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  #46  
Old 01-29-2006, 04:09 PM
ForcedInduction
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Quote:
Originally Posted by Brandon314159
why would the finnish guys rev their cars so high and adjust the max speed on the IP?
I believe the reason they raise the max RPMs is due to power fall-off at the topend. If the redline is 5150rpm and your revvs are getting to 4900rpm, the IP speed limiter will start to cut fuel (Not completely, but progressively). Raising the max rpm will allow them to get to 5150rpm with full power. Those 2050rpms can mean quite a few MPH increase in the top end and a faster 0-60.

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  #47  
Old 01-29-2006, 04:22 PM
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Sorry Brandon you need dyno charts to prove that. 617's reach max torque at 4,400 rpm according to MB. Maybe your mods have raised the rpm that it produces max torque, but thier is no way to no without dyno charts.

Still I don't see the point, even on these cars very best days a plain jane stock G35 or S500, 500E will still spank them. Whats the point they are about class.


Running 30 year old engines past the limits isn't a good habit. Bearings, oil pump chains, timing guide's and chains ect all have a lot of time and wear on them.

The Finnish guys can afford to blow up a couple of these, and a lot of their engines have bottom end mods as well.
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  #48  
Old 01-29-2006, 04:36 PM
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Here are some fun videos, enjoy!

http://www.mbworld.org/forums/showthread.php?t=132421&highlight=S600+video

http://www.mbworld.org/forums/showthread.php?t=93640&highlight=S600+video

http://www.mbworld.org/forums/showthread.php?t=134338&highlight=E55+Video

http://www.mbworld.org/forums/showthread.php?t=133928&highlight=E55+Video

Enjoy the bi turbo V12 fun. Those things will kick in the traction control to over 90mph!

Also enjoy the CLS, such a stunning design.
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  #49  
Old 01-29-2006, 05:33 PM
Brandon314159
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Revving my car higher is not to accuire more power/speed or anything of the sort...

...if I wanted a fast car I would go find a different project. I am just posting this stuff so that you guys can see that the 617 can, will, and does rev well past its redline and still makes decent power (atleast in modified form )

Is there some reason you posted videos to gas powered cars in the diesel discussion???
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  #50  
Old 01-29-2006, 06:06 PM
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Quote:
Originally Posted by Hatterasguy
617's reach max torque at 4,400 rpm according to MB. Maybe your mods have raised the rpm that it produces max torque, but thier is no way to no without dyno charts.
.............max horsepower at 4400 rpm.

And, I agree.........unless the engne offers maximum HP at rpm's above 4400, you don't get anything from revving it higher. The dropoff in torque is massive.

Now, I do believe that the figure M/B cites for maximum torque........2400 rpm..........must be in error. Anyone who drives a 617 would agree that it pulls much stronger at 2800 than it does at 2400.

So, it's entirely possible that the maximum horsepower at 4400 rpm may be low by several hundred rpm as well.
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  #51  
Old 01-29-2006, 06:18 PM
Brandon314159
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Quote:
Originally Posted by Brian Carlton

And, I agree.........unless the engne offers maximum HP at rpm's above 4400, you don't get anything from revving it higher. The dropoff in torque is massive.
While yes I agree diesel engines loose much torque at the top end, the reason that it falls off on a STOCK engine is becuase the IP is shutting down the fuel. If you turn up the max speed (aka the max idle speed adjustment...its confusing...don't ask) then the IP won't cut the fuel off and thus you won't see that same huge torque dropoff at redline.

Those who are more diesel engine savvy know that the "Full Load" adjustment is also known as a "torque capsule" adjustment on other types of injection pumps. This must be kept in mind that when you increase the fuel across the range...

