Dyno results from “Bonneville” motor, 765 WHP, 900 CHP
03-16-2011, 10:36 PM
#181
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Thread Starter
I appreciate that, George. Thats a good point and I did have trouble getting a cell signal when I was there last September. But, unlike your situation where you needed the speed-over-distance to time your leg correctly, I dont. My run willbe clocked by the officials. The MPH in-car is just for entertainment purposes...
my stock speedo will stop at 165ish and I don't know what it'll do above that.
my stock speedo will stop at 165ish and I don't know what it'll do above that.
03-16-2011, 10:42 PM
#182
Developer
Thread Starter
We swaped tranaxles tonight, and also swapped our 8-disk LSD from the "old" transaxle to the "new" one. We did this because we wanted to chase down a new vibration in the driveline that is happening now from 6 to 7000 under full load. We have already swapped out the torque tube and the tires and wheels. The transaxle was next.
There are two places on the transaxle that we took out where we can see the case expanded under torque and created a problem. On the right side of the transaxle the push-out of the case was significant enough to move the differential bearing carrier out to where it interfered with the inside of the bolts thru the half shaft!
We milled that out to clearance the area, but it tells us that we may have a limited number of runs before the G28.13 transaxle case cracks at these load levels.
There are two places on the transaxle that we took out where we can see the case expanded under torque and created a problem. On the right side of the transaxle the push-out of the case was significant enough to move the differential bearing carrier out to where it interfered with the inside of the bolts thru the half shaft!
We milled that out to clearance the area, but it tells us that we may have a limited number of runs before the G28.13 transaxle case cracks at these load levels.
Last edited by Carl Fausett; 03-17-2011 at 12:27 PM.
03-16-2011, 10:53 PM
#183
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03-17-2011, 01:45 AM
#185
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I had an unofficial high speed run last year also, (not in an airplane). Coming back from a dyno
tuning session with Bill, I decided to make a top speed run (on a closed private road...):
See Max Speed. But again this was not confirmed by any official sanctioning organization.
tuning session with Bill, I decided to make a top speed run (on a closed private road...):
See Max Speed. But again this was not confirmed by any official sanctioning organization.
03-17-2011, 10:11 AM
#186
Developer
Thread Starter
I'd LOVE to have a closed private road that was long enough to do some testing. Have had no luck thus far. We do have a .5 mile straight stretch we can (and have) used, but wish we had more.
03-17-2011, 02:05 PM
#187
Drifting
Carl,
Good find on the diff.
That would be expected as it was not built to handle that kind of power.
I had the same problems with north american muscle.
Increased the HP and 3 trans latter I had twisted drive shafts, broken axles when I got the ladder bars to hook up then broke a pinion.
I went to 3/4 ton re-splined axles and ended up welding gussets inside the banjo housing on a ford 9 inch.
It is a never ending design issue as the weakest link breaks.
I have no idea what you are going to have to do to keep yours together but it looks like you are on your way to solving it.
Wish you good luck and no high speed breakage.
Good find on the diff.
That would be expected as it was not built to handle that kind of power.
I had the same problems with north american muscle.
Increased the HP and 3 trans latter I had twisted drive shafts, broken axles when I got the ladder bars to hook up then broke a pinion.
I went to 3/4 ton re-splined axles and ended up welding gussets inside the banjo housing on a ford 9 inch.
It is a never ending design issue as the weakest link breaks.
I have no idea what you are going to have to do to keep yours together but it looks like you are on your way to solving it.
Wish you good luck and no high speed breakage.
04-14-2011, 12:39 PM
#188
Developer
Thread Starter
At yesterday's dyno session, we were testing the effects of exhaust back-pressure on crankcase pressure, and ultimately engine oil control.
We were able to reduce our crankcase pressure down to 2.5 psi when we had 18 psi in the plenum, with improvements in both windage, and HP as the side benefits.
I am working on a new exhaust system for the car now based on these findings, and will post when I know more.
We were able to reduce our crankcase pressure down to 2.5 psi when we had 18 psi in the plenum, with improvements in both windage, and HP as the side benefits.
I am working on a new exhaust system for the car now based on these findings, and will post when I know more.
04-14-2011, 07:31 PM
#189
Race Director
At yesterday's dyno session, we were testing the effects of exhaust back-pressure on crankcase pressure, and ultimately engine oil control.
We were able to reduce our crankcase pressure down to 2.5 psi when we had 18 psi in the plenum, with improvements in both windage, and HP as the side benefits.
I am working on a new exhaust system for the car now based on these findings, and will post when I know more.
We were able to reduce our crankcase pressure down to 2.5 psi when we had 18 psi in the plenum, with improvements in both windage, and HP as the side benefits.
I am working on a new exhaust system for the car now based on these findings, and will post when I know more.
Have you found any oiling problems, especially in the heads like Doc found?
04-15-2011, 01:07 PM
#190
Developer
Thread Starter
Problems? no. Potential problems - YES.
Unlike when I race at a road course, where I hit WOT for a few moments between corners and the heads have time to drain back to the sump befoire I do it again.... at Bonneville I will be at WOT for what we figure will be 1 minute 15 seconds.
I fear we will pump all the oil out of the sump via crankcase ventilation before the end of the run and hatch the engine.
Remember: the engine must last at least 2 licensing runs and at least 3 full course runs in order to make a new record - plan a minimum of 6 runs like this.
The good news is that there are no lateral G's slowing down head drain-back on left turns like road racing. Thats the only good news.
The 928's famous for its windage issues, and they have been lauded here aplenty. And then add boost and lots of it and the issue is magnified.
