Yes, mikey, I agree that there will be a SMALL loss on the low end side, below 3000 rpm, however the gains on the upper side above 3000 are DEFINITLY worthwhile, IMHO and experince.

As far as lumping all FI cars together, you really can my friend. As long as you have pressure on the intake valve the moment it opens, they would all respond the same, via turbo, supercharger, etc, etc. The engine does not know WHAT device is giving it the pressure, it is simply responding to it. Its simple physics. You are also correct that the turbo itself is acting like cork, aka restriction so that does play a larger role than a supercharged engine on the exhaust side which is why they are even MORE critical to an open free flowing exhaust. But the physics invloved in the combustion chamber DOES NOT change which is why you can lump them all together.

See yeah

 

That's for a naturally aspirated car. if you had a normal amount of overlap you'd just be dumping boost overboard. Too much overlap in a forced induction car will give you a false reading on the O2 sensor's (It will see too much oxygen in the exhaust) causing a rich mixture.

I know plenty well how a 4 cycle (Or 5 cycle if design the exhaust correctly) engine works

 

totally agreed that it's all the same when looking at it from an intake valve perspective. and you kind of made my point that turbos are different in that they create their own backpressure where s/c's don't. my problem is that in the application I use this car for (drag racing) the loss of low end power is not a worthwhile trade because the hp advantage won't make up the loss in that short of of a run.

either way, I think we're in total agreement, just placing different emphasis on what's important to us.

 

To a point ,you can bundle these to motors together, giving the fact that at low speeds & Mid rpm band the Kompressor on a E-55 is disengaged and the intake air is pulled through the Bypass valve at the intake / t-body manifold at the rear of the Kompressor.at least Until our right foot demands more power!! Then their is a big difference between the 2 types of induction.

IMHO I find The oem exhaust manifolds are so restrictive, No matter what I did ,I could not get my N/A motor to respond to my expectations, at lease until the Kleemann headers were install. Then Bam! a 29 Ftlbs rear wheel increase of torque at low & mid rpm band, So it being said that both motors ( N/A & FI ) are running in a N/A state of operation there would be little or no decrease in torque or hp. And the FI motor would really begin to shine when the kompressor gets engaged.

Vadim is on the right track for the M-113 motors. Do not expect the exhaust reversion pulse from one cylinder to bounce/ reflect back up another pipe with low or even negative pressure to help shut off the incoming air charge on that cylinder. My F/R charts shows I had a tiny bit of fuel removed to 11.9 to 12.1. Quote;the function of exhaust simply becomes to evacuate combustion and reduce backpressure as much as possible.

No 5th cycle here on the MB FI motor . On the N/A motor we are kinda stuck no real space to create a equal length header with proper exhaust pulse timing and if we could ,it could be a very narrow power band .

#1 In which the rpm would jump up/ increase sharply. hard to hold a steady throttle on the open road.
#2 we would blast through it so fast , it would be a real thrill
#3 So hi in the rpm band , the valve train would suffer.

Question ! Is their some intake pulse pressure on the top side of the intake valve when it is closed on a stock N/A motor at idle. . Hummmm. None to very very little. . A vaccum gauge may show 18 - 21 inches of mercury. if anything there is a little blow back pressure as the intake valve first snaps open. As the piston is still pushing spent air out the exhaust valve as it is approching tdc. the intake valve are starting to open and some of the spent exhaust gasses are pushed into the intake track. This will polute some of the fresh intake air charge. Mercedes keeps this to a minumum, with cam timing running late in the cycle and a mild cam grind ( SO TO SPEAK) Not much valve overlap at TDC Exhaust. I'll posted some of my dyno sheets .The 3rd& last run was with VRP Cams. < ( They show a 22 Rwhp increase)This shows headers do work well. If you need cam specs please do a search. Now let the arrows fly!!Cheers ___PTEngineering

 

^ How did you get the car to hold a gear at such a low rpm?

 

Dyno Mode . I must have at least 30 dyno runs of them.
Cheers PTE

 

Guess I'm SOL because I don't have that

 

Hi Ahmad: I went to a AMG meet several years ago . I remember went we went to the dyno ,Ted Baldwin's 01 E-55 with a full Kleemann K-4 ? would back shift/ down shift when full throttle was applied. He got under the hood and disconnected something , then he was able to do a 4th gear pull. With no down shifting issues. Maybe drop him a PM. He has a wealth of infomation. Take care ___PTEngineering

 

We talking about Manual Mode on the tranny or is there something that holds below 1K RPMs? Sorry for the late jump-in...

