Gator's 818R

[Sgt.Gator]

Gator, did you log crankcase pressure during these tests? Just curious if it changes when the scavenge pump is unable keep up.

Yes I do. The crankcase pressure slowly trends to less vacuum tracking along with oil temp. There is no major drop off or event.

We changed to the 10mm pump and back on the dyno. Once the oil reached 185 we revved her up and while one person watched the oil level in the tank. It went down, we stopped the test before it completely emptied. So we confirmed it's not the pump.
It wasn't a waste, I'm trying out a new 10mm pump from a guy I met at PRI. Once we have good data and track experience on it I hope to be a vendor for him if it works as well as expected.

New 12an scavenge lines are ordered. We are also upping the pump >>cooler>>tank line to 16an. That's the size Cosworth used on their system.

[Bob_n_Cincy]

I don't know if your interested in this. I did my Scavenge line with steel hydraulic tubing.

scav5.jpg scav6.jpg scav7.jpg scav8.jpg

[Sgt.Gator]

[QUOTE=Bob_n_Cincy;423431]I don't know if your interested in this. I did my Scavenge line with steel hydraulic tubing.]

That's a cool way to go. On my STI the plan this winter is to replace my cheapo AN lines with hard lines to and from the trunk mounted tank. I don't think we've ever considered doing the scavenge lines that way.
We've already ordered the BMRS lines. They custom build the lines to your specifications. It's interesting, every line you buy from them is serialized, if you need to replace it or change a size they already have your line build on file and they can replicate it overnight.
Thanks for the idea.

[Bob_n_Cincy]

I talked to John at Aviaid Dry Sumps.
I told him how the tanks was droping level when the oil got hot.
His thought was that it might ne a windage problem keeping the oil off the vaccum pick-ups in the pan.
I don't know, but just want to pass this info along.
Bob

[Sgt.Gator]

I talked to John at Aviaid Dry Sumps.
I told him how the tanks was droping level when the oil got hot.
His thought was that it might ne a windage problem keeping the oil off the vaccum pick-ups in the pan.
I don't know, but just want to pass this info along.
Bob

Interesting. I've thought about designing my own EJ pan and producing it. We actually created one in CAD that was very similar to the Cosworth pan. One change I would make now is to deepen the pan. Typically DS pans are very shallow because one of the benefits of a dry sump is dropping a V8, V6, I6, or I4 as low as possible to the ground. But a Subaru (and Porsche) is limited in how far you can go because of the exhaust headers coming out the bottom of the flat 4 engine. So there's a couple of inches there where the pan could be deeper without going lower than the exhaust headers.

I'd also put full -AN12 ORB ports on it, rather than some of the Subaru DS pans that are -10AN ports with -12 adapters.
The problem is the market is so tiny....that's why I never did it. Maybe I could 3D print one someday. And the future is the FA engines, which would require a different design.
Thanks!

[Sgt.Gator]

The issue is fixed!
<At least on the dyno.> We installed new -12AN scavenge lines, the tank no longer drains out on the dyno. Next stop ORP for 3 days of testing Sept 4-5-6!

[Frank818]

The issue is fixed!
<At least on the dyno.> We installed new -12AN scavenge lines, the tank no longer drains out on the dyno. Next stop ORP for 3 days of testing Sept 4-5-6!

YES!! Man I admire how quick and efficient you are at fixing weird issues.
Sep 4th is just around the corner! Can't wait to read your final approval on the fix.

[Sgt.Gator]

I didn't realize that I never posted how September testing went. It was a fail. The oil ran hot and the pressure dropped off dramatically. The same problem as before. We thought we could replicate it on the dyno but what worked there didn't work at the track. If we drove at 80-90% it was fine, but when I pushed it to 100% effort it failed.
We (Joshua Murray at Arcflash and myself) decided the scavenge pump with two stages just wasn't keeping up with even the 10mm pump. So we worked with John at Aviaid to come up with a new solution. He designed a 3 stage scavenge only pump where the third stage isn't as wide as the two main stages. That makes it possible to fit it in the A/C spot in front of the intake manifold. We figured why not try putting the third stage to the heads instead of a 3rd sump port? So we experimented with it. The third stage has a -10AN line to a Y, and from the Y it has two -6AN lines, one to each cylinder head cam cover. Arcflash in Bend welded in -6AN fittings to the cam covers and setup the new scavenge pump. That was the only engine change made, but what a change it made.

