Performance and Reliability upgrades for 1988 W124 300E
03-31-2005, 04:34 AM
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1988 300E
Performance and Reliability upgrades for 1988 W124 300E
I recently signed up for this forum when I recently learned that I would be acquiring my mom's 1988 300E. Currently the car is in my dad's shop with both the engine and transmission removed for a complete engine rebuild (apparently MB engines start wheezing past 160,000 miles). Due to the ease of accessibility of essentially all of the internals, I would like to perform as many cost efficient, reliable modifications as possible. I am posting this thread in order to get feedback from members who have performed any of the modifications listed below in order to avoid any reliability issues.
My dad has ordered J&E custom forged pistons with a slight bump in compression and the cams have been sent to be reground to euro specs. Though neither of these two modifcations will be extreme, I would like to install a set of titanium - or at least stiffer - valve springs. Does anyone know if the other engine sizes contain stiffer valve springs that can be fitted onto the W124 heads with no modifications? Is there a company that can custom make valve springs or currently carry them?
Consequently, opening up the internals will not be as efficient without increasing external air and exhuast flow. I have read several posts on the Remus exhuast but do not wish to waste money if I can buy another aftermarket muffler (and have a custom cat-back mandrel bent system installed for much cheaper at my muffler shop). This is of course, unless the Remus exhuast is a fully tuned cat-back system. Did Remus specifically design their exhuast for the 300E flow characteristics? For those with Remus systems on their W124's; given a second chance would you buy the Remus system again or opt for another aftermarket muffler mated to a cat-back system? On the intake side, I must warn everyone. DO NOT ALTER YOUR INTAKE DUCTS OR AIR BOX. I just had a long discussion with my dad about the engineering that went into the entire aerodynamics of the front end and engine compartment. If you have a stock intake assembly, you should notice that the stock air duct angles towards the space in front of the radiator. This is due to the air flow characteristics through the front grille. The high pressure zone in front of the radiator forces the cool fresh air to ram into the low pressure air duct tube and into the air box. This occurs even when the car is moving 10mph. If you are wondering how hot air manages to avoid getting sucked into the duct when it is so close, you have not taken physics. Essentially, once the car is moving, or a slight breeze moves through the grille, the hot air immediately in front of the radiator is blown back into the engine compartment. The hot air may get sucked in at the first instance of acceleration from a dead stop, but as soon as the pressure zone builds, a majority of the cold clean outside air glances off the pressure zone in front of the radiator and is literally vacuumed into the intake duct (which becomes an extremely low pressure point due to the continuous consumption of air caused by the sucking of the pistons). This is the truly outstanding part of MB engineering, along with all the air channeling for just the intake and radiator assembly, the air that blows through the radiator then travels over the engine and begins to get sucked toward the ground (think of an airplane wing upside down). MB prevented this with that large plastic shield that covers the entire underside of the engine compartment. The shield dumps close to the torque converter (right in front of the torque converter on autos and in front of the clutch housing on manuals). This causes another low pressure zone to form behind the front bumper and underneath the belts (this is a very important pressure zone and thus it is recommended that you do not cut into your bumper [such as widening out those tiny vent slits] or change your bumper as this can affect the pressure zones. the front bumper is designed as a true air dam by allowing dead air to form behind it to create a low pressure suction zone which then creates downforce). If this is somewhat hard to envision, imagine the air coming through the front grille. A majority of the cold air skims off the high pressure zone created by the resistance of the radiator fins and gets sucked - but really rammed at this point since the faster the air moves, the greater the pressure differential, thus the harder the air is sucked/rammed - into the intake duct. The remainder of the air that passes through the radiator blows over the engine and is suddenly thrust down to the very edge of the shield by the transmission. If you look at the shield, it is quite some distance. You are essentially looking at a rudimentary wing. This can be explained by that all-too-important dead air zone created by the front bumper. The dead air directly behind the bumper creates a low pressure zone because it catches and specifically slows all the air that is trying to move underneath the car (the air dam pushes the air to the sides to create that dead/slow zone behind it). So now the air underneath the shield is moving slow and the air above the shield (the entire engine compartment sits above the shield) is moving fast (the air flows onto the bottom of the inline six block and then rushes low towards the far back end of the shield.) In the simplest of terms, the faster air rushes to meet the slower air (an airplane wing creates lift with that teardrop shaped upper segment and the extremely flat lower segment. the air has to move around that small hump on the top of the wing and thus takes slightly more time to do so. the air underneath the wing flows freely past due to the flat surface. thus the faster [high pressure] moving air pushes up towards the slower moving air [low pressure] due to the lower resistance). If you flip that wing upside down, you are now looking at the aerodynamics of the engine compartment. MB designed the entire front clip to act as a more efficient cooling unit (fast air will move the heat away faster, and it can move this fast because it is actually being sucked towards the low pressure zone at the bottom) and as a giant inverted wing that creates downforce.
