When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So at Chuckwalla recently I observed a strange phenomenon on hard sustained lefts over 1.2G, the oil temp spikes very temporarily.
If you look at the highlighted section of the below data you can see spikes from ~240 degrees to 280 degrees and then back. This seems to happen when I approach high G loads.
You can see i dont seem to be indicating any oil starvation (pressure and temp measured in sandwich adapter). The car has a canton pan, and an upgraded radiator but otherwise no oil cooling or additional capacity.
Anyone care to venture a guess whats happening here?
I'm sure you already observed this, but where the oil temp spike in highest, along with the ~1g left turn, you also have a fairly significant rpm/acceleration curve. Doesn't seem like you have forward g's charted. Does your system have a friction circle chart? Maybe it's a case where you have both a max lateral and accel occurring (like at the 45* mark on a friction circle)?
Now, why this would cause this reaction I do not have a guess. Especially since most would argue it's the high g right turns that seem to drive the oil up into the head/catch can. Maybe the cars have the same issue with possible starvation in left turns that are not as evident due to lack of the smoke screen, like right handers?
Do do you have data from anywhere in a right turn with similar lateral and accel g's?
also, what system(s) are you using to log this info, it looks good.
All the oil draining back to the sump from the cylinder head is sloshed up on the exhaust side.
there's a neat internal passageway in the head, above the exhaust ports that's full of very hot exhaust gas. Aluminum conducts and radiates heat spectacularly.
this passageway is for secondary air injection, but when running, backflow is blocked all the way at the intake side, so the whole passageway is free to get very hot.. you can see the snaky-looking outside cover above the header, and holes in the exhaust ports..
Just a theory. I used to block similar ports in motorcycle heads, and significantly reduce cylinder head temps and oil heating.
I'm sure you already observed this, but where the oil temp spike in highest, along with the ~1g left turn, you also have a fairly significant rpm/acceleration curve. Doesn't seem like you have forward g's charted. Does your system have a friction circle chart? Maybe it's a case where you have both a max lateral and accel occurring (like at the 45* mark on a friction circle)?
Now, why this would cause this reaction I do not have a guess. Especially since most would argue it's the high g right turns that seem to drive the oil up into the head/catch can. Maybe the cars have the same issue with possible starvation in left turns that are not as evident due to lack of the smoke screen, like right handers?
Do do you have data from anywhere in a right turn with similar lateral and accel g's?
also, what system(s) are you using to log this info, it looks good.
The very next corner is a right where I see similar G-loads. No such temp spike as in the problem area on turn 8.
Also turn 4 is a 10 degree banked left where I easily see the highest G-load on each lap doesnt have anything close to the spiking i see in 8. Turn 8 is relatively flat, 1 degree banking according to the track maps.
This is an AIM solo DL + K-pro canbus feed (i did a how-to thread on my data system here)
Also I did a variant of the valve-cover mod so I dont get hardly any catch can collecton. Over a 2 day event, i drained my catch can and found 1-2oz of oil vapor only. No smoke screen ever
Last edited by anorexicpoodle; 11-27-2016 at 11:16 AM.
All the oil draining back to the sump from the cylinder head is sloshed up on the exhaust side.
there's a neat internal passageway in the head, above the exhaust ports that's full of very hot exhaust gas. Aluminum conducts and radiates heat spectacularly.
this passageway is for secondary air injection, but when running, backflow is blocked all the way at the intake side, so the whole passageway is free to get very hot.. you can see the snaky-looking outside cover above the header, and holes in the exhaust ports..
Just a theory. I used to block similar ports in motorcycle heads, and significantly reduce cylinder head temps and oil heating.
Hmm this is interesting. Any supporting theory why i would not see the same event in turn 4 which is a banked bowl as i do on turn 8 which is relatively flat.
Here is footage of the corner in question (unlabeled gauge on the data is oil pressure). In case the video link doesn't cooperate, the corner in question starts about 1:28 in.
Hmm this is interesting. Any supporting theory why i would not see the same event in turn 4 which is a banked bowl as i do on turn 8 which is relatively flat.
Here is footage of the corner in question (unlabeled gauge on the data is oil pressure). In case the video link doesn't cooperate, the corner in question starts about 1:28 in.
The ratio of lateral to vertical G's controls how much a liquid will slosh. I can prove that point in an airplane. regardless, in a banked corner, your oil will not slosh to the side anywhere near as much as it will in a flat corner.
If anything, that statement further reinforces the theory.
Hmm that is a unique perspective and makes perfect sense.
Ill be at streets of willow this weekend, which has a similar prolonged left on the skidpad. If the theory is correct I should see similar temp spikes there. Stay tuned!
11-25-2016, 02:53 PM
Oil temp rise on hard lefts?
