, it's unlikely to be because of anything you did to it. Here's a tip: Replace the main relay, fuel pump relay, and the fuel pump preventatively. Just bite the bullet. I was once stranded in at the base of the Dempster Highway outside Dawson City, Yukon Territory, in an 120,000-mile E30 rally car with a dead fuel pump. Trust me on this.

    If your daughter comes home late, it probably won't be due to the car. One other bit of advice: In my humble and decidedly non-sexist experience, the average life of a front air dam on a lowered BMW with a female driver is approximately one week. They are not wired to think of this kind of thing, just as men are not wired to remember dates and anniversaries. School your daughter in the perils of speed bumps, inhospitable driveways, and especially parking curbs. A label maker sticker on the instrument cluster that says, "Remember: 5 Inches of Ground Clearance," may help, too.


    Some good input (like proper maintence), some out-of-the-loop misses about turbos, etc. But more or less, i think it's good stuff.

    #2
    BMW 318 Engine Swap
    I was wondering how hard would it be to replace the early M42 engine in my 1991 BMW 318is with a newer M42 or M44 engine. Do I need to change the transmission also? I would like to know because I'm thinking of installing a Downing Atlanta Supercharger later on. I'm asking you because that's what you tell people with the same car as mine to do.
    Todd DeMeza
    via the Internet


    As engine swaps go, this would be one of the easiest. I would recommend a 1992-95 M42 engine because it will give you the poly-ribbed belt drive and knock sensors you will need for the Downing Atlanta supercharger, without the hassles of the M44's OBD-II electronics. You will need the engine harness and the ECU as well.

    BMW E30 M3 or E30 325is?
    I am hoping for some advise. Within the next year I hope to purchase either an E30 M3 or an E30 325is. I plan to drive it regularly and use it as a weekend fun car with the occasional track day. What are the pluses and minuses of each vehicle with my intended use? Also, which back issue had sort of a buyers guide to the E30 M3?
    Ed
    via the Interent


    The E30 M3 is fast becoming a cult car, with enthusiasts snapping up every example they can find. It's much more popular as a used car than it was new, due to the high MSRP this car had originally. And many E30 M3s were cut up for racecars, which never really made much sense--you can race a 325i much more economically and still lose to Porches just as well.

    The plusses of having an E30 M3 would be headed up by the fact that you'd have the first real M car to be imported to the U.S. (and some would say the last). It's a real driver's car, serious, unapologetic, with a high-strung screaming DOHC 2.3-liter four-cylinder and minimal "features and benefits"--a marketing weenie's nightmare. This last attribute alone makes the E30 M3 even more desirably--we like anything that is "anti-marketing". The E30 M3 is, in the most basic terms, a supremely fun and rewarding car to drive, street or track. The minuses? Well, every part you need for an E30 M3 that is not shared by the garden variety E30 will cost at least twice as much. The S14 engine, for all it's wonderful qualities, does not have the longevity of the M20 engine in the 325i. It is more race engine than street engine, requires 15,000-mile tune-ups including shim valve adjustments, and is very expensive to rebuild.

    The 325i, on the other hand, is a less cool car but still damn fun. It is also widely considered the most durable and reliable 3 Series ever made. Parts are cheap, and the M20 engine is responds well to performance tuning. The downside is that you'll need some aftermarket sport suspension parts--springs, shocks, sway bars, M3 bushings, wheels and tires, to bring the car into the realm of E30 M3 handling. Whenever you need parts, though, you'll be glad you have the 325i and not the M3.

    Regarding back issues, the following contain E30 M3 articles. To order a back issue, e-mail backissues@primedia.com, or call (866) 601-5199.

    September 1996-M3s Squared: Two modified E30 chassis M3s
    March 1997-Tech Procedure: BMW Installing a performance cam sprocket in an E30 M3
    December 1997-Super-buy #4: BMW M3 (1988-1991)
    March 1999-EuroSport Engineering tunes an E30 M3




    --------------------------------------------------------------------------------



    and also on the M3:

    E30 BMW M3
    I've been an avid reader of your mag for over 10 years, now, and it's always been a real pleasure. There is a black E30 BMW M3 in my neighborhood, and I think the guy wants to sell it. I would really like to build a true club racer out of it, but this will be my first project. At 26, I'm a late bloomer, but I haven't had a lot of money until now. Can you drop me a line on where I could shop for great parts on the internet for this car? I know the possibilities are endless with the E30, and I've always been a big fan. Thanks for any assistance, and keep it up with your fantastic magazine.
    Jonathan Dorsey
    Vancouver, Washington


    Thank you for the compliments, Jonathan!

