Superpump OM617

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Ben
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Joined: 12.12.2021
Location: Taunton

My automatic 300GD with OM617 had been fitted with a K26 turbo on a custom manifold and intercooler at some point in it's life. It had a 280GE exhaust fitted to it too, as these are larger diameter than the original 300GD version.

Since owning the car, I have replaced the fuel tank with a late model 463 plastic tank, and also fabricated a side exit exhaust out of 2.5 inch stainless, all the way to the turbo.

The car was still very slow, despite the turbo. I could just about get upto 60MPH shown on the speedometer with the 32 inch tyres I am running. The original MW injection pump was still fitted to the engine, with no tweaks or modifications to give extra fuel, so the turbo basically wasn't adding any power.

I recently bit the bullet and bought a DPUK superpump. Wow, what a difference. It's like a different car now. I now feel like I can enter busy roundabouts with confidence, pull out of junctions without planning a week in advance, and also make it to 70MPH with no problem to actually use motorways. It will actually push you back in the seat now if you step on the accelerator.

The engine also seems to run much more smoothly, with a much better idle. Driving sensibly, I am told the fuel economy should be better too, due to the shorter but higher pressure injector pulse. I also haven't seen any black smoke, which is something I wanted to avoid.

Boost is running around 0.9 bar, and the pump is set up very mildly. I didn't want the risk of blowing up the originally NA engine by running too much boost and fuel, though the pump has the capability upto 400hp on a 'built' OM617.

The only item I needed in addition to the pump was a vacuum control valve as fitted to OM603's. This is because I have an automatic transmission, and it will now flare on upshifts under power. The vacuum control valve progressively bleeds vacuum away from the transmission with increased accelerator position, which firms up shifting and prevents the flare.

gav.helme
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Joined: 29.04.2011
Location: North Lincolnshire
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Re: Superpump OM617

Good result!

Interesting on the manifold.... 300GD OM617 5 Cylinder ... 280GE M110 6 Cylinder

How have they done it? Chopped a cylinder off obviously....

The M110 manifold is normally a 2 piece affar with 3 cylinder per peice whereas the 617 is a one piece manifold

Never heard of it but great if it works!!

Ben
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Joined: 12.12.2021
Location: Taunton
Re: Superpump OM617

It was just the exhaust from the turbo back that was modified from a 280GE exhaust. This measures 60mm, so a good bit bigger than the 300GD exhaust. However, this is gone now and replaced with 2.5" stainless.

The K26 turbo was fitted from the factory to some later OM617A engines, so I know that it's a fair match. The other option was a T3 I believe.

The manifold is custom made from box section steel. I don't know much about it as it was already on the car when I bought it. The car certainly runs very well with it now though.

On the todo list is install an exhaust gas temperature gauge, so I can make sure that i'm keeping below a safe temperature threshold, before I start doing extended WOT runs. I.E. up long hills etc.

manz376
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Joined: 29.09.2013
Location: London
Re: Superpump OM617

Hey Ben,

I was thinking about fitting the superpump to my 300GD but was worried about the gearchange on the automatic box, you seem to have found a way to fix the issue.

Can you let me know what the part number of the vacuum control valve is and where and how is it fitted?

Cheers

Ben
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Joined: 12.12.2021
Location: Taunton
Re: Superpump OM617

A1403000833 is the part number of the vacuum valve. It fits to a couple of bosses on the side of the injection pump, with a keyed coupling which fits to over the throttle/accelerator shaft, on the opposite side to the linkage back to the pedal.

Three hose connections, One to the vac pump, one to the transmission, and one to atmosphere. It basically bleeds away the vacuum going to the transmission the further the accelerator is pressed, simulating what would happen in a petrol engined car.