Friday we went to ORP and ran the heck out of the car all day. What a difference having the heads scavenged made. Here's the summary of temps on my fastest lap of the day:



The full graph:



ECT is Engine Coolant Temp. Crankcase Pressure is in PSI, to convert that to Inches of Vacuum you multiply by 2 (approx).
My Engine Coolant never went over 185 degrees all day.
My Oil Temp hit one high of 205 F once, the rest of the day it was 197-199 F at most.
Oil Pressure was excellent, never going under 50 for the entire lap. Hot idle at the end of a session was still 19 psi.
Trans Temp is also solved for sure with the tail lowered, it maxed out 185.
And Crankcase Vacuums of 8" to 16". Wow. In all my dry sumped Subarus (all with 2 stage Aviaid pumps) I've never been able to keep that much vacuum at full boost!

Yippe Skippe!

Here's the -AN fittings in the cam covers:

..

Over the winter we are going to make the same mod to my STI enduro racer for sure.

And on another note, we switched out the springs for 500F / 700R. That cured the tires being ground down by the body at high compression loads.

Next Up: This weekend is the annual Cascade Festival of Endurance. Josh and I will be driving my STI in the 2 and 4 hour races on Saturday.
The 818 is probably done for the season, we may try to squeeze in one more track day before the snows hit. It's already snowing in the passes.

[Hobby Racer]

Trans Temp is also solved for sure with the tail lowered, it maxed out 185.

Those temps are great, do you still have a cooler?

And on another note, we switched out the springs for 500F / 700R. That cured the tires being ground down by the body at high compression loads.

That is the same spring rates I run and they seem to work very well, even at high speed / high downforce.

Glad to see you nailed the heat and pressure issues!

[Sgt.Gator]

Hi Hobby,
Yes I copied your rates. It did raise the car 1" so we are looking at ways to have the same rates but lower it back down. We also have a bunch of other springs to experiment with.

Yes, we still have the same trans cooler.
Thanks

[Hobby Racer]

Hi Hobby,
Yes I copied your rates. It did raise the car 1" so we are looking at ways to have the same rates but lower it back down.
Thanks

Are you out of adjustment on your coil-overs? I had to re-corner balance my car and lower the collars on the coil-overs when I went to the higher rates.

[Sgt.Gator]

We put it on the Arcflash alignment rack and did quite bit of adjusting. The right front caster was off a lot. We will start concentrating on suspension and downforce next spring now that the engine and trans issues seem to be solved, they were taking up all our bandwidth.

[Sgt.Gator]

To clarify what I think is happening:
The heads being scavenged probably has less to do with the temps and pressures. The third scavenge section is the key. We could have plumbed it to the pan since there is already a port there, but figured as long as we are going to this effort we should scavenge the heads at the same time. We know the heads fill with oil so we wanted to clear them out too.
The issue is that 2 scavenge pumps can't move as much oil as the OEM pump moves at high rpm. So when you are really pushing the car hard the DS Tank drains out because the oem pump is using the oil faster than the scavenge can suck it up and return it to the tank. For the system to work properly the scavenge pump max volume must exceed the oem pump volume. That's one reason why the 10mm oem pump is a partial cure, it pumps less volume than the 11 or 12 mm pumps.
One of the symptoms you will see is that suddenly the oil pressure that was fine goes all whacky. On a long straight you wind out to high rpm, the DS tank is emptying out, the oem pump has no oil for a second, the oil pressure drops, you brake for a corner, the engine rpm drops, the scavenge is able to partially refill the tank, oil pressure goes back up. But if it only refills for a second then in the high G corner the little bit of oil in the tank pushes up the sides and oil pressure drops again. You exit the corner and for a few seconds the scavenge exceeds the oem pump because the rpms are down, and the oil pressure shoots back up.
Meanwhile the engine is chock full of ALL your oil! Every drop from your DS tank is inside the engine, in the block, the heads. There it is being beaten by rotating assemblies and the oil temp shoots up.
If you have a data logger it's easier to see it in the graphs. Watching gauges is hard to do to realize what is happening.

