New DP, low boost

[Shimy87]

Installed a 3 in DP, set waste gate to have about 1/32 inch tension to get onto pin. Have RJC boost controller maxed out and only pulls 19 LBS boost. with stock housing this setting would produce 26 LBS boost.  Stupid question but if I adjust wastegate arm to 1/8-3/16 tension will it increase boost or is the boost controller going to override that setting?

Also related question, new DP has the large 1.5 inch puck. hole in turbo is 1 inch, whats the advantage of increasing the size of hole in turbo?

Thanks

[earlbrown]

Sounds like your wastegate puck isn't sealing against the housing. The MBC should be depriving the wastegate of any pressure signal if it's working right.


Tighten the rod and see what that does.  If boost stays the same, it's the puck.

[Steve Wood]

set the wastegate rod tension to an 1/8"

[Scoobum]

I'd tell ya' to ditch the boost controller and adjust via the rod...but that's not the cool way of doing it...so disregard what I just said.

You can put a thin smear of orange silicone on the puck and apply it against the exhaust housing to check puck alignment. Leave the hole at 1 inch...anythin g larger and you may not be able to go much over 25 PSI. There's some physics involved...Ste ve can explain. If the puck doesn't align...RJC sells a shim.

[Shimy87]

Thanks guys, I will check alignment, set it to 1/8 and go from there!

[gusszgs]

I've tried 2 boost controllers and neither one did I care for. One of them was the RJC. I run my car just set up the stock way and just control boost via the actuator rod and works ok for me.

[earlbrown]

Manual boost controllers have there place but they aren't a 100% sure shot every single time.

If the faster spool causes the tires to blow away, the can can go slower.  On the other hand, if the wastegate has to be stretched to 90% of it's available travel, the MBC can solve boost creep from not enough curtain area.


With any luck, the low boost issue here is because the puck doesn't have enough preload and the exhaust pressure is forcing it open a little.

[Shimy87]

Well it finally stopped raining so I got it on the road. TPS sweeps nicely and I don't notice any miss ( must have just been paranoid before). The puck covers the hole pretty evenly, long story short, through different attempts even with the adjusting rod maxed out and the RJC controller maxed out I only get 20 LBS boost. I have zero exhaust leaks. When it cools off I'm going to pull the RJC controller and take it apart and see if something is wrong there. It builds boost very quickly, but wont go over 20. Its a new HD actuator. I have always had this issue with boost. The most I have ever gotten this car to make was 24. What else can I check?? How do I run without the controller, if that would allow it to make more boost? Car sounds and runs better than ever, I just need to get this sorted out and I should be able to hit my goal of 11"s easily

Thanks for any help!!

[Scoobum]

Hook it up tuner style. Run the vacuum hose from the port on the turbo to the actuator. Toss the boost controller...a nd use the rod instead. If the puck is sealing...you should be able to run just about any boost you want.

[gusszgs]

Yep, I'd pull the controller off. Got mine hooked up factory with a HD actuator and MINIMUM boost is 18psi

[earlbrown]

tie the wastegate shut with wire and CAREFULLY give it the gas.

If you can only make 20PSI at WOT with the gate fully closed, that will eliminate all the controls and hoses as culprits.

I did that at the drag skrip one time since I had an unknown header leak. Tied shut I could only make 15 pounds at the time.

[Forzfed]

What Earl said!

Also, do you have some insanely ported heads?  There are guys that only get 24psi out of a TE44 but run high 10's.

[1 RARE T]

Plumb a different boost gauge into a vacuum line.


I wonder if your existing has a leak somewhere?

[Shimy87]

Thought about this all night. Took it out and ran tuner style with the rod set to about 3/16 pull to pin....only hit 14 LBS boost. Either I have an exhaust leak ( doubting that cause I was anal when putting it all on) or the puck isn't sealing. It lines up but maybe it isn't pushing tightly flush to the turbo and not sealing the hole? This afternoon I will be checking all exhaust connections for leaks and then the puck situation. Thanks for the help as always 

[Steve Wood]

Wire the puck closed as Earl suggested...if it does not make boost, then you have a leak most likely