    The E30 M3 ranks right up there with BMW's premier enthusiast road cars over the years. With characteristic E30 durability, a spot-on suspension right from the factor, and a sweet high-revving S14 engine, there's nothing not to like about the E30 M3. However, it's probably not the best choice for a club racer, even though it is highly competitive.

    The reason it's not a good choice has to do with money and rarity. First, you can have just as much fun if not more racing an E30 325i or 325e, which will have the same functional suspension and brake parts as the M3 by the time you are done building it for the track. Parts and the cars themselves are half the price. Second, the E30 M3 is a very rare BMW, and a wonderful street car. It's a shame, in my opinion, to cut one up for the track. And this ties into a final reason: Club racing is for fun. There is no prize money, no winners' circle, no champagne spray, not even a kiss from a pretty girl.

    I don't want to talk you out of the E30 M3, I just hate to see you cut it up for the track. Consider other E30s instead--God made lots of them, you know.

    For E30 performance parts, check out these places:
    This website is for sale! activeautowerk.com is your first and best source for all of the information you’re looking for. From general topics to more of what you would expect to find here, activeautowerk.com has it all. We hope you find what you are searching for!




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    it's good to read adult opinions and perspectives, although I'd probably agree with Maybach's guide too

    Comment


      #3
      Drivetrain Loss
      I have a question for you guys: Is the weight of the drivetrain constant? Other than the added weight of fluids, I would think it is fairly constant. Now let's say I have two naturally aspirated motors, one rated at 121 hp and the other at 250 hp. These motors are going to hook up to an E30 325 drivetrain. Because the drivetrain is the same why is the drivetrain loss greater on the 250 hp motor? For example, I have a high compression, chipped, stroked, ported and performance cammed engine. At the wheels, I have 194 hp and on the flip side I drop a 121-hp engine in place, at the wheels I have 91-95 hp. Now with the same drivetrain more power was lost with the higher hp engine. The weight deviates slightly but I can't see why it takes more power to turn the same weight.
      JT
      Atlanta, Georgia


      For your question, we turned to noted BMW engine builder Pete McHenry of Precision Performance in Winston-Salem, N.c. McHenry replied: We assume loss for a chassis dyno of the Dynojet or Dynopak type at about 17%. My son Alex's car for instance--a 1991 318is--pulled 250 at the rear wheels on a Dynopak. This converts to 290 at the crank. The engine is a 3.2 with stock M3 cams, euro AFM, Active Auto chip and injectors, and my newest head mods. It has stock exhaust manifolds and pipes.

      On the other hand, a Mustang dyno will correct with a 21% loss figure. Actual over-the-road loss is probably in the 17-20% range. A lot of front-wheel-drive cars do not have any 90-degree gear changes. All gearing is straight transfer. Losses are less; I'm going to guess at 11 to 12%.

      BMW 325i E30
      I have an E30 BMW 325i two-door, German version. Do you have performance figures for this car (0-100 kph, top speed, etc.)? The car has a factory close-ratio five-speed gearbox (Alpina?), with first gear down and to the left.
      CM
      via the Internet


      Nice car, CM! We don't have those performance figures, but you have the car. Get yourself a G-Tech Pro (www.gtechpro.com), test the car and let us know the numbers!

      Meanwhile, let's have a look at some of the cooler points of your German-spec E30 325i:

      Rest-of-the-world (ROW) E30 325i buyers had a choice between the Getrag close-ratio five-speed manual and a Getrag five-speed overdrive. Differential ratios varied in the ROW, because you could order the car with the gearing you wanted. Most close ratio cars got a 3.15 or 3.25 differential. Most overdriven cars got a 3.73 or 3.91 ratio. Of course, handicapped folks could chose a ZF automatic transmission. Here in the US, our choices were limited to the five-speed overdrive with a 3.73 differential (limited slip optional) or the optional slushbox. You could always order the close-ratio gearbox from BMW and install it after buying the car, but cost was close to $4,000. It's probably still available, but you can often find the entire E30 for four grand.