[NevaLift2Shift]

To clarify what I think is happening:
The heads being scavenged probably has less to do with the temps and pressures. The third scavenge section is the key. We could have plumbed it to the pan since there is already a port there, but figured as long as we are going to this effort we should scavenge the heads at the same time. We know the heads fill with oil so we wanted to clear them out too.
The issue is that 2 scavenge pumps can't move as much oil as the OEM pump moves at high rpm. So when you are really pushing the car hard the DS Tank drains out because the oem pump is using the oil faster than the scavenge can suck it up and return it to the tank. For the system to work properly the scavenge pump max volume must exceed the oem pump volume. That's one reason why the 10mm oem pump is a partial cure, it pumps less volume than the 11 or 12 mm pumps.
One of the symptoms you will see is that suddenly the oil pressure that was fine goes all whacky. On a long straight you wind out to high rpm, the DS tank is emptying out, the oem pump has no oil for a second, the oil pressure drops, you brake for a corner, the engine rpm drops, the scavenge is able to partially refill the tank, oil pressure goes back up. But if it only refills for a second then in the high G corner the little bit of oil in the tank pushes up the sides and oil pressure drops again. You exit the corner and for a few seconds the scavenge exceeds the oem pump because the rpms are down, and the oil pressure shoots back up.
Meanwhile the engine is chock full of ALL your oil! Every drop from your DS tank is inside the engine, in the block, the heads. There it is being beaten by rotating assemblies and the oil temp shoots up.
If you have a data logger it's easier to see it in the graphs. Watching gauges is hard to do to realize what is happening.

Sgt.,

I'm a complete newb at dry sumps, so excuse the dumb question. I'm running the Element tuning dry sump, 2 stage scavenge, like yours. Could you change the pulley size on the DS pump to get a little overdrive on the pump or is that going to cause other issues?

[Sgt.Gator]

Sgt.,

I'm a complete newb at dry sumps, so excuse the dumb question. I'm running the Element tuning dry sump, 2 stage scavenge, like yours. Could you change the pulley size on the DS pump to get a little overdrive on the pump or is that going to cause other issues?

That's a valid question and one of the first things we tried years ago, and even tried again as a last ditch effort in September!
We've used 3 different pulley sizes, up to 5.5" (to slow it down). Over in the R forum on the dry sump thread we detailed that and in this thread too. Driving it faster won't help because it's already going faster than any "normal" dry sump scavenge. DS pumps usually operate at 1/2 or less crank speed. The Element/Aviaid is running above crank speed and in the range of cavitation. However John at Aviaid says the scavenge side can run at higher rpms than the usual DS system that is both scavenge and engine oil pressure.
So he and I disagree on that. All I know is we tried it and it didn't work for us. I haven't talked to him yet on the cost to modify my other Aviaid 2 stage pumps. It shouldn't be too bad. I've rebuilt mine before, adding a third section and a new center gear set (longer) should be affordable. The rebuild pdf is on his website.

[Hobby Racer]

Sgt.,

I'm a complete newb at dry sumps, so excuse the dumb question. I'm running the Element tuning dry sump, 2 stage scavenge, like yours. Could you change the pulley size on the DS pump to get a little overdrive on the pump or is that going to cause other issues?

The problem with that is you are now driving the scavenge pump stages too fast and they can cavitate. Ideally you want to drive the dry sump pumps at 1/2 crank speed. We rarely get to do things ideally, but driving the pump faster is moving in the wrong direction. Adding an additional stage is the right way to go.

Just my $0.02

[NevaLift2Shift]

The problem with that is you are now driving the scavenge pump stages too fast and they can cavitate. Ideally you want to drive the dry sump pumps at 1/2 crank speed. We rarely get to do things ideally, but driving the pump faster is moving in the wrong direction. Adding an additional stage is the right way to go.

