ShouldveHadaV8

Ive been trying to think of ways to improve my clk430 and other w208's alike, what could make these engine run a little more efficient? As everyone knows the EGR system recirculates exhaust gases through our very sensitive 2 phase intake manifold building up copious amounts of carbon. So my question is this. Can I make an EGR delete? And will it benefit the car? What are possible downfalls, assuming you dont care much for emission laws as i do not. Also assuming i can find a shop here in NYC to make the block off plates.

2PRECISE

I removed egr and diverter valves as soon as I got my 208

ShouldveHadaV8

Could you possibly show me how to do that? You make it sound real easy..

jonUF02

I would be interested too. What is necessary to delete the EGR system? It really fowls up the intake manifold.

bobbyjo9

Unless your planning major mods like 2precise, a stock 430 w EGR vs wo EGR, will be more efficient and reward you with better mileage. Don't forget you'll also need a tune to eliminate EGR since the ECU will be looking for it. You can just remove the valve and reinstall with a piece of cut up coke can to cover the port. EGR will no longer circulate but I doubt you'll be happy with the results unless you do much more work.

jonUF02

I would have no idea where to start on a custom tuning for this.

ShouldveHadaV8

I'm more interested to know what it would take. Completely removing the system really intrigues me and sometimes it's alot more simple than it seems. It could simply be a matter or fooling the ecu into thinking it's still there. If that were even possible. Hell I could be completely wrong. But there is no harm in trying. I wanna go fast on a budget with a Mercedes! Is it too much to ask!? Haha. I'll also be cutting off my main cats which would leave me with just a muffler and no cats or resonator. Will be fooling the ecu there to not throw o2 codes :] . The possibilities are endless and I'm loving this car!

ShouldveHadaV8

2Precise is an inspiration to my cause! I wanna make my w208 as cool as his

Chadzu

EGR systems typically only send exhaust gasses into the intake under low load cruise conditions. This helps increase fuel economy and lowers NOX emissions. When you step on it the system shuts off. I don't really see how it could add any power to your car.

jonUF02

I deleted the second cats, I think it has just the right exhaust note now without being loud in everyday driving. Deleting the first cats is asking for trouble and constant dash warnings. The O2 sensor system in this car is complicated, so deleting the cats will screw up everything, and probably make your idle and gas mileage go to crap. These cars are really way too computerized to start modding things like that. If you want to go faster, then you should trade up to the 55 model. I also agree that deleting EGR will most likely not add any power. I just wanted to do it because I have seen what it does to the intake manifold and the butterfly valves in there.

ShouldveHadaV8

Precisely my point, I'm not expecting any real power gains. I've found a way around the o2 codes I'm gonna extend the o2 bungs after the main cat and get it further away from the exhaust stream to fool the ecu into thinking the cats are still there. I'll let you guys know how that goes, my cats are getting clogged up anyway. I'd love to get the 55 but it's out of my reach. I'll deal with my little v8 then soon enough, pinch it out to a 6.0 and use 55 internals with lower cr forged pistons and go forced induction as well as tranny swap and all supporting mods

MarcusF

The secondary O2 sensor problem can be solved by using a spark plug extender / non-fouler. Amazon has them for $5.

Remove the existing O2 sensor. Screw the extender into the O2 sensor bung. Then screw the O2 sensor into the extender. Now the O2 sensor is out of the immediate exhaust stream and won't throw a code. No welding and no wiring changes. Yes, angled versions are available and you'll see why that's important as soon as you slide under the car.

This fix also allows you to use metal substrate high flow cats, which will keep the exhaust hot. Hot exhaust flows faster than cool exhaust and good flow = HP (in minute amounts if that is the extent of the exhaust work).

ShouldveHadaV8

Now with just deleting the cats and not replacing them, using the spark plug non foulers and all. Will the car just sound nicer? (Louder) And would it be detrimental to the performance? I'm also running a flowmaster 10 series muffler

2PRECISE

what are your plans or goals with your car ShouldveHadaV8??

DarrenV8

This is all really interesting to me as I'm looking to disable/delete the EGR too, as well as "improve" the exhaust system to give a better note and perhaps better flow.

I was wondering if anyone had thought of tapping in to the electronics of the EGR valve so that is simply stays closed until you flick a switch, when it reverts to standard running (for MOT/emissions tests etc). The first thing I did on my Chevy was delete the damn EGR valve, and when you remove the intake manifold, you can see why they're such a bad idea. I had about 2mm of carbon build-up in the intake runners, which reduces the CFM of the manifold and most likely the velocity too.

*edit* Just realised this won't work as EGR's are vacuum opperated, but perhaps blocking the vacuum pipe would have the desired effect? If the EGR is closed by default and uses the low RPM vacuum to open it, there's no reason why it wouldn't *end edit*

As for EGR being better for economy, I'd say it was negligible. Compare the initial slight gain in mpg at low revs to the ever decreasing efficiency of the engine due to carbon build-up, I'd run without one any day. Don't forget that making more power from an engine without increasing the cylinder dimensions means making that engine work more efficiently. More efficiency means to achieve the same speed, you can use lower revs, which means better mpg.

For course, to get full benefits of an EGR delete, the intake system needs to get a damn good de-coking too.

As for my exhaust, the rear box is already an AMG box, which I'm guessing flows better? I plan on removing the centre box asap, and will most likely leave the cats until they need replacing, and fit sports cats. My CLK 320 is the early version with the single set of cats, so I don't know how it would fare from an emissions test point of view by getting rid of the only cats in the system.

My other plan for the moment, is improving the cold air feed to the air box and replacing the stock filter with a K&N replacement element.

astamir

I had about 2mm of carbon build-up in the intake runners, which reduces the CFM of the manifold and most likely the velocity too.

how did you clean that carbon build up?

DarrenV8

That was on the Chevy, I replaced the intake manifold from stock to an Edelbrock performer. Don't know what I'm going to do with the CLK yet. To do it properly will probably involve taking everything off and cleaning it, though something like sea foam spray (where you put a tube to spray in the sea foam after the MAF in the air intake) may work to an extent?

DarrenV8

Looks like the only option is the Sea Foam Spray. I've seen how the intake manifolds function (on the 320 at least) and it's not a simple beast and can't be torn down. It actually has a variable length intake system which alters dependant on the rpm of the engine. It's altered by the vacuum actuator on the front of the intake manifold.