Minimum boost with HD actuator and T70 BB

[turbojimmy]

Hi all,

I recently put a BB T70 turbo on my GN along with an HD actuator. I don't have the stock 'y' installed (the 'y' I have has no restrictor) and I am not using the stock solenoid. My only means of boost control is a bleeder valve - not fancy but it works. With the bleeder the whole way closed boost is around 21-22 PSI. Can't get it lower than that. It's not creeping - if I go WOT it shoots right up there and stays (I ported the housing to work with my THDP puck). Shouldn't I be able to get the boost lower than that (i.e., shouldn't I be able to get it down to around the spring value of the actuator, i.e., 14 lbs.)? I'm not sure I really care as I ususally have the boost set that high anyway but I'm more curious than anything else.

Thanks,
Jim

 

[AKplumber]

I could be wrong but I believe the hd actuators are a minimum 18lb's.

 

[turbojimmy]

I could be wrong but I believe the hd actuators are a minimum 18lb's.

Ahhh.....for some reason I thought they were 14 lbs. If they're 18 I think the boost I'm seeing makes sense.

Jim

 

[TurboDave]

You should be able to get it down close to what the internal spring is rated at.

Not sure why yours wont go any lower, other than maybe it has something to do with the manner you've chosen to control boost.


AKplumber
There is no set minimum for HD actuators. It all depends on what spring it is built with.

Mine for example was built with a 14# spring, and if I turn my boost controller down to minimum I can get it down to 14.5-15#

 

[D's GN]

Does your bleeder valve have a ball and spring? Chances are it does, and the way they work is the more you screw it in the more boost you have.
Try backing the knob out to the point where it stops or it is about to pull out completely and lock it off.

 

[D's GN]

I don't see less than 18lbs with my HD actuator.

 

[turbojimmy]

You should be able to get it down close to what the internal spring is rated at.

I assumed my HD actuator was a 14# spring. If it's really 18# then that explains the 21-22 PSI. I have a stock actuator that I can bend up to work with the T70 to see what happens.

Does your bleeder valve have a ball and spring? Chances are it does, and the way they work is the more you screw it in the more boost you have.

Try backing the knob out to the point where it stops or it is about to pull out completely and lock it off.

Mine's not spring loaded, it's really basic. You wind it out to bleed off boost, wind it in to close it off. I do have a spring-loaded deal (like RJC sells) but I haven't installed it yet.

I don't see less than 18lbs with my HD actuator.

I think that's probably what my 'problem' is. Probably an 18# spring. It's no big deal, but I was wondering why I couldn't get the boost any lower.

Jim

 

[Scott Atk]

How much "pull" do you have on the adjuster? Lenghten the rod so there's only about 1/8" of pull and see where your at.

 

[TurboDave]

How much "pull" do you have on the adjuster? Lenghten the rod so there's only about 1/8" of pull and see where your at.

I can't believe I forgot about that suggestion.

As Scott said. adjust your actuator rod until you only need to pull it out by about 1/8" to get it back on the swing arm.

 

[turbojimmy]

I can't believe I forgot about that suggestion.

As Scott said. adjust your actuator rod until you only need to pull it out by about 1/8" to get it back on the swing arm.

It's pretty far out - I'm not sure I have much left on the rod. I did need to pull it pretty hard to get it hooked up. I'll have to check that out. I can't believe I didn't think of that either. Sometimes you forget the easy stuff.

Jim