Just my $0.02

Thanks for both of the replies, glad ya'll are doing some of the R&D for the rest of us. I appreciate all of the information that is shared.

[Sgt.Gator]

We ran the Cascade Enduro again this year in the STI. We took 3rd place in the 4 Hour enduro. We could have done better but we had the same oil overheating issues in the 2 stage STI as we had in the 818. Pretty much identical.
We are converting the STI to a 3 stage scavenge. John is sending us kits to mod two pumps (one on the STI now, one on a spare pump).
There is a good chance we'll be at the last track days of the season at Oregon Raceway Park this weekend. I'm really looking forward to running the 818R with hopefully the trans and engine issues solved so we can do some decent aero testing on the wing setups! Although a high of 42 degrees on Sunday is going to be some chilly driving in an 818R and getting heat in the tires will be difficult.

[Sgt.Gator]

My wife and I cruised the length of Nevada and back last week. We spent a couple of days in Pahrump checking the latest at Spring Mountain Motor Resort. I went thru the Ron Fellows driving school there in 2015 and wanted see what's changed. All I can say is wow, what a great facility! And they are making it better all the time. The track is already the longest and most versatile in North America at 6.1 miles and 50+ configurations. They can run two events at the same time, such as the Ron Fellows Corvette school on one 2.5 mile course and members' club day on a 3.0 mile course.
With the new addition of acreage they are building the longest road race course in the world, over 16 miles long.
We are seriously considering joining the club. If anyone here is already a member please PM me, I'd love to hear your feedback!

[Bicyclops]

To clarify what I think is happening:
The heads being scavenged probably has less to do with the temps and pressures. The third scavenge section is the key. We could have plumbed it to the pan since there is already a port there, but figured as long as we are going to this effort we should scavenge the heads at the same time. We know the heads fill with oil so we wanted to clear them out too.
The issue is that 2 scavenge pumps can't move as much oil as the OEM pump moves at high rpm. So when you are really pushing the car hard the DS Tank drains out because the oem pump is using the oil faster than the scavenge can suck it up and return it to the tank. For the system to work properly the scavenge pump max volume must exceed the oem pump volume. That's one reason why the 10mm oem pump is a partial cure, it pumps less volume than the 11 or 12 mm pumps.
One of the symptoms you will see is that suddenly the oil pressure that was fine goes all whacky. On a long straight you wind out to high rpm, the DS tank is emptying out, the oem pump has no oil for a second, the oil pressure drops, you brake for a corner, the engine rpm drops, the scavenge is able to partially refill the tank, oil pressure goes back up. But if it only refills for a second then in the high G corner the little bit of oil in the tank pushes up the sides and oil pressure drops again. You exit the corner and for a few seconds the scavenge exceeds the oem pump because the rpms are down, and the oil pressure shoots back up.
Meanwhile the engine is chock full of ALL your oil! Every drop from your DS tank is inside the engine, in the block, the heads. There it is being beaten by rotating assemblies and the oil temp shoots up.
If you have a data logger it's easier to see it in the graphs. Watching gauges is hard to do to realize what is happening.

I teach exactly this at an A&P mechanic school in Lubrication. The certification requirements for a dry sump aircraft engine mandate twice as much scavenge pump capacity as pressure pump. One reason is that heated oil expands so there's more of it to pump. Another is that the used oil is foamy and isn't as easy to gather and pump. One of the teaching aids I use is a sump from an R3350, that's right - a thirty three hundred and fifty cubic inch dry sump engine. The pressure pump gears and scavenge gears are on the same shafts in separate chambers. The scavenge pump gears are twice as long, about 8" or so.

I just got a quote from John on a 3 stage system for the 2.14L stroker that I'm building for my S. If you compare it to a Killer Bee or IAG oil pan with all the fixin's and a decent catch can setup, the difference is about $1700. Makes it an easier decision, especially if you compare that to the cost of a lunched engine.

Ed Holyoke

[Sgt.Gator]

Thanks Bicyclops.

Here's the versions we have in both the 818R and STI. The installed pic is in the STI. Note the pressure exit is on the side, not the bottom:

..

