early dyno results
#481
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Im sorry, i didnt mean to imply I removed them, but I have NOT modified the stock stuff at all.
maybe its the fact that when accelerating or decelerating the oil is bunched up front or rear of the crank. (or left to right)
I also have a hard time believing that the oil cant get out of the heads. have you seen the 4-5 large 1.5" sqaure holes leading to the oil sump? i cant see that being a back up, but you never know.
I think a lot of the sucess ive had is due to an oil that probably doesnt foam much and possibly the lack of high rpms for longer for 15 seconds or so. as I mentioned, at road america the main straight, which is long, was about 17 seconds. laguna, probably half that. thunderhill, somewhere in between.
Now, about G loading, etc. Im running 4 seconds faster than Andersno when he did the bulk of his racing in club and his first few pro races back in 2000. (1:36.1 vs his 140.1 at laguna) with slightly less hp and none of his high end mods to the oiling system. (dry sump) He has not lost any engines since then, and I never have (and that has been over 14 years of racing 928s on my side, and much longer on Andersons. as I mentioned, I think there is the proper way to drive the 928 on the race track, and it doesnt mean you cant redline it, it means you need to keep it in gears that are fastest for a lap, while not using the High rpm if there is not a demand for max HP. (i.e. a sweeping high speed turn for example). also, I think short shifting is bad too running that same high speed in too low a gear can show a huge oil pressure drop and that can be a problem. generally, keeping the RPM from 4500 to 6500 constantly, with no other rpm being used.
The only thing that i did do, was to prop up the oil breathers up in the air slightly, so that if oil was to rise up, it would fall back down and not go into the intake. one of them had enough slack to do this, and the other I will make an extension. other than that, all stock configuration.
maybe its the fact that when accelerating or decelerating the oil is bunched up front or rear of the crank. (or left to right)
I also have a hard time believing that the oil cant get out of the heads. have you seen the 4-5 large 1.5" sqaure holes leading to the oil sump? i cant see that being a back up, but you never know.
I think a lot of the sucess ive had is due to an oil that probably doesnt foam much and possibly the lack of high rpms for longer for 15 seconds or so. as I mentioned, at road america the main straight, which is long, was about 17 seconds. laguna, probably half that. thunderhill, somewhere in between.
Now, about G loading, etc. Im running 4 seconds faster than Andersno when he did the bulk of his racing in club and his first few pro races back in 2000. (1:36.1 vs his 140.1 at laguna) with slightly less hp and none of his high end mods to the oiling system. (dry sump) He has not lost any engines since then, and I never have (and that has been over 14 years of racing 928s on my side, and much longer on Andersons. as I mentioned, I think there is the proper way to drive the 928 on the race track, and it doesnt mean you cant redline it, it means you need to keep it in gears that are fastest for a lap, while not using the High rpm if there is not a demand for max HP. (i.e. a sweeping high speed turn for example). also, I think short shifting is bad too running that same high speed in too low a gear can show a huge oil pressure drop and that can be a problem. generally, keeping the RPM from 4500 to 6500 constantly, with no other rpm being used.
The only thing that i did do, was to prop up the oil breathers up in the air slightly, so that if oil was to rise up, it would fall back down and not go into the intake. one of them had enough slack to do this, and the other I will make an extension. other than that, all stock configuration.
Kibo,
I believe the oil can make a difference!
However, you also indicated "no breathers". Does that mean stock breather set up, or have you eliminated the stock venting set up to the cam covers? If so, how? This, in combination with the oil, may provide some further clues.
There seem several variables at play here, coming at us from:
1. driving, and dyno, conditions, and
2. different motor configurations
I could be wrong, of course, but I keep looking at that temporary oil filler vent set up (pic below), created for this engine dyno, and wonder if it did not play an important role in helping us see how our motors can easily mis-behave (when provoked) ?
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However, you also indicated "no breathers". Does that mean stock breather set up, or have you eliminated the stock venting set up to the cam covers? If so, how? This, in combination with the oil, may provide some further clues.
There seem several variables at play here, coming at us from:
1. driving, and dyno, conditions, and
2. different motor configurations
I could be wrong, of course, but I keep looking at that temporary oil filler vent set up (pic below), created for this engine dyno, and wonder if it did not play an important role in helping us see how our motors can easily mis-behave (when provoked) ?
#482
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#483
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OK, I have never seen this warning when driving ever on any 928. I know the sensor trips at 5 quarts. It's a simple float switch. It would seem it should trip a lot if monitored while driving as there are many times when you would expect the level to be below the float, such as hard acceleration.
#484
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The one thing I do believe, whatever the cause it has to be diagnosed on each engine and the fix made to suit each engine. Trying to fix the problem on this engine by using someone else's reasoning or theories is a big mistake. You have to fix the fault in front of you with good engineering based upon what is seen on this engine. Hopefully the fault, cause and solution is the same as everyone else's. I have never seen an engine that could not have a fault fixed. It may have taken lots of time and money to fix the first engine, but every one after that was easy and far less expensive. The next time this engine is run it needs to be instrumented to fully understand what is going on. Then the real cause can be found and the solution made.
Forget the Dyno, get this engine on a Spintron and see the problem.
Forget the Dyno, get this engine on a Spintron and see the problem.
#485
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Either way, I am looking forward to seeing what Greg comes up with after he completes his experimenting.
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#487
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#488
Drifting
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UPDATE I just got word with photos of fabrication on engine and dyno will be next week for tuning session......
I will let Greg discuss technicals with photos at his descretion...
This is sure turning into quite a project.![Cheers](https://rennlist.com/forums/images/smilies/beerchug.gif)
andy
I will let Greg discuss technicals with photos at his descretion...
This is sure turning into quite a project.
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andy
#490
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#491
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Why would they make it active while running......because a GTS driven hard could be low on oil before it used up a full tank of gas and had to stop and refuel !!!! It happened to one GTS in Texas that I know of.
#492
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There may be a delay that allows for short periods of low oil. I would imagine that brief moments of low oil don't set off the alarm.
This is why I ohmed mine a hundred cycles when the pan was off. Mine works. But after fifteen minutes of hard hard windy mountain road driving, the check oil warning light would come on. And stay on even after sitting a while. But that was then. I haven't had a chance to really drive this thing after refreshing hoses, and whatnot.
This is why I ohmed mine a hundred cycles when the pan was off. Mine works. But after fifteen minutes of hard hard windy mountain road driving, the check oil warning light would come on. And stay on even after sitting a while. But that was then. I haven't had a chance to really drive this thing after refreshing hoses, and whatnot.
#493
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a GTS driven hard could be low on oil before it used up a full tank of gas and had to stop and refuel !!!! It happened to one GTS in Texas that I know of.
![](https://webfiles.uci.edu/redwards/public/GTS%20fuel%20flap%20notice%2011-22-10%20copy.jpg)
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I find the "rear tires OK" to be even more disturbing ...... why just the rears ! because underinflation with high speed driving can cause the drive wheel tires to fail. The early tire press monitor system wanted something like 45 lbs in the rear but complaints of a harsh ride caused then to reduce the pressure.