if you want to get technical, because its spooling later, it is affecting hp and torque downlow.

i know what you guys are saying though. i had my fair share of experience with clogged exhaust systems, leaking pre turbine etc.

the only time it would affect the peak HP would be if its affecting the actual ability for the vehicle to build or hold boost uptop.

 

I ordered the Manifold to turbo and manifold to head gaskets to install. The probably is not reaching boost, target boost is reached with MBC. Just hope this leak is the cause to my Car not making HP. If this is not it then I don't know what else to do, I have no boost leaks, timing is perfect, perfect turbo and tune. Just wish this is the culprit. Have you seen lose of HP with a pre turbo exhaust leak? I'm at 340whp on pump and should be close to 400 with my setup.

 

I had the same leaks on my Evo, both of those gaskets. It really messed things up way slower and fuel cut.

 

I think this car has a boost leak or leaky bov.. not all boost leak test methods will reveal a leak. if boost leak was done by removing maf or air filer and bov is recirculated you will not catch a leaky bov. just because someone told you they did a boost leak test doesnt mean they did it right.

 

^If you pull off the entire intake pipe and connect your tester to the turbo you will be able to spot a leaky BOV as itll still be connected to your UICP however will now essentially act like a VTA BOV rather than a recirculating it back into the intake.

 

+1 to this, i would personally change the bov its prob opening prematurely causing power loss i can vouch for this as i experience a similar situation.I had the stock 9 bov and when i did cams and injectors car only picked up abt 6 whp and it broke my heart.I changed the bov to a forge rs and i had to back boost down as car was boosting way more than 28 psi which it was not going pass before.
short story retune the car and made 403whp and 395tq vs 359whp and 357tq.
I hope this help and you find your prob good luck.

 

If the intake is an open element sucking form the engine bay, it's essentially an EGR valve when you have a leak like that. Boost goes higher, but oxygen content is low and it fails to make power.

I’ve seen open dump tubes cause 10% losses on the dyno because of this.

 

I just tested it now and it peaks to to 28psi then drops to 25psi

 

I guess I could change it out, I don't know if its normal but when it's building boost the blow of valve sputters air out but under full boost its closed.

 

A properly working bov at WOT should be able to gradually hold boost until it reaches a maximum number of psi. Boost can spike to a higher psi but after the spike it will level off and stay at a stable maximum.

 

very good point.

some open dumps tested on dyno lost power. but gained 3 mph at track.

 

The power lose on the Dyno as the car is obviously stationary and not having the 00+ MPH winds moving around and through the car. You also lose power on a Dyno from heat soaking almost every cooling element.

My Dump really helps make some top end pull and helps scare the **** out of unsuspecting morning commuters at 7 AM.

 

Needs a bigger back housing

 

I thought I would share the Stock Manifold to turbo gasket and the new Grimmspeed gasket I am replacing it with. It was broken in different places and the middle small piece was missing.

 

At first I was freaking out thinking the missing piece in the middle broke while I was removing it and fell into the turbo, but then I noticed on the turbo housing the different colors do to the heat was different on the center so that piece has been missing for a very long time.