Plavan's 818R Build Thread

[C.Plavan]

Looks good Chad. On my late model I plumbed the dry sump with aluminum tubing from the rear to front. and used shorter pieces of braided steel. When you are sure it will work you could probably run it with the cooling pipes under the side pods. obviously a winter project. Anyway I got the tubing from McMaster Carr and just welded AN fittings to the ends. Just in case you're 818 crowd funding takes off.

Thats a good idea. But I think If this works with the -12 hose, I'll just keep it. I will probably have to spend more money on other things.

No crowdfunding, just helping you guys out with money/time.

[Frank818]

Now if that doesn't work, nothing will!

[C.Plavan]

Here goes nothing. All packed for more testing tomorrow at Buttonwillow. Config #25 Counter-Clockwise.....yikes. Pray to the oil cooling god.

[Scargo]

Would a hydronic heater element going and coming make any sense? As an example, four foot ones are $112 each X 2. Big oil coolers are 2x times that. Save on $80 worth of -12 braided hose so two only cost $144.
Could be mounted low and weight difference is about 11 pounds. Seems only downside is the extra 11 pounds, but then you would need an oil cooler of less size/weight up front.
All aluminum finned tubing might be available which would make the weight almost equal to the hose...
21nzrGHX2jL.jpg

[Brando]

Never have run that config. Should be interesting.
You have made my upgrade list quite long with all the things you have done combating temps. Do you worry about kicking a rock into the front oil cooler or did you add a mesh on top of it?
Good luck Chad, may the gremlins not be with you!

[C.Plavan]

Never have run that config. Should be interesting.
You have made my upgrade list quite long with all the things you have done combating temps. Do you worry about kicking a rock into the front oil cooler or did you add a mesh on top of it?
Good luck Chad, may the gremlins not be with you!

Thanks Brandon- I'm sitting here at the track eating an early lunch. I'm only doing a half day and that starts at 1:00. I did not want to pay for a full day and have high temps the first session and waste that cash. I just have not had the luck I thought I would have with previous "fixes". I got everything all set up and ready. I never ran this config this way either. I don't like going CCW either, the last turn on the front straight likes to eat cars.

Sorry about the upgrade list, it's not finished yet. Haha. I did put mesh up there to protect the cooler. Fingers-crossed the oil stays cool. Outside temps are high 80's- so this is a good day to see what happens.

[Hindsight]

Keep us posted and good luck.

[D Clary]

Probably good for half day, High 80s should show you one way or another. Good luck

[Mitch Wright]

"Would a hydronic heater element going and coming make any sense? As an example, four foot ones are $112 each X 2. Big oil coolers are 2x times that. Save on $80 worth of -12 braided hose so two only cost $144.
Could be mounted low and weight difference is about 11 pounds. Seems only downside is the extra 11 pounds, but then you would need an oil cooler of less size/weight up front.
All aluminum finned tubing might be available which would make the weight almost equal to the hose..."
Click image for larger version. Name: 21nzrGHX2jL.jpg Views: 10 Size: 4.8 KB ID: 42484

Sargo, we used them on our TA cars and ASA cars primarily to save weight, we also made up Aluminum tubes with AN fittings on either end. Anyway we did feel that they helped to lower the oil temp a small percentage.

[C.Plavan]

Hehehehehehe Weeeeeeeeeeeeeeee

[D Clary]

Time fo new tires?

[Hindsight]

Ok spill the beans.... how did it go?

[C.Plavan]

Well, I spoke too soon unfortunately. The first session was awesome. Never got over 220. The second session was fine- got to 230. Last session it got to 250-260 again like before. Sucks- I was throwing down some crazy laptimes.

My new theory is that the oil tank needs to be moved to the front out of the hot engine compartment. Or insulated super good. I think the aluminum tank just keeps getting hotter and hotter and eventually making the coolers ineffective. Basically heat soaking the oil right before it goes into the motor.

