Need Advice on Adding More Power to HPS SC

If AMGSC's car is really making 479ish RWHP, why would he even need to add more HP???
I just witnessed another dyno at the Mechtech shop in Escondido of my car and the dyno again showed a similar lean A/F ratio & 317rwhp which confirms Josh R's dyno. I was present at both dyno's so there was no funny business going on here.
Jim stated that the problem may lie in the fuel injectors not being big enough for the MP112 running at 7 lbs of boots so he will change them out with bigger ones. He will also retune the car and MAKE SURE that the computer does not revert back to cutting off the fuel injectors in a few weeks or months. After this problem is corrected on Monday which I will witness and post another dyno. They will begin work on installing the pulley kit that will bring my boost up to 8-9 lbs saftely just as like the Kleemanns for free!
If I have recurring problems again then I may have to return the car to stock and then just sell it and buy next year's 4-valve model and supercharge it with the best available SC kit available at ANY PRICE!
I just witnessed another dyno at the Mechtech shop in Escondido of my car and the dyno again showed a similar lean A/F ratio & 317rwhp which confirms Josh R's dyno. I was present at both dyno's so there was no funny business going on here.
Jim stated that the problem may lie in the fuel injectors not being big enough for the MP112 running at 7 lbs of boots so he will change them out with bigger ones. He will also retune the car and MAKE SURE that the computer does not revert back to cutting off the fuel injectors in a few weeks or months. After this problem is corrected on Monday which I will witness and post another dyno. They will begin work on installing the pulley kit that will bring my boost up to 8-9 lbs saftely just as like the Kleemanns for free!
If I have recurring problems again then I may have to return the car to stock and then just sell it and buy next year's 4-valve model and supercharge it with the best available SC kit available at ANY PRICE!
Since they are changing out the injectors for larger ones, does that mean they have ECU software to tell the injectors to spray more fuel under boost? It doesn't really make sence to have larger injectors if nothing is telling them to deliver more fuel. I'm running only 4.5lbs and making 360whp on stock injectors. I was even making 338 when running 15.3 air/fuel
I'm not sure I would add a 8 or 9 pound pulley to a car that has 11.1 CR, sounds very dangerous to me. You mentioned Kleemann running 8-9lb pulley, but Dragon is only running 5lbs of boost on the same car and is making a ton of wheel power. You should ask Dragon if he feels comfortable adding 4lbs of boost more to his already high compression new C55. 9lbs would make your car a 14.1 CR motor.
I do hope your car make a 180 turn around. The HPS Gen 2 looks like a good system, but I think it just needs some TLC to make it run the way you deserve.
Mario
Since they are changing out the injectors for larger ones, does that mean they have ECU software to tell the injectors to spray more fuel under boost? It doesn't really make sence to have larger injectors if nothing is telling them to deliver more fuel. I'm running only 4.5lbs and making 360whp on stock injectors. I was even making 338 when running 15.3 air/fuel
I'm not sure I would add a 8 or 9 pound pulley to a car that has 11.1 CR, sounds very dangerous to me. You mentioned Kleemann running 8-9lb pulley, but Dragon is only running 5lbs of boost on the same car and is making a ton of wheel power. You should ask Dragon if he feels comfortable adding 4lbs of boost more to his already high compression new C55. 9lbs would make your car a 14.1 CR motor.
I do hope your car make a 180 turn around. The HPS Gen 2 looks like a good system, but I think it just needs some TLC to make it run the way you deserve.
Mario
I hear the Kleeman's are running slighter higher than 7 lbs of boost. Both Josh Rickards at HoP and Jim McFarland told me Kleeman's often run at 8-10 lbs of boost. Are you sure someone did'nt mispost? If AMGdragon IS running only 5 lbs of boost then I will tell them to halt the pulley kit project.
AMGdragon, Can you confirm what your boost is since I obviously was wrong about what I THOUGHT was my boost based on conversations with HPS.
Who elso makes a supercharger that has both the low-mid range power of a Kleeman AND the high-end power of a Vortech? Are the Wipple's better than the Kleeman's or are they the same identical AUTOROTOR twin-screw?
