Turbo Problems...
 

Hey everyone! I just put a DIY turbo kit in my 97 Miata. I went with the Voodoo box (I know its crap but I got a good deal) and 305cc supra injectors. Im running a T25 Garret turbo with a custom stainless manifold and downpipe. After putting everything on and turning the car on it sounded great. Everything appeared to work but when I put any load on the car the boost gauge wouldn't move into positive pressure. I hooked the boost gauge to the intake manifold and put a T fitting and split it and ran the other end to the Voodoo Box. I thought it would be a boost leak so I checked my piping and everything was nice and snug. I was wondering if anyone else had a similar problem and figured it out.

yes

Get a boost leak checker. Just because your hoses are tight doesn't mean you don't have a leak.

You either have a boost leak, a leak at the boost gauge (still a boost leak), or a junk turbo. Do you know the condition of the turbo?

How's the condition of the engine otherwise? Any issues or maintenance done recently?

WG isn't closing or you have a boost leak. I'm assuming you've taken the most cursory of diagnostic steps (i.e. "does turbo spin") before posting a thread here.

I had the turbo looked at by a professional and he said it was good to go. I also rebuilt the engine in the Miata so it has all new internals. Where would I get a boost leak checker?

I check the WG and yes the turbo does spin lol.

https://www.google.com/#q=boost+leak+checker. I'm a wizard, I know.

Please try to be nicer to the new guy.

I got mine here: Boost leak checker

Homedepot high HP turbo accessories:

Oatey 2 in. Gripper Mechanical Plastic Test Plug-33401 - The Home Depot

do you hear the turbo spooling when you floor it? do you feel any power gains in the car?

or it simply doesnt boost and no added power and turbo noises?

honestly I haven't floored it because I figured out the BOV I bought wasn't working so I took that off and have stopped until I get one. but I did bring it up to around 2000 rpm and didn't really hear anything. I made sure to let the throttle down slowly so that no damage was done to the turbo after I didn't hear the BOV. Once I get I new BOV i'll update the thread and let you guys know whats up. Thank you all so much for your help!

Wait, you only took it to 2 k ? Well that's probably your problem.

Well, you won't get any boost feathering the throttle at 2k, you're not supposed to be in boost until you floor it at 3k rpm.

Be a man, floor it. (As long as tune is decent).

Not saying take it to red line, but floor it from 3 to 4k rpm and you will see if you are making boost.

Your bov might be fine, you will never hear it feathering throttle at 2k.

Stop granny shifting and start double clutching lol

Double clutching? What the hell are you driving, an 18 speed Kenworth?

Hahah, I should have known.!

Really, really dumb question here but... Did you hook up the vacuum line to the BOV? The right port of the BOV? How you doing the BOV is not working?

Were you actually driving when you brought it up to 2k or just sitting reving in the driveway? You aint gonna build boost with no load...

What does load have to do with anything? The engine is still putting out exhaust gasses and spinning the turbines, load or no load.

Turbo spinning doesn't necessarily mean its making pressure above atmospheric. Your fuel map depends on load and unless you have a hell of an inefficient system reving it in neutral will not flow enough exhaust gasses for it to build any boost. That's why anti-lag systems were invented.

You will not build boost in neutral.

You dont make boost any time the turbo is spinning.

when engine under load, then you have much more exhaust gas going to the turbo and spinning to turbo MUCH faster than simply revving in neutral or coasting. thus creating boost.

dont think that because you have a turbo then you are now always in boost since the turbo is spinning.

Hey I just read on the web, that you won't make boost in neutral.

and here I thought this thread couldn't possibly get any more moronic

Dennis! There's some lovely filth down here!

But then how does stuff like this happen? For the BOV to open, that means there was pressure, and thus, boost was built, no?

Because the BOV is vac driven and not pressure driven. You don't turbo much do you.

"whoosh" doesn't automatically mean "boost"

I'm living a lie :(

Don't worry, so is OP

not to derail this thread off topic, but since we are talking about BOV's....

I have an HKS vent to atmosphere bov, so if i understand this correctly the valve is always open in VAC and closes in boost.

so basically the engine is sucking in non filtered air and potential debris through the bov? unless i have a recirculating bov?

Yes, but you should adjust the preload so that its only open on high vaccum and stays closed on idle.

I've honestly not seen many people actually get stuff inhaled into engine through a bov. Esp if it's high up and not near the belly or something.

But yeah, if you're worried about it, some people install little filters onto bov's

I imagine you'd have to be off roading or doing something pretty drastic to get that much stuff flying around in the engine bay

Not exactly, as long as the spring is set up correctly on the BOV. There is pre-load on the BOV that prevents it from sucking in air.

(I was going to draw something but I don't have the time)

Thanks for the replies.

I dont think my BOV is adjustable, i dont see any adjustment screws or nuts on it, so i might just throw a little filter on it.

im not worried about debris, but more so little sand particles that i find all over my engine bay from florida driving.

my bov is right under the 90 degree bend coming off the throttle body

https://www.miataturbo.net/attachmen...ine=1465415562

https://www.miataturbo.net/attachmen...ine=1465417185

Spring 'should' be keeping it closed... could always place your hand in front of it at idle :dunno:

I picked up a greddy fv to prevent this, made a huge difference with MAF control on my xede.

So I have a question about the idle speed control valve. Do I run that into the intercooler piping before or after the turbo? I have it right before the throttle body right now but I was just curious if I needed to run it somewhere where there would be a negative pressure.

The original BOV I bought wouldn't open at all. I did many tests and even tried to push it in with my finger, oh well it was $15.

The new TurboXS BOV I got sounds amazing and works great, the guy I bought it from had one just like this one and sold me this one because he didn't like the color haha

I went ahead and took the car out today to see if the problem had went away. I took all the intercooler piping back off and made sure that all the connections were secure and then reassembled the piping. The car still isn't producing any power. Even at 4k, which I would think the turbo would be producing some kind of power, the boost gauge doesn't even move past 0. If I really get on the throttle the boost gauge will go to about 1 psi but then will drop which leads me to believe there is still a boost leak. I did get the intercooler used so im going to check tomorrow to see if there is any visible signs of a hole or something. Any thoughts?

Take the pipe off the turbo oitlet, start the engine and verify that the turbo is spinning. Then disconnect your wastegate diaphragm and actuator arm, and wire the gate closed. Be certain you know what way is open and what way is closed.
Have you pulled the oil drain tube and verified with the engine running, that the turbo is getting and passing oil?
did you ever take the intake manifold off? If so, did it get the correct gasket? Is it sealing properly?

There isn't a lot to this mystery. Chase down every Avenue. It's just a fancy air compressor,

Do you have an adjustable wastegate actuator? Is the wastegate preloaded right? Is the wastegate door completely shut with some preload? Get some photos of your whole setup; turbo, piping, bov, etc...

You connect your iac to the same pipe that connects to the throttle body.

Please post pictures of engine bay, charge pipes, and intercooler.

Specific attention to turbo with various angles, intake manifold with various angles.

It may or may not be. It could be adjustable with a spring change. Either way, I doubt you will have an issue.The only time it should be opening is when there is excess pressure in the pipes and the throttle is closed. By the way - I don't see a vacuum line going to the top of the BOV, but I could be missing it.

im still in the build process, the car is on jack stands and there is no line currently going to the BOV.

This weekend i will finish running all the vacum lines and tidy up everything, and then all i will have left before i hit the road is depowering the steering rack FM style.