Bummed......

The good news- I have an awesome new setup that handled like a dream.

I have no other ideas other than that. I don't know what else it could be. I always said I was amazed at how hot that damn engine bay gets.

[D Clary]

How cool did the oil get between sessions, how long did you run? I am sure having the oil tank in that oven keep heat in but I think the engine in the oven is the real issue. I think you have all of the ducting you can get from the sides. Unless you open the bottom under the exhaust a little. Is there any room for the tank out front by the fuel cell, or maybe in the original fuel tank area. If it went to 260 in a half hour and stopped there I could live with that and just change oil after the race, any higher I don't know. The only other thing I can think of is separating the turbo oiling system from the engine. I have seen it done before just more work and $. The turbo is usually where the temp comes from.

[D Clary]

Just another thought, oil gauge is Accurate? I have had water temp gauges that were way off. Just thinking out loud

[Erik W. Treves]

I was going to mention ... one of the guys on the gtm forum initially did some water radiators in the same spot as your oil cooler. He ended up moving from that location. He said something about the air flow exiting the radiator was disrupted by the wind velocity generated by the rotation of the wheel.... basically at speed acting like the back of the radiator was blocked off.....not sure the aerodynamics of it...but there it is.

[Hindsight]

Well congrats on getting the handling sorted and making it go fast. That's a big feat in of itself. Just one issue you have to contend with now.

Are you sure the placement of your oil temp sender is in a place that provides an accurate and true reading?

It should be easy to prove your oil tank heat-soak theory by insulating the tank really well. Obviously where it is now, you'll need insulation that provides air space instead of just reflective properties (something with some thickness). It may not be pretty but it would be functional.... even if only done as a test. If it were my car, I'd get some duct insulation from home depot and wrap the tank really well, just for one track day to check the theory. If it works, maybe get something more appropriate.

The other thing that comes to mind is that you are still running without the engine cover right? Have you thought about removing the trunk cover as well? That might cause too much of a parachute effect back there at speed, but what about fabbing up some mounts so that you could mount the back of the trunk cover up about 2-3" or so, causing a big low pressure area behind it which would draw out a lot of air from inside the engine compartment. It wouldn't be a permanent solution, but just something to test the heat soak theory. If you are getting a ton of air circulation back there, it can't be heat soak on the tank. Have you thought about mounting an air temp sensor near the tank and hooking it to a gauge just to see what kind of temps you have back there? I'm just really surprised that the big back vents and the two big side vents aren't moving enough air. Think about some other rear and mid-engine cars (like your Spyder)..... most of them don't have side inlets as big as the 818 or rear outlets as big as the 818, yet they don't seem to have a lot of issues (even the turbocharged ones). Maybe there is something to what Erik said above, but that is impacting airflow dynamic in the engine compartment...... an imbalance of some kind preventing air from flowing in the intended path. Maybe spend more time with yarn and a go-pro, both under the car and inside the engine compartment to see what's happening?

Just thinking out loud. Would love to see this car out there lapping people in ST-2.

[bbjones121]

What does crazy lap times mean? At the refinery, I spec out nuclear level transmitters with a vortex cooler and jacket. It is a reflective jacket that is stitched closed and we run plant/instrument air through it. It puffs up to keep air space. I bet you could cut a funnel to place in part of the side duct and run an air tube to a jacket around the tank?

[C.Plavan]

I just got back home. I already ordered Fiberglass insulated reflective high temp tape, and a step further, header wrap. I'm going to wrap that *itch up like a Mummy!

I'm running with the full body on. Some good thoughts above- I should of removed the under engine tray and try running without it. That would of added more airflow in engine area, but I don't know if I would lose too much rear diffuser effect. Only way is to try it out.