Its difficult to explain...easier to understand after an IP is all torn apart on your bench
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  #52  
Old 01-29-2006, 06:24 PM
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Quote:
Originally Posted by Brandon314159
While yes I agree diesel engines loose much torque at the top end, the reason that it falls off on a STOCK engine is becuase the IP is shutting down the fuel. If you turn up the max speed (aka the max idle speed adjustment...its confusing...don't ask) then the IP won't cut the fuel off and thus you won't see that same huge torque dropoff at redline.
.........interesting.

So, the max HP figure is completely artificial and dependent on the fuel cutoff.........without the fuel cutoff you can keep the torque curve reasonably flat well past 4400??
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  #53  
Old 01-29-2006, 06:30 PM
Brandon314159
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Quote:
Originally Posted by Brian Carlton
.........interesting.

So, the max HP figure is completely artificial and dependent on the fuel cutoff.........without the fuel cutoff you can keep the torque curve reasonably flat well past 4400??
I would venture that when you change the fuel delivery and the maximum shutoff point, you will change the HP curve/falloff...I think the max RPM is listed for a stock engine at the point they put merely becuase redline is very near there and thus the IP is shutting things down.

Now the torque, yes I would agree that torque will not remain flat clear to the top however it would be safe to assume that you are widening that band by delivering more fuel at the top/across the band. Sorta like pushing that falloff you feel at 4400 up to about 5200-5300.

I would still execpt a reasonable falloff (hell I can feel it start kicking down at about 5250-5500) but I think the main reason you see the sharp torque falloff is due to the fuel cutoff on an IP that is setup for this to happen...
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  #54  
Old 01-29-2006, 06:35 PM
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Quote:
Originally Posted by Brandon314159

I would still execpt a reasonable falloff (hell I can feel it start kicking down at about 5250-5500) but I think the main reason you see the sharp torque falloff is due to the fuel cutoff on an IP that is setup for this to happen...
Clearly, the torque is in falloff from the rpm point of max torque upward.

The real question is whether the falloff of the torque is still less than the rise of the speed.

If so, then the horsepower is increased and the delayed shift is beneficial.

You do know the relationships between horsepower and torque.......don't 'ya??
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  #55  
Old 01-29-2006, 06:39 PM
Brandon314159
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Originally Posted by Brian Carlton
You do know the relationships between horsepower and torque.......don't 'ya??
I would hope so...I don't waste other people's time discussing things I don't understand. Pissing contents never have humored me.
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  #56  
Old 01-29-2006, 07:03 PM
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Let's settle this debate with a dyno run Brandon
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  #57  
Old 01-29-2006, 07:07 PM
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Quote:
Originally Posted by Brandon314159
I would hope so...I don't waste other people's time discussing things I don't understand. Pissing contents never have humored me.
Good.......because most folks.......even diehard "car guys" don't really understand the difference and the relationship between torque and horsepower.
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  #58  
Old 01-29-2006, 07:14 PM
Brandon314159
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Originally Posted by Ara T.
Let's settle this debate with a dyno run Brandon
I told you guys...I'm tryin'! hah.

Dyno runs are not cheap...and I don't know anyone nearby with a stock w126 300SD for comparison.

Trying to find the dyno shop is the trick...there is a guy next door to a metal fab guy doing some work for a friend...he has a dyno in his shop so I am going to talk to him next time I am there.

Remember...I haven't spent much money on my car and I cannot afford to do so
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  #59  
Old 01-29-2006, 07:16 PM
Brandon314159
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Quote:
Originally Posted by Brian Carlton
Good.......because most folks.......even diehard "car guys" don't really understand the difference and the relationship between torque and horsepower.
Heh I am the son of a diesel mechanic...I think I got it down

Besides, I've read many books on engine theory, design, and repair. All old stuff but the basics never change.

Irregardless you learn the relationship between torque and H.P in physics class..haha
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  #60  
Old 01-29-2006, 08:26 PM
ForcedInduction
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You can see my torque peaks at 2300rpm then goes downhill from there. HP and TQ start to drop off at 4400rpm and take a nosedive at 4600rpm.

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