[Sgt.Gator]

We spent Easter Sunday at Oregon Raceway Park running the 818R. It ran great other than a minor gas leak around the fuel sending unit when the tank is overfilled.
5 sessions. The first was with no wings, no engine covers, just to see if anything had sprung a leak or come loose over the winter. Then I did 4 more sessions testing wing configurations.
It was a cool day, in the 50s and 60s, and very windy in the afternoon which made the aero testing not very valid. But I was sure pleased with the engine/tranny data:

Coolant Temps under 190 all day, mostly in the 170-180 range.
Oil temps 190 to 196
Oil Pressures rock solid thru all the high G turns tracking with RPMs, from 55 psi to 65 psi.
Trans temps averaged 145. Never went over 155.
Crankcase Vacuum was excellent, its stayed in the -8psi to -3.5 psi the whole time. It never went positive.

It's so nice to track all day with solid temps and pressures!

I hooked up my new Garmin Catalyst, along with my AIM data and Racelogic Video HD2 Vbox. Up until now I've considered the Video Vbox to be the best driver improvement tool but I think the Garmin has changed my mind. There's nothing quite like having the little Garmin lady's voice in you ear, "At next right turn brake later"; "At next left turn apex earlier"; "At next right turn brake softer".....and so forth. She seems to speak to you on no more than three places on the track on any one lap so she's not overloading you on instructions. And she even gives compliments when you follow her instructions!
And the post session review process is so much less complicated than AIM and Vbox.
It's miles better than an AIM Solo. It doesn't have al the capabilities of the Vbox, but the Vbox doesn't talk to you while your cooking around the track either. The Vbox has a predictive lap timer, and so does the Catalyst, but having the voice is incredible.

It has an internal speaker and hooks up to Bluetooth thru your car's speaker system too, but in a race car there's no way to hear the internal speaker. So I bought a set of Bluetooth earbuds. They are uncomfortable under the helmet at first until the helmet liner compresses around them. but then the first time she says "Carry more speed thru the corner" she has you hooked.

I haven't figured out how to download the data or save the video. Still working on that. Garmin wants you to save it in the their cloud account.....

Next up is Test & Tune on Friday April 30 at Portland International, then racing on Saturday and possibly Sunday too.

[Rob T]

Great News Gator. You got similar temps, pressures, etc. to what I got with the extra stage on the dry sump. You are 100% correct about the great feeling of not worrying about oil pressures or temps....My next outing is also scheduled for April 30. I am so thankful that you discovered this solution to the dry sump issues.

[Sgt.Gator]

Scargo and White Zombie asked a couple of questions over on my NASIOC thread that I thought would be useful here too:

Curious to see/hear the Garmin video overlay experience if and when you get around to it.

I've been looking for a more seamless video/data overlay than my iPhone/Harry's Laptimer/GoPro. It worked awesome for a few seasons, but now I'm getting all kinds of frustrating connection and data overlay issues.

Good luck on sorting the car issues out soon!

Great info. I have my Aim EVO4S and GoPro but that's it. What you have sounds interesting. What G's do you sustain? I don't like my data going to a cloud that I have to pay additional for.
Thanks and keep up the info and feedback!

The Video/Data integration is outstanding if you are using the Review function on the Garmin device. The AI software shows you specific places on the track where it suggests you can improve. Awesome!

I looked further into downloading the video and data to post on YouTube and have on my laptop at the track and desktop at home. It's Awful! There is no explanation in the Owners Manual on how to do it, but I eventually found one on the Support website under the FAQs. It's possible to download the video as MPEG 4 files, but the data doesn't come with it. It's just raw track video with no data overlay. And the process is very buggy, it failed several times.

There is a second micro SD card slot on the side of the Garmin where if you put in a card it will hold the video (they say). That would make it a lot easier to load the files in a PC/Laptop. I've loaded a card but not tested it. But it still won't have the data.
Garmin spent all their engineering resources on the AI in this device for this first version. I expect updated software will make the video/data export a lot better eventually.

The Garmin cloud account is not for video/data. It's a BS sharing web platform.