With that said, the only modification I could see in this area was to wrap the outside of the air intake ducts with heat shield tape since it happens to sit very close to the radiator. Also one of the radiator hoses passes very close to the mid section of the short intake tube. This should also be shielded on both the radiator hose and the entire length of the intake duct assembly (essentially from the mouth of the intake tubing to where it enters the air box).
It becomes very clear that any intake modifications (cold-air intake kits) cannot achieve the same efficiency nor pressure differentials (and thus the same ram-air affect) as the stock ducting. Also the circular air box is so big to allow a broader power band and to allow the air to swirl in a vortex into the throttleplate. In essence the large filter can actually filter a larger volume of air with greater efficiency than a snub-cone filter.
Onto brakes: If you look on the stock 1988 W124 300E front bumper, you will notice that there are two square holes cut low for tow hooks. We plan on removing these tow hooks and fabricating brake duct inlets for the front brakes. These holes are stock and are engineered into the aerodynamics. Some of the more observant may frown at the thought of all that hot air from just above the road being ducted over hot brakes, but again, the sheer increase in air volume and its velocity over the hot brakes will negate the fact that you are venting hot air over them. If you don't believe me, walk up to any NASCAR Stock Car and observe how low the brake duct vents are cut into the body. Yeah, they put them almost on the ground. This should help eliminate the brake fade on stock rotors as long as you don't autocross. This modification is recommended for everyone due to the sheer physics of how rapidly heat can facilitate rotor/pad deterioration. The rear brakes need no scoops since a majority of the braking is done on the front and also the large surface area of the drums will allow them to cool relatively quickly.
I hope all this aerodynamics blabber is not boring anyone, but one does need to look at the rear of the car as well. Again, the rear STOCK bumper allows a dead air space to form right above the bumper and just below the lip of the trunk handle. The entire space is about the height of the tailights and the main reason why the trunk is indented in that whole rear midsection of the 1988 300E (allows a greater volume of air to remain trapped). Again, simple physics show us that the fast moving unobstructed air that is moving across the top of the trunk begins to push down on the low pressure zone nestled above the bumper. This validates the utility of the trunk lip (it is an aftermarket part that is placed at the very edge of the top of the trunk towards the rear and is seen on a lot of M3s). The lip acts as an air dam and creates resistance to the fast moving air that slips down the rear window and across the trunk and thus enlarges the area of slow moving air behind it. My dad loves the 16V wing but I find it a little too big and gaudy for my taste, I prefer the subtle trunklid lip far more for its sleeper qualities.
I'll post more to this later but I need to sleep before I stop making sense.
My dad has ordered J&E custom forged pistons with a slight bump in compression and the cams have been sent to be reground to euro specs. Though neither of these two modifcations will be extreme, I would like to install a set of titanium - or at least stiffer - valve springs. Does anyone know if the other engine sizes contain stiffer valve springs that can be fitted onto the W124 heads with no modifications? Is there a company that can custom make valve springs or currently carry them?
