SL/R129: Standing start acceleration
08-01-2003, 02:12 AM
#1
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Standing start acceleration
Other than just tromping on the gas pedal, is there a driving technique that improves the standing start of the R129?
I don't want to cause unnecessary wear and tear.
Not that standard 6.1 to 6.5 standard 0 to 60 time (as written in the magazines over the years) is bad. But in reality that seems to be a bit elusive.
A buddy helped time me on a few runs. The performance varies a lot from run to run. Sometimes close to 6.0 and other times up to 7.0 seconds.
That was befor MB replaced a air mass sensor on the extended warranty inspection / final standard warranty work visit to the service dept.
After that work I senced (or imagined?) better performance, but really have not timed accurately since then.
Some time in the future when it really counts (like maybe holding my own with a Mustang GT or other common sports / sporty car), with confidence, I'd like to be the best I can be off the line.
A professional car test drive article I read once (not Mercedes) claimed to achieve the best performance off the line with that particular automatic car by holding the brake and building revs before popping the break pedal.
I understand the basic numbers ... the 1999 R129 has 304 HP and 342 ft-lbs of tourque, the tourque being plentyfull and steady after 2,500 rpm. Not jumping off the line is a fairly often documented characteristic of the R129.
It is also written (and obvious on trial) that manually shifting the transmission is no better than the automatic doing it's work.
I imagine it would be pretty hard on the transmission to rev to 2,500 rpm while standing on the brake ... or dropping from neutral into drive at 2,500 rpm (I'm not 18 burning fish hooks any more).
Does switching off ESP on hot & sticky roads boost the initial tourque delivery? Whhel spin of cource is no good.
Not having any street racing experience, I wouild like to illiminate some trial and error.
Feedback would be appreciated.
I don't want to cause unnecessary wear and tear.
Not that standard 6.1 to 6.5 standard 0 to 60 time (as written in the magazines over the years) is bad. But in reality that seems to be a bit elusive.
A buddy helped time me on a few runs. The performance varies a lot from run to run. Sometimes close to 6.0 and other times up to 7.0 seconds.
That was befor MB replaced a air mass sensor on the extended warranty inspection / final standard warranty work visit to the service dept.
After that work I senced (or imagined?) better performance, but really have not timed accurately since then.
Some time in the future when it really counts (like maybe holding my own with a Mustang GT or other common sports / sporty car), with confidence, I'd like to be the best I can be off the line.
A professional car test drive article I read once (not Mercedes) claimed to achieve the best performance off the line with that particular automatic car by holding the brake and building revs before popping the break pedal.
I understand the basic numbers ... the 1999 R129 has 304 HP and 342 ft-lbs of tourque, the tourque being plentyfull and steady after 2,500 rpm. Not jumping off the line is a fairly often documented characteristic of the R129.
It is also written (and obvious on trial) that manually shifting the transmission is no better than the automatic doing it's work.
I imagine it would be pretty hard on the transmission to rev to 2,500 rpm while standing on the brake ... or dropping from neutral into drive at 2,500 rpm (I'm not 18 burning fish hooks any more).
Does switching off ESP on hot & sticky roads boost the initial tourque delivery? Whhel spin of cource is no good.
Not having any street racing experience, I wouild like to illiminate some trial and error.
Feedback would be appreciated.
08-06-2003, 01:22 PM
#2
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SL 500 AMG
Just like you said, hold brake and keep the rpm high and when ready to go release the brakes and step on the gas, I wouldn't recomond slammin' from N to D, that'll be harsh on your transmission. I'be beaten the new SL's 3 times already about a car lenght or so...
08-06-2003, 11:20 PM
#3
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To: SL 500 AMG
Your car with approximately 342 HP will beat a 2003 SL 500 (R230) every time wouldn't it. The R230 SL 500 has the same motor (302 HP) and transmission as my 1999 R129 ... plus they weigh a bit more.
I wonder if 1999 and later R129s (the latest standard V8 engine improvement) will actuall beat the new R230s by a bit because of the extra weight ... the SL 500s in each styling.
