Well, we have to have a flurries, melting, and freezing cycle every second day right now, and the roads are a mess!
Sustina 0W-20, 6,003 kms, Caterham
- Thread starter CATERHAM
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Good post - another positive miles/hours, not time in sump UOA. The Glen was always one of my favorite tracks, but I liked it better before the "inner loop aka bus stop" was put it. Of course for absolute white knuckle road courses, it's tough to beat Mosport - and of course Road Atlanta when it still had the flat out dip before the bridge. The good old days.
Originally Posted By: Gasbuggy
Originally Posted By: CATERHAM
As it turned out on a very hot track day at Watkins Glen in July/14, oil temp's actually approached 110C (230F) at the end of some afternoon track sessions
I forgot to add that for a vehicle spec'd for a 20 grade, 230F is not necessarily a temperature limit.
For example, the Subie BRZ/Scion FR-S twins can easily generate oil temp's higher than 230F but these cars were engineered from the get go with the 0W-20 grade as the specified lube.
Originally Posted By: bigt61
Good post - another positive miles/hours, not time in sump UOA. The Glen was always one of my favorite tracks, but I liked it better before the "inner loop aka bus stop" was put it. Of course for absolute white knuckle road courses, it's tough to beat Mosport - and of course Road Atlanta when it still had the flat out dip before the bridge. The good old days.
Originally Posted By: Shannow
CATERHAM, considering the usage, that's not a bad UOA...what do you calculate the KV100 of the brew should have been before use versus what it was at end of test Do you know where the Manganese resides in your engine ?
I know and agree that your Oil Pressure tests correlate to an HTHS value, what did you calculate the HTHS at start and finish of the test period ?
Originally Posted By: CATERHAM
Of course having oil gauges allows one to do away with having an excessively high viscosity reserve with no risk once you become comfortable relying upon them.
But the manufacturers need to specify an oil grade will a large viscosity reserve to deal with all the potential unknowns such as fuel dilution, oil shear and unexpectedly high oil temp's that could happen when one is driving blind so to speak.
The last factor, unexpectedly high or abnormally high oil temp's manufacturer's do have more of a handle on now than they once did through the use of electronic safety management controls which has enabled lighter oil grades to be specified.
So given the option, that's why it's best
to run the lightest oil a manufacturer specifies
and if that is heavier than a 0W-20, and you have oil gauges, you will know if can run something lighter with the way you operate your car.
Originally Posted By: Shannow
Originally Posted By: Shannow
CATERHAM, considering the usage, that's not a bad UOA...what do you calculate the KV100 of the brew should have been before use versus what it was at end of test Do you know where the Manganese resides in your engine ?
I know and agree that your Oil Pressure tests correlate to an HTHS value, what did you calculate the HTHS at start and finish of the test period ?
Those oil temps are pretty low. How hot is the coolant getting? How many times had you spun out into the dirt on that oci? That may açount for silicon. How fast are you getting at the end of the Mario straight? What engine is in that car?
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Normal coolant temp's are about 195F but can rise to 210F on a hot day in close racing.
I've never spun the car or driven under dusty conditions during this OCI. I did spin the car during the previous OCI on the back straight at Mosport after hitting some oil, ending up next to the inside guardrail. The car was covered
in dust and grass but otherwise undamaged other than a scraped rear fender and flat spotted rear tires.
Terminal speed at the end of the back straight before hitting the brakes for corner 8 is about 125 mph driving at 10/10th.
More typically at 8-9/10th 150-120 mph is more typical
The engine is a Vauxhall/Cosworth (C20XE) 2L 16v
four with about 190 HP in it's current state of tune.
I never knew they installed a Cossie head on the Vauxhall lump in the Caterhams (or did YOU install it?).
dailydriver, I thought we had discussed the history of the C20XE engine in my Caterham in the past but maybe not.
Anyway, in the late 80's GM of England (Vauxhall) contracted Cosworth to develop a high output four cylinder 2L engine based on an existing GM block. Vauxhall was to use this engine in a production based rally car.
A couple of Vauxhall models received this engine
and initially the cylinder heads were actually
made by Cosworth but eventually GM took over production of the cylinder head.
The engine remained in production until 1996.
Because of the engine's design it was attractive
to engine tuners and the small production specialty car company, Caterham.
Caterham wanting a powerful 4 cyl engine with relatively easy tuning potential up to 300
normally aspirated HP.
I have one of the actual Cosworth made engines.
Standard in the Astra/Vectra/Kadett range with the Cosworth designed and cast heads. Didn't know that Cosworth actually built engines for GM, but learn something new every day.
(Second part of my engineering thesis was to develop a test rig to study in cylinder flows of the SOHC version of this engine, as it was available globally with various displacements, and obviously this new head had heaps of opportunity to be reviewed regarding tumbling flow as opposed to plain old swirl...that, and AE Bishop engineering were working on a rotary valve head, which would have given more options to explore on the test rig.)
Originally Posted By: Shannow
I know you've discounted on a number of occasions that the temperature rises across the bearing because of oil shear, rather than the misconception that it's "carrying away" combustion generated heat, but it's there.
Piston cooling squirters (where fitted) are pressure driven, so targetting lower oil pressure is intentionally reducing squirter flow....and even Honda have stated that one of the challenges with low viscosity induced oil pressure is maintaining operation of cam phasing hydraulics.
turtlevette,
you can see how much frictional power is generated in motored engine tests in a paper I linked to the other day...happy to continue the conversation in there.
http://www.bobistheoilguy.com/forums/ubb...ils#Post4036102
As to squirters, they are purposely designed to be akin to sharp edged orifices, which are pressure/density related, unlike a hose.
http://www.bobistheoilguy.com/forums/ubbthreads.php/topics/3857079/Re:_Oil's_affect_on_motorcycle#Post3857079
As to why the engineers put squirters in is simply to keep the piston temperatures controlable, and that's the easiest way of doing it...Mains and Big ends flow heat INTO the water jackets, not out of it.
I'd rather have you explain it in your own words. That Chinese paper isn't loading. I dont trust any of their research, if you want to call it that. The other thread is 14 pages of stuff. I get lost in the hand waving. I also know how tenacious you are in attempting to win an argument, linking to some questionable stuff sometimes.
While far more anecdotal than scientific, place your hands on an air compressor head when it's being run in for the first time, as in half an hour of free-wheeling with the relief valve open. Then, try doing the same thing if it's been running for half an hour with a relief valve stuck shut, and "note" the difference in temperature. I would suspect the work being done is where the heat originates. Less load, less heat, and there's no gasoline or other petroleum fuel in this case.
Originally Posted By: Garak
While far more anecdotal than scientific, place your hands on an air compressor head when it's being run in for the first time, as in half an hour of free-wheeling with the relief valve open. Then, try doing the same thing if it's been running for half an hour with a relief valve stuck shut, and "note" the difference in temperature. I would suspect the work being done is where the heat originates. Less load, less heat, and there's no gasoline or other petroleum fuel in this case.
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