16v vs 8v head turbo application - max static compression ?
01-16-2011, 06:15 AM
#31
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http://forums.bimmerforums.com/forum....php?t=1575817
...sure it's a little laggy...but there's some $$$ being burnt out there....
...sure it's a little laggy...but there's some $$$ being burnt out there....
Before I would do that, I think I would just install a turboshaft.
01-16-2011, 06:30 AM
#32
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If you want to read further this is the actual forum that it appeared in. Of course you can't go with something like this on a forum without the usual forum wars....but in amongst this there is some interesting theory which gets quite involved. Especially by the O.P.
http://forums.evolutionm.net/evo-dyn...ne-2007-a.html
http://forums.evolutionm.net/evo-dyn...ne-2007-a.html
01-16-2011, 07:50 AM
#34
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It is insane alright. Even assuming this is for 8sec passes. What I wonder is what the hell they're using for driveline components???
01-16-2011, 08:27 AM
#35
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01-16-2011, 08:35 AM
#36
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Instead of that fancy computer-controlled multiplate clutch center differential, maybe just go with fixed longitudinal driveshafts, and front and rear spools, lock all four wheels in perfect sync? Not like it would cause problems when you live your life a quarter mile at a time
01-16-2011, 10:21 AM
#37
Nordschleife Master
01-16-2011, 10:30 AM
#38
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There is an interesting balance between static compression and boost levels. If you are building an engine that is primarily for the street you can raise the static compression, reduce the max boost and run with a turbo that is in the small side and you will get a very responsive engine. 9.5:1 with a GT30 turbo will do that nicely. On the other hand you could drop the compression ratio to 8.5:1 and run a GT35 turbo with higher boost – this can make more absolute torque but it will not be as responsive to throttle input. The lower CR / higher boost combo is a little more tolerant to detonation and it gives you the ability to tune around any problems with bad fuel.
So many choices…..
So many choices…..
01-16-2011, 11:10 AM
#39
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For all of you tuning experts, based on your experience...
How easy would it be to tune a bone-stock [EDIT: except for forged steel conrods] 16 valve 3.0L Variocam motor to handle about 15 psi at 112 octane (assuming the Variocam is reset to retard the intake cam whenever it's on boost, and ideal intercooling, maybe water-air)? Impossible? Reasonable? Leaving way too much on the table?
How easy would it be to tune a bone-stock [EDIT: except for forged steel conrods] 16 valve 3.0L Variocam motor to handle about 15 psi at 112 octane (assuming the Variocam is reset to retard the intake cam whenever it's on boost, and ideal intercooling, maybe water-air)? Impossible? Reasonable? Leaving way too much on the table?
Last edited by JDS968; 01-16-2011 at 12:44 PM.
01-16-2011, 11:27 AM
#40
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I would be a little concerned with the stock rods. The compression ratio is on the high side but it could be done for a street car, but not for a track car!
For all of you tuning experts, based on your experience...
How easy would it be to tune a bone-stock 16 valve 3.0L Variocam motor to handle about 15 psi at 112 octane (assuming the Variocam is reset to retard the intake cam whenever it's on boost, and ideal intercooling, maybe water-air)? Impossible? Reasonable? Leaving way too much on the table?
How easy would it be to tune a bone-stock 16 valve 3.0L Variocam motor to handle about 15 psi at 112 octane (assuming the Variocam is reset to retard the intake cam whenever it's on boost, and ideal intercooling, maybe water-air)? Impossible? Reasonable? Leaving way too much on the table?
01-16-2011, 12:31 PM
#41
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yep, and there are some stock rods that are not up to the task of even the stock power. I pulled my pan on my 3.0l variocam (Not that I was ever thinking of using them anyway!) and they (con. rods) are the "recalled" thinner rods that have had problems. If, in the very least, change out the rods.
01-16-2011, 12:42 PM
#42
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Rods would be aftermarket forged steel.
01-16-2011, 08:14 PM
#43
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Completely dis-agree with the first quote, and the very first and last statement from the second. I heard this a whole bunch in the 90's using 80's knowledge. Proved wrong over and over on the extremely efficient 4valve heads when I was working on them in the 2000's. Those theories certainly work, it just leaves too much on the table. You just need cheap Honda motors to not worry about cost and keep turning up the boost till it blows.. after a few hundred successful motors, confidence grows. About 100 (Probably a lot more actually) From my shop alone. Many others were blowerd up in the process though. Usually cracked ring lands on the intake side from cheap pistons. Others were bent rods. tons of other small reasons besides detonation. A few were clearly that though. Oil in the PVC, or blowing through the turbo. 9.5 CR Does make for a nice room for error though on Porsche motors. And I wouldn't want to push the money Spent on these motors as much as the cheapy Hondas.
Define low CR..
