PLEASE keep this thread for discussions only on Turbo PFI pass car PCPs only. The thread below is for those who desire to discuss GDI charge cooling, exhaust emissions, etc..
http://www.eng-tips.com/viewthread.cfm?qid=412274
durablack2-
There was no issue for me with your comment. I understood that you were referring to GTDI engines and that is why I noted they could have higher PCPs than conventional PFI S-I engines due to the additional charge cooling.
140airpower-
My comment on GDI charge cooling was in response to durablack2's post on PCPs in GTDI engines even though the original thread requested info. specifically on PCPs in PFI S-I engines. My comment was not intended to start a discussion on GDI combustion process and/or charge cooling...
The situation with major sludge that VW experienced a number of years ago in their 1.8L Turbo engines came primarily from people not using the proper engine oil as specified in the Owner's Manual. In severe situations even the specified partially synthetic oil would break down due to the severe...
Please use the thread below for discussions on GDI and the cooling effect on the induced air charge, etc. so this thread can remain on the subject PCPs.
http://www.eng-tips.com/viewthread.cfm?qid=412274
IME a hot wire mass flow sensor as used in a production vehicle would drastically impact air flow in a typical port. A very small hot wire would be required and even that might still cause air flow disturbances that would negate it's use. It's amazing how minute changes impact air flow in a port...
Please use this thread and NOT the "Current Peak Cylinder Pressures" thread for discussion of GDI and it's impact on allowing higher static compression ratio, lower fuel consumption, etc.
Is best not to go off-topic on a thread so that those reading or desiring to contribute do not need to wade...
There is no de-throttling or lean burn mode per se used in the VW VR6 model engines. As noted the vaporization/injection process lends itself to superior cooling of the air charge instead of the cooling being used to cool the valves or ports. VW uses the same T/body and induction system on the...
We're going sideways on the original topic folks... You really should start a new thread to discuss GDI.
Yes GDI is achieved at much higher injection pressures than conventional PFI and the "entire process" for the most part lends itself to cooling the intake charge and piston crown to deter...
The total vaporization energy exchange should be the same but when the vaporization occurs exclusively inside the cylinder it apparently is more efficient at cooling the intake charge vs. some of the cooling effect being transferred into the intake manifold or cyl. head with PFI. No one expected...
140Airpower -
Any number of auto companies can confirm in their testing that the DI gas vaporization process in the cyl. produced such a significant drop in induced charge chamber temp that they were able to increase the static compression ratio by as much as a full point, i.e. going from 11:1...
Yes, when rapid combustion tech is cost effective for pass car use, the PCP can increase some depending on all the other variables in the mechanical composition of a given engine design.
Thanks for the info. durablack2. I suspect many boosted port injected pass car gas engines are in the 100-120 bar PCP range primarily due to the octane limitations of pump gasoline. With DI of course you can run a tad bit more static compression or boost due to the cooling effect of DI over port...
Jack - The answer is yes. By knowing what the existing application can withstand for PCP, the goal was not to see what design/construction is viable for other applications, but instead to see what PCPs were being experienced in current boosted pass car engines of similar boost pressure.
As discussed you can not reverse engineer the reciprocating mass accurately because any recip mass from 30%-50% will appear to neutral balance.
The point being VW decided on a specific mass to cancel recip forces and that percentage is unknown resulting in shops using anywhere from 20%-50%...
As noted by the balancing personnel discussion in the original link above in my first post, it's not possible via reverse engineering to obtain the OE recip mass percentage as the crank will balance with any number of recip percentages.
I'm using the OEM crank, unmodified with slightly heavier...
gruntguru - Because no one except VW knows what that counterweight percentage actually is and they ain't talking. :)
My continuing research into this matter has led me to a series of tech articles which exposes that the current balancing methodology used by anyone outside of auto makers or...
Thanks for the recommendation on Haywood's book which I am familiar with. Charles Fayette Taylor also has extensive discussion on engine balance. What I am trying to determine is exactly how to properly balance the VR6 crank assembly for both the rotational as well as the reciprocating forces...
The Ford 2.3L rods are reported to be just std. material and design so they are probably less than ideal for use with high boost.
Pass car Diesel engines are starting to approach PCPs typical of HD Diesel designs for increased efficiency and power. As the PCP increases attention needs to be...