Consequently, opening up the internals will not be as efficient without increasing external air and exhuast flow. I have read several posts on the Remus exhuast but do not wish to waste money if I can buy another aftermarket muffler (and have a custom cat-back mandrel bent system installed for much cheaper at my muffler shop). This is of course, unless the Remus exhuast is a fully tuned cat-back system. Did Remus specifically design their exhuast for the 300E flow characteristics? For those with Remus systems on their W124's; given a second chance would you buy the Remus system again or opt for another aftermarket muffler mated to a cat-back system? On the intake side, I must warn everyone. DO NOT ALTER YOUR INTAKE DUCTS OR AIR BOX. I just had a long discussion with my dad about the engineering that went into the entire aerodynamics of the front end and engine compartment. If you have a stock intake assembly, you should notice that the stock air duct angles towards the space in front of the radiator. This is due to the air flow characteristics through the front grille. The high pressure zone in front of the radiator forces the cool fresh air to ram into the low pressure air duct tube and into the air box. This occurs even when the car is moving 10mph. If you are wondering how hot air manages to avoid getting sucked into the duct when it is so close, you have not taken physics. Essentially, once the car is moving, or a slight breeze moves through the grille, the hot air immediately in front of the radiator is blown back into the engine compartment. The hot air may get sucked in at the first instance of acceleration from a dead stop, but as soon as the pressure zone builds, a majority of the cold clean outside air glances off the pressure zone in front of the radiator and is literally vacuumed into the intake duct (which becomes an extremely low pressure point due to the continuous consumption of air caused by the sucking of the pistons). This is the truly outstanding part of MB engineering, along with all the air channeling for just the intake and radiator assembly, the air that blows through the radiator then travels over the engine and begins to get sucked toward the ground (think of an airplane wing upside down). MB prevented this with that large plastic shield that covers the entire underside of the engine compartment. The shield dumps close to the torque converter (right in front of the torque converter on autos and in front of the clutch housing on manuals). This causes another low pressure zone to form behind the front bumper and underneath the belts (this is a very important pressure zone and thus it is recommended that you do not cut into your bumper [such as widening out those tiny vent slits] or change your bumper as this can affect the pressure zones. the front bumper is designed as a true air dam by allowing dead air to form behind it to create a low pressure suction zone which then creates downforce). If this is somewhat hard to envision, imagine the air coming through the front grille. A majority of the cold air skims off the high pressure zone created by the resistance of the radiator fins and gets sucked - but really rammed at this point since the faster the air moves, the greater the pressure differential, thus the harder the air is sucked/rammed - into the intake duct. The remainder of the air that passes through the radiator blows over the engine and is suddenly thrust down to the very edge of the shield by the transmission. If you look at the shield, it is quite some distance. You are essentially looking at a rudimentary wing. This can be explained by that all-too-important dead air zone created by the front bumper. The dead air directly behind the bumper creates a low pressure zone because it catches and specifically slows all the air that is trying to move underneath the car (the air dam pushes the air to the sides to create that dead/slow zone behind it). So now the air underneath the shield is moving slow and the air above the shield (the entire engine compartment sits above the shield) is moving fast (the air flows onto the bottom of the inline six block and then rushes low towards the far back end of the shield.) In the simplest of terms, the faster air rushes to meet the slower air (an airplane wing creates lift with that teardrop shaped upper segment and the extremely flat lower segment. the air has to move around that small hump on the top of the wing and thus takes slightly more time to do so. the air underneath the wing flows freely past due to the flat surface. thus the faster [high pressure] moving air pushes up towards the slower moving air [low pressure] due to the lower resistance). If you flip that wing upside down, you are now looking at the aerodynamics of the engine compartment. MB designed the entire front clip to act as a more efficient cooling unit (fast air will move the heat away faster, and it can move this fast because it is actually being sucked towards the low pressure zone at the bottom) and as a giant inverted wing that creates downforce.
With that said, the only modification I could see in this area was to wrap the outside of the air intake ducts with heat shield tape since it happens to sit very close to the radiator. Also one of the radiator hoses passes very close to the mid section of the short intake tube. This should also be shielded on both the radiator hose and the entire length of the intake duct assembly (essentially from the mouth of the intake tubing to where it enters the air box).
