What does your tach read at 80 MPH?

JYO · 06-28-2009, 02:43 AM

If I set cruise at 80 MPH my tach reads 2800 RPM

at 70 MPH it reads 2500.

This seems too high compared to a 3.5L Honda Odyssey V6 (2200 and 2000 RPM respectiveley) or to my E320 V6. Almost seems like it needs an extra gear for highway driving. I have checked it on "comfort" and "sport" modes.

Is this just the way the transmission is tuned to operate?

To remove this ad, register today or login if you already are registered!

Ubergeist · 06-28-2009, 11:00 PM

Quote:

Originally Posted by JYO

If I set cruise at 80 MPH my tach reads 2800 RPM

at 70 MPH it reads 2500.

This seems too high compared to a 3.5L Honda Odyssey V6 (2200 and 2000 RPM respectiveley) or to my E320 V6. Almost seems like it needs an extra gear for highway driving. I have checked it on "comfort" and "sport" modes.

Is this just the way the transmission is tuned to operate?

I want to say I am at around 2400 at 80. I'll pay attention when I'm on the highway next trip.

ashutt · 06-30-2009, 05:49 PM

Read mine today at 2510 at 80 mph so 2500 looks like about the right number to be at.

JYO · 06-30-2009, 06:10 PM

at 80MPH I'm at 2800.

2500 at 70MPH.

we have same engine but I guess transmission is different. I still think mine runs higher than it should at 80MPH. I guess as long as there is no overheating I think the engine itself can withstand the revs. But it makes makes me a little reluctant to take a long distance trip.

neilbo75 · 06-30-2009, 07:30 PM

Last weekend I did a cross-country drive on one of France's autoroutes. The legal speed limit is 130 km = 81 mph. I up it a bit (no more - too many robots!) to 134 = 83 mph and set cruise control. The tach dozes at about 2650.

MarcusF · 07-01-2009, 01:08 AM

The fifth gear ratio in a W208 CLK55 is the same as a CLK430. The CLK55 has a 2.82 final drive, versus the 430's 2.87. That's less than a 2% difference, so this is very close to what you should see.

JYO · 07-01-2009, 01:56 AM

Thanks Marcus. Would the 55 engine in the W209 be any different. Does the transmission play much of a part in this? When did the AMG Speedshift start?

MarcusF · 07-01-2009, 12:28 PM

The W209 CLK55 has higher compression, but the differences between the two engines are minor.

If I understand the question, the transmission is the largest deciding factor in determining engine speed at road speed.

All AMG CLKs were equipped with SpeedShift. If you’re asking when SpeedShift itself was initially released, I don’t know.

JYO · 07-01-2009, 12:40 PM

Or when did the 7 sp auto come out? only on the CLK63's? i wonder what it revs at?

from all the replies i'd say my engine is working harder at 70-80 mph than most AMGs, however most replies have been from W208s ( I still love that body style!).

MarcusF · 07-01-2009, 05:10 PM

Sorry, for some reason, I thought you had a W208. The final drive in a W209 CLK55 is 3.06, not 2.82 (W208 CLK55)

The CLK63 has a different final ratio and completely different transmission ratios. I think you’re interested in the overall ratios. The overall ratios in the 63 are (1) 11.60, (2) 7.58, (3) 5.09, (4) 3.63, (5) 2.65, (6) 2.17, and (7) 1.93.

The overall ratios on a W209 CLK55 are (1) 10.98 (2) 6.70, (3) 4.31, (4) 3.06, and (5) 2.54

In a W208 CLK55, they are (1) 10.12 (2) 6.17, (3) 3.98, (4) 2.82, and (5) 2.34

Per my notes, the CLK63 is loafing at 2260 RPM at 80 MPH. The W208 CLK55 should be at 2670. Due to the W209 gearing (which may have been changed for the weight), it has an 8.5% penalty. According to my calculator (I don't have any RPM/speed notes from W209 AMG tests), that puts the W209 CLK55 RPM at 2898. Making your tach a little low. If you had gearing that brought the revs down to 2500, you’d pay a cost in acceleration.

Pauljay · 07-01-2009, 06:47 PM

Hi MarcusF.

A quick question for you.

I've got a 430 CLK with a 55 N/A AMG engine conversion running 430 gearing. At 3000 revs the car sits at 96 mph in 5th.

I was thinking of doing the W210 320 diff conversion with the final gearing of 3.07. What would that do for my acceleration and highway cruising figures?

I haven't done it because I think the gearing may be too low giving a much higher consumption of fuel.

What's your input please.

MarcusF · 07-01-2009, 08:09 PM

I think

If traction isn’t an issue, the car will accelerate faster.
If you’ve currently got a stock CLK430 final ratio, and at 96 MPH the engine is turning at 3,000 RPM, with a 3.07 it will be turning 3209 PRM. Or, with a 3.07 at 3,000 RPM the car will be traveling 84 MPH, rather than 90.
You will burn more gas. Although compared to what you’ve probably already spent . . . .

What kind of headers are you running?

JYO · 07-02-2009, 12:38 AM

wow. good stuff Marcus.