Scargo, the 818R on 200 treadwear street Toyo Proxes R1R tires was consistently generating 1.4 to 1.6 Gs lateral and 1.15 to 1.17 braking. I'm sure I can do little better on the late braking Gs, I have yet to lock them up front or rear. I'm pretty happy with the lateral Gs on the 200 TW tires.

[Sgt.Gator]

Prepping for the 1 hour Mini Enduro at Portland International Raceway on Saturday. We're taking the 818R and will be in the NWMECS P1 class. With R comps we'd be in P0, but we're trying out Toyo R1Rs 200TW tires which let's us drop down one class. There's several Spec E46 cars registered in P1 so it should be fun!

818R and STI ORP.jpg

[DSR-3]

Awesome! You must be pumped.
Wishing you the best of luck and success!

[Sgt.Gator]

Delays...Delays....The gas tank leak was a failed main gasket on the Boyd Tank. It literally was falling apart. So we ordered a new gasket a couple of weeks ago. FedEx somehow got it stuck for 7 days at our regional facility. So we ordered another one for FedEx overnight delivery. Overnight ended up being two days. And of course it was the wrong size!
So now we have ordered Viton gasket sheets from McMaster and will make our own custom gasket. Doing the Test & Tune on Friday is out. Saturday, no practice laps. My first full lap will be a "pressure" qualifying lap for the enduro. One lap determines starting order. Then on to the race....

If the car is competitive in P1 I will drop the $$$ for a custom 18 gallon Fuel Safe cell. I hate having the fuel fill next to my head during enduro pit stops anyway, the fuel cell will move it to the passenger side. I have visions like this one right next to and below me...

[Sgt.Gator]

Gas Tank leaks fixed, it was both the main gasket and the electrical connector gaskets...final check over discovered the right rear hub was going bad..replaced, then the ignition switch came apart. New one of those going in. And finally I switched out my tow truck snow tires for highway tires and two studs snapped off, one on the front and one on the rear. It's not the first time it's happened, the lugs must be getting metal fatigue.
There's always something...

[blomb11]

Dang sounds like a rough couple days, but glad to hear it’s all ready to go now. Good luck!

[Sgt.Gator]

The Mini Enduro at PIR was great. The car ran well with just a minor boost spike issue that I'm sure can be tuned out. The 818R showed it has promise in the P1 class, running about 1.5 to 2 seconds per lap behind the class leader. The most important thing was the data image, if you race a Subaru powered car you know how sweet it is to have these numbers on the fastest lap, 17 laps into the race. Now that the critical temps and pressures are solid we can get on to tuning the suspension, tires, and most important, the nut behind the wheel!
Thanks to our sponsors and partners at Subaru of Bend and Arcflash.

PIR Enduro Lap 17 Temps Data lg.jpgPIR Enduro 4a.jpgPIR Enduro 5a.jpg

[Sgt.Gator]

A couple of track notes:
When we fixed the fuel tank gasket leak I didn't notice the driver seat was put back one hole higher on the back base. As soon as I sat in the car at the track I knew it ddn't feel right but figured I could drive it ok, it's a pain to get down in there and change it. So I raced with it up on notch. Well that almost came back to bite...the Race Stewards met me at my paddock space to tell me my helmet was seen by the corner workers about 1/4" higher than my roll bar. They almost black flagged my race! But the stewards wisely allowed me to finish the race.
Do your broomstick tests! You may get by with your helmet above the roll bar /broomstick line at AutoCross and HPDE, but in a sanctioned race the corner workers are watching.

Post race go over: My front brake pads were worn to the metal on one pad, each side, due to heavy taper on the bottom edges. I'll have to remember to swap pads around every few sessions, I could have gotten 50% more wear out of them. Hawk DTC 50s.
The front brake dust boots are melted away, a right of passage.... (Even with front brake ducts). If you haven't melted your piston dust boots, you aren't really braking.

I was expecting that being a rear weight biased mid engine car the rear brake pads would show some wear, but almost none. I think a brake bias adjuster is in my future.