I was running constant 1:58's in traffic (this was the first time running this configuration.... its weird, but some places were really fun)- The car was handling perfect (camber is your friend, toe out in front and toe in at rear). Another thing I noticed, it seemed like I hit a wall around ~122 mph. I'm wondering if the tuner forgot to change the throttle values back to 100% (from when he reduced them from the tune before to limit HP)- He forgot to turn my 2nd radiator fan on, so its possible but unlikely since it would be effecting every gear. It could just be the weird feeling of having flat max HP from 4500 on up. You don't get that full accelerating feeling or something. Then again, it could of been a headwind. It's like nothing I have ever felt before. I'll look at the file later.

The brakes are awesome. I finally have them adjusted (dash bias knob on dash) perfectly. They did get a tad soft at one point, nothing that a left foot on the straights could not fix, but I did not bleed them since the last test. Nothing bad, but ducts may be added later. It did not take away from braking confidence.

There were some corners I wish I had a true LSD. The decel lockup would of helped in some trailbraking corners. But the TSB is still up to the task on tight corner exits.


Anyway- I'm beat. I'll have some videos later.

[D Clary]

Another thought Chad, I still don't like where you are getting your oil temp. The only oil temp you can control is the temp going back into the engine. Lets say you put the temp sensor on the turbo, it would probably be 350 degrees and you would really be nuts. The same hold true where you have it on the block. That portion of the block may just be 260 degrees. The only way to check the oil temp is in the oil reservoir or oil pan. There is no way that adding all of the cooling that you have could make no difference. I have used both wet and dry sumps in racing and always gotten the oil temp from the reservoir.

[C.Plavan]

Another thought Chad, I still don't like where you are getting your oil temp. The only oil temp you can control is the temp going back into the engine. Lets say you put the temp sensor on the turbo, it would probably be 350 degrees and you would really be nuts. The same hold true where you have it on the block. That portion of the block may just be 260 degrees. The only way to check the oil temp is in the oil reservoir or oil pan. There is no way that adding all of the cooling that you have could make no difference. I have used both wet and dry sumps in racing and always gotten the oil temp from the reservoir.

I would agree with you if I did not feel the performance difference with the motor when the oil shot up in temp. I have a thermo fan switch that turns on the rear oil cooler fans at 180, I tested it and the gauge reads 180 when the fans turn on.

It did make a huge difference. I could only get about 2-3 laps before I would have to pull off before. I could actually enjoy driving the car this time.

I went out for 20~25 min the first session (oil was cold since start)- the oil temp never got over 220 degrees. The second session about an hour later, the starting oil temp was not ambient (I can look at video of gauge later for exact temp *** just looked it was 160 degrees***) it never got over 230ish. The 3rd session, it got too hot after about 6-7 laps. This is why my oil tank theory came into effect.

[C.Plavan]

Well congrats on getting the handling sorted and making it go fast. That's a big feat in of itself. Just one issue you have to contend with now.

Are you sure the placement of your oil temp sender is in a place that provides an accurate and true reading?

It should be easy to prove your oil tank heat-soak theory by insulating the tank really well. Obviously where it is now, you'll need insulation that provides air space instead of just reflective properties (something with some thickness). It may not be pretty but it would be functional.... even if only done as a test. If it were my car, I'd get some duct insulation from home depot and wrap the tank really well, just for one track day to check the theory. If it works, maybe get something more appropriate.

The other thing that comes to mind is that you are still running without the engine cover right? Have you thought about removing the trunk cover as well? That might cause too much of a parachute effect back there at speed, but what about fabbing up some mounts so that you could mount the back of the trunk cover up about 2-3" or so, causing a big low pressure area behind it which would draw out a lot of air from inside the engine compartment. It wouldn't be a permanent solution, but just something to test the heat soak theory. If you are getting a ton of air circulation back there, it can't be heat soak on the tank. Have you thought about mounting an air temp sensor near the tank and hooking it to a gauge just to see what kind of temps you have back there? I'm just really surprised that the big back vents and the two big side vents aren't moving enough air. Think about some other rear and mid-engine cars (like your Spyder)..... most of them don't have side inlets as big as the 818 or rear outlets as big as the 818, yet they don't seem to have a lot of issues (even the turbocharged ones). Maybe there is something to what Erik said above, but that is impacting airflow dynamic in the engine compartment...... an imbalance of some kind preventing air from flowing in the intended path. Maybe spend more time with yarn and a go-pro, both under the car and inside the engine compartment to see what's happening?