      Contrary to what you may hear, the factory close-ratio five-speed manual was not made by Alpina. Alpina did use it in their E30's, though, and they may have offered optional internal gear ratios. This was back when Alpina made real cars for serious drivers. Today, Alpina has some nice keychains and scarves and stuff, and I hear they make pretty good wine. But their cars seem to have crossed a line where only 300-lb burghermeisters, Russian gangsters, the Sultan of Brunei, and other assorted poseurs may tread. The company has a wonderful history of building top-performing BMW's for serious drivers, but a wonderful history is about all they have in my opinion. But, I digress.

      The differences did not stop at the gearbox and differential. The early E30 325i was also treated to more attractive (but less effective) front and rear bumpers, together with matching a matching air dam. From 1988-on, BMW went to a world bumper design for the E30--we finally got the good-looking stuff.

      The engine was the same familiar M20 i-motor we all love so much, but better. The German spec car had higher compression pistons and a less restrictive exhaust system unhampered by a catalytic converter. It was a prime candidate for a Schrick cam, and many got one.

      The German-specification springs and shock absorbers are also quite a bit more aggressive than their U.S. counterparts. The cars are about 10mm lower, and Bilstein shocks were often fitted at the factory. Sway bar diameter is the same. Finally, some ROW E30's are fitted with cool options that would give U.S. lawyers fits of apoplexy--fire extinguishers, first aid kits, trunk-mounted auxiliary fuel tanks. Rear fog lights are not uncommon, and as on all E30's, top speed is limited by your brain and right foot, not some electronic killjoy.

      Can you tell how much I love the E30?

      BMW 325is Performance
      I'm wondering if you can help? I have recently acquired a 1987 325is and I'm in the process of boosting the performance. I've done some of the more common things like the chip, the suspension, awaiting a Supersprint exhaust, K&N element, etc. But given this car is 14+ years old, there are few if any articles that talk about this car. I am hoping that you can provide or direct me to such information. I'd love to know who's chip is better. Who's exhaust provides more hp and torque. What mods really work and which are a waste of time.
      Jason


      Jason, you're on the right track. The E30 325iS is one of the most economically sound performance bargains in the BMW world. While not as trick or modern as the E36 3 Series that followed it, the E30 is more durable, and more reliable. For bolt-ons, we'd recommend a K&N cone intake (instead of the drop-in element), a Conforti chip, a Supersprint exhaust system, and if you can swing it where you live, a set of Supersprint or Stahl headers. This is about the extent of what you can do without rebuilding the motor with trick internals.

      Things like larger throttle bodies and adjustable fuel pressure regulators are really helpful only if you've used one of the following: higher compression pistons, headers, a performance camshaft, or done some cleanup work on the cylinder head and valve seats.

      We get a lot of questions on adjustable fuel pressure regulators. On a relatively stock engine, you wind up leaving an adjustable fuel pressure regulator at the stock setting anyway. However, on an older, worn engine, an adjustable regulator can be used to dial in just a scooch more fuel pressure (maybe 1 psi), to rid the motor of flat spots and stumbles that result from worn injectors and crudded up valves. BMP Design makes the nicest unit--it has an integral VDO fuel pressure gauge that we absolutely love. There is also a school of thought that says fuel pressure regulators vary even when new, and if you can buy and adjustable one and dial it in, so much the better. We can see the logic in that, but these things are pretty expensive compared to a garden variety fuel pressure regulator--especially when you don't need to replace the existing unit.

      In the rear, you can always install a 4.10 limited-slip differential from an E30 M3 in place of the standard 3.73 unit for extra acceleration. The trade off would be a little off the top of the fuel economy, and a little bit more engine rpm at any given road speed. But with your fifth gear overdriven .81:1, the 4.10 would really be a 3.32 in fifth gear. It would be, well, like an E30 M3, only quicker.

      The E30 suspension responds dramatically to performance tuning. Bilstein sport shocks and shorter, sport springs are the way to go. We prefer H&R springs these days. Suspension Techniques still has the best deals on sway bars, although their hardware kits are not the best--that would go to Dinan or Racing Dynamics. At the front, you'll want E30 M3 offset control arm bushings. You can also use E30 M3 aluminum control arms to cut unsprung weight--particularly useful if you've fit heavier-than-stock wheels and tires.

