OK.. This didnt take as long as I thought.

I found a way to get cams done for our cars. These would be created from billet blanks just like the Kleemann cams. Specs are as follows:

Intake Duration: 256
Exhaust Duration: 268
LSA: 114

As far as I know these are the same specs as the Kleemann cams. I AM NOT 100% sure, but, that is what the feedback was to me.

I am sorry but I cant give any more details other than this for now.

The pricing looks to be $2,500 - $2,600 for the pair (dont have concrete pricing yet). I will be talking to someone tomorrow morning to get concrete info on turnaround time, etc.

This looks good and the pricing is in the range I wanted.

 

could you give me a short crash course on how cam will perfect the performance of our cars?. Sorry I am new to this, seems you are an expert in these things so who better to ask than you. Thanks.

 

I am by no means an expert.. I learn what I can as I go..

From what I know, this will move the power band a bit higher in the RPM range.. So, you will sacrifice a bit of low end torque for more mid-range to high end power.

How much extra power can only be seen on the dyno. It wont be huge gains by themselves, but, it would be interesting to see what they could do with a good set of flowed heads..

 

Victor: Good job on the cams!!

That is a very good price. Quotes that I got last year were at $3500-$4000 a set.

 

Thanks! I thought it was a good price too. I was hoping for $2,000 (I like that figure) but I guess I shouldnt be greedy.

I can get them for the C32 also (same specs as above) for the same price.

 

Hey who is doing the cams? I am just wondering. If you dont want to spill it then pm me.

 

Great job,

If they are the real deal I would be very interested. Would anything need to be done to our ECU's to compensate for the change?

 

These are definitely the real deal otherwise I wouldnt be wasting my time!!

I cant provide any more details to anyone because I dont want to create problems for my "source" with any of the vendors out there. Who knows who reads these message boards...

 

Will you have input into the final specs? There are tweaks you can do to a mild cam like this to improve upper RPM performance and exhaust breathing.

 

Cams in a lot of American cars give them a VERY nice and throaty exhaust note. Is it the same with the Benzes?

 

I am hoping I do.. If you have any input I would greatly appreciate it before tomorrow morning when I have the call. This way I can pass it along when I talk to him up front.

Thanks!!

 

The specs that I posted are a relatively mild cam.. There wont be any noticeable lopey idle.. It will be a little more lumpy than stock but barely noticeable inside or outside the car.

 

Hey Vrus i just sent you a PM.

 

OK. I can't right now, but I'll generate a response later tonight.


That throaty sound comes from opening the exhaust valve a little sooner. That is something that needs to happen with these engines to help with the exhaust flow.

 

It also come from overlap, which is the enemy of forced induction motors. We need to keep as wide a lobe seperation as possible to keep the boost in the cylinder instead of blowing it straight through and out the exhaust. If you open the exhaust valve too soon, you'll end up killing the effect of the blower forcing air into the cylinder. Natrually aspirated motors use narrow lobe sep. angles to increase velocity through the cylinder to aid it's filling. WE don't have that problem or need, as we have that big air pump sitting atop the motor.

Beware screwing with the opening and closing events on cams. Valve overlap will do more harm than good on these motors, regardless of how cool it may sound.

 

Overlap causes the lopey idle that Victor referred to. It doesn't have much affect the actual sound of the exhaust. By the time the intake valve starts to open (the beginning of overlap), the sound waves from the combustion explosion have already exited the tail pipe. Opening the exhaust valve sooner allows the combustion sound waves to exit the cylinder sooner, before they begin to dissipate, and hence, are a little louder. This is the troaty sound that you hear. Plus, opening the exhaust valve sooner has the added benefit of reducing pumping looses, which is a major HP drain on a boosted engine, especially one with poor exhaust flow, like the E55's.

The opening point of the exhaust valve has no bearing on cylinder filling efficiency. It can't - the intake valve is closed, and the piston is still traveling down on the power stroke.

 

Correct, what I should have said was "don't keep it open too long". My mistake. But hopefully, you do see the point of the overlap having a detrimental effect on the filling of the cylinder for a supercharged motor. The last thing we want to do is kill the bottom and mid-range power in favor of a few HP on the very top.

