rx7learner

She runs for 10 mins and begins to smoke. The drain is the suspect because I shut her off for a few mins and start her up again while shes still hot and she doesnt smoke... till about 10 mins later when the oil starts to back up again.

This is the second S4 turbo and I got this one from Robert so its good. I have a crushed ROPR and shimmed front and get like about 35psi oil pressure when warm at idle. I have a restrictor in my oil feed and my drain is the stock S4 drain line cut with 3/4 hydraulic line down to a 1/2 NPT barbed fitting in the front cover. The drain hole in the front cover is 1.5 inches lower than the drain outlet on the turbo. I mistakenly disconnected the drain while running and it was loaded with oil (I mean it gushed).

Is a 1.5 inch difference turbo drain to front cover good enough?

Is 35psi at idle too much flow even with the restrictor?

Robert the ebay AN fitting for the oil feed has an even smaller restrictor than the one you sent me but it still doesnt help the situation.

Any help appreciated.

yetterben

Pics would tell a little better story here man. Other than that it sounds like the drain is sufficient but hard to tell without pics. I have no restrictor in mine and it smokes just a tad not bad enough to want to fix. don't think Bad83 has a restrictor either. My idle psi is like 35 as well.

rx7learner

heres some pics. Theres a shot in there that shows my front cover in relation to the turbo. It's all set up in the car now.

http://rx7learner.pictiger.com/images/

rx7learner

OK I "ported" the bottle neck barbed fitting and re-cut a new drain line with less of a bend and the smoke seem very slight. Wonder if the turbo also might need to run through a couple heat cycles after storage... None the less onto the next issue...

OOOH anyone thinking of doing this please dont fall for the "just slot the holes in the turbo manifold and slap it on that 12a"

yetterben

Badazz that rocks!

steve84GS TII

I run 100psi of oil pressure, with no restrictor and I get no smoke from my S5 TO4B, with the same drain setup.Restrictors are only really needed on ball bearing turbos that just need a film of oil,unlike plain bearings that need a pressurized oil wedge.

A used turbo is a used turbo.No matter who you got it from,it could still need new seals/bearings,you just cant know what the last owner did to it, and for how long.

680RWHP12A

agreed, but i did drive the car and knew the history of the turbo before removing it for an upgraded full t4 setup.. it didnt smoke at all.. pull the turbo and see if there is oil in the exhaust manifold or in the downpipe and report back.. thanks

rx7learner

I'm assuming theres oil in the exhaust manifold because after shutting down there seems to be smoke coming from that area.

I will confirm tomorow.

680RWHP12A

if there is oil in the exhaust manifold then your motor is the problem, i would rather it be the turbo since thats the easier fix
if its in the downpipe only then its the turbo

rx7learner

Seems like the smoking has gone away... at least for now. I finished the setup but I'm not seeing boost the gauge is always on vacume. Not sure why or whats the best way to troubleshoot. When I rev the engine and put my hand over the bov I feel a gush of air after releaseing the throtle.

Also I idle at around 13 AFR and it leans out big time up top in the 16-17 range (new wideband). The fuel pressure regulator is set to start at 5 PSI but since the fuel regulator is not getting boost it doesnt increase.

My jetting on the mikuni is still set for a stock port 12a and my motor is now street ported and hopefully boosted soon. Any recomendation on jetting?

680RWHP12A

well give us your current jetting them we can make reccomdations.. glad the smoking has stopped for now

yetterben

make sure there is no leaks in the piping or carb hat!

rx7learner

pilot jet = 62.5
main jet = 200
main air jet = 240

rx7learner

Just not to leave this open ended. Robert pointed out that my jetting is wrong and almost reversed. I've ordered the correct jets from Wolf Creek. I've been driving hard NA with those jets without a wideband for over a year. That wideband pointed this issue out right away.

It pretty much reinforces that NA's dont pop running lean that easily but I wonder how much I lost in performance?... it was actually hitting 20 AFR way up top...