draw through turbo white smoke

SamT · Posted: Sat Jun 30, 2012 2:53 pm Post subject: draw through turbo white smoke

Im working on a 2332 with a draw through turbo. Turbo is cb performance, carb is lowbugget. I don't have any other engine specs.
It runs good in my shop, just a hint of dark smoke when you rev it. Fuel pressure is 5.5 with a pump from lowbugget . Guy says it goes to puffing white smoke and runs like a dog in the dunes. I pulled plugs and they are on the dark side. Also the intake pipe had some oil in it when I slid it off the turbo.

Where do I start to diagnose this?

Hotrodvw · Posted: Sat Jun 30, 2012 2:55 pm Post subject:

Water in the intake via condensation or? Overly rich causing white smoke?......I've had it happen with a stuck float. Too much oil in the oil feed line, to turbo, needs restricted. Did it suddenly develop, or has it always done it?
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'67 Sunroof
Eric

78x94 with IDA's....oober fun

Horsepower is an addiction........Addictions cost lots of money!

Hose & Fittings

SamT · Posted: Sat Jun 30, 2012 3:01 pm Post subject:

Its a new engine a guy I know had built. Guy who built it broke it in and test ran it. Oil line comes out of the fuel pressure sender with a maize of fittings and a braided hose into turbo, then back into fuel pump blockoff. I pulled the return line and fired the engine for 5 seconds or so and got a 6 inch diamayer pool of oil on the floor.

HRVW · Posted: Sat Jun 30, 2012 3:40 pm Post subject:

I have a draw thru Turbo.

Is the oil hose directly going from the engine case to the Turbo? as mine goes thru a adapter between Carb and Turbo preventing a icing problem.

I would check the braided oil hose for internal swelling from the HOT engine oil.....along with the drain hose into the fuel pump b lock off may need a larger nipple to prevent oil backing up into the Turbo.

Braided hose may look okay on the outside as mine did but still have some restriction on the inside.

Oil in the intake means a sucking of oil due to lack of proper oil flow (happened to me untill I replaced the braided intake hose) and my oil burning blue smoke stopped.

Just a thought.

SamT · Posted: Sat Jun 30, 2012 4:01 pm Post subject:

About what size should my oil lines be?

skills@eurocarsplus · Posted: Sat Jun 30, 2012 5:09 pm Post subject:

inlet can be 1/4 or so, it's the outlet that has to be huge, i would say 1/2 plus for the turbo return
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Hotrodvw · Posted: Sat Jun 30, 2012 9:49 pm Post subject:

I"ve run a -3 line with no restrictor. I' ve also run a -4 line with a .035" restrictor....either way works well. I ran a 90* adapter in the oil feed port on the turbo, and drill/tap the bottom of the addapter for a grub screw. Then drill the holse you want, now you can change it up if you need to.
_________________
'67 Sunroof
Eric

78x94 with IDA's....oober fun

Horsepower is an addiction........Addictions cost lots of money!

Hose & Fittings

Splitdog · Posted: Sat Jun 30, 2012 9:52 pm Post subject:

It's either carbon seal in the turbo, or valve guides. Ask me how I know. My turbo oil feed has a restrictor-it's like 1/64".
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Der Blitzkrieg Kafers

Hotrodvw · Posted: Sat Jun 30, 2012 9:55 pm Post subject:

Yup................once we determine the oil line size, we'll know. If the line is larger than it should be, than fix it first. If it's find, look at the seal.
_________________
'67 Sunroof
Eric

78x94 with IDA's....oober fun

Horsepower is an addiction........Addictions cost lots of money!

Hose & Fittings

miniman82 · Posted: Sun Jul 01, 2012 7:38 am Post subject:

White 'smoke' is actually unburnt fuel going out the tailpipe, it's probably pig rich so check your jets. If it's nasty smelling blue/dark smoke, that's oil nad you should suspect the turbo first.
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SamT · Posted: Sun Jul 01, 2012 11:53 am Post subject:

Inlet line is 1/4 inch metric brake line , it appears to have a restrictor. Outlet is 3/8 hose.
Turbo ia the second new one the guy installed. First one puked oil out exhaust, this one seems to be sending it into the intake.

