W123 OM617 w/ Trubo - Power Upgrades?

[ryanrod]

What do I need to do in order to give my W123 1985 300D Turbo more power while retaining the same gas mileage? This car has the OM617 engine with a stock turbo on it.

Would any of the following make a difference?:
- A better turbo than the stock version?
- An intercooler?
- Larger Fuel Injectors?
- Larger exhaust?
- Better air intake?


I know the car has around 125hp right now and I am looking for 200-250hp while retaining the same gas mileage if possible. If this cannot be done, how much will performace enhancements drop my gas mileage? I currently average around 23-25mpg.

Thanks

[Virginia-dude]

You won't be topping 200 hp with a stock pump...and the American market "MW" pump can't be modified like the Euro "M" pump. The proper size elements just are not available.

If you wish to turn up boost you need an inter cooler, You can't turn up fuel until you do both of those or you risk melting a piston.

[Forced_Induction]

Installing a pyrometer should be your #1 priority.

[Virginia-dude]

Installing a pyrometer should be your #1 priority.

Definitely....you can ruin your engine if you don't know what your EGT is at all times while adjusting. very good point.

[Haisuli]

That original turbo is quite good with the normal pump. You wont get very high boost pressures with unmodified pump. When the original elements are replaced with the Bigger elements. The injector pumps efficiency also increases and its possible that you get greater mileage than now. Also installing an intercooler is important, because you will get cooler air into the cylinder--> up to 30%more air to the machine. That makes it possible to increase boost and diesel injection to the cylinder, so you can get that 200+hp out. You should also install that pyrometer and im planning to install an exhaust pressure meter also, so i can be sure that i wont be teasing the engine too much. Cooling must be in order for achieving long term usable power. So, first i would do: Cooler installation, not very big, because big intercooler usually takes time to fill, so turbo lag is often too big with big cooler. Quite small cooler is easy to install and turbo lag is eliminated as small as possible. And the injector pump should be (so i remembered) replaced with the modified naturally aspirated one, then you will be quite close to 200hp.
Usable increase of torq is often higher than achieved max horsepower. Om 617 turbo doesnt breathe very well, so the sylinder head should be ported and matched to the intakemanifold and the exhaustmanifold. For those amount of power, should 2.5" downpipe do well. Better breathing pipe is necessity, cause the normal pipe is limited.