For discussion of all things Powell!!
04-20-2013, 07:40 AM
#126
i think that any engine with direct injection, these treatments like seafoam have marginal results. Read the links I have posted: the Mercedes link has some very good background, one guy is an engineer with a professional background in fuels and oils.
With an LSJ seafoam can work as the inlet charge (fuel + air) does "wash" over the valve stems. But the issue of coking is not so much on the LSJ if at all its the DI motors have it bad, and the 3.6 GM DI V6's , BMW/ Mercedes, Toyota, Audi, all have it a lot worse.
What part does the PCV play? The new C7 LT1 series of engines has a patented PCV system. PCV is very important.
There are two places that oil can get in the inlet with the LNF : the prime path is out of the rocker cover vent at the back of the motor, which goes straight to the inlet impeller of the Turbo, and that pathway is open under boost.
Inlet manifold vents are closed under boost so less of an issue. Not anyway as difficult as the rocker cover rear vent; early on in testing it was found that a 5 degree tilt back to the turbo would really make the issue worse - picture the car under accelleration at the drag strip. Road racing is maybe the hardest on a car, sustained WOT boost for typically two minutes or so in a three minute lap, OVER twenty laps or so.
The other thing I should mention is this. Folks may not like to hear this, but if you tune your car, increase boost, you risk compressing the base of the motor and blow by increases past the rings, which happens A LOT in slight detonation and the STOCK PCV cant deal with that at all.
If you have trouble with the PCV in your car, or oil in the inlet, the first thing so an engine health test. Compression/leak down.
Any low cylinder, say 10-15 lbs worse in compression compared to other cylinders, in #3 and #4, you have a BIG problem.
On the LSJ the second ring breaks first in my experience. On the LNF the ring lands collapse. Sleeves break.
Here is another thing to consider: forced induction motors particularly turbo, suffer from the risk of runaway detonation.
Detonation is sensitive to fuel quality. If there is any sort of reduction on octane or fuel quality lower than recommended, bad things happen.
On my SAAB wntrbtr2 with a 2.3 l turbo, the owners manual recommends 91 minimum. Says 87 will work. On the fuel door, the stickers says 93 octane.
IF like the previous owner,( my good buddy) runs 87 'coz he is frugal, and occasional 91, the oil change intervals on the OLM change to about 3000 km. If you run 91 on the motor all the time and kick it down (auto, meh) the car "misfires" or stumbles slightly. On 94 octane all the time, the oil change intervals increase to over 10,000 km and the car runs smooth as silk under all accelleration conditions; no stumble at all.
With the engine management system ,there is the capability on all our cars ( and my wntrbtr2 ) to pull spark to control detonation. BUT In other words, the engine has to see knock for the ECU to pull back spark)
This is very important, because it means the rings are having a hell of a job with premature combustion: the piston travelling up with the connecting rod ( an undeniable force) hits the the explosion of combustion ( an irresistible force) BEFORE the piston reaches TDC.
Something has to give- rings flex, cylinder walls flex (I believe thats the pinging noise- the walls and the piston pins flexing) and oil consumption increases, car misfires, fuel mileage is poor; engine damage will eventually occur and oil pours into the PCV as the combustion pressure goes past the rings into the crankcase.
SO:
no detonation.
tier one fuels
High octane gas.
upgrade PCV
conservative tunes
remember the MAF flatlines at 24.5 psi in an LNF.
Upgraded PCV helps a great deal, and thats being proven every day. But if the motor is hurt and the rings, ring lands or sleeves are damaged, then you will need an oil drum to catch the bypassed oil in the PCV.
Hope this helps.
http://mbworld.org/forums/c-class-w2...buildup-8.html
http://www.e90post.com/forums/showthread.php?t=682116
http://auto.howstuffworks.com/positi...ion-system.htm
With an LSJ seafoam can work as the inlet charge (fuel + air) does "wash" over the valve stems. But the issue of coking is not so much on the LSJ if at all its the DI motors have it bad, and the 3.6 GM DI V6's , BMW/ Mercedes, Toyota, Audi, all have it a lot worse.
What part does the PCV play? The new C7 LT1 series of engines has a patented PCV system. PCV is very important.
There are two places that oil can get in the inlet with the LNF : the prime path is out of the rocker cover vent at the back of the motor, which goes straight to the inlet impeller of the Turbo, and that pathway is open under boost.
Inlet manifold vents are closed under boost so less of an issue. Not anyway as difficult as the rocker cover rear vent; early on in testing it was found that a 5 degree tilt back to the turbo would really make the issue worse - picture the car under accelleration at the drag strip. Road racing is maybe the hardest on a car, sustained WOT boost for typically two minutes or so in a three minute lap, OVER twenty laps or so.
The other thing I should mention is this. Folks may not like to hear this, but if you tune your car, increase boost, you risk compressing the base of the motor and blow by increases past the rings, which happens A LOT in slight detonation and the STOCK PCV cant deal with that at all.
If you have trouble with the PCV in your car, or oil in the inlet, the first thing so an engine health test. Compression/leak down.
Any low cylinder, say 10-15 lbs worse in compression compared to other cylinders, in #3 and #4, you have a BIG problem.
On the LSJ the second ring breaks first in my experience. On the LNF the ring lands collapse. Sleeves break.
Here is another thing to consider: forced induction motors particularly turbo, suffer from the risk of runaway detonation.
Detonation is sensitive to fuel quality. If there is any sort of reduction on octane or fuel quality lower than recommended, bad things happen.
On my SAAB wntrbtr2 with a 2.3 l turbo, the owners manual recommends 91 minimum. Says 87 will work. On the fuel door, the stickers says 93 octane.
