need a little help with boost issue
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On The Tree
Joined: Jan 2015
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need a little help with boost issue hey guys, my car was being tuned earlier today and ran into an issue. The tuner I'm using knows his stuff, but he mostly tunes supercharged setups. my setup is l33 engine, huron speed v2t4 kit with precision 7675 turbo. pw46 wastegate just running off spring pressure. we started put on a 6lb spring, and it makes 6lbs for a second and then goes down to 3.5 lbs. so then we tried a 9lb spring and it made around 9 lbs for a second and went down to 6lbs by 6500rpm. I was thinking a boost leak at first but was unable to find anything. any suggestions on some things to check? any input greatly appreciated
Last edited by boostedxs; Jun 23, 2017 at 06:43 PM.
Thread Starter
On The Tree
Joined: Jan 2015
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car is making decent power, for a second then drops to ****. possible wastegate malfunction? we've checked for exhaust leaks and the system is tight no leaks found. otherwise everything is great, engine responds well, fuel pressure is stable evething else is good engine wise. Oh and since I'm only running off spring pressure all I did was run a line from the turbo to the wastegate, could that line leaking cause this?
Exhaust pressure is blowing the gate open. You can run an mbc or get an ebc. I'm running a 3 port solenoid with a manual boost controller, gives me the ability to run on spring pressure or double spring pressure. So on a 12lb spring I can run 12 lbs then flip the switch and run anywhere from 12 to 24 psi depending on how I have the controller set.
Thread Starter
On The Tree
Joined: Jan 2015
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I actually have an eboost 2, I just haven't hooked it up yet. all I was wanting to do was break the engine in on lower boost and then turn it up from there. I didn't realize this would be an issue with a brand new wastegate/springs. is this a common thing to happen when running off spring pressure alone?
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On The Tree
Joined: Jan 2015
Posts: 123
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Thread Starter
On The Tree
Joined: Jan 2015
Posts: 123
Likes: 0
FYI mine is referenced to the intake and it still does it. All the setups ive seen do it. I'm sure on a well optimized setup with a 1:1 back pressure ratio it would stay at the spring pressure but most setups are not 1:1
What type of dyno first of all? If it doesn't have something to load the roller you will drop boost everytime. My cars do the same thing on my buddies dyno but holds perfectly steady on the road.
