1985 300D Horsepower

[85300D]

Hello. I am looking for information on how to properly make about 300hp to the wheels of my 1985 300D. There is not much information in the U.S. from people who have actually done this. I know that the injection pump will have to be modified with larger elements (likely have to swap in an m-pump in place of my mw-pump). How large of elements will I need? For a turbo I was thinking of using a holset hy35, or a borgwarner s256. Some kind of intercooler (air to air or air to water) will be installed. Will I need to add an electronic lift pump to help supply fuel to the injection pump? Will I be able to use the factory intake an exhaust manifolds, or are they so restrictive that I will have to build new manifolds? Will the cylinder head flow enough air, or is porting it a must? Which fuel injectors are recommended? I was thinking of using the monarch injectors if they will be a good match. Will the pre-combustion chambers need modified? Is there anything that I am missing for the engine to be able to make the power? Will I need to worry about blowing a head gasket, or bending the connecting rods? What transmission and drive-line modifications will I need? Will I be able to build the stock trans with additional clutches, etc. to hold the power? I know this is a lot of questions, and I greatly appreciate any help.

Thank you,

Mike

[85300D]

Anybody? I have been told that you guys know the most about making these cars run!

Mike

[Siekkinen]

Hello. I am looking for information on how to properly make about 300hp to the wheels of my 1985 300D. There is not much information in the U.S. from people who have actually done this. I know that the injection pump will have to be modified with larger elements (likely have to swap in an m-pump in place of my mw-pump). How large of elements will I need? For a turbo I was thinking of using a holset hy35, or a borgwarner s256. Some kind of intercooler (air to air or air to water) will be installed. Will I need to add an electronic lift pump to help supply fuel to the injection pump? Will I be able to use the factory intake an exhaust manifolds, or are they so restrictive that I will have to build new manifolds? Will the cylinder head flow enough air, or is porting it a must? Which fuel injectors are recommended? I was thinking of using the monarch injectors if they will be a good match. Will the pre-combustion chambers need modified? Is there anything that I am missing for the engine to be able to make the power? Will I need to worry about blowing a head gasket, or bending the connecting rods? What transmission and drive-line modifications will I need? Will I be able to build the stock trans with additional clutches, etc. to hold the power? I know this is a lot of questions, and I greatly appreciate any help.

Thank you,

Mike

Do you guys really have mw-pumps on your cars? here in finland mw-pumps are on w123 engines but never on om60x engines only things you need are: at least 7mm elements, intercooler of course, minimum 3inch exhaust pipe, holset hx40 charger (hy35 is way too small), hardened tranny. Stock intake and exhaust manyfolds are fine enough for 300hp. Put enough fuel to the engine and keep boost under 2 bars (about 30psi) and you make it. If you go over that 2bar boostlimit you will break your head gasket you dont need to port the head. It will flow enough for almost 400-500hp stock injectors and rods are good enough. Pre-chambers does never need to be modified. I mean never So do you have an automatic or manual tranny? The automatic one can be modified/hardened sorry but I really have to ask that where did you hear that finns build mercs? cause I can hear that everywhere I know only one diesel shop in U.S and that is in maryland

[85300D]

Thank you for the reply. My 1985 300D is a w123 with the 617a. It is also an automatic. Everywhere I read says the finns know how to build mercs!

[Siekkinen]

Thank you for the reply. My 1985 300D is a w123 with the 617a. It is also an automatic. Everywhere I read says the finns know how to build mercs!

Okay I didnt notice that. Then its a bit harder to get 300hp but it can be done

[85300D]

Great. Would you be able to share some details?

[Siekkinen]

Great. Would you be able to share some details?

Same way that with om603

[85300D]

Oh, I was under the impression that the 617's were much more difficult to get power out of than the 603's. Are there head studs available (like ARP) to keep from blowing a gasket? Do I need to install an electric lift pump to help supply fuel to the injection pump?

[Siekkinen]

Oh, I was under the impression that the 617's were much more difficult to get power out of than the 603's. Are there head studs available (like ARP) to keep from blowing a gasket? Do I need to install an electric lift pump to help supply fuel to the injection pump?

Only way you can prevent the gasket from blowing is a metallic gasket but I don't know is there any of them available for the 617 engine. Or there is another way, keep boost under 30 psi No, you dont need to install an electric lift pump. The stock LP can supply the injection pump with 7mm elements but if you want to use 8mm then you have to install an electric pump and pressurize the fuel line. I recommend that you buy an om603 engine and use it with your project. They aren't too expensive and its a lot easier to get power from them. Of course an om606 is the best engine but its more expensive.

[85300D]

I will look into the om603. Will I need to upgrade the drive line, rear-end, or axles?