SL60 AMG rolling road rests.

[biturbo]

Hi,
I have had the sl60 AMG on a rolling road.
I am dissapointed by the results. Even though the work done the car feels faster it is only putting out 365 BHP at the wheel according to the sheet. I think the factory was 376 and i thought it might be over 400.
I used my mates telemetry thingy and we did some 0-60s on a straight dry road about 2 weeks ago and best time was 4.8 secs and was always around 5 secs.

what could be causing the hp to be lower? engine wear? I have looked at the engine only through the crank case and it looks immaculate like new.
Maybe the torque is up but the HP is down?

 

[Doodle]

Ah, dyno heartbreak...the rollers are a cruel mistress. There's a million and one reasons why a car doesn't match up to quoted figures, even more so on a one-off run.

Are you sure your figures are at the wheel though? Manufacturers normally quote crank or flywheel horsepower, but allowing 20-25% transmission losses would make the calculated figure (based on your quoted result) unbelievably optimistic.

Posting up the dyno sheet would help.

 

[Ierton]

Aren't factory engine (flywheel) hp or ps figures? 376hp at the wheels sounds good figuring in the auto box and drivetrain losses?

 

[Sp!ke]

what work did you get done?

 

[IanA2]

iirc you thought there was a power problem when you bought the car, iirc you thought that there was not a lot more power than your 500.

 

[Red C220]

Aren't factory engine (flywheel) hp or ps figures? 376hp at the wheels sounds good figuring in the auto box and drivetrain losses?

This is what I understand also. Factory numbers are at Flywheel.

365 through the wheels is huge, that's around 480hp at the flywheel allowing for 25% loss.

 

[Doodle]

what work did you get done?

IIRC it's just running a different exhaust, nothing major?

 

[biturbo]

my mistake ill try and photo the sheet. sorry the 365 is the torque and 350 is the HP at the wheel.

 

[biturbo]

Its had new stainless steel header custom made, KN airfilters, 200 cell sports cats.
muffler delete stainless steel and new eisenmann back box. Basically engine out reworked. i mean from the engine out exit manifold all redone.
I was looking at supercharging it only one company in uk said they would do it for 20k, i put my neck back in after that. Also when it drives its constantly spinning the wheels at the slightest touch. Never did that before, im sure there is more torque.

 

[Red C220]

my mistake ill try and photo the sheet. sorry the 365 is the torque and 350 is the HP at the wheel.

So 440 - 460hp at the flywheel that sounds about right as AMG did dumb down the numbers for the SL60 so it wouldn't top trump the then flagship model the SL600.

 

[Red C220]

The SL 60 AMG was the most numerous of these rare cars. Sold from 1993 to 1998, it used a 6.0 litre V8 engine producing 381 PS (280 kW; 376 hp) at 5500 rpm.[4] AMG claimed a 0-62 mph (100 km/h) speed of 5.6 seconds. Its top speed was limited to 250 km/h (155 mph), but with the limiter removed, it was capable of approximately 185 mph (298 km/h). AMG later unofficially conceded that 0-60 mph was more like 5.0 seconds and the engine produced between 405-410 bhp

405 - 410 standard, with good breathing work a 10% hike is reasonable. Which puts it around 440-450hp.

I'd say that would be making 350 or so at the wheels - that all seems to add up to me.

 

[Sp!ke]

Its had new stainless steel header custom made, KN airfilters, 200 cell sports cats.
muffler delete stainless steel and new eisenmann back box. Basically engine out reworked.

Can you elaborate on "engine reworked"?

 

[Doodle]

Was anything changed inside the motor, or is it just new airfilters and a new exhaust? 10% is a good ballpark for breathing mods, but it's not absolute across all power levels.

 

[biturbo]

iirc you thought there was a power problem when you bought the car, iirc you thought that there was not a lot more power than your 500.

That wasnt me, i have a s600 and i said it feel close to it in power, except you have to rev it.

 

[Red C220]

Was anything changed inside the motor, or is it just new airfilters and a new exhaust?

So lets say the true HP figure was 400.

Lets assume transmission loss is 20% rather than 25%.

350 at the wheels makes around 437 at the flywheel.

Full flow headers a de cat (to full flow cats) and free flow filters would comfortably liberate 37hp from a 400hp motor.

 

[Sp!ke]

It sounds like nothing was done to the engine, only exhaust and manifold.

I would have thought there would be a greater chance of some science behind the OEM manifold than on a one off custom myself.


The numbers don't seem far off standard from what you say but I wonder how the air fuel ratio's now compare throughout the rev range to a SL60 with a stock exhaust system.

 

[Doodle]

20% is very generous for RWD and an autobox - we used 18% as an accurate proven figure when testing the Type R, (fwd, manual with an LSD).

 

[biturbo]

Can you elaborate on "engine reworked"?

Nothing on the engine. sorry terrible english, and i am english.
I mean reworked everything after the engine. Manifolds , cats, pipes and exhaust.

 

[jaymanek]

My SL60 AMG is currently putting out 340 at the wheels and the guys said guestimate around 425 at flywheel... mine is totally standard AFAIK.

 

[Doodle]

No dyno run before the work was done?