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Hi Chris, There are a lot of us out here that are extremely interested in this project!!! I am building a Spec Cayman and really hope that you are able to come up with a reliable solution for us that won't break the bank. I hope you can involve Keith Fritze and Walt Fricke so that your dry sump system can be an approved solution for the relatively new PCA Spec Cayman class. Thanks for all your hard work on this project! We are very hopeful for your success!!! Tony Clinton
We got the win with 481 on Friday. The other car had some minor issues both days but finished each race. 481 went out early on Saturday after curb damage to the cooling system.
The dry sump systems both performed perfectly.
I had a real thrash getting everything ready on time but it all came together at the end.
Here is a screen shot of 481's (2.7 engine) oil pressure and other data on its best lap of the weekend.
You can see that oil pressure follows rpm perfectly with the exception of the small Variocam actuation dips.
Here is a screen shot of a SPB at Road Atlanta back in December. This engine is a 2.5 with typical deep sump and the data also shows the fastest lap of the weekend.
Obviously this configuration is eventually going to have trouble.
The first screenshot shows oil pressure being measured at the oil cooler, and the oil is Mobil 1 0W-40. The second screenshot shows oil pressure measured at the valve cover (the normal location), and the oil is Amsoil 15W-50. The coolant and oil temperatures are roughly the same between both engines
On another note, if you are not running with WRL yet you are missing out. We had serious competition this weekend and only managed that win by running a near perfect race (we had a 5 second underhood adjustment to make at one point).
This month I will be doing an installation on a 3.2 Boxster. I should have data from that car around May 10.
I also hope to get some data from Cayman S DE car later this month. That engine will be completely stock and the car only mildly prepped for DE.
Here is a screen shot of 481's (2.7 engine) oil pressure and other data on its best lap of the weekend.
You can see that oil pressure follows rpm perfectly with the exception of the small Variocam actuation dips.
Here is a screen shot of a SPB at Road Atlanta back in December. This engine is a 2.5 with typical deep sump and the data also shows the fastest lap of the weekend.
Obviously this configuration is eventually going to have trouble.
The first screenshot shows oil pressure being measured at the oil cooler, and the oil is Mobil 1 0W-40. The second screenshot shows oil pressure measured at the valve cover (the normal location), and the oil is Amsoil 15W-50. The coolant and oil temperatures are roughly the same between both engines
This month I will be doing an installation on a 3.2 Boxster. I should have data from that car around May 10.
I also hope to get some data from Cayman S DE car later this month. That engine will be completely stock and the car only mildly prepped for DE.
I welcome your questions and feedback.
Chris Cervelli
Cervelli Technical Service
Chris this is great data, thanks. I'd point out for anyone looking at these traces the oil pressure range on the non-dry sump car is actually starting at 0 (zero) bar and the dry sump equipped engine trace has 0-1 bar compressed into only a few points on the axis. So the result would look even better with the same range
Will be very interested in the 3.2 data, and nice work!
Chris, would you recommend a 2L deep sump along with this or would it be unnecessary?
No, that would be totally unnecessary. The stock pump is in place in my system, but it no longer supplies the oil pressure. Interruptions in its feed are of no consequence.
None of the deep sumps I tested solved the problem (although they can help) and they inevitably are damaged by going off track or straddling a curb. One of my design goals was that nothing hung any lower than the stock sump and that was easily achieved.
No other mods to the oil system are necessary.
The system also addresses the smoking/oil ingestion problem that these engines sometimes have.
With a Boxster smoking normally occurs when there is a long right turn followed immediately by a left turn. If there is an upshift just before or after the left turn the chances of smoking are much increased. Decreasing the oil level fixes the smoking but of course makes the interruptions in oil pressure worse.
The smoking is mostly an annoyance only but if the engine ingests enough oil quickly the #2 piston (this is for 2.5 engines only, the intake manifold aims the ingested oil at that cylinder) will break the ring lands. The engine will continue to run but with less power and more oil consumption and more trouble with smoking due to the increased blow by.
I actually have the transmission figured out. I came up with an effective cooler in 2014. They still don't last forever though. I was replacing 3rd and 4th gears at 4000 miles and then just throwing the trans away at 8000 miles due the pinion being worn out. They are just too small for the job, but if you use these intervals, they are reliable. Sooner or later there won't be any used ones left and I don't know what happens then.
...
With a Boxster smoking normally occurs when there is a long right turn followed immediately by a left turn. If there is an upshift just before or after the left turn the chances of smoking are much increased. Decreasing the oil level fixes the smoking but of course makes the interruptions in oil pressure worse.
