Mercedes V12 Bi-Turbo
09-10-2005, 10:00 AM
#46
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Sab,
The SL55 is out of it's league with a 928 at 10 psi, at least once at speed.
https://rennlist.com/forums/928-forum/153248-sl55-amg-kill.html
I was pleasantly underwhelmed.
The SL55 is out of it's league with a 928 at 10 psi, at least once at speed.
https://rennlist.com/forums/928-forum/153248-sl55-amg-kill.html
I was pleasantly underwhelmed.
09-10-2005, 12:04 PM
#47
Rennlist Member
Originally Posted by Jim Nowak
The SL 65 was running consistent 11.4's and the E55 on a 65 shot of NOS ran an 11.13 1/4 mile. The Sl 65 with an amateur at the wheel can run 11's so the 12.4's you are seeing are probably Mercedes factory specs that are way too conservative much like the hp ratings ofn their forced induction engines.
Normy, he must have been running the stock Conti crap tires and spinning his tires all the way down the strip. Those cars are truly lightning fast and can consistently beat many of the fastest sports cars in the world in a straight line. The tq and hp are truly sick for a such a luxo cruiser.
Normy, he must have been running the stock Conti crap tires and spinning his tires all the way down the strip. Those cars are truly lightning fast and can consistently beat many of the fastest sports cars in the world in a straight line. The tq and hp are truly sick for a such a luxo cruiser.
For $200K it better be. The SL 65's I saw in the show room came with Michelins stock.
They may be fast in a straight line but they can't handle. R&T shows a 12.0 1/4 which I usually find they are a bit optimistic and abusive to achieve the numbers they get. It was Normy who stated the 12.4's. Weighing in at almost 4500 pounds they have a heavier power to weight ratio than my car. I am sure they must have exhaust work or chip work done. I doubt they are running 11's bone stock. If they are I bet you can pick up these cars cheap in a few months with blown engines.
When numbers get so close and tenths of seconds make a difference it really falls on the driver to make the car perform. You can loose easily with just the slightest hesitation. MB has taken over 10 years to finally come up with the technology that Porsche was achieveing with a lot less HP and they still can't handle.
09-10-2005, 12:08 PM
#48
Race Director
A true SL65 is a beast....with slicks it should easily pull low 11's Look at this one from my local track....there seems to be quite a few local mercedes owners who actually take their rides to the track in sac!! 11.4 sure ain't slow!
http://videos.streetfire.net/Player....0E51&kw=33&p=1
Brian
http://videos.streetfire.net/Player....0E51&kw=33&p=1
Brian
09-10-2005, 12:23 PM
#49
The Lady's Man
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[QUOTE=cobalt]. R&T shows a 12.0 1/4 which I usually find they are a bit optimistic and abusive to achieve the numbers they get.
QUOTE]
FYI...I have worked with R&T for over 20 years now and they are one of a few mags that dont abuse the cars to get numbers. Most of the high end cars have autos these days so there isnt a lot one can do to be abusive.We have had manufacturers complain that the numbers are to high and we have invited them to bring in a hotshoe to show us how they do it. Some have taken us up on the offer and THEY beat the crap out of the cars trying to pull numbers.
QUOTE]
FYI...I have worked with R&T for over 20 years now and they are one of a few mags that dont abuse the cars to get numbers. Most of the high end cars have autos these days so there isnt a lot one can do to be abusive.We have had manufacturers complain that the numbers are to high and we have invited them to bring in a hotshoe to show us how they do it. Some have taken us up on the offer and THEY beat the crap out of the cars trying to pull numbers.
09-10-2005, 01:11 PM
#50
Here is a bone stock SL 65 doing the 1.4 mile in 11.7 at 126 mph. Stock tires, ECU, air filters, ETC....completely stock! stock SL 65 drag race
09-10-2005, 01:23 PM
#51
Rennlist Member
Jim,
i suggest you do a search on the torque vs HP discussion.
Torque is truely meaningless without it being attached to RPM. just as RPM is meaningless if not attached to a torque . Its Just one factor of HP. HP gives you the information you need to compare. Now, torque is important (as RPM is too) and you do need to find the speed that you are going to calculate gearing and then you can multiply torque to figure out what the actual rear wheel torque is that will give you the force that the system can apply to moving the mass. F=ma. also keep in mind that HP is a rate of doing work, while work is a force over distance.
So, when folks talk about torque, the almost alwasy look at flywheel torque, when its actually the torque at the wheels that needs to be known. by using HP, you, by default, know the speed as speed is an equal factor in HP.