SL 55s of cource are a different story.
Your car with approximately 342 HP will beat a 2003 SL 500 (R230) every time wouldn't it. The R230 SL 500 has the same motor (302 HP) and transmission as my 1999 R129 ... plus they weigh a bit more.
I wonder if 1999 and later R129s (the latest standard V8 engine improvement) will actuall beat the new R230s by a bit because of the extra weight ... the SL 500s in each styling.
SL 55s of cource are a different story.
08-07-2003, 01:21 AM
#4
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1992 Mercedes 300E
No, I think an R230 would smoke (but not by much) any stock R129. My 1996 SL500 develops 315 HP as compared to the 302 HP for the 1999+ SL's, but the 1999+ SL's are .2 faster 0-60 than my 1996 SL500. The R230, now, weighs 680 lbs LESS than the R129 (or at least less than my R129), thus should be substantially faster:
BTW, a Mustang GT isn't much to worry about stock - I've had two of them. The models through 1998 only produce 215 HP - barely beat a PT cruiser, trust me. The 1999+'s produce 260HP/302 Torque, but still don't seem as fast as my SL500. 2003 Cobra's are a different story - 390 HP. Very fast. And they weigh about 1200 LBS less than the R129. But not as fast as my current Mustang GT (for sale, BTW), which produces 460 HP/468 Torque. Supercharged and fast as hell, but not nearly the car that the R129 is.
BTW, brake stands (hold the brake and rev the engine) are bad for the torque converter, and I wouldn't want to see what MBZ wants for one of those (not that it's stopped me for...er...experimenting
).
BTW, a Mustang GT isn't much to worry about stock - I've had two of them. The models through 1998 only produce 215 HP - barely beat a PT cruiser, trust me. The 1999+'s produce 260HP/302 Torque, but still don't seem as fast as my SL500. 2003 Cobra's are a different story - 390 HP. Very fast. And they weigh about 1200 LBS less than the R129. But not as fast as my current Mustang GT (for sale, BTW), which produces 460 HP/468 Torque. Supercharged and fast as hell, but not nearly the car that the R129 is.
BTW, brake stands (hold the brake and rev the engine) are bad for the torque converter, and I wouldn't want to see what MBZ wants for one of those (not that it's stopped me for...er...experimenting
).
Last edited by Santron; 08-07-2003 at 01:27 AM.
08-07-2003, 01:50 AM
#5
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Tourque converter. Humm ... sounds expensive! But fun to try now and then. Is that part included on the extended factor warranty I wonder? No worry ... I'll never wear such an item out.
For more than 1/2 the miles I put on, I have an audible acceleration and speed control warning system. This system would never allow such behavior. Her name is Rose and we've been married for 15 years.
I seem to recall reading a professional review saying weight was a problem for the R230s. That larger brakes, hardtop hardware and other goodies on the R230s had increased the weight.
Maybe someone else knows the stats?
For more than 1/2 the miles I put on, I have an audible acceleration and speed control warning system. This system would never allow such behavior. Her name is Rose and we've been married for 15 years.
I seem to recall reading a professional review saying weight was a problem for the R230s. That larger brakes, hardtop hardware and other goodies on the R230s had increased the weight.
Maybe someone else knows the stats?
08-12-2003, 06:04 PM
#7
MBWorld Fanatic!
Agree with SL500 AMG, the 129 is a bit heavier than the R230 but the difference is less than the weight of a passenger. The engine output of the SL500 was lower at the end of its life than at the start because of emissions and gas consumption stuff and the 5 litre engine was carried over to the R230 pretty much unchanged, so although the performance is a bit better, the new SL500 does have a reputation for being a bit under-powered, or put it another way, the car can take more power which is what the SL55 and SL600 provide.
Heavy duty standing starts are bad news if you care about your car. The SL drive train is well made and robust but not indestructible and the costs of any major repairs to it are ruinous.
Heavy duty standing starts are bad news if you care about your car. The SL drive train is well made and robust but not indestructible and the costs of any major repairs to it are ruinous.