It becomes very clear that any intake modifications (cold-air intake kits) cannot achieve the same efficiency nor pressure differentials (and thus the same ram-air affect) as the stock ducting. Also the circular air box is so big to allow a broader power band and to allow the air to swirl in a vortex into the throttleplate. In essence the large filter can actually filter a larger volume of air with greater efficiency than a snub-cone filter.
Onto brakes: If you look on the stock 1988 W124 300E front bumper, you will notice that there are two square holes cut low for tow hooks. We plan on removing these tow hooks and fabricating brake duct inlets for the front brakes. These holes are stock and are engineered into the aerodynamics. Some of the more observant may frown at the thought of all that hot air from just above the road being ducted over hot brakes, but again, the sheer increase in air volume and its velocity over the hot brakes will negate the fact that you are venting hot air over them. If you don't believe me, walk up to any NASCAR Stock Car and observe how low the brake duct vents are cut into the body. Yeah, they put them almost on the ground. This should help eliminate the brake fade on stock rotors as long as you don't autocross. This modification is recommended for everyone due to the sheer physics of how rapidly heat can facilitate rotor/pad deterioration. The rear brakes need no scoops since a majority of the braking is done on the front and also the large surface area of the drums will allow them to cool relatively quickly.
I hope all this aerodynamics blabber is not boring anyone, but one does need to look at the rear of the car as well. Again, the rear STOCK bumper allows a dead air space to form right above the bumper and just below the lip of the trunk handle. The entire space is about the height of the tailights and the main reason why the trunk is indented in that whole rear midsection of the 1988 300E (allows a greater volume of air to remain trapped). Again, simple physics show us that the fast moving unobstructed air that is moving across the top of the trunk begins to push down on the low pressure zone nestled above the bumper. This validates the utility of the trunk lip (it is an aftermarket part that is placed at the very edge of the top of the trunk towards the rear and is seen on a lot of M3s). The lip acts as an air dam and creates resistance to the fast moving air that slips down the rear window and across the trunk and thus enlarges the area of slow moving air behind it. My dad loves the 16V wing but I find it a little too big and gaudy for my taste, I prefer the subtle trunklid lip far more for its sleeper qualities.
I'll post more to this later but I need to sleep before I stop making sense.
03-31-2005, 10:05 AM
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88 260 E
Dan-O,
U might want to contact BergWerks.com about your valve springs & Remus Exhaust questions.. They're the most knowledgeable on MB performance
especially W124's. The owner owns a 500.
~Cali
BergWerks
6318 Sepulveda Blvd.
Van Nuys, CA 91411
Tel: 818-781-2770
E-mail: Info@BergWerks.com
U might want to contact BergWerks.com about your valve springs & Remus Exhaust questions.. They're the most knowledgeable on MB performance
especially W124's. The owner owns a 500.
~Cali
BergWerks
6318 Sepulveda Blvd.
Van Nuys, CA 91411
Tel: 818-781-2770
E-mail: Info@BergWerks.com
04-04-2005, 05:15 PM
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That was quite a read. Seems like you've done quite a bit of research on the "Cold Air IntakeK I'm happy to see that you not going to go that route. IMHO, it is one of thoe modifications that people do so that they can brag to their buddies about.
How much is the cam profile going to change after your regrind? Somehow, I think it may not be enough to (IMO) justify stiffer valve springs. From my expirience with other cars they are not needed unless you get into cams that are high lift, long duration. (Once again IMO) this may fall into the realm of parking lot performance modification, great for when your parked but does little for real world performace.
I own a completly stock '89 300E. I've considered modifying it but when you look at expense vs benefit it wasn't good enough for me. Besides, it's a wonderful, durable, comfortable highway car, that all I need/want out of it.
How much is the cam profile going to change after your regrind? Somehow, I think it may not be enough to (IMO) justify stiffer valve springs. From my expirience with other cars they are not needed unless you get into cams that are high lift, long duration. (Once again IMO) this may fall into the realm of parking lot performance modification, great for when your parked but does little for real world performace.
I own a completly stock '89 300E. I've considered modifying it but when you look at expense vs benefit it wasn't good enough for me. Besides, it's a wonderful, durable, comfortable highway car, that all I need/want out of it.
