boostedxs

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

boostedxs

boostedxs

boostedxs

boostedxs

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?

MY_2K_Z

iTrader: (1)

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.

boostedxs

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?

ls3fox

run the wastegate line to the intake manifold it'll make 9lbs and hold it

MY_2K_Z

iTrader: (1)

Yes it's pretty normal. On a 12lb spring I'll spike to 12 then drop to 10.

boostedxs

so basically running from the wastegate to the turbo isn't worth a ****. if I run a line from the intake to the wastgate, do I then need to cap off the nipple on the turbo that I'm currently using?

boostedxs

thank you for the input. what your saying makes perfect sense to me and the data I have goes right along with it.

boostedxs

Oh and what makes the difference between using the nipples on the turbo and using a line from the intake? I'm just trying to understand is all, not being a wise ***

truckdoug

iTrader: (25)

pressure drop across the intercooler

ls3fox

even thow your seeing 6psi on the gauge your turbo is still making 9psi if you refrence from the manifold you'll see 9 psi on the gauge but your turbo might be making 11-12psi

MY_2K_Z

iTrader: (1)

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

boostedxs

Okay so wether I reference from the manifold, or just install my ebc, do I need to cap off the nipple on the turbo?

chiaj144

iTrader: (4)

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.

boostedxs

mustang dyno. it had a load on it othewise we wouldn't have been building any boost at all. manual 6060 trans

Dian

i dont know the gate your using, but if you can limit travel you get rid of the drop and you can have rising boost if you want.

stevieturbo

Every setup is different depending how you configure it.