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A Team Turbo A Year Later

I agree with both NVW and Buddy, but my question is more, about what we get with larger pre cups. Is it something that is voodoo science or is there a precup size for power and one for fuel economy. How is pre cup size determined in the design phase?
 
Seems to me that precup size and configuration would determine the egress rate and shape of the initial flame-front, which would have more to do with detonation time and duration than anything else. Those two attributes will have an effect on power and economy; ergo, start with the end in mind... if you want a faster detonation, you start with a bigger hole that reaches the whole area faster... a smaller, more reflective hole (given quench geometry) would give a slower, more sustained burn, meaning better economy.

Direct-injection engines are much more, uh, direct ... if that makes sense.

Here's a good example of indirect injection:

http://www.youtube.com/watch?v=ayJujtwWClQ

The time between slaps is the duration/propagation time. If she could have just hit him directly, she could control time that much more precisely. :D
 
Jim explained what I was trying to get at. With faster combustion you could get more force on the piston when its at its peak torque in the storke. Thats when the rod is at a specific angle with biggest torque on the crankshaft, which is somewhere like 30 degrees after TDC (havent calculated it) when rod has most perpendicular downward force on the crankshaft journal. Combustion may be present for 150 degrees after TDC, but precup design can affect the timing of when you get the majority of it.
 
JiFaire said:
Seems to me that precup size and configuration would determine the egress rate and shape of the initial flame-front, which would have more to do with detonation time and duration than anything else. Those two attributes will have an effect on power and economy; ergo, start with the end in mind... if you want a faster detonation, you start with a bigger hole that reaches the whole area faster... a smaller, more reflective hole (given quench geometry) would give a slower, more sustained burn, meaning better economy.

Direct-injection engines are much more, uh, direct ... if that makes sense.

Here's a good example of indirect injection:

http://www.youtube.com/watch?v=ayJujtwWClQ

The time between slaps is the duration/propagation time. If she could have just hit him directly, she could control time that much more precisely. :D
Click to expand...

Got to love it.

Now on the pre chambers how big would be to big and how does a person calculate where the power (torque) curve would be at what size. Any visuals of what the theoretical torque curve might look like for different size holes.
 
buddy said:
Jim explained what I was trying to get at. With faster combustion you could get more force on the piston when its at its peak torque in the storke. Thats when the rod is at a specific angle with biggest torque on the crankshaft, which is somewhere like 30 degrees after TDC (havent calculated it) when rod has most perpendicular downward force on the crankshaft journal. Combustion may be present for 150 degrees after TDC, but precup design can affect the timing of when you get the majority of it.
Click to expand...


My point exactly, would we be better having more force on the piston when it is closest to just after TDC ? Would injection time affect flame front and ultimately affect the peak pressure in the cylinder at a specific point after TDC.

Any detrimental affects on engine longevity by having a shorter faster pressure spike closer to TDC rather than a longer more gentle pressure spike, or would the faster pressure spike be less harsh if the timing was optimized to a specific point just at or after TDC?
 
Those are probably things that highly educated specialized engineers sit an ponder and get paid megabucks to make complicated calcualtions, models and simulations.
 
buddy said:
Those are probably things that highly educated specialized engineers sit an ponder and get paid megabucks to make complicated calcualtions, models and simulations.
Click to expand...


Yep but we have the ability to theorize, based on nothing more than speculation, and common knowledge.
 
i wish more people would make videos of their trucks unloaded and accerlating with the ATT. TD i like your vids you made im just wondering how fast it would be without the trailer
 
I might be a little biased but i still like mine and it has taken a whole lot of abuse. The truck is like holding on to a tiger by the tail. Just hoping I don't blow the bottom end out :)
 
Woody35 said:
i wish more people would make videos of their trucks unloaded and accerlating with the ATT. TD i like your vids you made im just wondering how fast it would be without the trailer
Click to expand...

Well I just got a new (ATT specific) tune from Bill, have blanket on turbo now, and new lift pump from Leroy is inbound, so maybe in not too distant future I can manage that.
 
Wouldn't do without it. I had to put a blanket on it after cooking my coolant reservoir. That was two years of pulling 20k to Burning Man and back. It needs a heat shield with that kind of regular hill climbing with a heavy load. I've got Heath's original ATT tune, it sounds like there is a fair amount of improvement with the latest. Might have to try that.
 
Turbine Doc said:
Well I just got a new (ATT specific) tune from Bill, have blanket on turbo now, and new lift pump from Leroy is inbound, so maybe in not too distant future I can manage that.
Click to expand...
TD is that the same tune he gave me or yet another improvement? I'm enjoying mine more and more each day. I've learned where the power starts to come in and how to ride it, much like my motorcycles of yesteryear, "on the pipe" it was called then, probably still is IDK.

Anyway, fuel milage is up where it was before the winter blends came in and 2 mpg higher than it was with the GM-5 so yeah, I'm sold.

Thanks guys.

Paul
 
Paul I'm not sure which one you have, I think I'm 3 tunes past the one you may have; when did you get your last one ?

This tune is 2.5 weeks old to me, I got it at the house, installed it in the truck drove it for 10 minutes after doing the theft deterrent learn, parked it; and came to this turbine emergency outage I've been on the last 2 weeks, hope to finish it up on site Thursday and get some time @ home and play with vehicles, wife's TDI bug has the priority though, it has a no start condition.

In addition to you learning where the power is, there is also some adaptive learn going on in the PCM as well with the OBD-IIs, I think that is one of the reasons Bill converted his OBD-I in the LSR to the OBD-II as it's a "smarter" for lack of a better description setup than OBD-I.
 
Mine was done in November, so whatever improvements he's added since I'm behind on. I may have an excuse to head his way a little sooner than I thought so I'll see what can be worked up.
He mentioned the "learning curve" of the PCM and I noticed the difference during the first set of runs with it, when I went back to GM-5 for a couple of months and now that I'm back to the ATT. I think the it works better with the ATT.

I get home tonight and my TDI has some needs as well, although it still runs.
 
Both; progressively better and also trying things.

I have not done any towing with new programs which will be proof in pudding for me as I'm not setting mine up to race, though everything thus far to make it a better towing rig has also helped it's nimbleness :)
 
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