MarcusF

Thanks Dan. The reason I asked about the cams is boosted cars don't like overlap. If the exhaust valve is open while the pressurized intake is open then it’s very common for the intake stream to go right out the exhaust port. This isn’t as common in an NA environment because the intake charge is working under a vacuum. That’s also why I asked about the HC/CO/O2 levels. Not that the car won’t pass smog, but the HC/CO/O2 levels are a very good indicator as to how much intake is being lost down the exhaust stream. The closer that number is to stock, the less power is being wasted by overlap. I can’t say for a Mercedes-Benz 430 (mainly because I have no idea what the factory cam specs are), but if someone doesn't change cams in a 911 (which is not the recommended route) it’s common to retard the stock cams in an aftermarket supercharger or turbo application. Using aftermarket cams in a 911 with an aftermarket turbo or supercharger makes A WORLD OF DIFFERENCE because of the lack of overlap.

The reason I asked about timing and plugs is ignition mods are quite common in aftermarket boost applications. Ignition can be a serious problem. Ditto for running super rich during extended periods of WOT. The extra fuel is not used for power, but to cool the valves and plug. The extra fuel may be already factored in to the existing ECU software. It is for Porsche. That’s how they can run for extended periods at 150+ without holing a piston (due to pre-ignition from a superheated combustion chamber).

Dan Wang

It's not my kit, so I can't really go into detail. But I understand the concerns. In my previously life time, Cams made a HUGE difference in the M3 that I owned. HOP uses stock software. There are other companies out there that will use their own software to pull back some timing. I don't think that is is necessary for low boost applications.

Josh K

Wow, thanks Dan!

CARLSS0N

Cam overlap only happens if you change to a very wild racing cam, let say if you have a 264 duration with 7mm lift and you change them to 304 duration and 10.5 mm then you will have a problem at idle and at low RPMs, let say if you change the cams to 278 durations with 8mm lift then your stock computer should be smart enough to recalulate the Fuel Map and the A/f

MarcusF

I’m a little confused. When you say “Cam overlap only happens if you change to a very wild racing cam”, you must mean something other than I mean. Every cam has overlap, the question is the degree. Overlap is when the exhaust valve, and the intake valve are simultaneously off their valve seat. Without “any” overlap, the powerband would be exhausted very early in the rev range (before 3K). The 430 makes peak HP at 5800 RPM, knowing nothing about the cam (lift, duration, or lobe separation specs), I know it has a fair amount of overlap. Are you using .050 as a baseline for cam lift?

LowRydeR

That's hot!

mtimmy

DAN: STOCK softwares

I highly doubt if there is no MAF problem .

Josh K

None whatsoever. I'll send you a PM that might help you out. ;0)

CHB

any updates?

Josh K

I ran it with stock wheels today but only picked up about 2 HP and 8 ft/lbs of torque (compared to my run with extremely heavy Carlsson 19"s), so I suppose the wheels don't rob as much power as I thought. Here's today's run.



I still haven't had time to edit a video together (or go to the track :0( ) but I'll stay on it.

MBenzNL

....sick....just sick....drop by nex week - wanna see (and feel!) that live

greetingz,

Josh K

Does this mean you'll be at the meet for sure? It'll be great to see you, it's been way too long since we've hung out. :0)

CurYousGee

looking forward to seeing it in person josh...if i make it to the meet that is.....

TMans

Sweeeetttt!!!! Congrats!

Clk&Slk

Josh, but you pick up 8 ft/lbs and that's good for your car. I have 20" Lowenheart wheels on mine. Who's know how much torque i lose. Btw, your car make hp all the way to redline but what happen to the last 700-1000 rpm, your engine is running leaner then it should be. The air fuel ratio changed completely at the last 700-1000 rpm. Air fuel ratio should be even richer as engine rpm increase specially at upper rpm and to redline.

Josh K

Linh, take a look at your own dyno graph for your s/c run.



Your a/f ratio shows the same change in a/f ratio only it doesn't look as drastic due to the smaller/narrower nature of your graph. Like my graph, yours rises into the 13's at almost the same place.

Here's my theory: I'm not sure what model year your CL is, but my CLK is a 2000. The ECU and injectors are completely different on the '01 and up models of CLK (Version 3.0, mine is 2.8), and the same leaning out is not present on the '01 208 that the system was developed on. My guess is that the ECU is the variable that's causing this. What year is your car, Linh? I'm curious to see if yours is doing something similar because we have a similar ECU version. If that's the case, some software tuning on a dyno would more than likely help both of us push out some more ponies. :0)

midget fidger

congrats on crossing the 2k post mark!

Josh K

oh daaaamnn!!! I didn't even realize!

(wipes away tear)

I'd like to thank everyone on MBWorld for making it all possible...

Clk&Slk

[QUOTE= What year is your car, Linh? [/QUOTE]

Mine is 2001 CL 55. HPS sc used difference injectors to provide more fuel. Here's another HPS dyno chart of the Clk 55 with good fuel ratio.

Josh K

Is that dyno sheet from a different car?

ah well, I'm not having any problems or detonation on 91 pump gas so I'm very happy with it, but I'd still like to figure out why the curve rises a bit. Perhaps the fact that I have 109k miles on the car has something to do with it. Most likely it's the old (2.8) software.

Phade

LOL CLASSIC

Dan Wang

Do you know what kind of injectors HPS uses on their system? What is the flow rate?

Clk&Slk

I can't give out those info.

Dan Wang

Can't or won't?

Clk&Slk

Won't !!