Just a thought but could it be the pressure drop across the intercooler and charge piping causing the discrepancy in measured pressure? In other words if the actuator is measuring pressure at the compressor outlet to determine its state (open/closed) after the pressure drop across the intercooler core and chage piping that could drop 1-2 PSI. A perfect example is the External gate on the Turbonetics single turbo. It has a 9 PSI spring in it and if you measure pressure at the compressor outlet will show 9 PSI. At the plenum however you see ~8 PSI of pressure. Just a thought. I've seen this in other cars as well. Thats the main reason most intercooler manufacturers will rate the CFM of the intercoolers in conjuction with thermal efficiency and pressure drop of a given flow rate. If Sharif or someone else is interested Turbonetics makes both single port and dual port actuators as well that you could try...

 

That could be an issue, I know Tig used a dual port actuator on his setup, and it relieved his boost drop..But he is also making 14-16 pis if he romps it in 4-5th gears at low RPM's...The problem with "testing" actuators on the APS kit, is the time and effort it takes to swap out the actuators themselves..Its a PITA..

 

Thats true. I must say I have never worked on an APS TT car myself. Have seen one or two in the air but certainly didn't even begin thinking about the labor to swap actuators. I wonder if tigs issue is the duty cycle setting on his boost controller. That could certainly lead to temprorary spikes. Well either way it will be interesting to see what you guys discover.

 

if i had to deal with the problems that the TT guys have as far as switching actuators, i think id just put up with the problem, that is one thing good about the single, i can swap actuators in less than 5 minutes. i can adjust the arm in less than 1.

 

hey man

found tears in both of my forge actuator diaphrams... that would explain the overboosting! played around with them today, will have more time to work on the car wed and see what the boost registers at...give me a call, interested to hear your ideas

TODD

 

I put Forge Actuators in a customer APS TT system and his diaphrams were tore after maybe 1000 miles of use. Don't feel too bad about it, it must be a pretty inheritly weak design - because I was extremely careful with them and then that happened.

 

I give up.

Anyone want to trade their Greddy kit straight up for my APS kit?

 

ive been running my forge actuators for a long time now, no tears yet, of course im not running 18psi, but funny thing is they sent me like 4 extra diaphragms.

 

We found BOTH diaphrams to be torn, and were pretty disturbed to find that one of the mounting studs for the actuator body had a "HELIX" coil inserted from the inside to hold the stud in. For those of you that do not know what a HELIX coil is, it is for when you strip out a bolt hole and can not retap it, you would drill a bigger hole and place in a helix coil, then thread the bolt inot that..Now seing how we never had the actuators apart,and they were purchased brand new, one can only assume that this is the way Forged had sent them to us Pretty lame if you ask me.

 

are there any alternatives for the forge actuators?

 

The turbonetics one as posted above, or the ATP Turbo Garrett style ones.

 

one of the studs that hold my actuator on actually stripped/pulled out of the aluminum actuator housing, i had to drill/retap and fabricate my own solution...

forge has been great to deal with customer service -wise, but, this overboosting issue caused me to have to pull my motor and several hours of unecessary labor!!!!

the new diaphrams look beefier as well, hopefully they dont tear, again, both of mine were torn as well!!!

 

can you get these, if so will you ship to Canada please PM I'd rather use these, my motor will be going back in 2-3 weeks.
PM thanks

 

I have poked around an APS TT car some but not with specific regard to space constraints - what do you guys think the possibility is of ditching the internal gates completely, welding them shut, and converting to external gates? Since no one's tried it in this thread and there are alot of experienced folks in here, am I to assume that is not really feasible?

 

We are actually looking into doing this, as we speak..Seems as if it would work.

 

LOL. I made a post about that on page one but nobody said jack squat. From what I've found out, you can use parts from the extreme kit on the standard kit. You just have to weld the gates shut as you said. That's what I plan to do when I build my motor.

 

It does seem it can be done.simply weld a flange on to the rear of the APS Manifolds, and run a pipe down to an external wastegate just like their extreme set up.However welding Ductile cast Iron and Steel can be a bit tricky, the Iron manifolds need to be properly pre heated to ensure proper penetration of weld..

 

I guess the question now is could someone use the APS extreme manifolds and wastgates with the originals kit's turbos (with welded internal gates obviously) I'm going to be pulling my motor and I would really like to have external gates on my APS kit WITHOUT having the buy the extreme kit. Greddy is not an option either.

 

i think it would be easier to just weld the wastegate onto the turbine housing and be done with it.

 

Westpak said the manifolds on both kits are the same with the exception of the flange being welded on the extreme manifold. You should be able to just buy the extreme manifolds and bolt the standard turbos to them.