The car currently has a Dinan Stage 5 engine. But that wasn't always the case!
I originally did a Dinan Stage 2 upgrade which consisted of the cold air intake and the software. I never dynoed the car, so who knows the performance benefit? The car did develop a wonderful voice with this mod - it sounds stock under 5000 RPMs but makes an amazing roaring sound above that (check out this wav file for sample: Sears Point).
The Dinan component is certainly a well made product and looks nice under the engine compartment. It has the added benefit of being CARB-certified which is great for me because I live in Kalifornia. But the product does have a few caveats: price, maintenance and possibly performance. Price speaks for itself. Maintenance for this product is a bit more difficult then competitive products from ECIS or Conforti because you have to remove the headlight to service the filter. It takes me 45 minutes to clean my air filter instead of 15 minutes. Performance is also potentially not as good as the other products because the long tube design of the air intake can theoretically increase the effort required by the engine to ingest air. As such, I would recommend to other drivers to look into the Conforti air intake, which is still expensive, but a very solid design and looks great under the hood or the ECIS intake, which isn't quite as smooth looking as the Conforti piece but offers similar performance Intake Shootout.
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| Stage 2 Engine | S&B Filter, Dinan Supplied K&N & Conforti Supplied ITG |
My next engine mod was to add a Supersprint DTM exhaust. Again I didn't dyno the car, but the car lost some weight (21.21lbs to be exact - Ron Stygar), and developed a slightly lower tone to the exhaust... so perceived performance was up:) The DTM tips normally are a bit much, but I think they integrate very well with the lower valence and the aggressive stance of the M Roadster. The Supersprint exhaust is of the highest quality materials and workmanship. It fits like a glove and is only ever so slightly louder and deeper then stock.
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The next engine mod was adding an ERT Underdrive Pulley. The underdrive pulley is a mechanical mod and therefore isn't prone to the "OBD-2-style" arguments of whether it is effective or not as shown by Chris P's Dyno (thank you Chris P). It is probably the most effective engine mod you can do. From the first pictures below you can see that the pulley makes power by "underdriving" the electrical components (not the A/C) and also improves "spool up" by lightening the rotating mass coupled with the crankshaft (like a lightweight flywheel). The amount of underdriving still maintains the required voltage of the system (click here). There is an article (click here) by Steve Dinan claiming the underdrive pulley can cause problems for an engine in two ways: tampering with the electrical system and increasing stress on the crankshaft. The problem is that Dinan never uses empirical data, just hypothetical examples. Sure, you can say that underdriving too much is a bad thing, but you can also say drinking too much water is a bad thing. I say, "Show Me The Data!" In truth, the above reference I cited shows there are minor electrical implications for the mod and ERT did a study (click here) which showed that a lightweight flywheel causes more resonance in the crankshaft then the underdrive pulley. Dinan (bless his heart because he does do some great work on BMWs) sells a lightweight flywheel (for many times the price of the pulley) and doesn't sell an underdrive pulley, so do you think he is biased? You make the call. Suffice is to say that the flywheel and the pulley should never be mixed.
My M Roadster has the new double pulley design from ERT, but I also have one of older single pulley designs to put into the 328i. The original design from ERT is the single pulley design and is the same design offered by a few other companies such as '02 Performance. The single pulley offers the same performance benefit as the double pulley design... the only benefit of the double pulley it that it is easier to install. ERT closed the older design out for $150. The pictures below show how the system works. In the stock setup the accessory pulley and A/C pulley are separate pieces that sit nested on the end of the crankshaft. The single pulley replaces the stock accessory pulley with a slightly smaller pulley made of lightweight aluminum as opposed to the heavy stock pulley but retains the factory A/C pulley (which is already made of lightweight aluminum). The problem is that there is some variance in the pulley alignment such that at the factory A/C pulleys and accessory pulleys have to be matched on each engine. In order to work around this problem, the single pulley design sometimes requires shims to properly space the A/C pulley out from the accessory pulley. The double pulley replaces both the accessory pulley AND the A/C pulley so there is no needs for shims. The weight and percentage of underdriving remain the same, so there is not performance benefit. Also notice that because the A/C is driven off a dedicated pulley the A/C isn't effected by the underdrive pulley. (I apologize for not getting the reference lines in the first picture more parallel, I was winging it in the garage).