The Boyd tank is too small for racing, the FF fill is too small and on the wrong side for safe refueling. To keep racing we are definitely going to need a 18-20 gallon fuel cell with fill on the passenger side. Fuel Safe is going to do it for us. Both Fuel Safe and Pyrotect are local here in Bend/Redmond. The guys at Fuel Safe want to build a solution that fits behind the driver for all 818Rs. More on the design soon.

[Sgt.Gator]

One more track note. I love the Garmin Catalyst. The little Garmin lady's voice..."next right turn brake later". "Good Job!". Amazing.

Except at the re-fuel we took the rear wing off to see how it effected my lap times. This race is a non-chicane race at PIR, which means a very long front straight at WOT. Would the higher top speed make it worth it?

It only took a few laps to say naught. At the end of the straight the braking was not nearly as solid, drastically reducing my braking confidence. So I started braking sooner and lighter. That meant each lap with no wing the Garmin Lady kept saying "Next Right Brake Later", "Brake Harder".

After I spun out in another corner I pitted again and put the wing back on.

Taking the wing off resulted in quicker acceleration down the straight 1-3mph faster, but ultimately with the wing and without the wing I hit the same top speed before the brake zone. The bad aero of the roll cage was limiting the ultimate top speed, the added drag of the wing didn't matter. My fastest laps were with the wing installed.

[mikeb75]

That's super cool that you've used the Garmin Catalyst to get real time confirmation of your testing on track.

At least for now I'm relieved that we're safe from having AI's driving our race cars for us (look up the last test... er spectacular failure) and just giving us performance tips (guess a Garmin is cheaper than hiring a professional race car driver for a ride along).

[Hobby Racer]

The Boyd tank is too small for racing, the FF fill is too small and on the wrong side for safe refueling. To keep racing we are definitely going to need a 18-20 gallon fuel cell with fill on the passenger side. Fuel Safe is going to do it for us. Both Fuel Safe and Pyrotect are local here in Bend/Redmond. The guys at Fuel Safe want to build a solution that fits behind the driver for all 818Rs. More on the design soon.

Interested in that! Do keep us informed.

Taking the wing off resulted in quicker acceleration down the straight 1-3mph faster, but ultimately with the wing and without the wing I hit the same top speed before the brake zone. The bad aero of the roll cage was limiting the ultimate top speed, the added drag of the wing didn't matter. My fastest laps were with the wing installed.

I love these types of posts. Great information for the 818R crowd. Kept it coming.

[J R Jones]

With no knowledge of rules:
If the cage aero is that influential, would the car be cleaner with a windshield?
Would the wing be more effective on/above the roll bar? Or set back from there?
I assume you run Wilwood brakes, same F & R or staggered? Our (heavier) EVO burned off the boots and blackened the paint. Rotors did not make a season.
Proportioning is critical. If you choose to not "skid balance" you could stick-on thermal tell-tails to find out the difference in working heat. Of course ducting is influential.
jim

[Santiago]

I'm in blue:

If the cage aero is that influential, would the car be cleaner with a windshield?
Much depends on the shape and rake of the windshield. Full canopy? Most likely. Just a windscreen? Maybe... but the challenge with the 818R is that the main roll-over tube is so wide and squared off (it's meant to protect two occupants). That makes a proper tear-drop canopy difficult and a windscreen's benefit suspect. I'll be fairing my tube, opting to clean the profile rather than work around the detrimental effects of a bad profile.

Would the wing be more effective on/above the roll bar? Or set back from there?
Between the two, I'd favor above rather than back (at least for purposes of getting it in clean air). The influence of the tube is going to be felt further back than you might expect. It may be easier to get the wing above the tube - but I'm not sure how much higher you would need the wing's belly above the top of the tube.

[J R Jones]

Santiago, A passenger with a strut and yarn tell-tails might indicate the layers of unstable and stable air.

The further forward the wing, the less downforce on the rear axle, and the less lift in front.
The higher the wing, the drag lifts the front. Hard to predict the magnitude. Compromises.

The benefit of a windscreen might be realized without going full height. A low, wide forward deflector wrapped over on top might loft the airstream for some improvement. The air stays attached at or less than seven degrees.

