Dont know how much room is under there, but it you wanted more boost (and steady), why not switch over to a external wastegate - Weld the wastegate flap shut on the turbos and weld on a Tial 38mm on the exhaust manifolds.

 

For what real benefit, all that does it add a lot of cost for no additional power, better to add higher poundage actuators imho, that will achieve the best power result at a much lower cost.

Peter

 

Pretty tough to weld on cast iron....you have to be REAL good and REAL careful. I had to weld, re-drill and tap a greddy TT manifold already and I had to have a cast iron specialist do it for me. They actually have to put the part in a kiln to get it super hot before they can weld on it. If you don't pre-heat it ...it cracks like nothing.

 

OK. This is my final attempt.

I think I will get the 5-10 pound actuator, fit for a T2. I will adjust the actuator to roughly 8.5 lbs, with a pump, off of the car. Then, with the Unichip output I will be able to modulate the control solenoid to obtain controlled boost anywhere between 8.5lbs (0% duty cycle) and 17lbs (100% duty cycle)? I think this is exactly what I would like to have - the ability to turn the boost down for every day driving and then a 'high' boost setting. I would imagine the Unichip would have to have separate maps for each setting, but I'll let the tuner figure that part out.

 

OK, I lied, once last question, just out of curiosity. Peter, you say the APS actuator is 6.5lbs, but what is its adjustable range. I've noticed looking for new ones that the range is typically 5 lbs or so. If I could just bump the APS supplied actuator up 2 lbs I would be right where I want to be. I know this is a long shot and would probably have been brought up already if it is possible, but its worth a shot!

 

I will have another attempt at explaining this boost control situation with the APS twin turbo system, hope this information makes the issue clearer for you.

The maximum boost pressure that's possible from the stock APS/Garrett boost control actuators including the electronic boost control bleed we utilize including APS test pipes and a zero restriction exhaust system is 12 PSI maximum.

if you were not going to use a electronic boost control system (we do utilize electronic boost mapping in the APS twin turbo system) and you wanted to run say 12 PSI turbo pressure then you would need to install 12 pound boost control actuators - this assumes that the total exhaust system has zero back prerssure as we do have with the APS true dual exhaust system and test pipes.

If there was any back pressure in the exhaust system you're using then you would need to install even higher poundage boost control actuators to achieve 12 PSI boost pressure, hope this helps.

Thanks

Peter

 

Last time I was used HKS EVC II Boost controller
now I try to remove APS Unichip and replace Greddy e-manage
and right now I had a e-01 Boost Controller ...

 

OK, I think we all understand the concepts of the actuators. (If not, please read the thread over again)

How do you "adjust" the actuators "with a pump"? What kind of pump do you need, and what do you hook up the pump to?

Thanks

Chris

 

On the Forge Actuators, you should be able to hook them up using the same reference point that the APS instructions list off the lower throttle body duct which is a positive pressure reference, no vacuum. Contact Angel or Mike at Forge Motorsport and they should be able to custom make the actuator rod for this application using a T2 size actuator body similar to this one. Just reference that I sent you and they may expedite the process since I used to work with both of them. I have a couple APS kit installs coming up so maybe I will adapt the Forge actuator to fit one of them.

 

Jesus, this is sounding like a monster pain in the ***.

Sweet, some people say "just switch the actuator", some say "switch the actuator and adjust it with the swedish mystery pump", and then now we need custom parts machined..

I guess I will call Forge up and see what they have to say.

Thanks

Chris

 

Use a mity vac pressure pump like this one, http://www.toolsource.com/ost/produc...F0G8AH4B500439

Disconnect the line running from the boost solenoid down to the t piece that feeds both actuators. Install the pump on the open line to pressurize the actuators. Make sure both actuator rods open at the same time. Easy if you have a friend to use the mity vac and you put each hand on an actuator rod. Thread each rods tension in or out as needed by disconnecting the wastegate arm, turning the turnbuckle, and then reattaching.
I just got done setting up the actuators on a '05 twin turbo chevy SSR we finished up this morning. At 12psi with very similar dual ball bearing turbos to APS' we should see about 625rwhp on the new LS2 engine with an auto tranny. I have a set of Forge actuators waiting if we need to up the boost.

 

Just for reference, actuators are built with a wide variety of rod geometry, length, bends, etc... Forge can build the rod just like the actuator that APS is using. It is simple when actuators are used with straight rods and you just cut them to length but when bent rods are used it is usually meant for clearance of something. This is a VERY EASY task for some of us which is why APS leans toward knowledgeable dealers who can handle these things in house during an install or tuning session as per customer build specs.

 

I asked APS about this....they cannot do 2 maps....only 1 currently with this version of Unichip.

 

I may have missed something, but I think I remember Peter saying on a different thread a while back that running more than 12 psi boost on the stock APS turbochargers wouldn't really give you much more power from the boost increase itself (without upgrading other parts like heads or something at the same time). I perceived that that meant that going much over 12 psi was kind of getting out of the efficiency range of the stock APS turbos and so you'd be running into the law of diminishing returns. So Peter, is there really that much potential power gain from running much more than 12 psi on the stock APS turbos (even if you upgrade the stock APS fuel system in order to do so)?

 

Interesting. It was my belief that a few maps could be done on this version of the unichip computer, toggled with a sort of mechanical switch.

 

That's what I thought as well. Here is the PM I recieved on the topic:


Hi Steve, it's Peter here good to hear from you. We don't have the computer ability right now to have 2 different sets of performance maps stored in the same computer, you see it's not just a matter of changing the boost control map, we would need to change many other maps at the same time.

When you alter the boost map from say 8 to 12 PSI both the ignition timing and air fuel ratio maps need to alter at the indentical time, otherwise you may detonate the engine to death in a worst case scenario.

In other words you need to have maps with specific ign timing and air fuel ratio to suit the 8 PSI boost map and then a completely different set of maps (ignition timing, air fuel ratio and boost map) for the 12 PSI turbo pressure, does that make sense to you? Hope I have not confused you.

It is our plan to have this capability in the future, mainly to have performance maps to suit 91, 92, 93, 94 and race octane fuel, it's possible that we may be able to store up to 5 different tuning maps then, each map will control boost, air fuel ratio and ignition timing, in total 15 different maps (5 Times 3).

Hope this answers your question and I hope that I have explained this in a way that you understand, if not let me know and I will try again.

Thanks

Peter

 

They hit there stride around 16psi, what was discussed is that beyond 16psi they run beyond ideal mass air flow. So there is still still significant extra power beyond 12psi with a built LB. With mild cams and minimal headwork should top out just under ~600rwhp on 93, of course the default fuel system needs a little upgrade to get to this level as well. The 500cc injectors at 58psi top out ~12psi with the OEM redline.

 

So when will this new version of the Unichip that can allow you to store 15 maps be available?

 

I am sure it will be a year or two away if ever. The way these cars change every 3-4 years I don't see it being a high priority for APS.

 

Forge will make actuators for these turbos but it will cost $180 per actuator, and take 4 weeks to manufactur. Sweet.

Chris