 

Some more info on the cam specs:

Valve Timing:

Intake Open: 14dg
Intake Close: 62dg

Exhaust Open: 68dg
Exhaust Close: 20dg

Valve Lift at TDC:

Intake: 0.5mm
Exhaust: 1.0mm

 

Without knowing the actual specs of the stock cam, I can only give you some basic guidelines.

As I see it, there are two goals for the new camshaft: 1) Move the torque band higher in the RPM range; 2) Increase exhaust breathing.

1) can be accomplished by increasing the duration, decreasing LSA, and retarding the cam timing (phasing).
2) can be accomplished with a dual pattern cam (more exh duration than int), opening the exhaust valve sooner, and more exh lift.

1) Duration
You can probably add 8-10 degrees of duration to the stock cam (not the SLR cam) w/o causing a problem. I would guess the stock cam is probably around 195 degrees (@ 0.05 lift). I would target intake duration in the 200-205 degree range (@ 0.05 lift) for the new cam.

1) LSA
Lower LSA results in more overlap, which enhances upper RPM scavenging. But for a boosted engine, this is not a desirable attribute. You need to be careful that you don't allow the LSA to drop below 114. That could increase overlap too much, which can bleed low-RPM boost and possibly necessate reprogramming the ECU. Overlap is the key parameter to control for a street-driven, boosted car with stock programming. Having a little more overlap than the stock cam should not be a problem, and can even help with emissions. Overlap in the 40-50 degrees range should be OK. Going below 114 degrees LSA can cause rough idle and lower vacuum, which usually results in reprogramming. The higher you go, the smoother the idle and the happier the ECU will be. The stock cam LSA is probably around 118. I would target 116 degrees for LSA.

1) Cam Timing
The most critical timing event is the intake valve closing. This defines the torque band - close it sooner and you enhance low-RPM torque - close it later and you enhance upper-RPM torque (within the RPM range of the chosen cam). The E55 has an abundance of low-RPM torque, so that suggets that the cam should be retarded. But the E55 supercharger increases the usable power band by about 500 RPM, so no cam timing adjustment is needed. I would suggest that the intake lobe centerline be straight up for the new cam. This will also help the exhaust timing below.


2) Dual Pattern - Exhaust Timing - Lift
Increase the exhaust duration as much as possible so that overlap (not LSA) stays within target. IOW, target 116 LSA, but increase duration so that the overlap is the same as a cam with a 114 LSA. With an LSA of 116, this will allow more exhaust duration and an earlier opening of the exhaust valve.

The second most critical timing event is the exhaust valve opening. The exhaust valve centerline is defined by the intake centerline and LSA. Opening the exhaust valve sooner allows more blowdown to occur before the piston begins to evacuate the cylinder. This helps exhaust breathing and is frequently done on boosted and juiced engines. It also helps to reduce pumping loses. Just reducing the pumping losses alone can be worth an easy 25 HP.

An assymetrical exhaust lobe can also be beneficial. Increase the ramp on the opening side to open the valve faster, but use the standard ramp on the closing side to prevent valve bounce.

There are no penalties for increasing lift, as long as the valve springs can handle it.

Caveats
The 114 value for LSA above is not a magic number. The actual limiting LSA value is also a function of duration. With the relatively short duration of the cam involved, 112 degrees LSA might be the lower limit. It's a function of how much overlap you can tolerate. The shorter the cam duration, the lower the LSA can be for a given overlap. Use the overlap value for the recommended cam or the SLR cam as a guideline - or see next caveat.

Before you proceed, I highly recommend that you get measurements off a stock cam. This will give you a better guideline of how far you can go with the new cam.

 

Victor...you need to open a testing faciltity as well...

If they work well, I would be intrested...

 

You have to keep Da Grump involved with this. I think his last name is Iskenderian ! Excellent explaination Grump.

 

Grumpy,

Thanks a million!! I think I am going to have to read your post 4 or 5 times so it sinks in properly.. Lots of info in there that apparently is over my head.. LOL..

I'll go take some time and digest it and then try to talk coherently with the CAM guy.

I'll let you know what the feedback is.

 

Thanks Grumpy, learn something new everyday.

 

Grumpy, what do you do again!? thats an extremely informative, educational, and specific post about cams!!!

 

Grumpy -- A++ on the explanation!