Is my turbine and compressor wheels too small?

[rabbitman]

no, it wont really work.
cause the turbo has nowhere for the boost to go, so it makes some boost, then surges until it can catch back up with its self. run a boost pipe from the turbo directly to the manifold. make it with hoses you know are good and have no holes in them. then run it again. you should have more than 4 psi.

Yeah I'm thinkin' I should put the regular TD intake on and try it with shorter hose, I doubt shorter hose has anything to do with it though.

i was only getting 4psi on my old gtd engine, it turned out that the actuator wasn't bolted to the turbo so the exhaust valve thing in the turbo housing (can't think what its called) was just blowing wide open. not sure if this could help you in any way but it might be worth looking into to see if there's any issues with this.
also my pump timing was out a fair bit on that engine and i still got 18 psi with it.

Sounds like you had a regular wastegated turbo, I'm tryin' a vnt. According to everyone that's put one on a 1.6 it is supposed to make 15+ psi with the vanes wide opened.

BTW, at 4psi I think I can feel a slight increase in power, so slight I'm sure nobody else would notice it but it feels like after I floor it power comes on just a bit more......or my mind made it up out of desperation .

[Rabbit on Roids]

no, it wont really work.
cause the turbo has nowhere for the boost to go, so it makes some boost, then surges until it can catch back up with its self. run a boost pipe from the turbo directly to the manifold. make it with hoses you know are good and have no holes in them. then run it again. you should have more than 4 psi.

Yeah I'm thinkin' I should put the regular TD intake on and try it with shorter hose, I doubt shorter hose has anything to do with it though.

if you already have a gasser intake manifold on there, leave it alone, just make sure the gaskets seal up really good. i had a teeny tiny boost leak at the head, right between the intake. last time i had my intake off, i put a super thin coating of black RVT on there and i gained power. pretty noticeable.

and as for boost, you should be able to make 15psi with the max fuel screw almost all the way out. my turbo is on its last half of a leg and it still makes 15 psi all the time. yours is not worn out. you should not be able to keep that thing from spooling nuts. when i first turbo'd my engine, i found out exactly how much boost one of these would take before they go *BOOM*. check EVERY GASKET in your turbo system. you have to have a MASSIVE leak somewhere. does your turbo spin super freely? i can blow on the compressor of mine and get it to spin.

[rabbitman]

if you already have a gasser intake manifold on there, leave it alone, just make sure the gaskets seal up really good. i had a teeny tiny boost leak at the head, right between the intake. last time i had my intake off, i put a super thin coating of black RVT on there and i gained power. pretty noticeable.

and as for boost, you should be able to make 15psi with the max fuel screw almost all the way out. my turbo is on its last half of a leg and it still makes 15 psi all the time. yours is not worn out. you should not be able to keep that thing from spooling nuts. when i first turbo'd my engine, i found out exactly how much boost one of these would take before they go *BOOM*. check EVERY GASKET in your turbo system. you have to have a MASSIVE leak somewhere. does your turbo spin super freely? i can blow on the compressor of mine and get it to spin.

arrrrg! I have checked every gasket, plug, the hose. Yeah my turbo spins real easy though I've never blown in the compressor though.

My 3-4psi happens at about 3500rpm pedal to the metal and plenty of blackness, the egt's quickly get up to 1250F and then I let off, I can hear the turbo the whole time...very high pitch whistle.

I'll try some more stuff today and see what happens. Thanks

[Rabbit on Roids]

yea, you should be making damn near 30psi at that kind of RPM. and with black smoke too? you are loosing all your boost somewhere. thats the only posibility. take your boost hose off the turbo and put your hand over it and rev it up, it should blow your hand off pretty easy and at fairly low rpms.

[rabbitman]

yea, you should be making damn near 30psi at that kind of RPM. and with black smoke too? you are loosing all your boost somewhere. thats the only posibility. take your boost hose off the turbo and put your hand over it and rev it up, it should blow your hand off pretty easy and at fairly low rpms.

Are you talking about vanes opened or closed?

I did put my hand over the turbo outlet when I first put the turbo on, I had the vanes opened and it hardly blew air at all.

With the vanes completely closed I can hit 12ish driving but it surges badly, I guess that's what it's called anyways were the boost gauge jumps up real fast? And it's gutless.

At idle vanes closed it'll make about 1psi, when I hit the gas it'll go up to 5psi @ about 3000rpm in neutral.


EDIT: I found a paper towel in the inlet to the airbox, mustuv been there from the PO. This is a gasser airbox so it has two inlets, one for heated air from the exhaust mani and the regular cold inlet. I had the little door set so air could come in from both (it wasn't heated though) the cold inlet is the one that was plugged, I unplugged it and it didn't help a thing .

[Rabbit on Roids]

make it so that you have nothing on the inlet of your turbo. like wide open so you can see your compressor. see if it will boost with the vanes wide open.

[rabbitman]

UPDATE: I have the weirdest problems.  

I removed the intake hose from the turbo and left it hooked to the mani and ran it, with the vanes shut air puffs OUT of the hose If I hold my face a foot from the hose it'll actually blow my hair around. When I rev it the air goes the right way into the intake. The air is going in the hose though, if I plug it the engine will die.
BTW, the turbo blows hard with the vanes shut so I guess that part works.