I do run 2800 at 80MPH so that's pretty close to what you calculated. I'll check it again and see if it might be closer to your figure.

Not that I want to lose acceleration but I wouldn't mind if the Comfort mode on transmission would allow it to rev less at 80MPH when cruising on a long trip. It would make for quieter drive and better fuel econ.

phoung · 07-02-2009, 03:47 AM

about 2450, i always thought are 5th gear was a lil short

neilbo75 · 07-02-2009, 08:18 AM

Quote:

Originally Posted by MarcusF

Sorry, for some reason, I thought you had a W208. The final drive in a W209 CLK55 is 3.06, not 2.82 (W208 CLK55)

The CLK63 has a different final ratio and completely different transmission ratios. I think you’re interested in the overall ratios. The overall ratios in the 63 are (1) 11.60, (2) 7.58, (3) 5.09, (4) 3.63, (5) 2.65, (6) 2.17, and (7) 1.93.

The overall ratios on a W209 CLK55 are (1) 10.98 (2) 6.70, (3) 4.31, (4) 3.06, and (5) 2.54

In a W208 CLK55, they are (1) 10.12 (2) 6.17, (3) 3.98, (4) 2.82, and (5) 2.34

Per my notes, the CLK63 is loafing at 2260 RPM at 80 MPH. The W208 CLK55 should be at 2670. Due to the W209 gearing (which may have been changed for the weight), it has an 8.5% penalty. According to my calculator (I don't have any RPM/speed notes from W209 AMG tests), that puts the W209 CLK55 RPM at 2898. Making your tach a little low. If you had gearing that brought the revs down to 2500, you’d pay a cost in acceleration.

Good stuff as always. Wow, I didn't realise the 209s were geared that differently. Did that penalize gas mileage as measured by the EPA or other testers? The gearing and the extra weight would make me think so.

Pauljay · 07-02-2009, 03:51 PM

Thanks Marcus!

You sure know your stuff.

I'm running stock headers at the moment. Being a right hand drive car space is limited on the left (facing the engine) I'm told. Still trying to find some one to make some.

JYO · 07-03-2009, 01:04 AM

I measured 3100 at 90MPH today.

06-30-2009, 05:49 PM	#3
ashutt Senior Member Join Date: Aug 2005 Location: Las Vegas Posts: 373 Drives: 2001 CLK 55 AMG & Range Rover Sport Supercharged	Read mine today at 2510 at 80 mph so 2500 looks like about the right number to be at. __________________ 2001 CLK 55 AMG 19" Moven C16 Rims Eagle F1 DS-D3 Tires (235/35ZR19 and 265/30/ZR19) H&R Springs Bilstein Sport Shocks Rear K-Mac kit Slotted/Cross Drilled Front Rotors StopTech Stainless Steel Brake Lines ATE Type 200 Brake Fluid Green Filters SpeedTuningUSA ECU Upgrade (6500 redline & removed speed limitation of 155 mph) Auto Meter Digital Pro Shift System (Level 2) Dynoed Power: (303/Wheels & 364/Crank)

07-01-2009, 01:08 AM	#6
MarcusF MBWorld Fanatic! Join Date: Apr 2005 Location: SCV SoCal Posts: 1,498 Drives: FIA approved Pumas	The fifth gear ratio in a W208 CLK55 is the same as a CLK430. The CLK55 has a 2.82 final drive, versus the 430's 2.87. That's less than a 2% difference, so this is very close to what you should see. __________________ Mercedes-Benz spec page Signal to Noise Join the Mercedes-Benz Club of America here

07-01-2009, 12:28 PM	#8
MarcusF MBWorld Fanatic! Join Date: Apr 2005 Location: SCV SoCal Posts: 1,498 Drives: FIA approved Pumas	The W209 CLK55 has higher compression, but the differences between the two engines are minor. If I understand the question, the transmission is the largest deciding factor in determining engine speed at road speed. All AMG CLKs were equipped with SpeedShift. If you’re asking when SpeedShift itself was initially released, I don’t know. __________________ Mercedes-Benz spec page Signal to Noise Join the Mercedes-Benz Club of America here

07-01-2009, 05:10 PM	#10
MarcusF MBWorld Fanatic! Join Date: Apr 2005 Location: SCV SoCal Posts: 1,498 Drives: FIA approved Pumas	Sorry, for some reason, I thought you had a W208. The final drive in a W209 CLK55 is 3.06, not 2.82 (W208 CLK55) The CLK63 has a different final ratio and completely different transmission ratios. I think you’re interested in the overall ratios. The overall ratios in the 63 are (1) 11.60, (2) 7.58, (3) 5.09, (4) 3.63, (5) 2.65, (6) 2.17, and (7) 1.93. The overall ratios on a W209 CLK55 are (1) 10.98 (2) 6.70, (3) 4.31, (4) 3.06, and (5) 2.54 In a W208 CLK55, they are (1) 10.12 (2) 6.17, (3) 3.98, (4) 2.82, and (5) 2.34 Per my notes, the CLK63 is loafing at 2260 RPM at 80 MPH. The W208 CLK55 should be at 2670. Due to the W209 gearing (which may have been changed for the weight), it has an 8.5% penalty. According to my calculator (I don't have any RPM/speed notes from W209 AMG tests), that puts the W209 CLK55 RPM at 2898. Making your tach a little low. If you had gearing that brought the revs down to 2500, you’d pay a cost in acceleration. __________________ Mercedes-Benz spec page Signal to Noise Join the Mercedes-Benz Club of America here

