i wonder if anyone else ran brad penn...i like it

 

There are quite a few Puerto Rican drag racers I've talked to out there that hold your same belief that it's not crank case ventilation or the lack there of causing it however I've never seen one of their cars without a huge line coming from either the oil filler cap or neck to a big catch can. I'm going to vent mine like rx72c and see what happens. Yes my air fuel ratios are rich and I will be dialing that back down a bit but I think some ventilation upgrades as apposed to half of what the stock setup came with is much better and needs to happen anyways. rx72c seems to have had the same problem with his car before venting modifications so I will take his advice being that he has never steered me in a wrong direction.

 

I can assure you that poor crank case ventilation will cause oil coming up your filler neck, i have seen it so many times. Having the incorrect level oil in an engine(i.e too much) will cause oil to come up as well.

If your mixtures are very rich. Dial them back. But your issue is crank case ventilation.

 

Well actually the issue is lots of gas in the oil... About a quart over in a week or so.

 

Is your OIl level rising?
What are your fuel mixtures currently at?

 

yeah they are rising bad! I mean within a week or so I'm about a quart over and it's gas!!! I'm running on boost at around mid to high 10's and off of boost around the 12-13's.

 

did you unplug that vent on the middle iron yet?

 

Sure did. I've also just bought 2 1.5" filters and am about to order two 1.5" npt nipples to weld or tap into the oil filler tube and oil cap.

edit: Maybe I should ask this again because maybe it got lost somewhere in the 5 pages of posts. Can improper crank case ventilation cause gas to get into the oil? I don't really have a big problem with oil coming out of the nipple at the top of the oil filler tube. My problem is that I get a ton of gas in the oil. Probably about a quart over within about a week or so of driving.

 

I'm not suggesting that - high fuel dilution is more or less a fact of life with turbo rotaries, all you can do is run a high viscosity straight weight with a good additive package to compensate for the inevitable thinning effects. I may try Brad Penn, looks interesting - right now I'm running Valvoline VR1 racing SAE 60

Yes....

 

poor crank case ventilation can cause this yes. lean your mixtures up.

 

Will do, I'll let yall know what happens. Do you have any pics of your breather filters installed?

 

This is my breather system.. my Oil pressure stays at 60psi.. Tapped the oil cap,. ran it into breather,. down back into the (2nd?) return in the oil pan from the stock twins.

sorry if this isnt what you are looking for, i just jumped in this and you asking for breather system pictures.

 

^That's a nice looking set-up. have you had your oil analyzed recently for fuel dilution?

 

No,. I should sometime, I havent seen anything out of the ordinary tho,.. and my Oil pressure stays at 60psi, even under load.

 

/\/\ you do realise that up to 91,, engines are supposed to make 70 psi by 3000 rpm
and that FD is a notch higher again

and there is something wrong if above 3000 rpm it can never get to the point where its forcing the reg open at 70 psi
- no matter what was done to the crank jets-


i think you have a rather average gauge,,or some very contaminated fuel and a **** oil pump
---------------------

as for the OP,

and am i correct if i believe its an 850 / 1600 combo on a half or full bridge at 40 psi ( no engine vacuum ) base ?

if so,, what is your normal idle vacuums ?

can you also disclose your staging information please

please tell me you dont have rev stage at 1350 or 1500 rpms and vac stage at -10 or -5 ( inch Hg )
i have suspicions you are staging almost straight off idle ,, and basically running most of the time in post staging

this will amount to basically being nearly always in 4 injector operation,, with extremely poor fidelity due to the injector sizings

mazda intended staged injectors so you could take the first pair out to around 75 % duty with all the fidleity that gives before bringing in the other pair

with 850's it should be 2500- 3000 rpm and around 2 psi ,, before even a bridge runs them short of duty


also,, shift that cruise threshold so that it actually represents a vacuum you will see whilst cruising
if handset 2.5 D tuning
then this should be around -10 inch Hg and the WOT tune threshold should be at -5 inch HG or 0 psi

 

THanks for the input man I'm going to get all my microtech setting and post them on this page so you can see them and let me know if this is what's going on. I am no tuner so I really can't say for sure what's going on but I know I had my car tuned by kilo in florida but I'm sure he usually tunes for track rather than street. It was running rich at something like 10.5:1 in wide open throttle. But like I said I'll post the tune here. Also you are correct 850cc and 1600cc injectors. with a half bridge.

 

bumpstart. If you want to stage 1700cc injectors are 3000rpm. Go right ahead. Will always be a flat spot. Stage them early and you wont have a flat spot.

10.5:1 is probably alittle rich unless your running 25psi+boost.


Posting your microtech settings here aint going to achieve anything. You need to get your car on the dyno and make sure your cruise settings are dialed in ok with at least 13.5 or leaner afrs in most areas. And on boost dial it back to mid 11s on your higher boost settings and low 12s in low boost areas.

 

I think your oil pressure will stay up even with high fuel dilution. Does it smell like gas? You should send it in, it's only $25, and post the result in the "UOA" thread in the third gen section. I have a hard time believing adding a catch can and breather really decreases fuel dilution all that much, but maybe it does....I still think it's blow-by past the oil control rings under high boost and rich mixtures

 

had the same issues till i did this, drilled and tapped the by the oil filler tube for a -8 fitting and ran one from there and the other from the top of the oil filler neck. haven't had a problem since. i would have atleast a quart or two overfull in the sump from dilution within 1000 miles

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