IF like the previous owner,( my good buddy) runs 87 'coz he is frugal, and occasional 91, the oil change intervals on the OLM change to about 3000 km. If you run 91 on the motor all the time and kick it down (auto, meh) the car "misfires" or stumbles slightly. On 94 octane all the time, the oil change intervals increase to over 10,000 km and the car runs smooth as silk under all accelleration conditions; no stumble at all.
With the engine management system ,there is the capability on all our cars ( and my wntrbtr2 ) to pull spark to control detonation. BUT In other words, the engine has to see knock for the ECU to pull back spark)
This is very important, because it means the rings are having a hell of a job with premature combustion: the piston travelling up with the connecting rod ( an undeniable force) hits the the explosion of combustion ( an irresistible force) BEFORE the piston reaches TDC.
Something has to give- rings flex, cylinder walls flex (I believe thats the pinging noise- the walls and the piston pins flexing) and oil consumption increases, car misfires, fuel mileage is poor; engine damage will eventually occur and oil pours into the PCV as the combustion pressure goes past the rings into the crankcase.
SO:
no detonation.
tier one fuels
High octane gas.
upgrade PCV
conservative tunes
remember the MAF flatlines at 24.5 psi in an LNF.
Upgraded PCV helps a great deal, and thats being proven every day. But if the motor is hurt and the rings, ring lands or sleeves are damaged, then you will need an oil drum to catch the bypassed oil in the PCV.
Hope this helps.
http://mbworld.org/forums/c-class-w2...buildup-8.html
http://www.e90post.com/forums/showthread.php?t=682116
http://auto.howstuffworks.com/positi...ion-system.htm
Last edited by Powell Race Parts; 04-23-2013 at 07:14 AM.
04-22-2013, 08:52 PM
#128
Here is something I "uncovered" today. I get rocker covers returned as cores, and one I received had been powdercoated ( badly) . But it was also broken on one part of the rocker cover gasket channel.
so I could not "recycle" it.
we take a lot of time and effort to make sure our powdercoated covers are done right, clamped on a cylinder head fixture, to keep media out of the interior as they are prepped. We also control oven temperature to the minimum required levels. Understanding that oven temps of about 300- 350 degrees F are needed, and the covers themselves deal with oil that can reach temperatures of 300 degrees C. So one would assume that 350 deg F would be easy to withstand. And it probably is, done right.
But the oil carries heat and gets rid of it, so its not a direct relationship to baking a dry rocker cover.
and we preheat to be sure of good powder distribution with consistent coverage.
This bandit did not: look at it.
two of the three seperator biscuits are melted and block the vent passages from the block. UGH
LNF are different in detail but have similar seperator biscuits on the exhaust side, and one on the inlet side. Vent paths are different.
Some PC vendors on here offer covers pc'd for less than the price of a new cover. I figure the only way low prices can be achieved is by cutting corners.
You get what you pay for. What the PC vendor did to this cover is a scandal and there is no doubt that the engine will suffer for it. Dont ask me who, but they are not a vendor on this site. In fact afaik they dont do PC anymore.
so I could not "recycle" it.
we take a lot of time and effort to make sure our powdercoated covers are done right, clamped on a cylinder head fixture, to keep media out of the interior as they are prepped. We also control oven temperature to the minimum required levels. Understanding that oven temps of about 300- 350 degrees F are needed, and the covers themselves deal with oil that can reach temperatures of 300 degrees C. So one would assume that 350 deg F would be easy to withstand. And it probably is, done right.
But the oil carries heat and gets rid of it, so its not a direct relationship to baking a dry rocker cover.
and we preheat to be sure of good powder distribution with consistent coverage.
This bandit did not: look at it.
two of the three seperator biscuits are melted and block the vent passages from the block. UGH
LNF are different in detail but have similar seperator biscuits on the exhaust side, and one on the inlet side. Vent paths are different.
Some PC vendors on here offer covers pc'd for less than the price of a new cover. I figure the only way low prices can be achieved is by cutting corners.
You get what you pay for. What the PC vendor did to this cover is a scandal and there is no doubt that the engine will suffer for it. Dont ask me who, but they are not a vendor on this site. In fact afaik they dont do PC anymore.
04-23-2013, 07:06 AM
#134
no e-commerce on our site. orders@powellraceparts.com cheers
04-24-2013, 08:11 AM
#141
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two questions fro Mr. Powell (or anyone else that can answer)... 1) how low do the lowering springs lower the car and do they come with everything needed for installation (may order them with the hardcore sway bar) 2) do you sell a strut bar? If not, do you recommend a particular one if one at all?
Thanks
Thanks
04-24-2013, 08:53 AM
#142
two questions fro Mr. Powell (or anyone else that can answer)... 1) how low do the lowering springs lower the car and do they come with everything needed for installation (may order them with the hardcore sway bar) 2) do you sell a strut bar? If not, do you recommend a particular one if one at all?
Thanks
Thanks
You do not need a strut tower bar. It is nothing more than a show piece on our cars.
Look into Powells rear sway bars.
04-24-2013, 08:56 AM
#143
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already decided on getting a rear sway bar (thinking hardcore) but figured if i was gonna get anything else from him i should try and make shipping as inexpensive as possible so i decided to look at springs... not sure if i really need them though... not autoxing
04-24-2013, 10:02 AM
#145
back in the day strut bars helped out tremendously. if you look at a lot of the older muscle cars where the strut towers are like 5 feet away from the firewall adding in a triangular brace could help them out a lot. now for a lot of newer cars where the strut towers usually pinch welded to the firewall and frame rails theres no need and they wont provide anymore structural support. strictly a show piece on a lot of newer cars