Is there a step by guide to tuning this carb? Also what should I set the timing at? Compression is supposto be 8.5 and boost set at 10.

mcmscott · Posted: Sun Jul 01, 2012 12:13 pm Post subject:

1/4 inch metric? 3/8 return is way too small

SamT · Posted: Sun Jul 01, 2012 12:19 pm Post subject:

Well not exactly 1/4 inch but real close. Im gonna swap the return and see what happens. It has a pretty restrictive looking elbow on it too.

Shouldn't be valve guides, motor is supposto be new and by a reputable Sandrail shop. But im not a fan of all the aviation sealant slopping out of everything. Looks like some rednecks built it.

miniman82 · Posted: Sun Jul 01, 2012 1:13 pm Post subject:

It's easy to go overboard with the aviation sealer, probably won't cause any hard as long as it didn't get into any bearings or bearing return slots. 3/8 is way too small for turbo return, I think mine is 5/8.
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Build thread: http://www.thesamba.com/vw/forum/viewtopic.php?t=212747

modok · Posted: Sun Jul 01, 2012 3:01 pm Post subject:

yeah, I think you'll want so smaller than 1/2", including the ID of the fittings

Sharig1979 · Posted: Sun Jul 01, 2012 3:26 pm Post subject:

It does sound like your return line may be too small. I run a 5/8". This might be the reason that this set up is on it's second turbo. That hot oil must move as freely as possible from the turbo.

I'm going to say that before you go any further guessing on where you are at with your setup you get a wideband O2 sensor and gauge. For 175$ you will know exactly where you are without guessing. This will point you in the right direction tuning the carb. If you are rich now and you just start swapping jets to lean it out it could end badly.

What type of fuel pressure regulator are you using? Fuel pump? Is the lowbugget carb have a Percy's Adjust a jet on it?
_________________
1969 Beetle, turbo 1915
~118 mph on the salt at WoS 2012, 7k in 3rd, can't wait to figure out how to drive that engine on that stuff.
1972 914/4, 1.7
1991 GTI 1.8 8v, 4speed

Splitdog · Posted: Sun Jul 01, 2012 3:47 pm Post subject:

Mine blew white/gray smoke when I revved it, and it was the valve guides. Valve job cured that right up!
_________________
CH3NO2.

Der Blitzkrieg Kafers

Sharig1979 · Posted: Sun Jul 01, 2012 3:51 pm Post subject:

It could very well be the valve guides but if this is new build that shouldn't be a problem unless new means bolted together old parts.

If he doesn't know where he sits with his carb I don't want to be the one who says to pull the heads if it is as simple as going to smaller jets, or if he has the adjust-a-jet just turning the needle.
_________________
1969 Beetle, turbo 1915
~118 mph on the salt at WoS 2012, 7k in 3rd, can't wait to figure out how to drive that engine on that stuff.
1972 914/4, 1.7
1991 GTI 1.8 8v, 4speed

SamT · Posted: Sun Jul 01, 2012 4:09 pm Post subject:

Ok, swaped the return line and no more smoke. But I still have a nasty flat spot at abou 2000a rpm and then it takes off eventually. Im talking flat spot from he'll.

Timing is locked at 24 btdc. I notice plugs were gaped wide, like. 040. Is that ok?
And yes it has the lowbugget adjustable jet carb and their fuel pump, I checked pump at 6.5 psi or something like that.

Sharig1979 · Posted: Sun Jul 01, 2012 4:37 pm Post subject:

Pugs typically aren't gapped that wide but depending on the plug and engine setup I've ran wide gaps. I can't tell you in your application if it's a good idea or not.

Not enough information to tell you where to go on the "flat" spot. Could be too little fuel, not enough, either way with your timing too.

I'm going to say it again. Get a wideband AF setup. You will never get the most out of that engine without it.
_________________
1969 Beetle, turbo 1915
~118 mph on the salt at WoS 2012, 7k in 3rd, can't wait to figure out how to drive that engine on that stuff.
1972 914/4, 1.7
1991 GTI 1.8 8v, 4speed

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