R200 Differential cooler pump and plumbing

[tube80z]

Hi Jon,

 

You don't have to drill any holes into your panels.  You use a thin pressure puck mounted to the surface usually with tape.  If you look at a few of Julian Edgars vids he shows off a purchased one.  It's a slice with a axial hole down to a radial passage that you hook the tube into and either run to a pressure sensor, manometer, or magnehelic guage.  You can find some gauges in inches of water on Amazon too.  

 

cary

Edited March 3, 2023 by tube80z
added magnahelic gauges

[JMortensen]

Hmm... saw one with a pitot tube, looked them up on ebay and they're $300. I've been watching a bunch so I'll probably run into it.

[JMortensen]

This looks like the video to watch for measuring devices. 

 

I am a bit confused by the pitot tube vs the puck measurement. I had thought that if the aerodynamic forces were working on a specific part eg a diffuser since that's the focus of the thread that you would want to test pressure on top of the diffuser and on bottom, not the bottom vs a pitot tube way up higher than the car. I'm questioning the need to have that huge stand on the hood too. Porsche's looks more modest:

Edited March 3, 2023 by JMortensen

[JMortensen]

Think I figured out my question about where to test pressures. You can test before and after a radiator because that's where the air flow is different and affects flow through the radiator. On the diffuser it's affecting the airflow over the car vs underneath. Pressure on top of the diffuser or in the cabin is irrelevant because it should be the same on top and bottom, so it's pushing as much up on the floor as it is down and whatever effect is that has is negated. 

[JMortensen]

If anyone wants to buy some of those pressure patches, I'll have 3 extras.

Diff sold, so I'm spending some money.

Edited March 3, 2023 by JMortensen

[calZ]

You're exactly correct on the pressures. Each individual control volume effectively cancels out

[JMortensen]

Well, this is all snowballing.  

Still waiting on my electric motor to arrive. I did go ahead and buy the adapter for the shafts so I didn't have to wait even longer for that. Have all of my plumbing fittings for the diff cooler, pushlok hose arrived today. Have to drill another hole for the oil return and weld a bung to the diff cover for to feed the cooler. I found an old thread of Coffey's on another site where he talked about welding fittings to the cover, so I'm confident that it can be done. I can probably weld it myself, even though my tig work is shit. Doesn't really matter what it looks like, as long as it doesn't leak. Nobody is going to see it. 

Bought 5 cheap used 1" magnehelic gauges off of ebay and a pitot tube. $75 min order from the mfr of the little puck things, so I bought 8 of them. Figure if I'm going to do it, might as well set them up in different areas and that way I can test a bunch of stuff at the same time, and not have to do 1000 runs, seeing as how my car isn't street legal. Should have about $300 into it by the time I can set it up and test. Gauges were between $15 and $25 each.

Thinking I can grid out spots to test on the car and then do a track day and just change the position between sessions or even just pull in to the pits and change positions and go back out, and just pick a comfortable rpm to run down the front straight (no speedo) and set up a camera to watch the gauges. Do 1 or 2 runs to test pressures, and then enjoy the rest of the session. Probably have to extrapolate a lot of info, but seems like should be able to get a pretty decent idea of what is going on.

Little concerned about how to hook up 5 manometers to the one pitot tube. Edgar had a video where he attached the pitot to an aluminum bottle, for all intents and purposes, and then measured off of that. I watched a couple days ago. Should have bookmarked. Thinking might be able to do that and then run 5 taps out to the manometers. Just not sure that I can run 5 manometers with tees off of the 1mm tube alone. That seems like a problem.

Thinking of making a removable dashboard for them that hooks to the cage so I don't have to set it up every time, and pitot bracket that attaches to the cage near the window, so it can be bolted and unbolted easily.

Also really want to get a cheap wing to put on the car. It has a lot of tricks on the front and I feel like it is probably going to need something to balance it out. This one I found looks similar to the 9 lives racing setup at a fraction of the cost, just have to make uprights and have the mounts welded to the wing (will pay someone to weld this part, if the wing comes off it's a big problem). 65" width, chord is 9 3/4, profile looks reasonable. Has a built in gurney, could stick a bigger one in front of it if necessary. Then I can work towards a better one later on. later. https://www.ebay.com/itm/324563472720
 

[JMortensen]

FYI, the shaft size on the motor is not 5/16, it's 8mm. About .015 difference, but it's enough that the adapter won't fit. I've got an 8mm drill bit coming, seems like the quickest fix.

2 of the 5 manometers have shown up.  They're pretty heavy. Looking like I will have gauges all the way across the pass side of the dash.

[JMortensen]

Still trying to figure out what material to go with for the panels on the bottom.

The more I think about it the more I think I might want to drop the floor down an inch or so in the back. The car has a pretty good rake to it and the splitter was 2.5" off the ground in front, but I think the rear of the frame rails might be more like 4 or 4.5" up off the ground. Dropping it down I could make the diffuser longer and move the CP forward.