This is why you can be at peak torque in any particular gear, and somone in the same car can be a gear lower and floor it and have 20% more accelerative forces than you. Peak torque (engine torque is usually an indicator of what the torque curve and HP curve can look like) really is meaningless unless you know either the HP, which tells you most everything you neeed to know, especially if you know the shape of the HP curve or average HP over the operational range. again, as i have shown in an example, 2nd gear usally 6:1 and 3rd gear, usually close to 4.5:1 shows the point that the torque at the wheels is what counts as it is multiplied through the gear box. if we talked in these numbers, discussions would sound like this. "hey, my mustang has 2300ftlbs of torque. " " yeah, but my porsche has 2900ftlbs of torque, " yeah, but you did this in 2nd gear and i did this in 3rd," ................... it would be a headache of a discussion. where smart folks would just say, " i have 400hp. (by definition, you now can determine any torque at any gear at any speed!)
And if you really want to compare, you estimate your average HP over the rpms that you can use.
Hope that helps.
MK
i suggest you do a search on the torque vs HP discussion.
Torque is truely meaningless without it being attached to RPM. just as RPM is meaningless if not attached to a torque . Its Just one factor of HP. HP gives you the information you need to compare. Now, torque is important (as RPM is too) and you do need to find the speed that you are going to calculate gearing and then you can multiply torque to figure out what the actual rear wheel torque is that will give you the force that the system can apply to moving the mass. F=ma. also keep in mind that HP is a rate of doing work, while work is a force over distance.
So, when folks talk about torque, the almost alwasy look at flywheel torque, when its actually the torque at the wheels that needs to be known. by using HP, you, by default, know the speed as speed is an equal factor in HP.
This is why you can be at peak torque in any particular gear, and somone in the same car can be a gear lower and floor it and have 20% more accelerative forces than you. Peak torque (engine torque is usually an indicator of what the torque curve and HP curve can look like) really is meaningless unless you know either the HP, which tells you most everything you neeed to know, especially if you know the shape of the HP curve or average HP over the operational range. again, as i have shown in an example, 2nd gear usally 6:1 and 3rd gear, usually close to 4.5:1 shows the point that the torque at the wheels is what counts as it is multiplied through the gear box. if we talked in these numbers, discussions would sound like this. "hey, my mustang has 2300ftlbs of torque. " " yeah, but my porsche has 2900ftlbs of torque, " yeah, but you did this in 2nd gear and i did this in 3rd," ................... it would be a headache of a discussion. where smart folks would just say, " i have 400hp. (by definition, you now can determine any torque at any gear at any speed!)
And if you really want to compare, you estimate your average HP over the rpms that you can use.
Hope that helps.
MK
Originally Posted by Jim Nowak
HP = tq * RPM/5252. Torque is the only number that matters. HP is just a measure of torque at a given rpm. Of course, gearing is a torque multiplier and does help with acceleration.
09-10-2005, 01:28 PM
#52
Race Director
Found another tuner for the SL65....damm impressive numbers the Kleeman kit gives 739hp & 1300 NM of torque (or 959 ftlbs)!!!! Of course its probably a $10K chip too! But still 740hp-959 torque for a street legal nearly stock car is very impressive! With 959 torque in a 4500lb car...that tranny can't last very long! So it should dyno around 600+rwhp...damm
Brian
Brian
09-10-2005, 01:36 PM
#53
Rennlist Member
yes,
if wheel spin is an issue, then you are right. However, i have a hard time believing that wheel spin is an issue past 2nd gear . If it isnt, then you want to take your old dog to redline to shift in all cases where you are not getting wheel spin.
redline alows for a higher average HP to the ground. to find your average hp, take the redline hp, look at the peak Hp, and look at the hp you would be at after a shift. (usually a 70% drop in rpms) take these three numbers and average them. that is a pretty good approximation of your total available accelerative forces.
based on your engine curve description, if your torque falls off at a 45 degree angle , that means your hp is constant from 3500 to 5400rpm, and that would be 300hp with your max torque being 450ftlbs at 3500rpm. Is that right?
bottom line, look at the average HP and you can find your best shift points and max potential for running with the new mercedes.
