J spaulding

As we all know most people sign on to these forums only when they need something. That's fine but I would like to take some time to talk about the
unbelievable engineering achievement of the R129 cars. Very few of us have ever even begun to tax the cornering ability of these cars or challenged the braking ability. These cars are close to 4,200 pounds of steel that is designed to protect us in case of a high speed collision as well as keep us automatically warm or cooled, entertained in a big way and provide us with a driving experience that parallels the substantial price of them. What other car can automatically raise the roll bar in a fraction of a second if we exceed the laws of physics? Plus.....a solid 28 mpg and 155 mile per hour top speed. I have had mine up to 120 mph twice and both times I let go of the steering wheel to play with the radio and the car didn't even move 6 inches out of its track. The convertible top, although not functioning perfectly after 15 years of use, still gathers attention from other sports car owners. I have personally owned 106 cars and this car is easily one of my top 5 favorites. My car is almost completely rattle free at
102K miles. Try that in a 1998 Corvette!! The trunk and doors shut with a
good solid sound that conveys the level of engineering that this car represents. Used parts are getting to be very reasonable if you look around on the web for a half an hour. I see these cars as one of the best $10-12K values around

cliffyk

You are getting 28 MPG; under what driving conditions?

The EPA rating for the '98 SL500 was 14 City/21 Highway for an average of 17 MPG. I do about 15-17 around the suburbs (45 to 60 mph here in the flatlands of NE Florida) and a consistent 22.5 during 80 mph or so long runs on I-95 and I-10.

I cannot imagine even getting close to 28.

The SL320s were rated 16/22...

J spaulding

My last check showed 19.3 with all town driving in Seattle. The trip I took to Oregon showed 25.6 and previous trips straight down I-5 showed just a hair under 28 but this is a straight 70 mph flat trip. I do all the small tricks that by themselves don't amount to much but together they probably add up to a 2-3 mpg improvement. Of course this entails using the only recommended oil of Mobil One 0W-40 European Formula. Secondly I try to limit if not completely clean out the engine by putting a 21 oz bottle of Techron in about every fourth tank. The first bottle or two causes all kinds of junk to fly out of the tail pipe but now I just get the added fun of having better performance. I don't know if it acts as an octane booster but it feels just the same. Good maintenance such as clean air filters, good plug wires and correct spark plugs always helps along with tire pressure at its recommended level instead of the smoother riding compromise.
By the way....I just tried a 99 cent bottle of octane booster from my local Dollar Store. It is superb....about as much fun as a guy can have for 99 cents. I looked into any possible problems with the cats on this mixture and I cannot find any factual information on the subject but only rumors.
I'm going with the magic juice until I find out for sure. The above mileage readings were WITHOUT any additives. The cars has a serious shine on it at all times by using liquid silicone on it (Speed Shine from Griots Automotive).

cliffyk

No one drives 70 on the Interstates here in Florida, 80 is the norm with 85 to 90 not being unusual, More than once I have been in a line of cars following FHP troopers at 90+

I will have to try driving 70 sometime and see how i can do.

BTW smooth, polished surfaces have higher drag than rough/dimpled surfaces. The roughness creates a turbulent boundary layer that is less likely to detach from the surface, it thus delays separation of the laminar flow from the surface as well. This reduces the volume of the objects vacuum "wake" and therefore reduces drag--more about that here.

A sphere has the highest drag of any shape, here is a graphic illustrating flow around about a smooth and a dimpled sphere:



The same is true for more aerodynamic shapes as well, the longer the flow separation can be delayed the less "wake" and drag.

For this same reason, polishing of intake tracts has fallen out of fashion (except among those who know no better). Here again a rough surface creates a turbulent boundary layer, however in an intake tract the turbulent layer serves to separate the laminar flow from the tract's walls, reducing friction for the main flow.

This is all quite counter-intuitive, it is however the way it is...

rich8566

I just averaged 25.6 mpg in my 2000 SL500 over 150 miles - 90% highway, 10% rural roads. Highway speeds averaged 70-75 mph. Not bad for an old V-8.

Jimmy Chen Shib

I do concur with the OP regarding the overall solid build quality. My 1997 SL600 has clocked north of 100k kms. and still going strong. Things that need attentions are the perishables and need to replace items. The latest (last month) was the A/C register unit.

Saying that, I do find the brakes a bit more desired if one wishes utmost confidence in stopping. However, this is all relative.

All in all, great to hear other owners who are happy with their SLs.

w/ smiles
Jimmy