The smoking is mostly an annoyance only but if the engine ingests enough oil quickly the #2 piston (this is for 2.5 engines only, the intake manifold aims the ingested oil at that cylinder) will break the ring lands. The engine will continue to run but with less power and more oil consumption and more trouble with smoking due to the increased blow by.
Chris, this is an eerily familiar description of what my original engine experienced. It had 140K miles (I am the original owner) with probably 25K track miles. This was before my SPB conversion. I had three incidents of huge smoke clouds one day at Sonoma. Exiting Turn 6 and Turn 12 (which are both much as you describe -- long right turn T5 / hard right T11, followed by a left) and then upshifting to 4th gear after the left, spit a mushroom cloud out the back. After checking the AOS and doing a leakdown, we found low compression on 2 cylinders, and during teardown discovered broken ring lands. I had assumed the broken lands were the cause, but per your description, they may have actually been the casualty. (Only difference being that I don't think either was cylinder #2.)
Anyway, I had never heard a diagnosis of the situation like you gave here, but it read like you were documenting what happened to my engine.
I am a CTSR customer, a friend of Chris,' but have no interest in this project other than as a fellow Boxster racer, and motorsport engineering enthusiast. Many of you know me.
I just finished driving one of CTSRs WRL GP1 dry sumped Boxsters (481) this weekend in the two day High Plains WRL event. These endurance cars are equipped with full Motec systems including prominent oil pressure on the data dash readout. All weekend long, oil pressure was constant, and we knew you could lean hard on the motor for the whole race without worry, and we did. Saturday we blew a CV joint from the class lead, but Sunday, in a 7 hour race, we got within striking distance of the two BMW M2 Cup cars in GTO class campaigned by Mike Vess. These GTO M2s are 330hp 3L twin turbo flared body factory cup cars. After 6.5 hours we were on the lead lap and finished just one lap back from the BMWs after backing off to ensure the class win in the last 20 min. We were 6 laps up on the next closest class car, another Boxster.
The point is you can run hard and worry free with regards to the bottom end of the motor now. I see that this is the solution to the problem. After studying Chris's design I can report that it is both elegant and spectacularly engineered. It is so clever that the engineer types out there will just smile when you see how he did it, then you will marvel at the components in the system.
It has been really cool watching this thing develop. The amount of time, effort and resources that have gone in to studying this problem and developing a solution is impressive. Most of you know this already, but for those who don't, Chris is a data driven engineer who employs the principal of Occam's razor as good as anyone. If there were some other simpler solution, he would have found it. Those who know him recognize his designs as being factory motorsport like in their execution. Porsche could not have done this better. This is not a Summit catalog project.
The best thing about this solution is that Chris is testing this, old school, in front of the community, so customers know it works. The WRL schedule this year for CTSR is grueling. After a full season of endurance racing that includes Road Atlanta, Road America, Daytona, Mid Ohio, HPR twice (one a 24 hour race), and Hallett, they plan to campaign these dry sumped cars at the 25 hours of Thunderhill in December. I am participating as a team driver in some of these events. That is over 140 hours of racing on each car plus test days. They are two events into the season and already have two race wins with the dry sumps and no oiling related issues. This would not be possible without either the dry sump or a room full of spare engines. My participation in this endurance effort is partly driven by the confidence I have in this system.
PCA, POC and NASA need to adopt dry sumping as a permitted modification in SPB and other M9x classes. There is no power advantage, and reliability has always been a guiding principal in club racing. Just about everyone I race with running M9x motors has lost at least one motor due to this problem, and I personally lost a podium finish because of it in 2015. I hope that the rule makers in these organizations take this seriously, and clarify that the oil accumulator rule includes non-pressurized external sumps. Only a simple rule clarification would be needed, because the principle of external oil storage, and the recognition of aeration and pickup problems has been part the rules since the beginning of the class. Cost should be considered relative to the life cycle cost of engine, and impacted down time. It is very easy to justify.
I would be also, but between the $2k installation (reasonable guess to remove/replace engine and do the work) and the cost of the kit, it's not going to be a low cost exercise!
Try getting a quote for a custom dry sump system from someone like drysump.com - I did. $2k is about right for the dry sump system components. That being said, Chris's design would have much more development time focused on our m96 engines - and testing ..
Try getting a quote for a custom dry sump system from someone like drysump.com - I did. $2k is about right for the dry sump system components. That being said, Chris's design would have much more development time focused on our m96 engines - and testing ..
I agree, and if I was to go dry sump I would definitely go with Chris, just have to balance the cost with the cost of a replacement junkyard motor and labor and materials to make it ready to race (LN ISB, PW flywheel, water pump, etc). Ideally I would get a newly rebuilt LN motor and add the dry sump to it...
04-06-2017, 12:55 PM