      Getting into more expensive things, there is also a factory five-speed close-ratio gearbox that was optional in Europe. This works excellently with a 3.25 limited-slip differential from a E28 535i or late E24 635CSi. --Mike Miller

      Comment


        #4
        E30 Engine Swap with 850
        I have a 1987 325is and have been looking to do a engine swap. It's really fast already, but I'd like to make it even faster--show the rice boys what BMW's are all about. I'm just not sure what kind of engine is best to put in my car, and what engines are most reliable. I'd like to put a newer M3 engine in, but I'm not sure if it will fit, or how many parts I'll have to get made to make it fit. But then the other day I was looking for engines and came across a engine from a 850i. What are the possibilities of putting that beast in my little E30? And if I can, what kind of mods would I have to do, so that the car could handle all that extra torque and horsepower? Any info you have would be great. I haven't been able to find anything on this.
        Jon Enns
        Steinbach, Manitoba
        Canada


        If you want to show the rice boys what Bimmers are all about, just keep your car and maintain it well, or set about restoring it. You don't see people restoring classic Japanese cars, at least not anywhere near the level of classic BMWs--not that a 1987 325is is old.

        The E36 M3 engines, both the 3.0-liter and the 3.2-liter, will fit an the E30 chassis. The latter requires a bit more parts swapping, as you'll need to use the 3.0-liter fuel injection system to avoid the complexities of OBD-II. There's a one-stop-shop for this conversion information: Zionsville Autosport has an excellent instruction CD on the swap. Visit the company at www.zionsvilleautosport.com.

        The M70 V12 conversion is another matter. We only know of one shop that is either considering it or in the process of doing it. Visit www.koalamotorsport.com and fire off an e-mail to owner Brett Anderson. There is no doubt that this conversion would require a great deal of fabrication in the engine compartment and perhaps the transmission tunnel. You would need to find a six-speed manual gearbox from an early 850i, which would be extremely difficult unless you want to order it from BMW. A custom driveshaft would have to be fabricated, but the large E30 differential is quite robust. There is no doubt that you'd need the largest brakes you could find, and I would say a conversion to E30 M3 5x120mm hubs would be in order. You'd need custom threaded front struts, custom Bilstein shocks, and there would be a great deal of trial and error with the suspension. My feeling is that, by the time you're done paying Anderson, you could have yourself a spiffy 850i six-speed with the drivetrain already installed, and some change left over for a tuned suspension, chips, and exhaust.



        --------------------------------------------------------------------------------

        E30 325is
        I recently bought a 1987 BMW 325is in mint condition. I wouldn't mind getting over 200 ponies to the wheels. What do you think would be a good start? Bavarian Autosport computer chip, exhaust and intake. Lets hear what ya think!
        John Meagher
        via the Internet


        The chip, intake and exhaust are the standard mods, John, and they'll put you over 200-hp. Bear in mind you'll want to have the rest of the engine is good tune as well--plugs, cap, rotor, valve adjustment and coolant service.

        Let's talk a bit about coolant. Coolant service is particularly important on Bimmers. I recommend changing coolant every two years using Original BMW anti-freeze mixed 50-50 with distilled water. For some reason, BMW engines are very suceptible to aluminum oxidation caused by the phosphates in every brand of anti-freeze except the factory product--the oxidation is the white schmoo that forms under water hoses. This stuff clogs coolant pasages, causing phantom overheating and head gasket failures.

        On the M20 "i" engine, aluminum oxidation clogs the water jacket on the throttle body, causing a coolant leak. Coolant can dribble from the water jack on the throttle body down onto the big electrical connector underneath it, causing driveability problems and precipitating a potentially expensive repair. If the pins in the connector are ruined, you have to replace each one individually. It can easily take a skilled technician eight to ten hours.

        Remember: Change brake fluid each year, coolant every other year. You may also wish to consider a suspension upgrade. BMW's in general and the E30 in particular respond dramatically to a set of shorter, stiffer springs, Bilstein Sport shocks (use Bilstein HD shocks with stock springs), and larger sway bars. On the E30, you can also swap out the original front control arm bushings for sold offset units for the E30 M3. In addition to being a stronger bushing, the offset will aid in high-speed stability by dialing in more postive caster. You can even buy E30 M3 aluminum control arms and save 4 lb per side over the garden-variety steel E30 control arms.

