I know you guys have seen countless posts on heat issues with our cars and you've read a couple of posts from people who are having trouble with their cars because of one reason or another (most of them heat related issues)..

I know that alot of people have a first instinct to increase boost and put a bigger pulley on the car to get more horsepower.

I thought I would throw out a couple of thoughts and summarize them into this 1 post since alot of these thoughts were scattered amongst different posts in the past...

1) The bigger the pulley, the more horsepower it takes to turn it, the more heat you generate. With these cars, it's the law of diminishing returns. It gets to a point where you actually waste more than you make in terms of power and the actual benefits become negligable.

2) This car is super sensitive to heat (as you've heard a 1,000 times).. The ECU's first order of business is to pull timing on you and if IAT continue to soar, you will end up with the compressor being shut down. Basically, I would summarize this thought by saying that the car with the bigger pulley WILL make more peak power BUT will get to use that power LESS than a guy with a stock pulley.

As an example: If you took a stock E55 and and put it against an E55 with a bigger pulley on a road course and had them run for 10 laps full-out, what do you think the outcome would be? The bigger pulley car would be ahead for the first 2 or 3 laps.. I bet you it would be heat soaked by then and the ECU would pull back timing and power and he would actually be slower than the stock car.

So, what's the point of having more peak power if it's only good for a couple of blasts?

3) On most cars when you want to increase boost on a supercharger, you usually would purchase a SUPERCHARGER pulley which would spin the supercharger faster and give you that increase in boost. On the E55, because the supercharger pulley is also combined with a clutch mechanism, tuners have to get around this by supplying a bigger CRANK pulley to spin the supercharger faster.. Well, guess what... The bigger CRANK pulley will also spin everything else on the belt faster also.. Water pump, alternator, etc.

The water pump and alternator (all driveline accessories basically) will be put under higher stress with the increased crank pulley. They will be more prone to failure and SOONER.

4) The ONLY tuner that I have seen provide a proper solution for a bigger pulley is EVO. For some reason they are the only ones who provide UNDERDRIVE pulleys for the water pump and alternator when you buy the bigger CRANK pulley to compensate for the driveline accessories being overspun. I mean, Brabus, Renntech, Kleemann, MKB, HPE.. You name it.. They all just provide the 1 pulley.

5) Let's have a little reality check here... Bear with me for a moment: Corvette C5, 5.7L, 350hp STOCK (305 - 311rwhp). Add magnuson Supercharger (similar roots style blower), *** 6psi BOOST!!! ***, 420RWHP - 440RWHP!!! I've seen them as high as 480RWHP with a blower CAM in the car!!!!

compare that to:

E55, 5.5L, 11.6PSI BOOST, TWIN-PLUG heads, 420RWHP!

Are you telling me that our cars are so inferiorly engineered that the engine in the E55 needs TWICE the boost to make the same power???? NO!! The only difference is the EFFICIENCY levels of the 2 cars.

------
Now, you want to do it right.... Take the time and make the car as efficient as you can and UNLOCK all the available horsepower that is already on the table before increasing boost.

We're talking about running 14 - 15PSI of boost on a bigger pulley.. 1 - 1.1BAR??? That is extremely high.. Do you guys have any idea what kind of power an efficient supercharged motor would put down with that kind of boost?? We should be talking 600RWHP here.. That is assuming that these blowers could move enough air to support that power, but that's for another discussion.

My opinion on modification order is:

1) Heat wrap and protect all the intake and other sensitive components to lower the heat soaking of the motor: Intake tubes, air boxes, spark plug wires, etc.
2) Increase the cooling capacity as much as you can by whatever means. Better coolant, better pumps, better fans, fuel coolers, trany coolers, oil coolers, etc, etc..
3) Increase the breathing ability of the motor.. Better headers, higher flowing exhaust, high flow cats, better intake system.
4) Retune ECU to maximize timing and properly set A/F maps to optimize power for the increases in efficiency.
5) Get a better intercooler system than the factory one that is sandwiched inbetween our superchargers and the engine block.. Worst design I've ever seen for a supercharger intercooler. (this is probably is not in the realm of possibility since the only one in existence is currently made by MKB and they want $15,000 for it... Well, there is the SLR style ones, but that's another thing altogether.)
6) Play with anything else you can think of to increase power without touching the pulley.
7) Once you've hit the proverbial horsepower wall, re-evaluate your position, and then if needed, put the bigger pulley on, retune the ECU and have a blast!!

These are my thoughts and I wanted to put them up for discussion...

 

Vic good points but using a corvette as an example of blower/engine efficiency is misleading. You are forgetting a major difference between both motors which is the stock compression ratio. A c5 has a Compression ratio of 10.1:1 the new c6 has 10.9:1. A clk 55 03 and up has a Compression Ratio of: 11:1. Our motors have a Compression Ratio of 9.0:1 that is the difference in horsepower per pound of boost you are referring too.