Just thinking out loud. Would love to see this car out there lapping people in ST-2.

Good ideas. I like the rear trunk prop idea. That is easy to test.

I'm also going to block off the humps. I think the flow may be fighting and pulling air out the front. I looked at an old video of when I was overheating (coolant, not oil). I noticed water coming out the rear overflow (my guess) and being thrown around in the cockpit! I could not see it because of the halo seat and driving. I was wondering where dried water droplets were coming from on the dash and fuel cell. Maybe by also closing off the humps, it will force air out the back.

[C.Plavan]

I was going to mention ... one of the guys on the gtm forum initially did some water radiators in the same spot as your oil cooler. He ended up moving from that location. He said something about the air flow exiting the radiator was disrupted by the wind velocity generated by the rotation of the wheel.... basically at speed acting like the back of the radiator was blocked off.....not sure the aerodynamics of it...but there it is.

Thanks for the info. We have used coolers in this spot with old Porsches for years. Granted, the cooler is farther away from the wheel than the 818. My cooler is more offset to in inside, but it is something to note and think about.

[D Clary]

Do you think that the performance difference could be fuel temp because of the high engine compartment temp. I don't see the oil temp causing performance issues at 260 degrees. The fuel temp could get very high as well as the electronics on the motor.

[Hindsight]

I'm also going to block off the humps. I think the flow may be fighting and pulling air out the front.

Yeah I think anything you can do to figure out exactly what the air is doing back there would be helpful. The things that make me wonder about weird airflow are the video you posted of the yarn on the various vents, and out the upper rear vent was actually drawing air IN instead of out, and the fact that your intake was sucking hot air even though it was positioned right in front of the side vent (back when you had it over there). Both of those things tell me something strange is going on back there with the flow and if you can figure it out, there will probably be one simple thing you can do to get everything in balance and properly flowing (assuming that's the issue).

Ok back to the garage to work on my own oil cooler.

[C.Plavan]

Do you think that the performance difference could be fuel temp because of the high engine compartment temp. I don't see the oil temp causing performance issues at 260 degrees. The fuel temp could get very high as well as the electronics on the motor.

That is a possibility. Either way- I have to cool down the back end.


For you data gurus- Here is a friction map from old suspension and brake adjustment, to yesterday. The car is handling and braking better with the suspension changes (same old tires, they were new on the left graph).

[C.Plavan]

Beating up on some super old tires now. Having a blast putting down some decent lap times for never running this configuration...backwards.

I think I need to take some more out of my wing. I think the feeling I was describing before is Aero drag. I'm new to this full aero stuff.

[Erik W. Treves]

Thanks for the info. We have used coolers in this spot with old Porsches for years. Granted, the cooler is farther away from the wheel than the 818. My cooler is more offset to in inside, but it is something to note and think about.

Yep...no problem... the solution on the GTM was the same location but moved further away from the tire as you stated...I should have said have made that clearer...sorry

[D Clary]

Temp or no temp, you need to get new rubber before you wreck

[C.Plavan]

Temp or no temp, you need to get new rubber before you wreck

That takes the fun out of it. The 818R is easier to drive than the old 911's without aero.

[Frank818]

He said something about the air flow exiting the radiator was disrupted by the wind velocity generated by the rotation of the wheel.... basically at speed acting like the back of the radiator was blocked off.....not sure the aerodynamics of it...but there it is.