        And in the rear, you'll get a lot more zoot out of an E30 325i five-speed if you swap in a 4.10 limited-slip differential from an E30 M3. This swap is plug-in and play, and will afford a great deal more acceleration at the expense of increased engine speed at any given road speed, and a little more fuel. Real world top speed should not be affected, because the car won't pull redline in the overdriven fifth gear with the 4.10 or the stock 3.73.

        Comment


          #5
          hell that's a lot of words. Seems like some good info though.
          BEERTECH

          Comment


            #6
            Mike Miller, Pete McHenry... others, good advice is abound.

            The E30 3 Series is extremely versatile in terms of tire sizing, able to run 14-, 15-, 16-, and 17-in. tires. However, getting a wide contact patch while maintaining the proper overall tire height is another matter. The widest tire you can run on an E30, assuming proper offset and a willingness to roll fender and quarter panel lips if necessary, is 225/50-15 on a 7x15-in. wheel. I've never seen anything larger than that without fender flares. In terms of profile, the hottest setup is 215/40-17 on 7.5x17-in wheels, which given correct offset will not rub the stock bodywork. If you're set on the BBS RKs, try some better tires and see what happens. But on balance, I would say 215/40-17 is probably best suited to your car in terms of contact patch width and tire profile.

            Now, 7x15-in. E30 wheels are easy to find--the factory even has two different styles you can order through dealerships. But finding 7.5x17-in. E30 wheels with 4x100 bolt patterns in the proper offset so as to avoid spacers is more difficult. I would recommend you get with www.tirerack.com or www.tires.com and see what is available. Also bear in mind this setup is likely to be a great deal heavier than the original wheel and tire assemblies. Keep close tabs on wheel bearings and suspension parts, and consider swapping in E30 M3 aluminum control arms for a 4.4-lb weight savings per side. The E30 offset control arm bushings, which may be used with steel control arms too, are also wonderful things. Either job will necessitate a front end alignment to reset the toe.

            I would not recommend staggering the tire and wheel sizes front to rear unless you don't care about maintaining correct tire height and don't care about creating a grossly understeering car. And they would probably rub, too.

            Comment


              #7
              E30 325is Exhaust Question
              Hey, I just googled to this site when I was searching for help with my exhaust system. I have a 1989 325is with 204,000Km. It runs great, and it's the best car ever! I have recently put on an Ansa cat-back system, and I was wondering if there is a big difference between a $300 free-flow system and a $700 free-flow system. Will removing the catalytic converter noticeably increase power?
              Kav
              via the Internet


              Nice car. The 1988-on E30 325is is a very durable and desirable Bimmer.

              A big difference? No. But you can reasonably expect a high-performance cat-back exhaust system to net some increase in power on the E30 -- if you're a dynamometer. Whether you as a driver would notice it on a mature engine is not something we can predict. It will certainly sound better.

              The restriction in these cars is not the catalytic converter or exhaust system behind it, it is in the exhaust manifolds and downpipe. So, the way to free up the exhaust on a 325i engine is to fit headers with a cat, and whatever exhaust you want downstream. Stahl and Supersprint make headers for this application. Supersprint headers are commonly available, but Stahl units are harder to find. Try www.perfauto.com.

              That said, if your catalytic converter is partially clogged or otherwise worn, you might notice an increase in performance from removing it. But that increase wouldn't be due to any inherent restriction in the design of the unit.

              Comment


                #8
                i'm waiting for summer brake to dedicate so much to reading all this with out pics

                Comment


                  #9
                  Originally posted by Aptyp View Post
                  i'm waiting for summer brake to dedicate so much to reading all this with out pics
                  Whats with bumping all these several year old threads ??

                  E30 M3 / E30 325is / E34 525iT / E34 535i

                  Comment


                    #10
                    Haha uh oh I smell and incoming flame attack
                    Advanded Delphin Division
                    My e30s: 1987 325i/1994 318iT

                    Comment


                      #11
                      old school

                      never too old to read again ! Great

                      Comment

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