ABALONE

Hi!

Going to rebuild my engine this winter.
Going for low compression pistons (Havn't decided the CR yet) going to port and polish the heads and do a complete head renovation while i'm at it.
Bigger fuel pump and larger injectors and my Kleemann/Eaton M112 blower on top of that.

My question is:

Do i want my (W210) stock or a aggressive cam with this setup? Thinking of duration,overlap etc etc Some say that you want a milder cam on a F/I engine and some don't? What's the truth?

Thanks // Mag

MRAMG1

More cam, aka higher lift and more duration will give you ALOT more power with a FI engine, but this power will also be higher in the RPM range, with a loss in bottom end. Its really a trade off of where do you want your car to make the most power

On my 91 stang, running a whipplecharger at 10 pounds for street, and 8 for road racing, think heat and longevity here.

Anyway, I stayed with the stock cam, as it gave me MORE power in the 3000-5000 rpm band where MOST of my driving was on the raod courses. The bigger/hoter cams would have given me about 60 HP and almost 100 LBF of torque, but this would have been at 6000 rpm and up.

Think about what EXACTLY you plan on doing with the car, and BE HONEST with yourslef. Too much cam, and you will loose ALOT of bottom end, but it will make HUGE gains above 5000 rpm.

The biggest thing I can tell you is stay away form ANY cam that has a huge overlap, as this will bleed off the boost, aka the intake and exhaust vlave open at the same time. Smaller overlap cams are BIG on FI motors as you have pressure forcing the charge in and out, rather than just relying on scaveging.

Good luck

Yacht Master

ABALONE,

IMHO your first best choice, easy and cost effective would be stock (W211) 55K cams, That gives you a known to work well cam, rather than trying to reinvent it. After that member PTE did a special grind and a few of the faster members here can comment on that cam. A few of these may still be around, Victor, VRP had them at one time. Now lastly the SLR cams from the 722 would be nice but $,$$$.$$

Last thought, I think your best move would be larger valves and stock 55K cam first, you can always change out cams in an afternoon if need be.

blackbenzz

Nice! Have you thought about what company you are going to use for rods/pistons? Keep in mind that we have an alusil coat. In terms of cams I think thats been covered very well in this thread already lol

hooleyboy

I'm kind of in the same boat with cams. I'm running stock C55NA cams and my over all take is.. Its just blowing boost out of the engine. I'm running a Renntech 168mm pulley and the boost increased but the power wasnt what we thought compared to the E55K. My surge tanks are tapped to monitor boost but that doesnt help to monitor cylinder pressure. Leads me to think the stock 55NA cam has to much overlap and shoots boost right out of the engine.

A thing to think about is... With a custom cam swap you might find the overlap issues. weather the cam is allowing to much boost to build up or not enough. In my situation the NA cam blows off to much boost. Its not a bad thing as it will make the car safer from detonation as it shoots the boost on out. However it will hinder overall power.

The E55k cam has less overlap (i think?) allowing for cylinder pressure to build and make more power. As for the SLR cam. I've seen a few of them installed and then Dyno'ed. My over all take on them is it may not be worth the cost over an E55k cam.

Check with your dealer and get a price on the E55k cams and the SLR cams. If the E55K cams are significantly lower than the SLR cams get them. If the E55K cams are right around SLR cams then get the SLR cams.

Also If your still thinking of what Compression ratio to run in your new project. I would model it around other factory supercharged AMG's

stevebez

I think the CR on an E55 is 9.0 and SL55 9.1 ... I seem to remember reading this on the AMG website... I could be wrong but I remember being surprised by the difference...

ABALONE

Thanks guys! Sounds like cams are not to bad. Specially if the stock NA55 cams have to much overlap like Hooley is writing.


BB --> They are going to bore the cylinders and place new fodders (<--- is it called that) in the engine. And i will most likely go with custom made JE Pistons.

Regarding the CR i'm not sure. I have the less efficent Eaton blower so i'm a bit worried to overspin it.
But i will have a larger fuel pump (Audi RS4 or Bosch 044) and larger injectors and a modified TB. So i guess there will be no problems with fuel support.

Any tips on the CR with my set up?

// Mag

Marcus Frost

abalone,

I appreciate your enthusiasm but the truth is there are entire fields of study dedicated to the questions you are asking. They are not questions that can be accurately answered in a paragraph on this forum. There is no easy answer, and the truth is EVERYTHING is a tradeoff. CR, camshafts, blowers, etc. The type of project you are pursuing needs the oversight of a tuner that is very competent and capable of addressing your needs and building a package around that.

There are many, many variables when talking about camshaft profiles and compression ratios that need to be discussed prior to even being able to suggest anything. I'm not trying to sound like a dick, but I am trying to avoid half-truths and "theories" being given as advice when they could put your project at great risk. MRAMG1 is good to try and use his experience as some guidance, but the Windsor and for that matter Cleveland Ford motors are pushrod engines with vastly different characteristics than your M112.

-m

Exotic-metal55

Set your CR up to the amount of boost you plan to run. CR is a great asset, maximize it! JE pistons are nice!


I would have the N/A cam measured. It seems most the MB cams, even N/A are still have a wide LSA angle (little overlap)..

So you are putting steel sleeves in?

c32AMG-DTM

I believe he's running an M113... otherwise, well said.