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Yep, power corrupts. My next mod was the entire Dinan Stage 5 setup. The Dinan Stage 5 engine consists of the cold air intake, an oversized airflow meter (HFM) from the European M3 (3.5" instead of 3"), a bored-out throttle body (66.5mm vs 64.5mm), a Schrick intake manifold and software designed to bring the whole package together. To help with cost, I purchased the HFM from ECIS who has a much better price. The Schrick was ported and polished by hand (instead of eXtrude Honed) because the manifold is made of aluminum and is very rough inside the runners and plenum in comparison to the stock thermoplastic manifold that is smooth. The Schrick is also powdercoated to appear stock. As it stands the car needs a bit more tuning. There is a slight, but noticeable drop in torque, but the high RPM operation of the engine is fierce.
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| Stage 5 Engine | ||||
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The engine mods are fun, but I believe the biggest bang for the buck driving improvement came from suspension mods. Once again I stepped my way through a few stages to get to the present state of tune.
The first mod was to switch to the Dinan shocks/struts and springs. On the street it is very evident that the stock suspension is allows the car to squat under acceleration, dive under braking and roll in the corners. On the track the stock suspension shows some really weird hopping attitude which makes the car really twitchy. And lets not forget the giant amounts of understeer the factory dialed in to keep us from wrapping the car around a pole. The Dinan Stage 1 suspension does a great job of giving the car the ride it should have some with from the factory. It lowers the car every so slightly (maybe a 1/2"), stiffens the springs and refines the dampening. The end effect is a ride that doesn't feel harsh (though it is stiffer then stock it could easily be mistaken for an OE sport suspension) but rids the car of the motorboat-style squatting and diving. It also lessons the body roll (not enough) and understeering (also not enough) while curing the car of the twitchiness it displayed on the track. NOTE: If you are track or autoX bound don't limit yourself to just upgrading the shocks and springs because you should update you camber while the shocks/springs are out of the car... it will save you money down the road. Read on to see why.
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| Koni Adjustable Strut |
The next step in the suspension world was the sway bars. The Dinan sway bars are adjustable in the front and rear and measure 22mm/22mm front and rear in comparison to the stock 22mm/18mm. The sway bars make the car corner very flat and make a significant contribution to getting rid of understeer. The ride quality also seemed to improve over the Stage 1 suspension, but I am not sure why that would be the case. The Dinan sway bars are very well engineered and fix two other problems that the factory sway bars have. The first problem Dinan addresses is that the factory bars tend to pop out of the links when you jack the rear end up (although sometimes they jump out on their own). Dinan sway bars have cotter pins on the end to hold them in place. The second problem Dinan addressed is the tendency for the stock sway bar mountings to bend, or in extreme cases rip off! The Dinan setup welds in place gussets to the factory mounts which provide plenty of reinforcement.
Understeer still dominates the ///M Roadsters handling attitude even with the Stage 2 setup. The only way to turn the ///M into a neutral handler is to get more negative camber for the front wheels. The best way to do that is through camber plates (aka upper strut bearings). While there are adjustable camber kits and camber plates you can buy from Dinan, you can get a great camber setup by merely swapping the stock camber plates (sometimes called upper strut bearings) from side to side. Take the left plate and mount it on the right side, and take the right plate and mount it on the right side. If you do this when the shocks/springs are removed it is a 30 minute job. If you don't do it then it is a two hour job later. I wish somebody told me that before I did my Stage 1 install! NOTE: This mod only works on e36 M3, M Coupe and M Roadster. Standard e36 models need to purchase the M upper strut bearings which will work fine on the standard cars.