 

Jangy: We are writing about the dyno mode that is accessed through the steering wheel and key switch activation. It works on most 03 & newer Mercedes. There is a few stickys posted. I found it real handy, But I personally would not drive on the street in this mode. The steering gets heavy and the brakes are lazy. I've got several witness watch me put my car in the sand lot It's is nice to see all you guy's back !!
Cheers PTEngineering

 

Good to see some knowledgeable forum members exchanging opinions on exhaust flow, which is by no means a simple concept.

To the original poster: Victor from VRP built a full 3 inch exhaust a while back for his car and the loss of torque in the low RPM range was significant enough for him to take it off. Without getting to deep into the exhaust flow discussion, what MR AMG is saying is true within a certain context - that context being ultimate power. However, as with many considerations, total flow is not always the path everyone really wants - and while for the most part the more flow the better, remember there is often a price to be paid. IN this case, with a super high flow exhaust system, sometimes throttle response can become the collateral damage.

Cam specs can have the same pros/cons... the more aggressive you make a cam profile, the more adverse effects it can have on everything from idling to throttle response and power band. It's not always as cut and dry as physics would lead us to believe.

Just my $.02

-m

 

Then why would Vadim tell me to do dual 3" piping? I just wanna go faster, is that too much to ask?

 

Perhaps Vadim said that because you mention that you didn't want any more torque. Maybe Vadim removed his full 3 inch exhaust to regain his torque back.

 

I agree that there could be a loss of low end torque if you have the stock torque converter but blackbenzz has a 2900 stall torque converter in his car so the loss in low end torque wont be an issue...

 

Agree. Stall speed makes a difference.

 

were do you get a performance torque converter for mercedes?

 

^ You have pm

What kind of tradeoff are we talkin about? Yes I have a higher stall tc but if I'm losing 50wtq in exchange for 20whp its not worth it. I cant even launch higher than 1500rpm without snappin axles

 

Okay guys, the bottom line is I am all about the area under the curve, aka dyno graph. I REALLY could care less what the peak numbers are, as I have always used the readings at 2500, 3000, 3500, 4000, 4500, 5000, 5500, and 6000 add them up and divide by 8. Bottom line is the LARGER exhaust system on a FI engine is ALWAYS going to win with my math vs the stock system.

See yeah

PS: I'll take any bets

 

What is the procedure on this dyno mode activation?
How does it work?
for a '04 E55

Does this works on some AMG older MBZ models too?
'01 E55, '01 ML55?

 

Some good conversation in here; I just want to clear one thing up that could pop into peoples minds from reading this thread.

Bigger is better to a certain extent but, as pointed out above, too big will hurt performance. This is true for all cars though, not just MBZ's, or else we'd see everyone running around with dual 6" exhaust. Some people might read this discussion and fear going freer flowing on the stock exhaust because they don't want to lose power; that is not the case however. The stock exhaust is terrible, especially at the manifolds, this is why headers yield such high gains. Go bigger than stock, just don't go too big with it or you will start to hurt things rather than help them.

 

Agree 1000% my friend, please don't but a 6" trash can exhaust on ANY AMG like the ricers do guys.

As was stated above, a good mandrel bent 2.75" or 3" is good enough.

"Friends don't let friends drive with a trash can muffler"

See yeah

 

don't know if it's the same on a 208, but i heard on 210's this is the plug to disconnect for esp....

 

do the 3 inch how much can you lose 5 the most. i think the car would sound mean. but then i dont know dont have mine yet. good luck


edit never mind i just read the rest.

 

Everything depends on ultimately where you want to be. FI cars are a lot less touchy to exhaust tuning than NAs.

 

I had a feeling that's what PTE was refering to that was unplugged on the W210 E55. My C43 has the same-ish unit. I had mine disengaged from the interior control panel side when it was removed for my CF overlay. It was scary as I found out the hard way that it also shuts down ABS and any other "you've gone tooooo far" parameters..LOL!

I guess this would be the 208's version of "dyno mode" Ahmed? I just shut off the traction control via the dashboard switch when using a dyno, which I hope yields all available power, yet retains the ABS. If we should be disconnecting the ESP/ABS unit I want to know! Also, if its the only way to crawl through the band like PTE did it would be a nice thing to know.