JAYCL600

Has anyone taken their CL55 to the dragstrip yet, Iam curious as to the 1/4 times and MPH.

CME4BENZ

You are a nut Jay.

Let me see. I have just: sold my company/cashed my fat bonus/successfully sued Mickey D's over that lap full of hot coffee/found Ed McMahon at my door with a 5 foot wide check, (pick one) and the first thing I'm going to do with my new CL55 is take it down to the drags and smoke off a set of tires!

I think not. But if I did, do you think I'd pick up a tenth if I off the Nav, ventilated seats and lumbar massage? Could you just set the distronic for 1/4 mile and the cruise for 155 and let it accelerate by itself ? What happens with the ESP if you brake with the throttle on to load the torque converter? Can you install a line-lock system and the Hurst reverse pattern ratchet shifter like my 440-6 pack Challenger?

Now let's get the air shocks under the back end so I can get these Mickey Thompsons under the quarter panels.

Just raggin, you Jay. It's all good.

P.S. Adam? Brian? I smell a dragstrip challenge. Be the first one to post your timeslips.

JAYCL600

Hahaha, you have jokes also? I will be the first to post my 03 E55 dragstrip results, guaranteed. And yes Iam a dragstrip nut, certified, the whole bit, my current E55 has over 65 trips down the dragstrip, and I plan on doing alot of racing and documenting on the new one also. So someone please take their 493 horses to the track so I can get some type of comparative times!!!!!!

CME4BENZ

I smell V8-Kompressor drag strip challenge night !

Sponsored by the good folks at Bridgestone, Pirelli and Michelin.

Light 'em up if you got 'em!

Can I bring my FJR1300? I should be able to put down some low 11s to shoot for.

JAYCL600

Definitely bring the Yamaha, all vehicles are welcome, maybe even your little Vespa if you get it!!!!!

Dave OH

Not if I get there first! Oh... wait... you're one slot in front of me at the dealership... Maybe I can break it in faster. Keil... any chance you wanna swap mine and Jay's spots so I get my car first? haha jk

But Jay, whoever gets down the strip first is one thing... the one with the fastest time is another

CME4BENZ

It does my heart good to know that you guys are going to put the first 2 incoming E55s to good use (or is that abuse?).
AMGs at the strip, count me in! I would pay to see you guys go head to head at the track. Let me know when and where.

Hey Dave, maybe you want to rethink shipping the car. I think a triple digit run out the PA turnpike would be fun! Can I offer my services? Did I mention our special high speed delivery program?

Dave OH

On behalf of Jay and Myself, We will do you Proud my friend!

A xxx mph delivery run? How generous of you!

treynor

> [...] and the first thing I'm going to do with my new CL55 is
> take it down to the drags and smoke off a set of tires!

That's pretty much the first thing I did with my '03 S600 . I did, however, break it in first. Chronology:

3/14/03: Pick up '03 S600
3/21/03: Reach 1000 miles, change oil
3/21/03: Stock dyno pulls: 481 RWHP, 570 RWTQ
3/22/03: First runs at Sacramento Dragstrip, best run 12.45 @ 114.3
3/25/03: Spooned on 275/40-18 Potenza S-02A rear tires for better traction
3/26/03: ECU out of car and FEDex'd to RENNtech
3/29/03: (morning) ECU returned by RENNtech and reinstalled
3/29/03: (evening) Second runs at Sacramento Dragstrip, best run 11.99 @ 117.0
4/12/03: Modified dyno pulls: 522 RWHP, 660 RWTQ

JAYCL600

Treynor, I have been following your posts and hope to be eclipsing your times at some point (hope ). Soon after break in she will be off to RENNTech for ECU and pulley upgrade, similar to your chronology. Dave, we have to get up sometime and and go to the strip, it would make for great video!!!!!

CME4BENZ

Treynor, you are my new hero.
522 HP and 11 second 1/4s in an S class!
You go boy!

Usually when I picture an AMG track day I'm thinking road course.
You guys are slowly shifting my paradigm. I can see it through the haze, or is that tire smoke? Upgraded chips, disabled ESP, rear tires with 20 PSI, blowers screaming, turbos whining. Yes I think I can see it now. Thanks for the peak into the dark side.

I'll be installing some AMG badges on the FJR. It's already silver and it's the only machine I have that has a chance of posting in the 11s.

I smell track day! Oh no, I'm sorry that's just another pair of Treynors Potenzas going up in smoke.

JAYCL600

Whoa, we have to draw the line there, there are to be no AMG badges on the FJR!!!!

treynor

Just out for another weekend drive in the Benz...



As for beating my 1/4 mile times, more power to you! I will of course need to respond... maybe 17" rear wheels and drag radials are in my future...

AndrewEclipse

Do you know what kind of numbers I can expect if I send out my ECU to Renntech? (For a '03 CL55)

Its about that time for some more power.....

hinhin7

Treynor: so, with the modified ECU from Renntech, you have like another 40hp at the crank?
I am sorry if Im wrong, but isn't 522RWHP = 650hp at the crank?

May I know how much it cost you to upgrade your ECU from Renntech.


Thanks

treynor

The '55 cars do not pick up as much power with ECU changes alone, because the ECU cannot change the boost level as it can on turbo cars. The ECU + pulley swap on the supercharged V8s pick up comparable amounts of HP, although less TQ than the turbo V12s.