In order to get some additional camber quick I used a BMW part (add number) known as a crash bolt. Crash bolts were designed to adjust camber on cars that have some sort of alignment problem usually caused by a crash. The camber bolts typically yield plus or minus .5 degrees of camber and on my car resulted in a total front camber setup of -2.1 degrees. The downside to cambers bolts is that they are somewhat of a kludge. It is possible for the bolts to slip which would result in camber changes while you drive - UGLY! So that is what I run for now, but I will be swapping my camber plates when I have a chance. Here is a good reference on camber bolts: Camber Bolts.
The Dinan strut brace is a great piece of jewelry. In some ways I believe it could be helpful, but I believe there are some other solutions that potentially yield better results. The number one choice for a strut brace in my opinion is one that is a solid unit with no hinges (most of the big name units use some sort of joint or hinge... Dinan, RD, Eibach, Bavarian Auto, BMP, AA, Strong Strut and others). The only bar that I know of that will work on the ///M Roadster is the JT Designs bar.
The stock ///M brakes have great stopping power. The problem with them is that they generate more dust then Pig Pen and they fade on the track faster then a cheap pair of jeans in the wash.
My first mod was to change my brake pads. The first set of aftermarket pads I tried was the EBC Red pads. Compared to stock these pads produced much less dust on the street, required no warm up for street use and didn't fade on the track. The problem was that while performance didn't fade on the track the pad material disappeared down to the backing plates in two track days! Ouch. So my next idea was to switch to EBC Greens (cheaper) for street use and to use EBC Yellows on track days. By staying with the same company the street and race compounds will not interfere when run on the same rotor. The EBC Green pads were great on the street. The had by far the best feel and "bite". The problem was the EBC Yellows didn't offer any better track life. So for street use only, I would say my experience with the EBC Greens was excellent, although some people have had warping issues. So my current setup is now PFZ's pads for street use and PF90'ss for track use. The PFZ's don't dust much and have comparable feel to stock, but less bite then the EBC Greens. The PF90's are amazing. Absolutely no fade and after two track days they show little wear and the rotor don't look any worse off.
European ///M's come with cool two-piece floating rotors. The rotors differ from the US rotors because the "rotor hat" is made of lightweight aluminum and connects to the braking surface with several small pins. The benefits are three fold: One, the rotors are less susceptible to warp because the rotor hat and braking surface can expand at different rates allowing some play in the system before warping occurs. Two, the rotor hats won't conduct as much heat to the wheel bearings. And Three, the rotors are a little lighter in a crucial place to loose weight... they are an unsprung mass and a rotational mass. Hardcore track junkies know that unsprung mass is a key element in determining the suspension's ability to adhere to the road as it changes topography and rotational masses are critical in that they are 3-10 times more of a factor in braking and acceleration then a the car's body weight. Saving a pound in the rotor is like saving 3-10lbs from the car.
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| Fischer Brake Line On Front Of Car |
After the shocks/springs (okay, and the cupholder) the worst OE part on the car is the Dunlopsided tires. And for performance gains you can't beat a set of lightweight wheels (as an unsprung rotating mass lighter wheels allow the car to handle better, brake shorter and accelerate faster).
The M Roadster is very hard to find wheels for. The very small offset means most wheels flat out won't fit and the few that do typically require spacers. In my search for lightweight wheels that are affordable I came to BBS. BBS makes very high quality wheels that differentiate themselves immediately when shown next to cheaper wheels. There were two BBS wheels that I liked... the BBS RC and the BBS RK. At the time of my purchase the BBS RK was only available in a painted finish that I liked, but didn't love, and the size for the rear wheels was going to have to be 17x10 which would have screwed with my autoX classification (which I shot to hell anyway, but wasn't originally planning on doing it). So I went with 17x8 and 17x9 BBS RC wheels in a polished finish. The polished finish not only looks better but increases the strenght of the wheel because the polishing process uses small balls to polish the wheel and this creates a "shot-peen" like strength increase. Recently the BBS RK became available in the same finish as the RCs (Press Release).
