What engine?
 

I recently purchased a 1986 300E and its performance is mediocre at best. I have access to some various Mercedes engines including a 1991 560 V8. Should I improve the straight 6 or go with the v8. Will it fit? I can also get the 4 speed transmission. Or should I look for something else. This car will be a daily driver and autoX toy sometimes.

Thanks, Joe

Well the m103 is not known for power especially paired with 2nd gear start. They do respond very well to forced induction if you want to go that route. If you autox, maybe a manual swap?

It is going to stay an autotragic since it will also be a family car. I have a Volvo for a track toy. So it sounds like the V8 + turbo or kompresser? Will it mate up with the tranny in the 300 or should I get the other transmission and will it all fit? What ECU should I use, and is it a fairly simple swap or is it worth it for the gains? and finally what output could I expect if I don't do anything crazy?

He was saying put a turbo on the M103. LOTS of threads here on that topic. The M103's compression ratio is only 9.2 to 1, not much different than your Volvo turbo's 8.7 to 1. It's like it's ready made for boost! A turbo M103 will spank that 560 V8 in the same car. Yes, boosting that 560 engine will make for an even faster car, but I think you'd be blazing your own trail there whereas with the M103 turbo others here have already done most of the heavy lifting so to speak. You'd pretty much only have to copy what has already been done.

M103s aren't that slow though, unless you consider high 15s slow. I gained a full second improvement in E/T in the 1/4 mile with my 235,000 mile 89 300E by just hacking off the resonator and muffler despite the fact that many folks (including Stu Ritter) claim that they aren't restrictive. Your car has three, count them three, cats. Maybe one or more of them is plugged? I would consider playing with the current combo before I would even think about undertaking a major project. I have a low 14 second 400E yet I still thoroughly enjoy my 300Es very much! In the cut and thrust of fighting So Cal traffic, they more than hold their own!

Are you on Turbobricks? What's your username? I'm "ThickasaBrick" over there.

If you do go forward with the 560 V8 swap, please do a build thread here. Also, I have an ECU for that V8 engine that will plug directly into your 300E's harness that I will trade you straight across for your stock 86 300E's ECU, provided that it is the original one. (We'll verify that by it's part number if and when you get ready to do the swap.)
Regards, Eric

with fuel prices rising you don't need a thirsty v8.

Good point.
Regards, Eric

Get rid of it, and go find a 400e/500e. With all those mods, you will spend just as much money, and wind up with a worthless, butchered car.

While I respect the 124.034 and .036, my vote is turbo 103. If you have good tools and fab skills it can be done relatively cheap. A friend of mine, fellow wagon owner and mechanic was planning to do a 117 swap. That is until I took him for a ride in my wagon. 9 PSI will make a runner out of a 103.:D

Yea Eric, I am on TB. Same name there as here.

The 300E is new territory for me, as is Mercedes in general. I wanted a 190E simply because it is a small car with potential.

However I couldn't pass up a $400 300E that runs and most everything works. I had some minor electrical issues and a busted window but those have been sorted for the most part. I'm still learning all the numbers and combos for this car.

So it sound like turbocharging is the way to go? Could someone be kind enough to point me to a build thread?

Start with the ones in the stickies. Also, check and see if the guy who posted just before you did has a build thread. (I seem to remember that he does.)

Remember that the CIS system on the M103s changed from CIS-E III to CIS-E V starting with the 90 M.Y. So if you are copying someone else's set-up, keep in mind that what may work well for a 90 and later may not work well for you and vice-versa.

Whatever you end up doing, please do a build thread, even if you are just copying someone else's set-up!
Regards, Eric

I agree, with the fuel prices here, (AK) you definately don't need a gas-thirsty V8, that is why i plan to get a 1989 190D, gets about 45 mpg and i am not going to be hotroding it, although it is always fun to have a hotrod like the new shelby. :cool:

Yes don't use a gas thirsty V8. Get a more fuel efficient M113, M119, or even an M120.

An M120 gets good fuel economy?

Compared to a CIS M117 engine, a top fuel dragster is economical.

Yes my M120 107 gets about 21MPG on the highway compared to 18 for my stock 1988 560SL.