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Hello, it has been some time since I've been on here, i recently added a turbo to my ls swapped obs chevy. It will not make boost, i figured it was to do with the cheap WG i used so, i bought a turbosmart WG60 with the 7psi spring installed. No luck with seeing any boost and now, for whatever reason it became so hot in that area that the nylon lines melted. This was never a issue until the swap to the
this is all while driving around town a short distance, coolant temp is normal (208*+-) with good afr.
I have a AEM tru-boostX set at 20 percent duty cycle. I do not appear to have any exhaust leaks, despite the shity welds lol, also, i am currently using a 50mm Vsracing BOV. This is my first FI vehicle and i am still learning. I've googled as much as i can, but I'm at the point i feel i need someone to hold my hand, figuratively speaking. i do plan to have a professional tuner look it over on a Dyno, but i feel it sould be making boost before I go to do that.
also, the motor is healthy, and built for boost. The turbo is new, 80mm VSR, Vband flange, cast GM truck manifold on DS, and a cast Log style on the PS.
Intuition would have me assume that the melting would be a result of excess exhaust flow. Assuming the turbo is good, since it's not making boost we can deduce exhaust is flowing around the turbine and not across it. What could cause this? In my mind, there are two likely causes- 1) the wastegate is open because boost pressure exceeds spring pressure or the flow of exhaust gas is otherwise unrestricted by the wastegate (e.g. WG door cracked/fell off) or, and I'm not trying to offend, simply explaining my train of thought, 2) something is installed wrong/backwards or there is a mechanical failure.
It's not making boost, and I'm pretty sure you would have noticed a missing door. It's tough to say how'd I'd do it without seeing your setup and what was most readily accessible, but you can find the leak- oh, by the way, there's a leak- by using the exhaust of a shop vac (WITH A CLEAN FILTER) to simulate either exhaust gases or intake flow and see where it goes. MY hunch is that somehow the WG is being mechanically held open perhaps by something that binds only when installed, or you have boost/vacuum lines crossed somewhere.
Sorry for the rambling, I have no business being awake right now.
Intuition would have me assume that the melting would be a result of excess exhaust flow. Assuming the turbo is good, since it's not making boost we can deduce exhaust is flowing around the turbine and not across it. What could cause this? In my mind, there are two likely causes- 1) the wastegate is open because boost pressure exceeds spring pressure or the flow of exhaust gas is otherwise unrestricted by the wastegate (e.g. WG door cracked/fell off) or, and I'm not trying to offend, simply explaining my train of thought, 2) something is installed wrong/backwards or there is a mechanical failure.
It's not making boost, and I'm pretty sure you would have noticed a missing door. It's tough to say how'd I'd do it without seeing your setup and what was most readily accessible, but you can find the leak- oh, by the way, there's a leak- by using the exhaust of a shop vac (WITH A CLEAN FILTER) to simulate either exhaust gases or intake flow and see where it goes. MY hunch is that somehow the WG is being mechanically held open perhaps by something that binds only when installed, or you have boost/vacuum lines crossed somewhere.
Sorry for the rambling, I have no business being awake right now.
I'm not offended, I'm Thankful for you taking the time to explain.
If the exhaust pressure is over powering the mechanics of the WG, would putting a larger spring be the only solution to correct this? I'm a little confused, i was thinking the boost controller would aid in controlling that. Although, I do understand if the turbo isn't producing enough psi in the first place, it can't.
About the Boost controller, I'm using a 3 port mac valve, fitting off the housing, to a 'T' going to port 1 of the mac and to the bottom port of the WG. Port 2 from the mac to the top port of the WG. And port 3 of the mac is vent to atmosphere.
Turbosmart shows "method 2" off the housing to port 2 of the mac, from port 1 of the mac valve to top port of WG. Port 3 of the mac to the bottom port of the WG.would this be a better way?
FYI, the exhaust pipe that exits from the turbo is a 4" that is a fender exit. Overall length is approximately <24".
Method 2 as you state will help in spool as it cuts all pressure to the bottom of the gate while the solenoid is on.
I have tried that method but it was harder to dial in with the heavier springs i have in mine...with lighter springs it would really help almost like a 4 port valve.
Are you sure exhaist isn't leaking at the vband for the wastegate melting those lines?
Is your gate dumped to atmosphere? And if so can you hear it dumping when you get on it?
