Engine Oil & Last Century Porsche Road Engines , some light reading
01-04-2018, 11:59 AM
#31
Rainman
Rennlist Member
Rennlist Member
A lot of detail is on manufacturer websites so you may find viscosity at various temperatures, usually 40 or 100C and HTHS figures for 150C iirc.
Thus as Bruce stated I can compare Millers XF 5W-50 providing 17 Cst @ 100C to Millers CF 10W-50 providing 20 Cst @ 100.
We should be grateful for technology, I remember as a child we had a fleet on straight 40; on a cold frosty morning nothing started!
Thus as Bruce stated I can compare Millers XF 5W-50 providing 17 Cst @ 100C to Millers CF 10W-50 providing 20 Cst @ 100.
We should be grateful for technology, I remember as a child we had a fleet on straight 40; on a cold frosty morning nothing started!
https://msdspds.castrol.com/bpglis/FusionPDS.nsf/Files/E06073C8EBB011BD80257DFD00582FDA/$File/BPXE-9UF2AZ.pdf
Typical Physical Characteristics Method 20W-50
Viscosity @ 100C, cSt ASTM D445 20.3
Viscosity @ 210F, SUS ASTM D2161 99.8
Viscosity @ 40C, cSt ASTM D445 187.7
Viscosity Index ASTM D2270 126
01-07-2018, 05:21 PM
#32
Race Director
Interesting thread.
Bruce brings up some excellent points. Some I never considered when I raced 928's. While I have blown or personally witnessed at least 7 track driven 928's blow. Some had unique odd issues, 2 to be exact. One was over revved and sucked a valve, which Bruce theory supports. Another was a build mistake. The others were all classic 2-6 rod bearing death.
First two I witnessed were Dennis Kao, a year apart in his track but street legal 928.
3: my black widow in 2008. A gutted widebody 928 built in LA with help from Mark A and Carl's parts. I was a novice driver at the time, so I wasn't pushing the car very hard. But 2800lbs with 295/30-18 front and 335/30-18 rear was fun to drive on stock aero, that dynoed at 300whp on its stock 89s4 engine. I shifted at 6000rpm. After 9 hours at thunderhill (15 turns, 3 right three high speed lefts) using Mark K infamous amsoil, I noticed the stock oil pressure gauge dropping to under 2 bar in turn 2. So I had the engine pulled to rebuild it. There was damage to 2-6. I installed a "Chevy" cross drilled crank, accusump and oil cooler with GTS baffle. At the time this was the best known option other than Mark A drysump. Unfortunately my engine builder messed up and poof....gone.
4: 1984 lemons racerin 2009. This was cursed from the beginning. Due to a rushed race schedule we never solved many oil leaks, ran out of amsoil and had to resort to crap Walmart 20-50. It held up well, blew up 1/2 way through day 2! Both Marks and I got to drive and have fun. Still had a great time. For an abused 928 I bought for $256 that shifted too high (6500rpm) it did pretty well. NOTE: car still races in lemons today. Has finished as high as 2nd overall on east coast.
5: black widow again. Now owned by Sean F. Sean had a high rpm engine built that lived about the normal 9 hours on track.
6: black widow x3. This was a bone stock S4 engine that ran on the high rpm chips from previous engine. Got over revved and blew up at thunderhill.
7: Casper my 79 euro with a full built custom 4.5L engine that a previous owner spent $12k on in 1993. This is partially my fault for turning timing up too far. Ran stock 79 oil pan, no oil cooler and amsoil 15-50. It lasted almost 26 hours (note hours not days as some quote, if a day equals less than an hour on track?) on track on slicks at over 1.5g, plus two seasons for the prior owner who raced it.
Here is what I know. Racing a 928 is not cheap nor easy. Building the forced budget lemons 928 was the best thing I ever did. The next engine installed cost $300 and ran for over 176 hours on track both lemons trim and slicks, it set the lemons record at thunderhill for over 5 years and ran 2:06 over top with a station wagon automatic..... Casper ran 2:02. Mark K best is 1:59...Mark A or Joe F 928 stroker could turn low 1:50's....when you consider cost-speed hard to beat the krankenwagen
Bruce brings up some excellent points. Some I never considered when I raced 928's. While I have blown or personally witnessed at least 7 track driven 928's blow. Some had unique odd issues, 2 to be exact. One was over revved and sucked a valve, which Bruce theory supports. Another was a build mistake. The others were all classic 2-6 rod bearing death.
First two I witnessed were Dennis Kao, a year apart in his track but street legal 928.
3: my black widow in 2008. A gutted widebody 928 built in LA with help from Mark A and Carl's parts. I was a novice driver at the time, so I wasn't pushing the car very hard. But 2800lbs with 295/30-18 front and 335/30-18 rear was fun to drive on stock aero, that dynoed at 300whp on its stock 89s4 engine. I shifted at 6000rpm. After 9 hours at thunderhill (15 turns, 3 right three high speed lefts) using Mark K infamous amsoil, I noticed the stock oil pressure gauge dropping to under 2 bar in turn 2. So I had the engine pulled to rebuild it. There was damage to 2-6. I installed a "Chevy" cross drilled crank, accusump and oil cooler with GTS baffle. At the time this was the best known option other than Mark A drysump. Unfortunately my engine builder messed up and poof....gone.
4: 1984 lemons racerin 2009. This was cursed from the beginning. Due to a rushed race schedule we never solved many oil leaks, ran out of amsoil and had to resort to crap Walmart 20-50. It held up well, blew up 1/2 way through day 2! Both Marks and I got to drive and have fun. Still had a great time. For an abused 928 I bought for $256 that shifted too high (6500rpm) it did pretty well. NOTE: car still races in lemons today. Has finished as high as 2nd overall on east coast.
5: black widow again. Now owned by Sean F. Sean had a high rpm engine built that lived about the normal 9 hours on track.
6: black widow x3. This was a bone stock S4 engine that ran on the high rpm chips from previous engine. Got over revved and blew up at thunderhill.
7: Casper my 79 euro with a full built custom 4.5L engine that a previous owner spent $12k on in 1993. This is partially my fault for turning timing up too far. Ran stock 79 oil pan, no oil cooler and amsoil 15-50. It lasted almost 26 hours (note hours not days as some quote, if a day equals less than an hour on track?) on track on slicks at over 1.5g, plus two seasons for the prior owner who raced it.
Here is what I know. Racing a 928 is not cheap nor easy. Building the forced budget lemons 928 was the best thing I ever did. The next engine installed cost $300 and ran for over 176 hours on track both lemons trim and slicks, it set the lemons record at thunderhill for over 5 years and ran 2:06 over top with a station wagon automatic..... Casper ran 2:02. Mark K best is 1:59...Mark A or Joe F 928 stroker could turn low 1:50's....when you consider cost-speed hard to beat the krankenwagen