Race Breather Setup
 

what breather setup should be run on a turbo race setup. races are 20 mins long so i don't think there will be a need to return oil to the sump. should a pcv still be used to evacuate or a simply vent to atmosphere via a catch can? or something else?

Thanks

I killed the PCV, I run a -10 line from the turbo-side of the valve cover to the small Jeg's can with steel wool stuffed in the top. I have an insanely low amount of blow-by and I accumulate about 2oz of water/fuel in the can after 2-hours of track time...and I'm over-estimating.
https://www.miataturbo.net/attachmen...ine=1330807345

that's how i have it at the min. just wasn't sure that was enough. guess i am just over thinking it.

Depends entirely on the power level, but at some point you will either need a quality ($$) air-oil separator with a gravity drain and a quality vacuum source, or a separator+vacuum pump setup ($$$), or a dry sump ($$$$$).

power level is around the 300whp level. FM bottom end, fettled head, GT2871. nothing crazy. seems to have very little blow by.

what about running pcv with a separator between the pcv and the inlet manifold and a separate catch can on the exhaust side for when under boost?

We're going to separator/vacuum pump on all our engines. We'll have a prototype system in few weeks. If it's something we can produce at a reasonable cost, we'll either add it to our site or give you the drawings and buy them from you :)

Vacuum pump FTW.

If I could do over, yet again, I would do a vac pump. Or a dry sump.

are there any decent 12v vacuum pumps available that would suit the purpose rather than something belt driven? seems to be plenty available but will any of them be any good for this?

I think you can buy diesel vacuum pumps from summitracing. Would that do the job?

not sure... has it been tried?

no, not exactly, but its a vacuum pump. They use them for brake boosters usually, I think. So its the same idea! I thought about it, but I am NA and I am not exactly racing here, so I figured it was overkill.

cant see why it would not work but there must be a reason they are not used regularly.

not exactly the biggest issue before. I think up until recently, most FI worries was about reliability and tuning (I can't really say for sure, as I am new to the miata game compared to most around here).

As you can see, Emilio is considering a setup with a vacuum pump at this time. As higher priority concerns have been taken care of, I think people have more time to dot the "I"s and dash the "T"s sort-of-speak.

Anyways, for now I would listen to what Hustler said on this one (or try your hands at a vacuum setup).

OHhh, before I forget. There is some non-miata relevant information on this:
http://www.sr20-forum.com/informatio...d-edition.html

http://forum.diyefi.org/viewtopic.php?f=24&t=357

There's a reason why you run your AN line from that side of the valve cover, right?

Yes, it puked oil out of the left hand side in that pic when he tried it.

The baffles on the passenger side don't work so well and they end up puking lots of oil.

Belt driven pump or electric?

Here's the vacuum pump that I'm using for my set-up:
http://cn1.kaboodle.com/img/b/0/0/1b...=1322360428000
Obviously I put my name on it.

Belt. Using the OEM damper with a 4 rib and tensioner off the drivers side down low. Other potential variation is a 6 rib with our new billet dampers S/C version.

I wonder if belt and pulleys get involved, isn't it better instead of a vacuum one to add a real oil pump and go dry sump? It would be a bit more expensive but at least done right.

You wonder if the more expensive and complex alternative is higher functioning?

You'll have to spend time on designing pulleys, brackets, vacuum regulators, etc.

The comment was if you were going to spend all that precious time on R&D why not do it with dry sump pump ;) Somewhat more expensive but your engine will be happier

The only cons is that the drysump total weight would most likely be higher than the traditional setup with vac pump. Now is the weight penalty worth it performance wise ... :)

Having just done a custom dry sump setup in my car, I'd probably go the vacuum pump route. It just makes life easier as far as plumbing goes and the stock oil pump with some BE gears does a great job.

Now if we didn't have BE gears available and were having this discussion, I'd say dry sump all the way to get rid of the gear failure point.

I was all excited till I read this. That area is pretty tight with the Rotrex and tensioners.

I would like to see some posts on dry sump systems, and how people designed and administered them.

administered in low doses only.

Did you lower the engine? Dry sump is great for preventing oil pressure loss (under braking in the case of the miata) but the biggest reason pro teams I work with go dry sump is vehicle dynamics. You can drop the engine several inches in many cases, providing quantifiable benefits for a full race vehicle.

At present I still have the msm PVC valve dumping who knows how much into the intake. The driver side port was dumping into the msm separator which was dropping about 1 quart per track weekend into the intake. I put a valve on the return of the msm separator to see if oil was coming up the return pipe. This didn't change the oil dump rate. Not running much boost, leak down and compression good. Probably going to go with hustlers setup before looking at vacuum pump. Basically, the stock setup is not very track friendly once you drive past 1.2gs.

By the way most vacuum pumps I've seen like to run at about half the engine rpm. If the stock damper is used the pulley on the pump itself would have to be huge (twice the size of the crank pulley).
Maybe the better choice is to make a small pulley which bolts on in front of the OEM crank pulley and drive the pump with a tiny belt?
Or are you using some high rpm pump?

Come down to the shop and check it out in a few weeks. BTW, where are the pictures of your car?

I'll resend the email

Not really feasible in a Miata, either with an LS or the factory BP - the proximity between the oil pan and the steering rack makes lowering the motor difficult/impossible. Even with a dry-sump pan, there just isn't room to significantly lower the motor in the chassis.