Stock boost?

[xblzr03]

Re: Stock boost?

I think you might be a little confused. The stock actuator open at 8-9 psi when connected to a vacuum/boost source, (the stock turbo has this port). The ECM controls the boost above 8-9 though information from the MAP (ie what boost level its at) and a boost solenoid. The boost solenoid is between the actuator and vacuum/boost source and doe so by bleeding off to delay the opening of the wastegate.

So if you ran just the actuator, it will open at 8-9 psi and this can be adjusted a little bit by the length of the wastegate rod. The manifold has nothing to do with boost control unless it has a big hole in it (ie this would create little to no boost)

An aftermarket boost controller would go in place of the boost solenoid and ECM.

Yeah I had to go back and edit my last post.... had something else on my mind.

So what could I do to keep the max boost at 7-9 psi? Boost controller and a new wastegate spring?

 

[dgoodhue]

Re: Stock boost?

No boost controller, just run a line from the port off the turbo to the wastegate actuator.

 

[xblzr03]

Re: Stock boost?

Okay I have been thinking about it... I know the stock 17c will be fine for my application FOR NOW, but would I be better off just putting the GT35R on it from the get go?

I have been thinking about keeping the boost real low.... but seing that my weak points are the cast pistons (which will be switched with lower compression Keith Black forged pistions) and the lack of the nodular caps (which you guys have). I found out this guy TJ put 14 lbs s/c into a heads, cam, NO intercooler, and meth injection and the timing chain wasn't up to the task and sent the valves crashing into the pistons. Which means while I am in there I might want to put a cloyes timing chain on it.

Someone said the rods are a weak point, but here is a comparison shot of them with the 350 rods

 

[schrgds]

Re: Stock boost?

Part of the issue with running the same boost that we have been with the superchargers (up to 14psi) is that a turbo is putting boost pressure on the motor where it makes peak torque. 8psi at 3000 rpm will give much better results than 14psi at 5500 rpm since the engine makes peak torque at 3000-3500 and much less at 5500. A turbo will be harder on the engine since its boost on top of peak torque.
Think of the turbo as being more like a nitrous hit. There are some guys running 100-125 shots with some longevity (Sebast). In reality thats only about 260-285rwhp maybe 300rwhp depending on base mods.