It's actually pretty simple. When the wheel rotates it moves air around in circle, pushing it away from the wheel. The faster rolling the higher the pressure generated by the rotating wheel. Therefore if a rad is located in the path of that high pressure zone, air will want to go through it or slide along top to bottom. But on the other side of the rad, air is coming in, so you get a collision at the rad which means the air exiting from the rad is blocked by the high pressure of the rotating wheel. This is one reason why those (Porsche for instance) locating rads in that area do it at an angle so that the airflow is less disrupted. Porsche is master at that. This is also a reason why we often see louvers on top of front fenders, to get the pressure out of the wheel well area.

Now I haven't checked exactly where and how Chad located his, but the above is the principle.

[metros]

If you could rig the oil to keep circulating between sessions then your oil wouldn't be heat soaked at the start of a session.

Video looked like a lot of fun.

[D Clary]

When/ where is you're next race?

[C.Plavan]

When/ where is you're next race?

Next weekend (Buttonwillow- same direction as video, but without the long back straight- we dive into the infield for the "Bus Stop"). Getting ready to drain the oil and take the tank out to wrap when parts get here. I'm also blocking the humps off with aluminum, and adding two 90 degree L aluminum pieces above the front oil cooler to possible break the aero from the wheel. Cheap easy fix/test.

[David]

Chad,

Just ran across your build thread... really nice work! I noticed your sig, and realized we have another Porsche brother in our midst. Im currently building a 73 ST tribute as well. I ran across your blue ST a while back while digging around the pelicanparts forum. Gorgeous car!

Anyhow, wanted to say hey and give you props for your great taste in rides!

On another note, how is the 818 doing on the track compared to the ST?

David

[C.Plavan]

Chad,

Just ran across your build thread... really nice work! I noticed your sig, and realized we have another Porsche brother in our midst. Im currently building a 73 ST tribute as well. I ran across your blue ST a while back while digging around the pelicanparts forum. Gorgeous car!

Anyhow, wanted to say hey and give you props for your great taste in rides!

On another note, how is the 818 doing on the track compared to the ST?

David

Hey David. Thanks on all fronts. As you know early Longhoods prices are skyrocketing, that was my main reason of buying the 818R. It was getting crazy racing the "Angry Smurf" 911ST as often as I was. At the last Rennsport and at the SVRA national Championships at COTA, I was getting unsolicited offers to buy the 911. One offer made me think twice! Thats when I decided I would race it at special historic events. I have had it for 15 years, and raced it every one. Shoot me some pictures when you get yours done. I love the ST models.

This 818R has been an adventure. I can't imagine trying to get this thing running if I did not already have built and raced cars. It would of cost even more money in mistakes if I didn't (Blown motors etc)

As for the difference on the track, the 911 is more mechanical, violent, old school. It will bite you when you are not focused. As for the 818R, it is way easier to drive with the Aero. I call it "point and shoot", where as the 911 is "I hope this holds". So far the 818R is 6 seconds faster than my best time at Buttonwillow in the 911, 3 seconds faster at WS. This will for sure change as I get more comfortable in the 818R- and once I figure out the 818R issues.

[C.Plavan]

Worked on the car yesterday. The oil tank insulated with reflective fiberglass tape first (1100 degree), then header wrap. I'm going overkill on it before the race this weekend to test the theory.





I call it R2, my personal racing Droid.


Then I had to modify the hump block offs for my air intake, R chassis changes. The passenger side is done and sealed up nicely, I just need to finish riveting the driver side and put the bulb seal on.

Hopefully the air will go where I want it, instead of out the humps.

[bbjones121]

Looks good, hope it goes well!

[D Clary]

I kind of thought they could have made a different block off and deleted the roll bar cutouts. I remade the block off to cover the cutouts in the fiberglass.

[Frank818]

Where exactly (or what brand) did you get your reflective fiberglass tape from? I found a few similar items on ebay (even one to 1800F if you really need overkill ), but not sure I found the one you are using. And I know you are using great stuff, race proven, so I know for me, on the road, it would be a great choice.