Well yesterday on the dyno the red was hitting 31psi and falling to about 25-26psi... Do you think by tightening up the wastegate it would possible hold the spike to redline

 

is that on Meth?

 

The nature of the turbo is to fall off in boost up top. If you force it to hold more boost, it's just gonna spit hot air.

 

Q16

 

What psi you pushing on pump gas? tapering to?

 

perhaps it is the nature of the actuator and not turbo to taper the boost at high rpms. Maybe it just needs more preload. Do you guys think a forge will hold more boost at the same actuator settings?

 

Did you check the WG preload?

My Red came with no preload on the WG actuator, the metal tab slipped on and off the pin easily until I tightened it 3.5 complete turns.

 

The forge should help and will be more durable as well. We have held over 30psi to redline with the red without "blowing hot air". Our red has a extreme amount of porting done to it though.

 

Using a Halman or other MBC can result in some taper since they cannot completley remove all the air pressure off the diaphram of the actuator. Increasing preload can help this some. Dropping to 25psi is underachieving if you are giving it all there is onthe controller. Of course a leak in the charge air system will result in this also. If you knew your turbo RPM then you could tell if the turbo was maxed out of not. That would also tell you if you were overspeeding the turbo and feeding a leak and ending up with a boost falloff from that.

 

No. Made for high PR's.

 

I like the sound of that

 

Well what type of boost controller would resolve this a electronic? I have no boost leaks that I can hear with the pipes filled to 30psi. The hallman I could definitely go higher than 30psi, I still have another 5-6 full rotations approximately before its maxed, and I over rotated it before and it buried it past 30. I will try to increase the preload and see what happens

 

i am not sure how much porting will help with holding 30psi to redline. I guess someone has to test a red before and after porting to see if it helps with taper.

Also how should the EBC or MBC be connected to reduce taper with the red? Through the BOV line or turbo nipple directly?

 

In order to get an internal gate to start closing or maintain position at high flow, you need to really drop the pressure at the actuator diaphragm. Either an electronic setup with a solenoid that can achieve a 95%+ pressure drop (most CAN'T), or maybe a manual WITH the factory or aftermarket BCS after it to reduce pressure further at 6500+ RPM.

If you put a large enough bleed hole in the manual, you tend to spike badly.

Using a pressure source pre-IC will in itself cause a 1-3 psi taper because of the total system pressure drop (all pipes, bends, IC, etc.) at high RPM/flow rates, but the actuator will react quickly and not spike. Using a manifold boost source tends to react slower, spike a bit, and not have a natural pressure drop at high flow rates.

A quick and easy test would be to use boost pressure sources, pre-IC, and somewhere near the throttle body (NOT the BOV line, you DO NOT want to bleed any pressure off the BOV) and see if this reduces boost taper. Experiment with restrictors between the two pressure sources.

 

Heres our boost plot from our red on 110oct.






This is on the stock ecu, with a forge wga, and GM solenoid.