Kleemann strongly advised that it is very unsafe to run higher boost on these motors being that they are 11:1. They are comfortable with 7lbs and that's it. DO NOT go higher than that. Can you run 10lbs... probably.... but not for long and definitely not safely. If one thing is wrong with your fuel delivery .... BOOM ... kiss your 25k motor goodbye. Is 3 extra lbs worth it? I think not.
What is all this talk about getting new injectors????
You don't need that. What you need is TUNING!!!! Simple as that! Kleemann didn't change out my injectors.
I'm running stock injectors and averaging 20 miles to the gallon with a heavy foot.AMGSC - I'm sorry to hear you're having problems. In all honestly, I think that's something you should expect when just slapping a supercharger on a mercedes that uses a piggy-back FMU. Kleemann is expensive for a reason - "peace of mind, comfort and reliability" -- IMO, Kleemann is worth every penny. I haven't had a single problem with the car. It idles stock, never had a check engine light, no funnny noises, consistent power, etc.
Anyways -- good luck and I sincerely hope everything works out. Maybe your should just consider cutting your losses, getting them to take your HPS kit back for a small loss, and going the Kleemann route. If you do that you will be extremely happy!!! And you won't ever again have to start a thread titled, "Need advice on Adding More Power to HPS SC'd C55".
Last edited by dragonAMG; Jan 28, 2006 at 05:38 PM.
Nicely said! That's the reason why it's only 7lbs of boost is because of the engine longevity.
You don't need that. What you need is TUNING!!!! Simple as that! Kleemann didn't change out my injectors.
I'm running stock injectors and averaging 20 miles to the gallon with a heavy foot.

The Best of Mercedes & AMG
In all honesty, I'm actually thinking about keeping it and just getting a 996 911 4s. Instead of selling it and just having a GT2. It's really more practical doing it that way.
I hear the Kleeman's are running slighter higher than 7 lbs of boost. Both Josh Rickards at HoP and Jim McFarland told me Kleeman's often run at 8-10 lbs of boost.
The loss of boost between the 4.3 and the 5.5 comes from the increase in displacement i.e. cylinder volume. He did say that "A positive displacement supercharger making 8lbs of boost or higher on a motor with 11.1 compression is asking for serious problems to happen unless you have the ability to re-tune the software within the DME".
Also according to Josh R he saw the fuel injectors that HPS is using on their system and they are wrong in his opinion. The injectors they use are a Bosch Design 2 fuel injector rated at 32lbs. These fuel injectors have a ohms resistance rating on the primary windings of 14.7. The factory Mercedes Benz injectory being used on a 203 C55 is a Bosch Design 3 injector with an ohms resistance rating of 12.3. In turn the design 2 injector has a higher duty cycle than the duty cycle of the design 3. Basically they are the wrong injectors and without re-tuning the fuel value, injector voltage value, and duty cycle within the fuel map of the software they will never work correctly.
Also keep in mind that without this customer going to HoP and Mark paying for the Dyno this would have never been known. Remember according to his original dyno given to him the car was making the advertised power "safely". Now suddenly it's not, and Mech Tech's Dyno verifies the findings on "HoP's" dyno as well. Something is obviously not right.
The hardware has been improved and looks a lot more professional now. But the problem is still the same, no tuning.
Giving customers fake dyno graphs from other cars is only going to get HPS an adverserial meetings with local judges.
My car will be the FIRST with this ECU upgrade. It has already been fitted with the new fuel injectors, smaller pulley (adding 1lb of boost). The SC is currently makes 6 -6.5 lbs of boost because I was holding the gauge when Josh R was stepping on the gas during the 3rd dyno pull. This pulley will bring it up to 7.5 lbs. The ECU upgrade will also improve my shifting and raise the rpm and speed limiters.
I am hoping this will work. HPS told me they had no problem with giving me a full refund but at this point I am confident that my car will be back in order with a HP rating even better than the 147 gain chart they sent to me the first time. I will witness the next dyno and post the chart in one week.
