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M117 Intake Refurbishment

Started by TJ 450, 07 December 2008, 10:12 AM

Big_Richard

Quote from: TJ 450 on 09 December 2008, 04:20 AM
Hmm, I see what your saying, although increased control pressure would counteract the force of the air on the plate wouldn't it? I suspect that it (the metering device) also works in a linear fashion, which should be fine, as there is a larger volume of air across the board with a larger throttle body.

Tim

Increasing the force required to move the plate would take away any power ganes from a larger throttle ;)

And also sevearly impede the accuracy of the system to meter fuel at any given throttle position.

We can talk rubbish all day, but at the end of the day someone has to try it and tell us the results ;)

TJ 450

Quote from: Patrick Bateman on 09 December 2008, 04:24 AM
Increasing the force required to move the plate would take away any power ganes from a larger throttle ;)

And also sevearly impede the accuracy of the system to meter fuel at any given throttle position.

We can talk rubbish all day, but at the end of the day someone has to try it and tell us the results ;)
True, as it would increase resistance therby restricting the flow.
Indeed, we can speculate all day long and not get anywhere. Perhaps this could start a new field of K-Jet tweakability? 8)

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

s class

Your solution is 8 throttle bodies, 8 D-jet injectors, a fuel rail and some electrickery.  ;)


[color=blue]'76 6.9 Euro[/color], [color=red]'78 6.9 AMG[/color], '80 280SE, [color=brown]'74 350SE[/color], [color=black]'82 500SEL euro full hydro, '83 500SEL euro full hydro [/color], '81 500SL

TJ 450

Now, that would be impressive! :D

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

It would be really awesome to know what these engines can do with modern engine managment.

I still have the article describing how a holden 5 litre engine managment system was adapted to a 450 SEL 4.5 and dyno tuned. I cant remember the power output but it was a shitload more than the original 165Kw  8)

koan

Quote from: Patrick Bateman on 09 December 2008, 03:36 AM


More air voliume - but then what?

Isn't tje K-jet system pretty crap in this regard, you'd probably need to run modern engine managment also. I'm pretty sure the 65mm throttle gets the air flow meter flap close to bottoming out anyway at wide open throttle, all a larger throttle would do if its bottomed out already would make it run too lean at wide open throttle.


Good point PB. I was thinking the meter flap bore is much bigger than the throttle plate so it wouldn't be a problem. The flap does move quite a distance but whether or not the movement still relates to airflow at large displacements I don't know.

Increasing control pressure might get the flap to operate linearly with more airflow then fuel pressure could be adjusted up to get more fuel to the injectors. But I suppose the last thing needed when trying to get air in to an engine is bloody great round plate in the way.

One of the K-Jet sites mentions one manufacturer, (Ferrari, de Tomaso?) used a dual K-Jet system.

The size of the air filter snout is even less than the throttle body.

koan
Boogity, Boogity, Boogity, Amen!

TJ 450

I managed to get those pics I took during removal, off my phone. If you look closely at the cylinder heads, you can see the channel below the ports I was talking about.






...Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

koan

Quote from: TJ 450 on 09 December 2008, 10:14 AM

If you look closely at the cylinder heads, you can see the channel below the ports I was talking about.


That's the channel that distributes air from the air pump, there will be four drillings off the channel in each head that carry air to the exhaust ports.

The equivalent channel in m100 engines is in head / block surface of the cylinder heads and partly in the RH cylinder block surface.

Visible in the following pictures, in the head



and the RH block surface as the dull gray wavy channel near the top edge.



koan
Boogity, Boogity, Boogity, Amen!

TJ 450

#23
Interesting, I wasn't actually aware that the air was injected into the exhaust ports. Now it makes sense. That would also explain the solid carbon deposits, which seem to have actually accumulated so as to block the passages. On this car, that system is defunct anyway.

By the way, those pics are serious eye candy!

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

TJ 450

Today, I removed the remainder of the bolt. I don't like the look of the surface in this area either. It's possible that some coolant was leaking into #5.





Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

Big_Richard

Quote from: TJ 450 on 14 December 2008, 09:42 AM
Today, I removed the remainder of the bolt. I don't like the look of the surface in this area either. It's possible that some coolant was leaking into #5.

Tim

That just looks like old crusty gasket material thats baked on there, never to be removed, with a little bit of corrosion to add to the excitement. Nothing a good clean and a good gasket sealant cant fix.


TJ 450

I have finally assembled the intake manifold with all new gaskets and rubber parts. I'm just awaiting a fuel distributor o-ring, then I can install it this weekend. The car will then be driveable. :)

I miss driving a W116! :'(




Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500

WGB

You sure are doing beautiful work.

Bill

Niclas

Looks nice but before you put the manifold back have a look at the surface roughness.
On mine 4,5 D-jet intake manifold the surfaces inside the channels were extremely rough. I think you can gain power here. Looking into some american V8 porting sites I learned that a polished intake manifold only gave 0,5% increased power but they use very short and very wide channels that narrows down to aproximately 85% of the intake valve diameter.
Our channels are long and narrow to give low end torque, on this type of channels the surface roughness must be quite important. They are however quite time consuming to polish so I understand that they did not bother at the factory.

There is another place I think you can gain power too but then you have to take your heads off.
Look here, a standard 4,5 (-75 Euro) exhaust port has a zero millimeter radii at the short side. This will generate a turbulance and increased drag.



Here is a smoothened radius.



I made a very home made flow bench and found out that the four I grinded gave an average flow speed of 24,7 m/s and the other four had an average of 23,7m/s, that's a 4 percent difference for a very easy job (if your heads are off).

/Niclas



TJ 450

That's very interesting, Niclas. I can see that the radius there will reduce turbulence. I haven't removed the heads, as they are fine at this point. The engines are certainly designed to give high low end torque at the expense of high RPM performance, a compromise that makes logical sense.
The aim of this project was to eliminate any vacuum leaks present and to improve performance that way. 8)
I'm considering the idea of running a carbon cleaning system through the engine once it's up and running again, too.

Tim
1976 450SEL 6.9 1432
1969 300SEL 6.3 1394
2003 ML500