I would like to measure IAT pre intercooler and post this will tell us what kind of job the intercooler is doing. Lets kick this idea around.

 

Hey Albert,

I took into account the compression ratio of the engine.. The FINAL compression ratio on the E55 is still higher:

Final Compression Ratio = ((Boost / 14.7) + 1) * Compression Ratio

C5: ((6 / 14.7) + 1) * 10.1 = 14.22 : 1
E55: ((11.6 / 14.7) +1) * 9 = 16.10 : 1

I believe that there is more power to be gained by lowering static compression and raising boost compared to raising static compression and lowering boost so we are still in a better situation.

Our engines are just very low on the efficiency chain I think..

I agree with you on the IAT. Would love do some testing pre & post supercharger that would tell us how efficient it really is.

I have been searching for a vendor that sells pyrometers and displays.. I wanted something that takes 4 pyrometer inputs and displays the results (I need 4 in order to accomodate water injection testing). ANDIAL sells a 2 unit system they use to measure pre & post intercooler temps.

I may end up getting the ANDIAL unit if I cant find anything else.

 

Not so fast...... The 113K engine's use a dual plane belt- the supercharger drive is independent of everything else. every pulley on the market only increases the diameter of the plane driving the SC (the 8-rib belt), not the accessories drive, which uses a 6-rib belt, so in all reality, you are only spinning the SC faster, and nothing else.

 

Not only should you measure IAT's, but pressure drop as well. You'll be suprised at how much boost pressure you loose across the intercooler core.

 

Glad to have you around Cory!!

That one thing has been in the back of my mind for a while. I appreciate your input.

 

No problem!

 

Hmm... You know.. If that is true, then I have the opposite question.. Why is EVO supplying UNDERDRIVE pulleys as part of their kit? If it has absolutely no effect on the accessories, what is the point of underdriving them?

Vadim: Can you shed any light on this?

 

The slower you spin something, the less enegery it requires from the drive component, in this case, the engine- less parasitic loss. I suppose they are trying to squeeze a bit more power of of their kit.

 

So, Cory. my question is considering I am about to get a stage 2 and possibly stage 3 Kleemann kit installed, should I do the things that vrus suggests at the same time? I.E., lower heat soaking, increase cooling, etc.? What vrus says seems to be logical but I am the first to admit I am a novice mechanically.

 

Victor I had a feeling you were using that formula as your base-line. That number is a theoretical calculation while the static compression is measured. For example 5.5 n/a merc motor vs 5.7 c5 motor would be a better comparison. Slightly smaller engine with more compression versus bigger with less compression.

I think it all goes back to intercooler efficiency. Thank you Cory for bringing up the pressure drop that also plays a critical role.

 

Not necessarily. We've got tons of E55 K2 and K3 cars running around all over the country, with zero issues. Obvioulsy it can only help if you increase the efficiency of the intercooler, etc., but it is not required to have a smooth, powerful, reliable car. You can do small things, like coating the headers to reduce underhood temps, etc. You can only go so far making the stock AMG intercooler better- a Bar end plate type heat exchanger has it's limits, and unfortuately, the AMG unit is a piece of junk. In the end, you can do just K2, K3, etc., and have a perfectly driveable, reliable car without doing intercooler upgrades and the like. There's really only so much you can do before you start spending huge $$$ making what's already there, better.

On a side note- It's not uncommon to see poor dyno results with these cars- modified or stock. The majority of dyno shops in this country will never be able to simulate 180 MPH worth of airflow over the car. Without this airflow, successive dyno runs will net in huge losses to heat build up- I can guarantee this. I've seen very poor Dyno results on modified E55's, only to have them run 11.9's on street tires, compared to 12.4's stock. Sometimes, it's not all in the Dyno numbers, but the actual performance of a car on the track.

 

The real dyno = local 1/4 mile dragstrip

Hey Cory what does a c55 or clk 55 make with 6 pounds of boost to the rear wheels ?

 

Typically they'll make between 418 and 425. I've seen a couple make close to 440.

 

Ask and you shall recieve

https://mbworld.org/forums/c32-amg-c55-amg-w203/116837-kleemann-55k-s7-update-pictures-dyno.html

Mez

 

This is an excellent discussion.

 

Way over my head but interesting none the less.

 

Thanks Cory and thanks for the link Mez.

