Builds boost slowly

[RyAn007]

My car builds boost really slowly, and does not feel like a boost leak because it doesnt bog at all, and it all happened just earlier today. It will get to about 3 pounds and all it does is run slowly, not worse, just want to get some ideas, i plan on putting the old exhaust manifold on because this one sounds like its leaking, but any other ideas?

 

[viperlp01]

Well no mod list but i will try

1. Wastegate arm fell off making the wastegate flapper stick open creating no/slow boost
2. Extreme pre-turbo exhaust leak or crack
3. Wastegate flapper slide out of its spot leaving an open section for the exhaust flow to make its way out.
4. Turbo is shot and no longer working right....

 

[mindset]

Fill out your profile with your mods. It helps us answer your question.

Since it sounds like your boost guage is stock, the stock ones are garbage. Get a real one to tell you an accurate about of boost.

If your building boost slowly, it could be an exhaust manifold leak.

 

[lazyazzdaddy]

did you check the wastegate?

 

[GRAVEDIGGER]

Check to make sure your wastegate arm didn't come off. If it did, it would not be able to hold the flapper door closed and would not let you build any (or very low) boost.

 

[RyAn007]

Mods list, 16g, 2g mani and 2g o2, dejon tool short route fmic, mbc at 15 psi, safc1, ultralite boost and pyrometer. I went out and looked around, wastegate seems to be in place, checked arm and its still connected, exhaust manifold has a little leak, which I was going to deal with but was the same as it was previously when it boosted fine, so its not excessive. I am going to assume its the turbo because it does whine a tad bit, Im going to check for play and if thats bad ill swap to my 14b, but if that does not work I will get back to you guys to see what you think.

 

[RyAn007]

Update, just checked for saft play, tad bit side to side but nothing ridiculous, I am going to assume that its the exhaust leak at the manifold, but I would love to get some input on any other possibilities out there I might not be thinking about. Plus I did a compression test for safe measures and its all at 150 so that is not the cause. And while it buiilds boost it kind of tops off almost at about 4 psi.

 

[GRAVEDIGGER]

Although it doesn't sound like it, I'd do a boost leak test just to make sure. Another thing that might be worth a before you just yank the turbo/manifold is to take off the o2 housing and take a close look at that wastegate flapper door and make sure it is closing and being held closed and sealing good etc.

 

[RyAn007]

I did that before, the flapper is in the rightspot covering the hole and is sealed, and its not crcked. I am not going to change the turbo just yet because of the thing not having much shaft play, I am putting my old 1g exhaust manifold on, and I guess I will try a boost leak test, but if it were a boost leak its would be ridiculous, its runs to 4.5k no problem full throttle only at 4 psi, just feels slower, no difference in how clean it goes. So I am banking on a manifold problem or a turbo problem, the wastegate itself couldnt be bad, or how would I go about testing if it were.

 

[GRAVEDIGGER]

It could be, but as long as the wasgate spring has your wastegate flapper door held in the closed position normally, I would think it would hold more than 4psi before it opened. You could always hook up pressure from an air compressor and feed it to the wastegate and see when it opens. If it opens real quick with almost no air pressure then it could be the culprit.

 

[RyAn007]

Thats what i was thinking, but it would be less troublesome to throw my 14b on there because that sounds like its a pretty elaborate setup i dont have the time to actually setup.

 

[DSMeclipse4G63]

Not boosting or very little boost was a symptom of my turbo failing. I would say fix the exhaust leak and go from there. But to be perfectly honest, unless the leak is substantial then you may have a bad turbo.

 

[jrohner]

Pre-turbo exhaust leaks make a lot more difference on spool time than a boost leak. I've had massive boost leaks before and built boost just as fast, but when I had a leak between the turbo and manifold it took me more than 1000 rpms more to build full boost.

Fix your exhaust leaks, then check to make sure your wastegate flapper has some pressure pulling it shut by pulling the pin and taking the actuator arm off; if you don't have to pull the actuator arm slightly to put it back on, put washers between the actuator and compressor housing to space it out.

My friend's 1g sounded like supercharger wine when the j-pipe was leaking at the compressor housing, and that is a pretty common place to have a boost leak.