We ran a Sorrell 50's vintage front engine (open) Can Am car. The pontoon fenders directed air at the driver and got under a full face helmet. Chin strap was almost decapitating at/over 100MPH. A small screen made it tolerable.
A winner-lap in a windshiedless Sunbeam Tiger broke my girlfriend's glasses when I shouted "Hold my flag and watch this schmidt".
jim

[Sgt.Gator]

I agree with Santiago.
Jim, there's a FF aero testing post on the 818R. Mounting the wing on the roll bar resulted in the driver's helmet trying to be sucked off his head!
https://thefactoryfiveforum.com/show...dtunnel-Tested

Quote: "On another car, a modified challenge car, we once made an airfoil around the cage for a track test. The goal in that case was to produce downforce from a part of the car where we already had to have the drag penalty. The result was a car that was undrivable, not from a handling standpoint but because the low pressure under the airfoil was trying to pull the drivers helmet off."

Earlier in the thread you will see where I am testing having a wing mounted on my front roll bar. I didn't try it at PIR Non Chicane because I thought the drag would be too much for the high speed front straight. See Post 241.
So far having it on the front hoop has not been a problem with helmet buffeting.

Brakes are the FF optional 4 Piston, 12” Front / 4 Piston, 12.18” Rear. For racing the 6 piston might be better, except that would eliminate using a 15" front wheel, which I am considering. It's hard finding 15" 5 x 100 wheels in anything wider than 7".

And for the newer R builders who may not be familiar with Dave Smith's own 818R testing:
https://thefactoryfiveforum.com/show...FFR-s-own-818R

My car is evolving closer and closer to his....

[J R Jones]

Sgt. Thank you, I read the (2015) wind tunnel thread. I have done wind tunnel development on street and racing motorcycles and a lot of hydrodynamic development.

There are details to note. I think the 818R they tested did not have a full-box cage as you do. Like your Miata photo, lots to shield, and more turbulence in the cockpit.
The improved airflow on the Radical is partly to do with the windscreen and small cockpit.
I think the wing on top of the 818 roll bar has too much baggage and rule issues.
A wing has low pressure on top and high pressure underneath, not what I expect to suck a helmet off.
They put a symmetrical airfoil shape on the roll bar which creates low pressure top and bottom, therefore it sucked.
That Radical has a very nice windscreen, nice sweep back and a lip spoiler on the rear edge. (Gurney lip?)
Daves 818R appears to have a wider wing on back with outer ends operating in clean air beyond the body width.
It is encouraging to see that development effort from FFR. Wind tunnels ain't cheap.
Nascar teams scan cars and make scale models to do aero development on rolling road wind tunnels. I have been to Penske's in Mooresville.
They develop the model then scale it to make full size cars. Saves money and time.
I did race bikes in Wichita aircraft model tunnel at 100+mph , and street bikes at Modine at 120MPH and up to 100 degrees F.

Seems that before you can develope the wing, someone has to get a handle on the turbulence ahead of it.
Anyone try a whale tail like a 917 30 Porsche? Center steering and a narrow cockpit......
jim

[J R Jones]

Sgt, Opps, I was "testing" in the wind tunnels, not racing. Up too late methinks.
The issues here are formidable. Obviously the turbulence presents consequences for cooling as well, like John's H6 818R intercooler. I regard cooling as a priority.
If the cockpit turbulence has to be accepted, then (cooling) must find a more suitable environment, like the sides or front. Maybe the intercooler is what I saw in front of the radiator on Bob in Cincy's car.
Porsche uses front mounted coolers and radiators on 911 race cars. Porsche works hard on issues like that.

Brainstorming:
Your headlight apertures could be cooling air ports.
I developed a ram air (engine) intake for a racing motorcycle that netted 7hp at 100MPH. (+6%) The intake was a port on the faring at the base of the windscreen where high pressure lived. The port/plenum had two hoses to the airbox to balance swirl in the airbox.
In a similar manner can you mount ducts in or under your windscreen, through the cockpit to your intercooler?

In the back of my mind the P51 Mustang is always idling with that marvelous cooling system on the bottom of the fuselage. That scoop/duct worked so well the coolant temperature was regulated with an articulated "trap door" exit.