 

I agree with rflow306 that the C5 is not an optimum choice to compare to the E55, but for a different reason. The LS1 engine was intended to propel vehicles that weigh about a 1000 pounds less than the E55. Its torque peak is over 4000 RPM. The E55 torque peak is probably near 3500 RPM. Since HP is a linear function of torque and RPM, adding the same amount of boost to both engines will result in more peak HP from the engine whose torque peaks at a higher RPM level. So the C5 will make more peak HP.

These engines have two different design philosophies. The E55's engine was designed to produce torque down low to propel a heavy car, the opposite of the LS1. Also, the cylinder head on the LS1 can flow amazing amounts of air. It responds well to all upper RPM mods. In its stock configuration, it can support well over 500 NA HP. This, coupled with the more aggressive cam, will push the torque peak higher, but will result in a somewhat narrower power band. I've never seen any info published about the E55"s head, but I suspect it has small ports to keep the intake charge velocity high for good low-end torque.

I'm not sure what your comment on low efficiency means. Are you referring to volumetric efficiency (the amount of air an engine can ingest compared to its swept volume), or thermal efficiency (the amount of power an engine produces compared to the amount of fuel it consumes)? Please elaborate.

In general, I think you're putting too much emphasis on peak HP. This should only be applied to pure race cars that operate near max RPMs the majority of the time. I think your emphasis should be focused on the amount of area under the torque curve. This is what truely makes a street car perform the best. But, if my suspicions are correct, I think you may be getting close to an air flow limitation in the heads and/or camshaft. Are there any MB tuners out there who actually mod engines and have flowed the heads? Does anyone know the cam specs?

 

Grumpy I have been looking far and wide for this information. The people that know the information are not being very forthcoming with it. That is why I used the 5.5 or actually 5.4 n/a amg motor if you want to get technical in our comparison. If I am not mistaken it is the same motor with a slightly different stroke, pistons and camshafts. This info is from the amg website http://www.mercedes-amg.com/
Clk 55
Baumuster engine type. .
AMG-built SOCH 24 valve 90 degree V-8. High-pressure die-cast alloy cylinder block. Alloy cylinder heads. Reinforced crankshaft and valve-train. Lightweight camshafts. displacement. . 5.5 L
bore. . 3.82 in
stroke. . 3.82 in
compression ratio. . 11.0:1
output. . 362 hp @ 5,750 rpm
torque. . 376 lb-ft @ 4,000 rpm
valve gear. . Belt-driven SOHC, 3 valves per cylinder.
redline. . 6,700 rpm


E55
Baumuster 211.076
engine
type. .
90 degree V-8, high-pressure die-cast alloy cylinder block, alloy heads.
displacement. . 5.5 L
bore. . 3.82 in
stroke. . 3.62 in
compression ratio. . 9.0:1
output. . 469 hp @ 6,100 rpm
torque. . 516 lb-ft. @ 2,650 - 4,500 rpm
valve gear. . Belt-driven SOHC, 3 valves per cylinder.
redline. . 6,500 rpm

 

Cory is the man I am one of the "tons" of cars running on the roads and have had zero issues over the past 5 months. Maybe one issue, the car is so darn fast for the street and turns heads when hammered from a light....thank God for my V1

 

The LSx family of engines are in everything from the C5 to 3/4 ton trucks. The GTO came out in 2004 with the LS1 engine in it and it's curb weight isn't far off from the E55. The LS6 is in the CTS-V Caddy, too. I think they tip the scales around 3900lbs.



Here is the stock dyno from my Z06 - 2003 Z06 dyno chart.

And here is a great set of graphs showing an LS6 on boost - all 3 blowers The first set of numbers (blue) are a 2003 Z06 with an ATI blower @ 7psi and LG headers. The second set (red) is a 2003 Z06 with a Magnussen @ 9psi, cam and Kooks long tube headers. The third set (green) is my 2003 Z06 with a Vortech @ 6psi and LG headers.

The point? The blower design makes more difference in the power curve than the basic engine characteristics. The Maggie, which is a roots-type blower, makes it's power down low and drops off up top, where the centrifugal blowers really start making power (ATI and Vortech).

And even though these engines make great power on just 6-7psi, they don't last long with boost. Hypereutectic pistons, high compression and boost just don't mix Most of us know were have ticking time bombs and it's just a matter of time before we pop a couple of pistons

An E55K motor, designed to be blown will last forever (well, within reason).

 

Hey Wayne very good power thanks for posting the graphs. What kind of vortech did you have an S-trim or T-trim?. With some race fuel and more boost scary. Albert

 

I have been dying to see a dynojet graph of a header, ecu, pulley car. I really want to see how the torque and power curves are affected. Also, I am curious as to whether the car can hold its power after successive runs.

Any chance you can do 3 pulls on a dynojet and share the results with us?

 

Wayne,

Thanks for posting. Was trying to locate a couple for comparison.