I am working out systems now to
1) reduce the amount of oil pumped up to the heads during high rpm's (keeping more oil in the sump)
2) lower the crankcase pressure as much as possible to assist in ring seal
3) evacuate and separate the missive oil from the air stream at high speeds, and
4) return the oil to the engine quickly.
So far, so good. Like I said, I am down to only 2.5 psi in the crankcase when the plenum is fully charged, and we are very happy with our build and our ring seal.
The last test I ran proved to me that I am going in the right direction.
I'll post the "solution" when I have it completed.
Unlike when I race at a road course, where I hit WOT for a few moments between corners and the heads have time to drain back to the sump befoire I do it again.... at Bonneville I will be at WOT for what we figure will be 1 minute 15 seconds.
I fear we will pump all the oil out of the sump via crankcase ventilation before the end of the run and hatch the engine.
Remember: the engine must last at least 2 licensing runs and at least 3 full course runs in order to make a new record - plan a minimum of 6 runs like this.
The good news is that there are no lateral G's slowing down head drain-back on left turns like road racing. Thats the only good news.
The 928's famous for its windage issues, and they have been lauded here aplenty. And then add boost and lots of it and the issue is magnified.
I am working out systems now to
1) reduce the amount of oil pumped up to the heads during high rpm's (keeping more oil in the sump)
2) lower the crankcase pressure as much as possible to assist in ring seal
3) evacuate and separate the missive oil from the air stream at high speeds, and
4) return the oil to the engine quickly.
So far, so good. Like I said, I am down to only 2.5 psi in the crankcase when the plenum is fully charged, and we are very happy with our build and our ring seal.
The last test I ran proved to me that I am going in the right direction.
I'll post the "solution" when I have it completed.
04-15-2011, 01:54 PM
#193
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Have you looked in to what Porsche did to those marine engines ?
They put a foot long extension on the oil pickup, calculated the internal volume of the heads and half the crankcase, then built an oil pan that held an extra gallon beyond that.
04-15-2011, 02:15 PM
#194
Developer
Thread Starter
Great pics! Extending my sump wont help me. Thats not the problem (anymore). We developed a good crank scraper and windage tray for stroker cranks in 2010 and it is working well.
04-15-2011, 07:56 PM
#195
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Problems? no. Potential problems - YES.
Unlike when I race at a road course, where I hit WOT for a few moments between corners and the heads have time to drain back to the sump befoire I do it again.... at Bonneville I will be at WOT for what we figure will be 1 minute 15 seconds.
I fear we will pump all the oil out of the sump via crankcase ventilation before the end of the run and hatch the engine.
Remember: the engine must last at least 2 licensing runs and at least 3 full course runs in order to make a new record - plan a minimum of 6 runs like this.
The good news is that there are no lateral G's slowing down head drain-back on left turns like road racing. Thats the only good news.
The 928's famous for its windage issues, and they have been lauded here aplenty. And then add boost and lots of it and the issue is magnified.
I am working out systems now to
1) reduce the amount of oil pumped up to the heads during high rpm's (keeping more oil in the sump)
2) lower the crankcase pressure as much as possible to assist in ring seal
3) evacuate and separate the missive oil from the air stream at high speeds, and
4) return the oil to the engine quickly.
So far, so good. Like I said, I am down to only 2.5 psi in the crankcase when the plenum is fully charged, and we are very happy with our build and our ring seal.
The last test I ran proved to me that I am going in the right direction.
I'll post the "solution" when I have it completed.
Unlike when I race at a road course, where I hit WOT for a few moments between corners and the heads have time to drain back to the sump befoire I do it again.... at Bonneville I will be at WOT for what we figure will be 1 minute 15 seconds.
I fear we will pump all the oil out of the sump via crankcase ventilation before the end of the run and hatch the engine.
Remember: the engine must last at least 2 licensing runs and at least 3 full course runs in order to make a new record - plan a minimum of 6 runs like this.
The good news is that there are no lateral G's slowing down head drain-back on left turns like road racing. Thats the only good news.
The 928's famous for its windage issues, and they have been lauded here aplenty. And then add boost and lots of it and the issue is magnified.
I am working out systems now to
1) reduce the amount of oil pumped up to the heads during high rpm's (keeping more oil in the sump)
2) lower the crankcase pressure as much as possible to assist in ring seal
3) evacuate and separate the missive oil from the air stream at high speeds, and
4) return the oil to the engine quickly.
So far, so good. Like I said, I am down to only 2.5 psi in the crankcase when the plenum is fully charged, and we are very happy with our build and our ring seal.
The last test I ran proved to me that I am going in the right direction.
I'll post the "solution" when I have it completed.
I am not sure if this information will help you as mine is a 16 valve, but I will add it here anyway...
My Top Speed runs were well in excess of the time you quoted, several including the final run were over 5 minutes...at WOT (no rev limiter plus huge amounts of Nitrous)
Regarding oil use at high revs....
When I did my top speed runs, i "used" around 1.5 ltrs of oil...
I had better explain "used"...
Firstly it blew around 1 ltr into my catch can as I dont vent back to the engine on mine...
Secondly the excess crank pressure blew BOTH rear cam cover gaskets and spat a lot of oil out of the rear of both cam covers.... as an educated guess, around another half a litre...possibly as much as 1 ltr..
It didnt worry me too much as on Nitrous mine ALWAYS "uses" a fair amount of oil due to excess pressure...after a days drag racing as an example, I will usually have to add between 1 and 2 ltrs...
I hope this is helpful..if for nothing else, than to point you at the rear cam cover gaskets if you develop an oil leak...lol
All the best Brett