Method 2 as you state will help in spool as it cuts all pressure to the bottom of the gate while the solenoid is on.
I have tried that method but it was harder to dial in with the heavier springs i have in mine...with lighter springs it would really help almost like a 4 port valve.
Are you sure exhaist isn't leaking at the vband for the wastegate melting those lines?
Is your gate dumped to atmosphere? And if so can you hear it dumping when you get on it?
It doesn't appear to be leaking, and i didn't mention but bases on when the large amount of smoke was coming from under the hood, they didn't melt until half way through the 5 minute drive.
The WG does dump to atmosphere, via pipe routed to under the truck. Unfortunately, since the exhaust exists on the same side, i have not noticed if it is dumping out of the WG
Method 2 as you state will help in spool as it cuts all pressure to the bottom of the gate while the solenoid is on.
I have tried that method but it was harder to dial in with the heavier springs i have in mine...with lighter springs it would really help almost like a 4 port valve.
Are you sure exhaist isn't leaking at the vband for the wastegate melting those lines?
Is your gate dumped to atmosphere? And if so can you hear it dumping when you get on it?
It doesn't appear to be leaking, and i didn't mention but bases on when the large amount of smoke was coming from under the hood, they didn't melt until half way through the 5 minute drive.
The WG does dump to atmosphere, via pipe routed to under the truck. Unfortunately, since the exhaust exists on the same side, i have not noticed if it is dumping out of the WG
I'm going to suggest again that you either take a smoke machine or the shop vac exhaust and blow air into the exhaust upstream of the turbo. For all that to melt I strongly suspect the wastegate was mechanically open, whether commanded or not. If it is not open then you are dumping pre-turbo exhaust directly at the melty spot - and a LOT of it if you're still achieving essentially zero boost.
**Back to your MAP table- and I'm not a tuner - but typically absolute pressure starts at 0 being a complete vacuum. and ~14.7 atmosphere. That's how it would read on a scan tool anyway.** - See note.
**I could delete, but I'll own it- I misread the MAP table, ignore this portion of my comment.**
I'm going to suggest again that you either take a smoke machine or the shop vac exhaust and blow air into the exhaust upstream of the turbo. For all that to melt I strongly suspect the wastegate was mechanically open, whether commanded or not. If it is not open then you are dumping pre-turbo exhaust directly at the melty spot - and a LOT of it if you're still achieving essentially zero boost.
**Back to your MAP table- and I'm not a tuner - but typically absolute pressure starts at 0 being a complete vacuum. and ~14.7 atmosphere. That's how it would read on a scan tool anyway.** - See note.
**I could delete, but I'll own it- I misread the MAP table, ignore this portion of my comment.**
i will take your advice with the shop vac, tomorrow after work. Btw, you mentioned upstream of the turbo, would blowing air in at the 4" exhaust give the same results?
The chart i have picture is showing VE table and the numbers represent the percentage between commanded and actual. Ideally -5 -0- +5 is the goal.
Update: because of how my small shop-vac exhaust, i ended up using the air compressor, i did not find any leaks.
I added a 3lbs spring, now a total 10lbs spring pressure. I also routed the boost controller to match method 2 i mentioned in a prior text.
Now, at 3-3,500 rpm the boost psi was 11.4. I adjusted the duty cycle to 70% from the 20% resulting in no improvement in performance. Made it worse. Which i feel has to do with the tune.
I plan to get it dyno tuned, but i want to get everything where it needs to be before the schedule Dyno tune.
questions i have,
how much does the tune effect when the boost comes on?
Update: because of how my small shop-vac exhaust, i ended up using the air compressor, i did not find any leaks.
I added a 3lbs spring, now a total 10lbs spring pressure. I also routed the boost controller to match method 2 i mentioned in a prior text.
Now, at 3-3,500 rpm the boost psi was 11.4. I adjusted the duty cycle to 70% from the 20% resulting in no improvement in performance. Made it worse. Which i feel has to do with the tune.
I plan to get it dyno tuned, but i want to get everything where it needs to be before the schedule Dyno tune.
questions i have, how much does the tune effect when the boost comes on?
Kfxguy,, thank you for your input. I have about a month before my schedule Dyno tune, I'm a little nervous i went with to big of a turbo. At the time i was getting a good amount of suggestions to go that route because of the engine displacement (398ci).
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Boost issue 
