300CE turbo trouble
 

i started a project in the summer. i'm going to turbocharge my 1989 300CE coupe. now it is time for me to order forged pistons because my project is a lot like PUMPISH's car. i was going to order custom from CP pistons but i need info. for filling out their order form because there are like 50 measurments that i don't know. so please help me fill out the form. the engine is 1986 m103 3.0l. with about a 100k mi.

Why not ask Roman for the measurements he used? If you get even one of the measurements wrong the pistons could be unusable, it's not something you want to guess at.
I'm using new forged Oettinger pistons in my engine (they were made for Oettinger's 300E-24 3.6 conversion) and I had to get some bearings custom made so that they could connect to the rods properly.

How much Hp are you planing to get?
What other part are you planing to use?

I can fix the pistons but you know that you can get pretty high Hp with stock parts as long you can control your injection and ignition.

If you planing to use stock K-jet injection then no forget pistons can help you fron the damage.

Everything is about right tuning injection and ignition curve.

Before you thinking about BOOST you must instal the standalone magament system and drown K-et in the toalet:D

Please tell me about your setup you planing to make

I promise you that standalone system makes unbelievable differense so it feels like you got a new engine!

I agree 100%... Tell us how much boost you plan on running and/or how much HP your looking to make. If your only looking to add 7 or so PSI, just use the stock 9.2:1 compression. Now, If your looking to run 2 Bar (28 PSI) like Roman, your gonna need to go lower....
Adam

Hold on for a second.....are you building this motor yourself? If you are having a shop do it, they should be able to order everything that you need for you (once the motor is torn down). If you are building it yourself, it sounds like you have a lot to learn in a very short time and you probably aren't ready for this (yet). But again, assuming you are having someone else build the motor for you, I would advise against just up and buying some pistons. Once the motor is torn down, 1) you will need to decide if it needs machining (bores, valves, etc), 2) given the nature of your project, you will need to determine what kind of pistons to use, what physical properties (like land thickness, squish, effective compression, etc) you want. All of those things will need to be actually looked at, and could very well affect the dimensions of your pistons.....dimensions that your motor may or may not share with other m103's. Also, spending $1500 on a set of custom pistons right now, that you may not be able to use later, with little chance of selling, is probably not the best thing to do. I know it seems as if buying the pistons (or whatever else) will make your project happen sooner, but sometimes this is a waiting game. Good luck

off topic
 

No, don't do that please! Put it on a bookshelf, aside of you other antiquities, or use it as a presse-papier. One day it will be worth al lot of money:ukliam3:

By the way we have my old K-jet on the wall in our workshop becaurse we hate it so much:D
So it just hanging on the wall and looks like one ugly octopus:nice:

Im getting a set of pistons made up for my e320, they have asked me to send in a sample piston. Id suggest you do the same, much less room for error that way.
Regards

realy? what company is that 'cause that would save a tonn of work. and how much are you paying for your pistons?

Not really, the measurements for the M104 and your 86 M103 are different in many ways. Even if the piston manufacturer was to go ahead and blueprint a design, you will still need to give them specs on what your looking to use them for. I would highly suggest reading a couple of books and put a plan together before you just have pistons made. Nobody is going to do it better than "YOU" if you put the time and research in.
Hope this helps,
Adam

If you know what to do with the K-Jet III on a twin turbo install you can go fast and save a lot of money by not modifying the engine internals.

So far with the "ugly octopus" with two small Garrett T2's and a fixed .48 bar boost we're seeing a best 0-60 of 5.49 seconds measured with a G-Tech three axis accelerometer.
This was in a 90 degree f / high humidity ambient environment.

Cooler weather should bring the 0-60 time down a few tenths....
Will track the car soon to complete the tune.

If you can bolt on and go fast, along with building a reliable motor then why not ?