With the vanes opened all is normal.

When I shut the vanes it hisses pretty loud, I assume it's the exhaust accelerating as it's shoved through the vanes

It appears when the vanes are shut the exhaust mani pressure goes up somehow puffing out the intake

So I wonder if the increased EMP's are leaking through some exhaust valves and into the cylinder when the intake valve is opened before the piston is starting down from tdc on the intake stroke? That's the only thing I can think of. Hope that made sense

The engine runs perfect, starts good and idles nice. Thanks for the help

EDIT: The vanes position don't make any difference in the amount of air coming out, when closed they make the intake louder though.

[Rabbit on Roids]

the vanes should make the idle turbo howl sound faster or slower. i would say you have something seriously wrong with your vane setup or something.

[rabbitman]

the vanes should make the idle turbo howl sound faster or slower. i would say you have something seriously wrong with your vane setup or something.

What I meant was air comes OUT of the intake manifold when the engine's running and the hose isn't hooked up.
The vanes work correctly and the compressor outlet blows real good.

[rabbitman]

Overall the air is going in, like if you could measure the airs movement in the hose it would be like 1 inch out 6 inches in. Like at the rare moment when no cylinder is intaking the air that's sitting in the hose waiting to get sucked in moves backwards out of the hose, then when an intake valve opens it goes the into the engine and when that valve shuts it moves out again......
I don't know if it makes any sense, it sounds so weird yet that's what it's doing.

Could somebody do me a huge favor and disconnect the compressor to intake mani hose and at idle see if the engine appears to puff air OUT the intake?.....Please? Then let me know I'm getting desperate...... Thanks

[theman53]

my N/A would do that until a certain RPM then it would suck like crazy. I noticed it one time reving the engine and my other hand was in front of the intake tube.

[rabbitman]

my N/A would do that until a certain RPM then it would suck like crazy. I noticed it one time reving the engine and my other hand was in front of the intake tube.

Thanks, that works I guess it doesn't need to be a TD to do that, I guess I'll start looking somewere else for my miserable problem. grrrr. I'm gonna do a better air leak check tomorrow I guess. Come to think of it, when boost hits it's max of 2-3 psi I hear a kind of whistle/hissing noise, but I couldn't tell if it's a super high pitch whine or a leak......

[Rabbit on Roids]

check your valve adjustment. there should be no "out" flow on the intake setup. when my valves were really out of adjustment it would do that. and if your valves are mis adjusted, then they wont be able to hold boost. do you have pics of your engine bay? i want to see how you have it set up, and maybe see why it doesnt work right. i have a feeling that your turbo works. and everything else works too, you just need to set it up to work together. are you sure you plugged up every port on the gasser intake off? put the TD intake back on there just to be sure its not the problem. even when i have a pretty big boost leak, i still get boost. only 10 psi or so, but thats better than your 4 psi. i actually had a boost leak ever since i put the intercooler on my car. i always thought i could hear one, but it still made boost. then one day i was messin with my intercooler pipe and i stuck my thumb through it. well, i fixed the hose, put it back on, and my car was a rocket again. god i love it when you shift 2nd gear and burn the tires off, and first gear is kinda useless now if you wanna get on it.

[rabbitman]

Checking valve adjustment is on the todo list

Here's a shot of the engine bay, the blue hose isn't connected to the turbo in the pic, the orange hose is the filtered air.


I'll do a good leak check today.

[rabbitman]

Well I did a very good leak test, first I plugged the compressor inlet, then I removed one of the brass plugs you can see in the above pic.
I used a pressure regulator and blew 10-15 psi's in where the plug was, there are no leaks. But since this was pressuring all of the the cylinders (depending on which valve(s) were opened) I had some leaking past the rings but it wasn't much.

I found this a while ago, http://www.4crawler.com/Diesel/SAE/vwtdsae.shtml , here's the bit I was looking at:

The intake valve has a maximum valve lift of 8 mm. Intake opening is at 5 degrees aTDC and intake closing at 14 degrees aBDC where both timings are rated at 1 mm of camlift. The maximum valve lift of the exhaust valve is 9mm, with opening and closing at 27 degrees bBDC and ~ degrees bTDC respectively. Intake valve clearance is 0.2 to 0.3 mm, and exhaust valve clearance is 0.4 to 0.5 mm. All these geometrical dimensions are identical with that of the 4-cylinder naturally aspirated Diesel engine.

By looking at those numbers it seems there shouldn't be any valve overlap. Today I found that the exhaust valve isn't quite shut yet when the intake valve starts opening, so at the very beginning of each cylinder's intake stroke the air I was pumping in was escaping out the exhaust pipe.....sounds like valve overlap to me.

check your valve adjustment. there should be no "out" flow on the intake setup. when my valves were really out of adjustment it would do that. and if your valves are mis adjusted, then they wont be able to hold boost.

I checked valve clearance also, some were a couple thousandths tight so I loosened 'em, now they are all on the loose side.

BTW, my boost gauge read high, the pressure regulator had a rarely used liquid filled guage on it, when my boost gauge read 14 the regulator gauge said 11.5psi. So I'm really getting less boost than I think.

Haven't tested it yet.