Off-season curiosity

[scott fairchild]

Ok Apex community, I've already spoken with a few of you about this in the last 4-5 years, but wanted to ask the collective as my development has ground to a hault for other projects.

Has anyone ever run a dry-sumped transaxle in a FF application? I've always wondered why the heaviest oil has a bunch of gears rotating through it? Shop testing showed a repeatable 30-35% increase in how many revolutions the wheels would spin. This was just from evacuating the R&P on a mk9. I realize this may decrease with wheel speed.

The pump could be driven by an electric motor (I was using a DeWalt drill for testing). The transaxle would be lubricated by nozzles in the main case and gear case. Two 'suction' ports are needed (one for R&P, one in the gearbox). Since sensors are not allowed in the transmission, a mechanical fail-safe is necessary. I'd been working on an automatic shuttle- spool valve combo. When pressure is lost, a spring moves the spool, which drains the tank back into the transaxle reverting back to a wet-sump system.

Anyone ever ventured down this rabbit hole?

Cheers,
Scott

[R. Pare]

The Staffs gearbox had the option of dry-sumping it. That was mostly done with the 4 speed version for the FA's, but we had a couple FF and FC customers who got the pump. Yes,it does help - as long as you spray it back to the release site of the gears.

[scott fairchild]

The Staffs gearbox had the option of dry-sumping it. That was mostly done with the 4 speed version for the FA's, but we had a couple FF and FC customers who got the pump. Yes,it does help - as long as you spray it back to the release site of the gears.

Do you think there is much to be gained from an electric pump vs one driven by the power train?

[Rick Kirchner]

sensors aren't allowed in the transmission?

[scott fairchild]

sensors aren't allowed in the transmission?

I believe that's what I read a few years ago. Maybe it's changed or I misread. The only sensor I would prefer to have is a pressure light or gauge.

But if allowed, you could heat the oil in the external tank to further help the first couple of laps

[Rick Kirchner]

I'm trying to figure out what twisted BS SCCA justification there might be for this. I could guess it might be related to some kinds of fears over automation, but I don't get it.

[stonebridge20]

I'm trying to figure out what twisted BS SCCA justification there might be for this. I could guess it might be related to some kinds of fears over automation, but I don't get it.

Traction control.

[Rick Kirchner]

Traction control.

would be just as easy to say "no transmission sensor can provide information to an engine ECU or be used to perform a traction control function"

[BeerBudgetRacing]

Traction control.

IIR gear position too.

[problemchild]

Rules like this are good. It is too bad that more "visionary" rules were not not added in the 80s and a whole bunch of expensive gadgetry we have now would be out of the class. But remember that the SCCA boards of those days were very vendor driven and the classes exploded as there seemed to be lots of racers looking to spend money. The class does not need traction control or dry sump transmissions now anymore than it ever did. Hopefully, now that Scott brought it up. we can add rules to ban dry sump transmissions. Considering what Hewland parts sell for these days, the learning process would be expensive. I know that I am now happy to overfill my wet-sump transmission for the extra comfort it brings me.

[scott fairchild]

Rules like this are good. It is too bad that more "visionary" rules were not not added in the 80s and a whole bunch of expensive gadgetry we have now would be out of the class. But remember that the SCCA boards of those days were very vendor driven and the classes exploded as there seemed to be lots of racers looking to spend money. The class does not need traction control or dry sump transmissions now anymore than it ever did. Hopefully, now that Scott brought it up. we can add rules to ban dry sump transmissions. Considering what Hewland parts sell for these days, the learning process would be expensive. I know that I am now happy to overfill my wet-sump transmission for the extra comfort it brings me.

I agree 100%. Part of my reason for making it public was to either allow someone else to use it, or close the loophole.

In researching this and applying other's research papers on the subject in other applications, it looked like 4-6 more hp was available at the wheel. I didn't get far enough to validate that on track. Each car would have to fabricate its own system which is where most of the risk could occur. Considering what most racers/ fabricators have laying around, I figured someone could make a system for $1200-1500.

I got as far as having a mk9 sideplate 3D printed with viewports, delivery nozzles, suction ports and bench testing. Next steps would've been to make a stand that would turn the input shaft at 6000 rpm, temp paint bearings and gears, hook temperature sensors up to lab-scope, I think the brakes would need to be installed to provide variable resistance and replicate that heat. I've been using an old FF 2 stage pump, but I'm not convinced it's up to the task. Something like a Stock Car Products pump is probably better suited, I'm guessing. Then, the fail-safe system would be verified. Then, if ALL those extra hurdles checked out, the transaxle would be installed in my car for testing. It's probably got another 80-100 hours of development left.

Cheers,
Scott

[s800racer]

I know that I am now happy to overfill my wet-sump transmission for the extra comfort it brings me.

LOL, I thought it was just me - overfilling my trans and giving up wheel hp. I feel better now knowing that a well-respected team owner overfills his cars too!

[DanW]

Popular with a lot of FF drivers here on the left coast.

https://www.redlineoil.com/superlight-shockproof

[billtebbutt]

I have heard tell that some hotshoe dudes looking for that last real edge will drain the gbox oil for a couple of quick quallies. This makes no sense to me, but if the dry sump gives 4-6hp and I assume a drained dump is about the same, I "guess" I could see why someone would try it.... Although the risk of it not working seems silly to take, to me.

Apparently, it is doable with little risk to the gearbox. I don't buy it, but that's what I've heard.

cheers,
BT

[scott fairchild]

I have heard tell that some hotshoe dudes looking for that last real edge will drain the gbox oil for a couple of quick quallies. This makes no sense to me, but if the dry sump gives 4-6hp and I assume a drained dump is about the same, I "guess" I could see why someone would try it.... Although the risk of it not working seems silly to take, to me.

Apparently, it is doable with little risk to the gearbox. I don't buy it, but that's what I've heard.

cheers,
BT

yeah, that sounds super risky, I wouldn't want to risk a gearbox. Properly aimed nozzles could provide better lubrication than already exists to areas like the side plate bearings. Might even help the Kents out of the corners. Done right, it's probably cheaper than a set of canister shocks.

I can remember not that long ago, being nervous about 0 weight oils in street engines that had 4 psi at idle. I was wrong on that one.

[Rick Kirchner]

With polishing, cryo, and the right bearings and clearances, I don't see why not, especially if you monitor temps in a couple of places during development. Might be a costly development though.