My car will be the FIRST with this ECU upgrade. It has already been fitted with the new fuel injectors, smaller pulley (adding 1lb of boost). The SC is currently makes 6 -6.5 lbs of boost because I was holding the gauge when Josh R was stepping on the gas during the 3rd dyno pull. This pulley will bring it up to 7.5 lbs. The ECU upgrade will also improve my shifting and raise the rpm and speed limiters.
/QUOTE]
This is very exciting to hear. I've been pushing for ECU upgrade from day one and you get the be the first one to get it.
....J/K. So the new injectors and smaller pulley fitted, what was the hp and A/F ratio like? You probably didn't get a dyno yet since the ECU required a couple hundred miles for re-adaptation. Can wait for your dyno chart.
I will dyno the car and then wait drive it for a week before returning for the ECU upgrade. I trust that they know what they are doing because if I did'nt I would have asked for a full refund.
By the way, to get 600hp, you are going to need cams, headers, ECU, bigger coolers, more boost and lower compression pistons or thicker head gasket.
Keep us udated
I hate to say it, but this is exactly why I didn't purchase the HPS kit months ago for my C55. When I talked to Adam & Bill (though they were quite nice) they couldn't give me any meaningful answers to my questions befitting "technically inclined" people. Frankly, I've dealt with these tuning issues before on my BMW's and it's a joke if someone expects it just to work right & adapt by only changing the injectors. Also, there were many tricks required (even with the older OBD1 DME's) to force the computers adaptation into working with you, instead of fighting you. Many inexperienced tuners (when I was more involved back in the late 90's) took the incorrect approach to ECU reprogramming, and the ECU simply worked to undo what they've done as the car was driven.
I can't say for certain what's happened here without far more information, but I'm way too skeptical to believe that simply bolting on a s/c and larger injectors & relying on the ECU to adapt will work on any car, even one with a more advanced modern OBD2 DME. Also, if you have a basic tuning problem from the changes that were previously made (original s/c & injectors), just throwing more new parts at it is probably the worst thing to do until someone figures out the TRUE CAUSE of the problem, and not just trying to cover up the symptoms. Any of this of course figures the basic parts are still functioning within their designed range. I thought I remembered hearing your car ran OK for the first week or two, correct? So ask yourself what changed & why...
Last edited by rbaker; Feb 1, 2006 at 12:38 AM.
I hate to say it, but this is exactly why I didn't purchase the HPS kit months ago for my C55. When I talked to Adam & Bill (though they were quite nice) they couldn't give me any meaningful answers to my questions befitting "technically inclined" people. Frankly, I've dealt with these tuning issues before on my BMW's and it's a joke if someone expects it just to work right & adapt by only changing the injectors. Also, there were many tricks required (even with the older OBD1 DME's) to force the computers adaptation into working with you, instead of fighting you. Many inexperienced tuners (when I was more involved back in the late 90's) took the incorrect approach to ECU reprogramming, and the ECU simply worked to undo what they've done as the car was driven.
I can't say for certain what's happened here without far more information, but I'm way too skeptical to believe that simply bolting on a s/c and larger injectors & relying on the ECU to adapt will work on any car, even one with a more advanced modern OBD2 DME. Also, if you have a basic tuning problem from the changes that were previously made (original s/c & injectors), just throwing more new parts at it is probably the worst thing to do until someone figures out the TRUE CAUSE of the problem, and not just trying to cover up the symptoms. Any of this of course figures the basic parts are still functioning within their designed range. I thought I remembered hearing your car ran OK for the first week or two, correct? So ask yourself what changed & why...
I believe Kleemann also recommend a couple hundred miles for the ECU to fully adapt. My guess is, it gonna require alot more then just 5 mins of freeway driving for fully adapt. One thing i do know is that, Mercedes manual recommend not to disconnect the battery a week before smog check because the ECU will automatic fail the test due to all the sensors not readiness. As you can see it, it require alot of driving for all the sensors to be ready.