Hinhin - 650 BHP is about correct for 522 RHWP; it depends on what you assume for driveline loss percentages. Suffice to say Mercedes is clearly underrating their engines. For current pricing of the various ECU options, you should contact Bob Brady at RENNtech.

victoryroad

treynor:
I just passed 1000 miles with my 55. It has noticably loosened up and there is much better throttle response and power. Most tuner companies site some federal act that apparently requires manufacturers to honor warranties even if the car has been modified with their equipment. More power would be nice, but for me, not at the expense of voiding the warrantly on what could be a very expensive engine/drivetrain fix. Have you had any experience with dealers honoring warranties when after-market engine mods have been installed?

Richandall

IMHO measured RWBHP on the print-out from your local dyno-shop isn't the actual BHP measured at the rear wheel but an estimated figure for the output at the crank, derived from the power as measured at the rear wheel. Everybody does it so it creates a sort of benchmark and saves the expense of an engine-out test-bed run.

Mercedes' published output is an actual test-bed figure including waterpump, gearbox and exhaust, but without other accessories or the rest of the driveline, rolling resistance etc. But true RWBHP it ain't.

If the dyno-shop guys didn't tweak the figures and instead gave uncorrected RWBHP the result would be an apparently lower output than Mercedes' own published figures and you'd take your business elsewhere. So don't blame them for giving you the figure with a correction factor dialled into the software even if it makes for problems comparing RWBHP claims.

Just my 2 cents.

JAYCL600

Richandall, there is RWHP and then there is BHP, but I dont think there is "RWBHP". RWHP-Rear Wheel Horsepower is after your engine has gone through all of the accessories, drivetrain and to the rear wheels. BHP-Brake Horsepower is just the actual engine out of the car attached to a brake to resemble load. Correction factors on a rearwheel dyno factor altitude and temperature.

Richandall

Take your point about the use of BHP. I guess the term RWHP has been adopted by the dyno-shops from convenience, as it has no standard international definition. Even so, dyno-shops use a flexible formula that 'corrects' measured output so the final read-out equates to the manufacturer's test configuration. If they didn't correct the RWHP readings to equate them to the manufacturer's BHP test configuration you'd get RWHP dyno printouts showing 10% - 20% less than the manufacturer's published BHP figure. Just mho

treynor

Actually, there are several different correction factors which dynojet dynos can apply: STD, SAE, DIN and Uncorrected. For forced-induction cars I usually use uncorrected HP, as the correction factors used for (say) atmospheric pressure don't make sense on a car responsible for its own atmosphere.

For what it's worth, my S600 made 461 RWHP (SAE) stock and 502 RWHP (SAE) with the RENNtech ECU. In general, rear-wheel HP will be 12-25% less than the actual flywheel HP (BHP) because of losses to accessories and (more importantly) drivetrain friction.

Richandall

For me, the question is, what does a dyno operating on the rear wheels actually measure? As I understand it, it measures just two things: torque and rpm. The rwbhp figure is derived from these two parameters, adjusted for environmental variables including drivetrain losses.

To explain, the dyno operator measures both the positive driving torque at full throttle and the driveline drag, measured by the deceleration force acting on the dynamometer when the throttle is closed in neutral at the same rpm. He then adds back this 'drag' torque figure to the driving torque measured at the rear wheels, to give an approximate figure for the total torque delivered by the engine. 'Drag' torque includes power losses from transmission, driveshafts, bearings and tyres.

This adjusted torque figure is corrected for environmental variables like air temperature and pressure to produce a final torque figure, which is converted to rwbhp by multiplying it by the rpm at which it was measured, and dividing the result by a constant.

So the resulting rwbhp already has contained in it a correction for drivetrain power losses. The estimated drivetrain power loss shouldn't be added back to the result the dyno operator prints out from his PC and gives to you, IMHO For these reasons the rwhp is not the power that is actually delivered onto the road. It's a series of torque figures measured at the rear wheels but back-calculated in the manner described to tell you what power the engine itself is capable of producing.

Any dyno operators out there care to add to my 2 cents?

treynor

That turns out not to be the case.

At least for dynojet dynos, which are the most common type by far here in the USA, power is measured by examining the rate of acceleration of a steel drum of known rotational inertia as it is spun up by the rear tires.. Given a series of data pairs [r1, t1], [r2, t2], [r3, t3], ... and the rotational inertia of the drum, it is trivial to calculate the energy added between each interval [t1, t2], [t2, t3], etc. From that it is also trivial to calculate power, which is simply the rate of energy delivery per unit time.

If you run a car on a dynojet dyno without taking a tachometer reading, you will get a graph of horsepower vs speed.

There is no attempt to "back-calculate" the engine HP from the rear-wheel HP, because there is on way for the dyno to measure driveline loss under load. Obviously, frictional losses under full acceleration are much higher than they are under coasting...

Richandall

Ben, leaving aside the question of what corrections the dyno operator applies, cos I think there are differences between UK and the USA practices, this still leaves open the question which you raised earlier. Where did Mercedes put all those unpublished horses? Your answer is (quote) 'Suffice to say Mercedes is clearly underrating their engines.' Maybe, but that's an odd thing for a German car manufacturer to do.

Using the guesstimate you applied in an earlier post would give a 'corrected' crank output for the S600 of 599 in stock tune. M-B publishes on its UK website an output of 500. So what is M-B measuring?

Just to get things started, imo M-B measures its engine power at the crank in kilowatts and converts these to BHP using the SAE criteria and that's the basis of the published output. But that's an intelligent guess and not hard fact. The Germans do engineering precision better than most so it would be interesting to know how their published figures are produced. Any M-B spokesperson out there?

absent

Not all 600's are created equal,my CL had stock 433rwhp.