Was settled on 10mm Alumalite for the undertray and then Alumanate for the diffuser. Alumanate is flexible, which is why I'd want to use it on the diffuser, but then started trying to figure out side splitters.

First thought was to put an angle aluminum frame around the perimeter of the side boards, then lay the alumalite into it. Then I got to thinking of people stepping on them getting in/out. I don't think the Alumalite is strong enough to be walked on, but have no experience with it, maybe I'm wrong on that. I got to thinking what if I used Alumanate everywhere, and made either a .5" square aluminum tube frame and used 6mm Alumanate on top and bottom or  .75" aluminum tube frame with 3mm Alumanate. That would definitely provide the stiffness needed to walk on the thing and the aluminum tubing is really light. 

I want to make it so that all the undertray parts except the center section between the frame rails are able to be taken on and off in a matter of seconds. Center section will screw on. Following AJ Hartman's videos, I'm going to do a square tube receptacle welded to the frame of the car, front back and sides where the splitter and side boards and diffuser plugs into, and then have cotter pins on brackets around the frames to support them vertically. 

I'm also going to redo my splitter mount. I'm keeping the part that tube80z suggested where the splitter is hung on 2 pivots that are able to be raised and lowered into the frame, but I'm going to build a steel tube frame and have it go out to the sides - currently splitter mounts only near the middle and with splitter rods in the front. I'll attach the steel frame to the chassis similar to the way AJ does, and then probably ditch the splitter rods. I don't think the rods are necessary and they require tools to remove.

 

[clarkspeed]

 

I know very little about aero design.  My race classes are fairly restrictive.  I did attend a seminar by Jeff Braun where he described a small flap mounted slightly in front of front fender cutout and in the radius of the cutout, not really a dive plane and certainly not a gurney flap.  Generating turbulant air next to the wheel pulls a vacuum under the hood.  He said it works every time and called it the cheapest easiest way to make downforce if legal to do so.  You can see this design on every NHRA Funny Car.

 

 

Here are some cool videos showing F1 and Nascar Aero design.  The F1 video is amazing.

 

 

 

Edited March 9, 2023 by clarkspeed

[JMortensen]

Just cleaning up the diff cover so I can weld a drain to feed the pump, and looking at the plastic vent. Might be a good time to upgrade that. Never pulled one out before, looks like you can just lever the plastic vent out of the cover. 

After that seems like there is enough meat there to drill out the hole to 1/4NPT, then run a fitting off of that and attach to a catch can positioned somewhere convenient. Anything else to know?

Edited March 13, 2023 by JMortensen

[JMortensen]

Easy to do. Don't know why I had any hesitation. Vent popped right out with screwdriver. 1/2" drill bit, then 9/16, then tap. The hole is pretty close to the edge so I tried to work the drill away from the edge when I drilled the holes. No problem.

[JMortensen]

Pulled the diff oil pump out and decided to start on a mount. Immediately noticed a ton of play in the shaft. Not many parts in there, so I took it apart. Wasted. I guess I'll have to get another pump.

Oh, and my wing looks like UPS lost it.

FML.
 

 

[JMortensen]

Apparently youtube shorts are not just short youtube videos that go to your own channel. Oops. I put a couple of videos on my diff pump fail on there, and apparently they're out there getting viewed by people who want TikTok kinds of videos. Now one has several hundred views and 7 likes. LOL.

EDIT--Good news is the guy who sold me the bad pump agreed to refund me, so at least I didn't lose that money. 

EDIT 2--Found another seller with a better looking pump, and a seller with a rebuild kit for these pumps. So I bought the pump and the rebuild kit, hopefully this one is in good shape and it will get fresh bearings and be ready to go before installation.

Edited March 15, 2023 by JMortensen

[Ironhead]

Just to add my $.02....

 

I installed a diff cooler with an electric pump and electric fans during the build of my car.  I also have a diff temp sensor, and the pump/fans are set to go on when diff oil temp reaches 240 F, and goes off when it's down to 220 F.

 

I am running an R200 short nose with Giken LSD with the Giken oil.

 

In street driving, even in 100 F weather, it never goes on.  Diff temp stabilizes at about 210 F.

 

On track, with 20 minute run sessions, the diff just barely reaches 240 F at the end of the session.  The system usually switches on just as I am entering the pits, cools the oil to 220 F in a minute or so, and switches off.  This was the case even during a 93 F track day.

 

So I am wondering, for my purposes, if diff cooling is even needed.  The oil would cool anyway as the car sits between track sessions.  On street it's a complete non-issue.  The Giken people said their diff oil is fine up to about 270 F.  Obviously it would be needed for endurance racing or long track sessions, but neither is me.

 

So I read all the machinations here about diff coolers, and thought I should mention that I am considering removing mine, just in the interests of simplicity and lighter weight.  The pump, cooler, mounts and plumbing probably weigh 5-10 lbs.

Edited March 29, 2023 by Ironhead

[JMortensen]

That is interesting info. And you're V8 swapped too, which is one of the reasons I really felt I needed it. Might be a bunch of wasted effort here. Wouldn't be the first time. LOL.