Mark
if wheel spin is an issue, then you are right. However, i have a hard time believing that wheel spin is an issue past 2nd gear . If it isnt, then you want to take your old dog to redline to shift in all cases where you are not getting wheel spin.
redline alows for a higher average HP to the ground. to find your average hp, take the redline hp, look at the peak Hp, and look at the hp you would be at after a shift. (usually a 70% drop in rpms) take these three numbers and average them. that is a pretty good approximation of your total available accelerative forces.
based on your engine curve description, if your torque falls off at a 45 degree angle , that means your hp is constant from 3500 to 5400rpm, and that would be 300hp with your max torque being 450ftlbs at 3500rpm. Is that right?
bottom line, look at the average HP and you can find your best shift points and max potential for running with the new mercedes.
Mark
Originally Posted by cobalt
You most likely are correct. It has been a long day and I am not thinking clearly. ALthough it has always been argued that the torque is what gets the car moving and the hp is what gives you top end.
I achieve max hp at 5200 rpm and it falls off 10% to redline. Max torque is achieved at 3500rpm and falls off at 45 degrees at 5400 rpm.
I guess I need to be more clear by loosing power, I ment more along the lines of loosing useable power or traction, the 295 PS2's spin easily when dropping 2 gears and punching it making it very hard to keep control. By the seat of the pants feel it is pushing just as hard at the lower rpms without loss of traction as it is by downshifting and I don't loose the time in shifting. I may be totally wrong. Then again, I didn't think it was more than an SL 55 to begin with. (which it may have been
) The turbo has quite a bit of punch so long as boost is on full and it doesn't take long to get to redline like the 928 engine does. (remember their lazy 
just joking)
I have always used the downshift method on all other cars the turbo is a bit of a handful to begin with and attempting a full 2 gear drop is abusive.Besides it achieved the end results needed. I am sure you are correct but I don't think I would gain much of anything if I am fighting the car with spinning wheels or even worse if the rev limiter cuts in because the wheels have spun and caused me to shoot into the red.
I still think that the MB's are over rated and if you notice most of the 1/4 times on these SL's and E55's are also using NOX.
I achieve max hp at 5200 rpm and it falls off 10% to redline. Max torque is achieved at 3500rpm and falls off at 45 degrees at 5400 rpm.
I guess I need to be more clear by loosing power, I ment more along the lines of loosing useable power or traction, the 295 PS2's spin easily when dropping 2 gears and punching it making it very hard to keep control. By the seat of the pants feel it is pushing just as hard at the lower rpms without loss of traction as it is by downshifting and I don't loose the time in shifting. I may be totally wrong. Then again, I didn't think it was more than an SL 55 to begin with. (which it may have been
) The turbo has quite a bit of punch so long as boost is on full and it doesn't take long to get to redline like the 928 engine does. (remember their lazy just joking) I have always used the downshift method on all other cars the turbo is a bit of a handful to begin with and attempting a full 2 gear drop is abusive.Besides it achieved the end results needed. I am sure you are correct but I don't think I would gain much of anything if I am fighting the car with spinning wheels or even worse if the rev limiter cuts in because the wheels have spun and caused me to shoot into the red.
I still think that the MB's are over rated and if you notice most of the 1/4 times on these SL's and E55's are also using NOX.
09-10-2005, 03:29 PM
#55
Hope that helps.
Torque is truely meaningless without it being attached to RPM.
This is why you can be at peak torque in any particular gear, and somone in the same car can be a gear lower and floor it and have 20% more accelerative forces than you. Peak torque (engine torque is usually an indicator of what the torque curve and HP curve can look like) really is meaningless unless you know either the HP, which tells you most everything you neeed to know, especially if you know the shape of the HP curve or average HP over the operational range. again, as i have shown in an example, 2nd gear usally 6:1 and 3rd gear, usually close to 4.5:1 shows the point that the torque at the wheels is what counts as it is multiplied through the gear box. if we talked in these numbers, discussions would sound like this. "hey, my mustang has 2300ftlbs of torque. " " yeah, but my porsche has 2900ftlbs of torque, " yeah, but you did this in 2nd gear and i did this in 3rd," ................... it would be a headache of a discussion. where smart folks would just say, " i have 400hp. (by definition, you now can determine any torque at any gear at any speed!)
And if you really want to compare, you estimate your average HP over the rpms that you can use.
And if you really want to compare, you estimate your average HP over the rpms that you can use.
09-11-2005, 12:43 AM
#60
Rennlist Member
thats almost funny. com'mon!!'
MK
MK
Originally Posted by m21sniper
"Didn't I supply you with the formula to get hp: tq * rpm/ 5252"
I assure you that mark has been supplied with that formula in the past.
I assure you that mark has been supplied with that formula in the past.