qianlimoro

Okay. This may be obvious to those who understand this stuff but could somebody explain this...?...

I have a C-coupe. I have a Jeep.

The C-coupe specs, horsepower: 189 hp @ 5800 rpm and torque : 192 lb-ft @ 3500 rpm
with a curb weight between 3250-3280 pounds. 6 speed manual. 0-60: 7.6 sec.

The Jeep Cherokee specs, horsepower: 190 hp @ 4750 rpm and torque : 225 lb-ft @ 3000 rpm
with a curb weight between 2891-2993 pounds. 4 speed Asin-Warner AW4 automatic. 0-60: 11 sec.


The Jeep is a slug.
The C is quick.

Aside from the obvious (yes one a Mercedes/car, the other a Jeep/truck), why such a huge difference in straight line acceleration?

MercFiveHundred

First, the closer ratio 6 speed of the C and second, the smaller/lighter wheels on the C - less effort to spin the wheel.

lkchris

You've got the curb weight wrong for the Jeep--it is NOT lighter than the C.

Light wheels make almost no difference whatsoever.

qianlimoro

You would think. I rechecked the manual. The two wheel drive, four door is listed @ 1358kg or 2993lbs.
This is the old XJ chassis, not the current Grand Cherokee.

The coupe information I have is perhaps suspect. The only weight reference in the manual is the roof load limit.
The door jamb label list a GWR of 1900kg or 4185lbs.

With no curb weight info at hand, I searched the web and found one here:

http://www.modernracer.com/mercedesbenzc230coupe.html

Perhaps these guys got it wrong. I don't know how to (or if you can) extract a curb weight from the GWR.

I realize their HP peaks arrive at different revs, I just don't know what that means in the real world.

epmills

Based off Edmunds.com, your Jeep is 3354lbs, and your C is 3250lbs. Reasons why your C is faster- Jeep has larger diameter tires, more drivetrain power loss due to a transfer case and front driveshaft/axles, auto trans (yet again more drivetrain loss vs. a manual trans), weighs more, less aerodynamics, gearing mean't for lower end power (not speed), engine designed for low end power, ect.