The BBS wheels are very lightweight, 17lbs for the 17x8 and 17x9. The stock wheels are 21lbs front and 24lbs rear. Losing weight in the wheels is like losing 3-5 times as much weight from the body of the car... or in my case 66-110lbs. The difference is noticeable. The RC's and RK's both require a spacer to be used. It is a custom BBS piece and BBS supplies the spacers and special lug bolts to make the setup work. I have no complaints about the setup except that it is a pain cleaning the RC's... it would be much easier to clean the RK's.
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There is nothing like new tires to help fix what ails the M Roadster/Coupe. The Dunlopsided tires that come stock are the worst. After doing my darnedest to grind these things down to the treads at track events I decided to get new street tires and dedicated track tires. After a lot of research I decided to go with Yokohama AVS Sports in 235/40 and 255/40 sizes (stock was 225/45 and 245/40). The front tires are a little smaller in diameter then the stock tires, but this appears to be a good thing because the car was just out of the BMW-specified rake spec. With the lower aspect front tires the car now falls right in the middle of the BMW rake-spec and the larger width allowed me to get larger rear tires and yet still maintain the stock front to rear 20mm difference in width. The rears going up one size means the tires no longer have that "too small" for the wheel look and, coupled with the rim protection lip of the AVS Sports, offer much better protection for the rims. The AVS Sports have excellent grip on dry or wet asphalt as well as instant turn in (probably in many ways attributable to the lower ratio in the front).
For track use I opted for the equally impressive Kumho VictoRacers. Not only are these tires the favorite tire in the paddock at most track events, they also are the cheapest R-compound tread out there. The tires are sized as 225/45 and 255/40, but the width of the tires is exactly equal to my street tires. The diameter for the 225/25 is larger. The tires provide amazing amounts of grip on the track (far more then any street tire) and are the biggest performance improvement you can make to a car for track use. I would however caution against it getting R-compound tires too soon! R-compound rubber can mask a driver's bad habits at low speeds and then fling those bad habits back in the driver's face at high speeds. The R-compound also allows more stress to be placed on the car's suspension because the higher levels of grip allow more energy to be transferred to parts like sway bar mounts and shock mounts. So make sure you are ready for the tires in terms of skill and have all your suspension parts checked and strengthened as necessary (like the Dinan sway bar mount gussets) before running with R-compound tires.
My first day with race rubber was a strange one. At first the tires felt like more of a hindrance then they were helpful. I was used to the instant turn in that the lower profile AVS Sports exhibit. The trick (as always) was in the driving. The Kumho's require (and reward) the driver that allows the tires to take a good "set" before turning in. Something as simple as an extra half second of setup for these tires and allows them to take a set where they grip at forces that would have put the AVS Sports into a spin.
UUC offers a very comprehensive short shift kit. In the end Ron Stygar seems to have developed a kit that is much cheaper and just as effective. If you drive any BMW other then the M Roadster it is probably worth the money to upgrade to a short shift kit. But I feel the factory M Roadster/Coupe has a short enough shift and isn't really necessary (though the e36 M3 does need a shift kit).
Clutch stops have been discussed ad nauseum on the message board, so I'll keep this short and sweet. I bought the UUC Clutch Stop which was the only available clutch stop at the time. Ron Stygar has since developed a gorgeous stealth clutch stopped manufactured in Delrin. It is the clutch stop I would get. If you have any problems with side-to-side play in your clutch you shouldn't purchase a bigger clutch stop... ask Ron about his fix which properly replaces the spongy factory bushing with high-tech Delrin bushings.
Ever notice how if you try to shift (especially in a corner) that the gear isn't always where it should be? The factory BMW tranny mounts are designed for comfort instead of performance. They have an hourglass shape that easily deflects. After having this strange phenomenon happen to me at the top of the Corkscrew at Laguna Seca and the top of the Cyclone at Thunderhill I decided to do something about it. I installed a set of the Tranny Mount Enforcers from UUC. The product works as advertised in that it has greatly reduced the deflection inherent in the stock mounts and it doesn't raise the interior noise level like some of the products out there that replace the entire transmission brace.
