entropy
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posted October 25, 2005 12:04 AM
 Edited By: entropy on 25 Oct 2005 01:07
oil questions answered by an expert
Like many of you I have read a shit load (sometimes literally) of stuff about oils wrt built motors. Lots of opinions...
Brilliant idea: find a motor-head-lubes-Engineer in my Company (Chevron); ask him. It only took me 5 years to come up with that flash of inspiration, Doh!
I sent him a description of my motor (ZX12 1427cc 15:1 4.6mm stroker) and application (drags) and asked his opinions. This is a guy who is responsible for actually specifying base oil and additive formulations which result in the oils you see on the shelves.
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Karl,
Again, sorry to be so slow in responding. My answers to your questions are below.
M.
1. popular trackside wisdom:
Run conventional oil during break-in, then switch to 15W50 full synthetic.
Q: is there really any need to breakin w/conventional oil???
A: I really don't think so. I think it used to be that precision of ring faces and cylinder bores was not terribly high, and some synthetics may have had a little higher lubricant film thickness (not necessarily true at all anymore). So, some extra wear was useful for helping rings to seat. Nowadays, rings are generally very precise and have very thin coatings on the faces that don't need much wear to seal well; and cylinder bores generally are very precise also. Also, I don't think that simply being synthetic gives better lubrication. They can have some advantages, but the wear properties depend more on the additives than the base stocks.
2. OEM oil pressure relief valve opens @ 10,500 = 82psi (and stays at 82+/- till 12000)
Q: is it advisable to shim the relief valve so that max pressure goes to say 100psi??
A: No, if the oil pressure is sufficient now (meaning that your bearings look good and engine durability is good), increasing oil pressure will only rob horsepower. In general, you want to run oil pressure as low as acceptable to provide good bearing life and adequate lubrication. That will maximize power. Unfortunately, knowing where that "edge" lies is pretty hard, and cost engines if you go too low. Best to be conservative here.
3. popular trackside wisdom:
Higher viscosity oil gives better bearing & piston life (for this type motor)
Q: is this true?? (lower viscosity does SEEM to free up a lil hp)
A: This could be true to a point. Higher viscosity results in thicker oil films, which will resist metal-to-metal contact under higher load conditions. However, as long as there is a fluid film between parts, a thicker film doesn't serve any purpose, and if it results from higher viscosity, it means higher drag (power loss). So, there's a limit to the point where higher viscosity helps; and at some point a higher viscosity will actually hurt lubrication because it causes too much heat generation in the bearings.
4. popular trackside wisdom:
Full synthetics give a few % more hp (very bit counts in drag racing)
Q: with cost being no object; am I better off w/full synthetic??
A: In most cases this probably is true. The advantages of the synthetic is that it is thinner at lower temperatures before it is fully hot (when you are starting your run), and the viscosity in high-load areas is probably a little lower than for a conventional oil of a similar viscosity grade (giving lower drag). However, there is a whole world of different ways in which oils can be formulated, so no rule is universal.
A final consideration for you is that whatever you put in the crankcase must also provide adequate friction for the clutch to work right. There is Japanese test qualification called JASO MA that ensures adequate friction properties for wet clutches. While most older engine oils (SF, SG) met this easily, some of the latest fuel-saving formulations (GF-4/SM) have special friction modifiers that may cause clutch slip. So, that puts some limits on formulations for your application.
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oof440
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posted October 25, 2005 03:10 AM
very informative, I feel enlightened.
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vozizm
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posted October 25, 2005 06:30 AM
Very kewl read Sir!!.. very Kewl!!
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zrxdean
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posted October 25, 2005 07:50 AM
Good info, thanks Karl. How's you're beat running these days? -Dean
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Megabyte
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posted October 25, 2005 09:20 AM
What kind of power are U making w/your 1427, and 15:1 compression ? How do you start it 
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entropy
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posted October 25, 2005 10:42 AM
Dean,
my motor is running fine, an i'm keeping my fingers crossed. haven't really got a clean pass yet. YOU are smoking, Dean. What did you do, turn up the boost???
Megabyte,
with thin oil and .005" less quench it was making 225-229, but not lasting too long... I have turned it down a bit...
24v does the trick! 
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osti33
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posted October 25, 2005 10:50 AM
Good info. Thanks for posting it.
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zrxdean
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posted October 25, 2005 11:00 AM
Good luck with the motor - I know how it is to keep breaking chit everytime you get close to a good tuneup.
I have been playing with the launch mostly, trying a bunch of clutch setups. It's taken a me a long time to get anywhere with this turbo. Actually turning DOWN the boost a little on the launch has helped, along with more boost (with longer ramp) in the second stage.
Cool weather here now- I am shooting for new bests tomorrow nite at Gainesville TNT.. Kevin and Ryan will be there with a badass dryshot Busa.
Dean
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ZXALAN
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posted October 25, 2005 12:26 PM
Karl did you ever get your bike to shift at the shootout?
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osti33
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posted October 25, 2005 12:51 PM
quote:
Karl did you ever get your bike to shift at the shootout?
Nope. However he did get it fixed later on.
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entropy
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posted October 25, 2005 04:27 PM
quote:
Karl did you ever get your bike to shift at the shootout?
Alan,
osti is right, got it fixed yesterday; the gnd to the microswith got un-hooked up while we were playing with the LM-1.
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Wideout
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posted October 26, 2005 07:36 AM
Did you take it out back behind the neighborhood and REALLY test it?
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entropy
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posted October 26, 2005 03:53 PM
quote:
Did you take it out back behind the neighborhood and REALLY test it?
Nope, not yet: this saturday i'll test, then Sunday to HRP.
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