Yes it works with K-jet but far away from the Standalone system.
My first turbokit I had I used K-jet too and if I boost more then 0,5 then I blowned all vacum hoses and it was leaking everywhere under the octopus. And my gas account was just rising everyday.

If you some day try standalone system you never want to go back to K-jet.

When I opened the engine I could see many spike mark on the pistons and the head only after 0,5bar.

With standalone system I boost 1,7bar with 85 the whole last season and 1,4 bar with gas on stock engine. 1 year later I opened the engine and I could not find a mark of spiking and the engine looked like a new.

This season I boost 2bar and even I blown head gasket and was driving 1 week with water in the engine when I opened the engine the pistons and the head stil looked like new. Only crank bearings was damaged becaurse of water and 1 bearing came loose.

I got much lower gas account too. I consumed more gas with K-jet without turbo then I consumed with standalone system with turbo.

I ispected my car and exhaust gas last week without Kat:

CO: 0,01
HC: 22
Lambda: 1,3

I can say that the standaalone magament system is the best think you can ever to for your car even if you dont have a turbo.

You get more Hp even without turbo and lower gas account

Mercedes engines is very good but with standalone system they are the best:D

But of caurse everythink about how much the poeple want to pay. Megasquirt is very cheap in USA and works very well and can give you a possibility to boost much more so why not. You dont need to boost 2bar like I did but you can boost 1-1,2 bar and be safe.

But I understand that everybody can not install those kind of things and they choose bolt on kit for 0,5bar and I am agree with that

I'm using two additional injectors in the air body assembly above the throttle body for enrichment.
The additional injectors are controlled by a stand alone controller that is software set and 3D mappable.
The stock KE-Jet control functions as it should and doesn't even know when under boost.
Able to infinitely adjust the AFR from idle to max boost.


I'm required to run cats, so I use two 2.5" Magnaflow high flow spun metal cats.
Curious about your Lambda of 1.3.....seems like an extremely lean ( 1.3 x 14.7 = 19.11 ) air fuel ratio.
Would think you will damage the engine at these levels.

I'm set at .85 Lambda under boost and about Lambda at idle for optimum stoichmetric and no chance of detonation.

I use a Split Second additional injector control which will deliver enough enrichment via the two added injectors to the boost ranges that you quote.

Max boost I would ever consider would be around .7 bar using an untouched stock M103 with 9.2:1 compression ratio.

I'm prefer to do mods that will not effect the durability of the engine.
As you increase horsepower your performance returns tend to diminish as you now have a drive train that will fail.

If you can't get the power to the ground in a consistent manner then your power is negated !!!

About ratio in Sweden is the law for exhaust gas for all cars with Kat:

CO: 0,5
HC: 100
Lambda: 1,0-1,3

At the idling.

My Kat was broke but I could tune the system to get even better value. And this is imposible to do with K-jet.

At the low load as 50-60kpa I have choose lambda 1,0 and at 100kpa 0,95 and when i boost 1bar around 0,84 and 2bar around 0,75.

When I used K-jet with my first turbokit I used piggyback SMT6 with 4 extra injectors so it was not only K-jet.

With standalone system is like day and night!
I promise you u must try it and you will never to back to k-jet again.

To compare 20 years old K-jet and modern magament engine system wich developing every month and getting better and better is absurd.
With standalone system you have completly 100% control over the engine and it is real fun too.

In sweden racing is very popular this days and it is many racing companys and many many intusiasts everywhere allmost on every corner and every car has standalone magament systems.
Standalone system is the future of all kind of racing.

Good example: We had a customer with Audi 100Turbo with stock K-jet injection (k-jet for turbo, better then mercedes k-jet) and he got 260Hp with 1,1bar at the Dyno and then installed NIRA (standalone system) and with the same boost 1,1bar we got 410Hp!

Like I sad it is impossible to compare a modern thing with 25years old thing

And about to get the power to the ground is just to use slicks if i wanna go to streetrace otherwise I love to drift:)

that is exactly why i will use Megasquirt.