07-01-2009, 06:47 PM	#11
Pauljay Member Join Date: Mar 2008 Location: Surrey, England. Posts: 105 Drives: Mercedes 430/55 clk cabriolet	Hi MarcusF. A quick question for you. I've got a 430 CLK with a 55 N/A AMG engine conversion running 430 gearing. At 3000 revs the car sits at 96 mph in 5th. I was thinking of doing the W210 320 diff conversion with the final gearing of 3.07. What would that do for my acceleration and highway cruising figures? I haven't done it because I think the gearing may be too low giving a much higher consumption of fuel. What's your input please. __________________ " Star in the hood. "

06-30-2009, 06:10 PM	#4
JYO Member Join Date: Nov 2001 Location: Dallas Posts: 142 Drives: 1999 E 320, 2005 CLK55 Cab	at 80MPH I'm at 2800. 2500 at 70MPH. we have same engine but I guess transmission is different. I still think mine runs higher than it should at 80MPH. I guess as long as there is no overheating I think the engine itself can withstand the revs. But it makes makes me a little reluctant to take a long distance trip.

06-30-2009, 07:30 PM	#5
neilbo75 Senior Member Join Date: Mar 2006 Location: living in Paris, France and San Diego ... Posts: 454 Drives: 2002 CLK 55 AMG Coupé	Last weekend I did a cross-country drive on one of France's autoroutes. The legal speed limit is 130 km = 81 mph. I up it a bit (no more - too many robots!) to 134 = 83 mph and set cruise control. The tach dozes at about 2650.

07-01-2009, 01:56 AM	#7
JYO Member Join Date: Nov 2001 Location: Dallas Posts: 142 Drives: 1999 E 320, 2005 CLK55 Cab	Thanks Marcus. Would the 55 engine in the W209 be any different. Does the transmission play much of a part in this? When did the AMG Speedshift start?

07-01-2009, 12:40 PM	#9
JYO Member Join Date: Nov 2001 Location: Dallas Posts: 142 Drives: 1999 E 320, 2005 CLK55 Cab	Or when did the 7 sp auto come out? only on the CLK63's? i wonder what it revs at? from all the replies i'd say my engine is working harder at 70-80 mph than most AMGs, however most replies have been from W208s ( I still love that body style!).

07-01-2009, 08:09 PM	#12
MarcusF MBWorld Fanatic! Join Date: Apr 2005 Location: SCV SoCal Posts: 1,498 Drives: FIA approved Pumas	I think If traction isn’t an issue, the car will accelerate faster. If you’ve currently got a stock CLK430 final ratio, and at 96 MPH the engine is turning at 3,000 RPM, with a 3.07 it will be turning 3209 PRM. Or, with a 3.07 at 3,000 RPM the car will be traveling 84 MPH, rather than 90. You will burn more gas. Although compared to what you’ve probably already spent . . . . What kind of headers are you running? __________________ Mercedes-Benz spec page Signal to Noise Join the Mercedes-Benz Club of America here

07-02-2009, 12:38 AM	#13
JYO Member Join Date: Nov 2001 Location: Dallas Posts: 142 Drives: 1999 E 320, 2005 CLK55 Cab	wow. good stuff Marcus. I do run 2800 at 80MPH so that's pretty close to what you calculated. I'll check it again and see if it might be closer to your figure. Not that I want to lose acceleration but I wouldn't mind if the Comfort mode on transmission would allow it to rev less at 80MPH when cruising on a long trip. It would make for quieter drive and better fuel econ.

07-02-2009, 03:47 AM	#14
phoung Member Join Date: Nov 2007 Location: Gulfcoast MS, Katrina town Posts: 87 Drives: '03 clk 500. WTB slk55	about 2450, i always thought are 5th gear was a lil short

07-02-2009, 03:51 PM	#16
Pauljay Member Join Date: Mar 2008 Location: Surrey, England. Posts: 105 Drives: Mercedes 430/55 clk cabriolet	Thanks Marcus! You sure know your stuff. I'm running stock headers at the moment. Being a right hand drive car space is limited on the left (facing the engine) I'm told. Still trying to find some one to make some. __________________ " Star in the hood. " Last edited by Pauljay; 07-02-2009 at 04:37 PM.

07-03-2009, 01:04 AM	#17
JYO Member Join Date: Nov 2001 Location: Dallas Posts: 142 Drives: 1999 E 320, 2005 CLK55 Cab	I measured 3100 at 90MPH today.

Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)

Thread Tools	Search this Thread
Show Printable Version Email this Page	Search this Thread: Advanced Search
Display Modes	Rate This Thread
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode	Rate This Thread: