New TT will have 10:1 compression. Massive HP mod gains gonna be limited?
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From: Salt Lake City (but not Morm)
2003 E55 & 2014 GL550
New TT will have 10:1 compression. Massive HP mod gains gonna be limited?
Been debating a buddy of mine who claims that the new 5.5 will be limited on "massive cranking up of the boost" due to it's 10:1 compression ratio.
He's got a point in that most massive hp monsters are running 8-9:1 compression.
Wild card I keep bringing up to him is the Direct Injection system which is gonna let us run more boost on higher compression (just going from what Benz is saying on press releases)
Interesting.
He's got a point in that most massive hp monsters are running 8-9:1 compression.
Wild card I keep bringing up to him is the Direct Injection system which is gonna let us run more boost on higher compression (just going from what Benz is saying on press releases)
Interesting.
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From: California, USA
E63 P30, CL500 Sport
I'm not sure the compression ratio will be as big of a problem as the new round of ECUs. I heard Mercedes will be locking down many aspects of the ECU leaving the aftermarket tuners very few locations to play with.
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GT63S ePerformance 4dr, '25 Bentayga Black Ed.(wife), Wrangler and 250 MLB(kids)
Renntech is already planning some decent (50-60hp gain) ECU reprogramming.
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CLS63 PP
DI engines by their nature run higher compression. They also run substantially leaner due to the improved swirl and combustion. I do not think compression is a limiting factor to more boost in a DI engine as dentonation point is much higher.
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From: S.E. FLA.
05 ML-500 , 03 CLK5.5 AMG has left the Garage
DI engines
Di engine can run higher compression , do to the fact the cool fuel is directed to the splash cup / dish in the piston top.
The problem is VVV
1St Di injectors are highly unreliable, Do not run the fuel system low on fuel , too the point of air getting into the fuel system.
2nd this is that spark plug technology hasn't quite caught up to the DI demands. They will not make 30.000 miles , High tip erosion , from high pressure fuel being sprayed at them . and long spark duration , to light it off in stratified mode.
3rd packageing. on a 4 valve head motor there is not much room for a centrally mounted DI injector , & then find a place to locate the Spark plug so it can light off the fuel correctly
There is a ton of issues with DI on a 4 stroke engine. It works well on 2 strokes. My guess it will take another 5 years, before you will see it in car engines Sorry for the sad news . _PTEngineering
The problem is VVV
1St Di injectors are highly unreliable, Do not run the fuel system low on fuel , too the point of air getting into the fuel system.
2nd this is that spark plug technology hasn't quite caught up to the DI demands. They will not make 30.000 miles , High tip erosion , from high pressure fuel being sprayed at them . and long spark duration , to light it off in stratified mode.
3rd packageing. on a 4 valve head motor there is not much room for a centrally mounted DI injector , & then find a place to locate the Spark plug so it can light off the fuel correctly
There is a ton of issues with DI on a 4 stroke engine. It works well on 2 strokes. My guess it will take another 5 years, before you will see it in car engines Sorry for the sad news . _PTEngineering
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From: In my garage
E55, GLS450, GL63, GLE350
Welcome to 2010. Cars already using direct injection:
Audi A3
Audi R8
Audi S4
Cadillac STS
Chevrolet HHR SS
Pontiac Solstice GXP
Volkswagen Jetta GLI
Ferrari California
Porsche 997
Porsche Caymen
X6 XDrive 50i
Ford Ecoboost - multiple applications
Checy Ecotec - multiple applications
Audi A3
Audi R8
Audi S4
Cadillac STS
Chevrolet HHR SS
Pontiac Solstice GXP
Volkswagen Jetta GLI
Ferrari California
Porsche 997
Porsche Caymen
X6 XDrive 50i
Ford Ecoboost - multiple applications
Checy Ecotec - multiple applications
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From: PA
S600, GL450, GLC 43
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From: NoVa
2004 S55 (SOLD, miss it every day), 2009 GL550
Welcome to 2010. Cars already using direct injection:
Audi A3
Audi R8
Audi S4
Cadillac STS
Chevrolet HHR SS
Pontiac Solstice GXP
Volkswagen Jetta GLI
Ferrari California
Porsche 997
Porsche Caymen
X6 XDrive 50i
Ford Ecoboost - multiple applications
Checy Ecotec - multiple applications
Audi A3
Audi R8
Audi S4
Cadillac STS
Chevrolet HHR SS
Pontiac Solstice GXP
Volkswagen Jetta GLI
Ferrari California
Porsche 997
Porsche Caymen
X6 XDrive 50i
Ford Ecoboost - multiple applications
Checy Ecotec - multiple applications
Also, the 4.2 in the Audi A8 has been DI since 2007.
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haters crazy
Doesn't the BMW 335 also run DI and their pumps always fail?
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From: Oldsmar, FL
2005 E55 Wagon, 2017 C63S Cab, 1986 560SL
OK, this all made me laugh. I did think that Ford was a good example. Let's face it, if you can get it in a Focus, it's pretty mainstream.
But apparently technically impossible.
But apparently technically impossible.
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From: San Jose, CA
2007 E63 w/P30 and Eurotech CF Diffuser
Which is why there is a huge amount a technology and research that goes into the physics/mechanics of these systems. There is a ton of research to make the flame front detonate in a way that prevents clogging of the injector which may have to deal with fuel pressures on the order of 1700PSI.
One of the properties of DFI is the ability to run higher compression because the flame front moves much faster which allows less advance on the spark and reduces the chance of pre-detonation.
From what I have read, everything needs to become more and more finely tuned. So I am willing to bet that reliability will likely fall off much faster as you move from "stock to awe".
One of the properties of DFI is the ability to run higher compression because the flame front moves much faster which allows less advance on the spark and reduces the chance of pre-detonation.
From what I have read, everything needs to become more and more finely tuned. So I am willing to bet that reliability will likely fall off much faster as you move from "stock to awe".
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From: NoVa
2004 S55 (SOLD, miss it every day), 2009 GL550
Which is why there is a huge amount a technology and research that goes into the physics/mechanics of these systems. There is a ton of research to make the flame front detonate in a way that prevents clogging of the injector which may have to deal with fuel pressures on the order of 1700PSI.
One of the properties of DFI is the ability to run higher compression because the flame front moves much faster which allows less advance on the spark and reduces the chance of pre-detonation.
From what I have read, everything needs to become more and more finely tuned. So I am willing to bet that reliability will likely fall off much faster as you move from "stock to awe".
One of the properties of DFI is the ability to run higher compression because the flame front moves much faster which allows less advance on the spark and reduces the chance of pre-detonation.
From what I have read, everything needs to become more and more finely tuned. So I am willing to bet that reliability will likely fall off much faster as you move from "stock to awe".
), and one of the issues I came across was concern about buildup around the valves, etc., *outside* the cylinder due to absence of the detergent effect of fuel. I tried surfing for it just now but could not find the posts (admittedly I did not try very hard).
Last edited by i_am_amused; Aug 27, 2010 at 06:42 PM.
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From: Toronto
CLS63 PP
Most DI engines suffer from excessive carbon buld up due to PVC and blowby gasses hitting the dry hot valves or lower IM. Because in a traditional injected motor injectors "Wash down" the back of the valves and intake ports you don't usually get that in a non DI engine.
There are different strategies manufactures employ to keep it in check. DI engines make more power because they run more compression and have more oxygen per combustion cycle( due to running much leaner than traditional stoich ratio). The injectors produce more swirl and combine with the airflow to make a more heterogeneous mixtrure. This higher compression and "leaner" burn mean the engines run alot hotter than non DI. That is the first way they deal with carbon buildup. Extra heat to cook off alot of the blowby gases. They also add complex PCV Catch cans( or cyclone filters) to prevent much of the gunk from getting injested. Lastly they also add supplementary injectors in the IM to provide the "wash down" that I mentioned earlier. The new engine will employ this in some fashion I am sure.
There are different strategies manufactures employ to keep it in check. DI engines make more power because they run more compression and have more oxygen per combustion cycle( due to running much leaner than traditional stoich ratio). The injectors produce more swirl and combine with the airflow to make a more heterogeneous mixtrure. This higher compression and "leaner" burn mean the engines run alot hotter than non DI. That is the first way they deal with carbon buildup. Extra heat to cook off alot of the blowby gases. They also add complex PCV Catch cans( or cyclone filters) to prevent much of the gunk from getting injested. Lastly they also add supplementary injectors in the IM to provide the "wash down" that I mentioned earlier. The new engine will employ this in some fashion I am sure.
Last edited by KLR CLS; Aug 28, 2010 at 04:49 PM.
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From: Jacksonville, Florida
2006 E55 AMG --old cars -- E39 M5, 2.7tt Audi S4, E36 M3 **Ducati 996, 748
my guess is the high compression added to the foreseeable ECU problem will handcuff the car from reaching its ceiling -
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