Boost control issues

[Michael30815]

I am having boost control issues, Just installed a T 66 turbo onto the car I've already ported the hole out on the turbo to 1 1/8 for my Terry Houston downpipe puck, Still can't get the boost to come down under 25 pounds even with the wastegate rod all away out. I have a standard wastegate actuator. What is next to get this under 25 pounds besides going to external, Would like to get the boost 20 pounds.

 

[Michael30815]

Help anybody

 

[LEW_86]

do you have an external boost controller? What is controling boost besides the rod?

Posted from the TurboBuick.Com mobile app

 

[Michael30815]

I had a RJC, it was overboosting before I ported.

 

[Michael30815]

Do you think that may bring boost down now that its ported?

 

[Phoneguy]

Is this a CPT 66 or a T66 form GN1 ?
How big is the wastegate hole in the exhaust side of the turbo?
If it hasnt been opened up, that is your problem, or at least part of it.

Bryan

 

[Michael30815]

Gn1 turbo, and I've ported it on exhaust side 1 1/8 already ?

 

[Michael30815]

Any other suggestions

 

[1fastcobra]

The actuator arm off.
Go for a ride see what happens
If nothing changes. The puck may be stuck closed


Posted from the TurboBuick.Com mobile app

 

[Michael30815]

Puck moves freely, boost still won't come under 25lbs, someone said I may need to go bigger than a 1 1/8 on the turbo exhaust. Any other measurements bigger 1 1/8 that people are using with terry houston down pipe.

 

[huntsg]

I was dealing with this not too long ago (http://www.turbobuick.com/forums/th...ctuator-and-the-bstc-boost-controller.403250/) and you can try to run the car "tuner style" and see if the boost still goes to 25 lbs. My solution turned out to be porting the hole bigger than I already had (I didn't measure it) and making sure the hole was tapered (not on the downpipe side but on the inside) so that there was a smooth flow.

 

[scgnx2]

You could replace the 1.125" puck and increase the ported hole diameter by using RJC's 1.625" version.
http://rjcracing.com/product/exhaust-systems-2/flanges-weld-bungs/

 

[1KWIKSIX]

I don't believe RJC's 1 5/8" puck can be retrofitted into a THDP without extensive machining to the down pipes flange (not enough clearance for this large puck in the mounting flange area of the DP). My THDP has a 1.5" puck.
Check yours as you can hog out the waste gate hole provided you leave at least 1/8" (.125" sealing area for our puck). If you're puck is centred you could open it your hole to 1 1/4" (1.250" ) & still maintain this. Mark the puck imprint with your DP installed on the turbo housing to be sure its centred & sealing. Be sure to radius the inside edges of the opening to aid in exhaust flow.
You may need to purchase an RJC DP with the larger puck otherwise.

 

[Michael30815]

Thanks, I will try and open the hole more to see if it helps. Hopefully it will bring boost level to 20 lbs.

 

[JP112_89]

Don't open the wg anymore. Are u running hose from RJC to turbo nipple and other hose from actuator to RJC?
Don't use the "T" fitting.

 

[Michael30815]

What do you mean by T fitting, I am running RJC like you said

 

[JP112_89]

What do you mean by T fitting, I am running RJC like you said

Okay RJC is hooked up right. Do a nice inside radius inside the wg hole. Picture the exhaust leaving the header and exiting wg hole. Smooth out like 3pm-9pm inside hole... Smooth out the inside but leave the wg hole diameter alone till you try this.

 

[toomanymodz]

Don't port the WG hole any larger than 1 1/8. Try this: run a hose straight from the turbo to the actuator, no T-fitting, no RJC, nothing but a hose.

 

[Michael30815]

I tried running the hose straight from actuator To turbo already, stays at 25lbs, when I use with RJC, goes past 25lbs pounds.

 

[toomanymodz]

I tried running the hose straight from actuator To turbo already, stays at 25lbs, when I use with RJC, goes past 25lbs pounds.

Generally, if the WG hole is too small, you'll get boost creep. That experiment should yield very low boost. Have you tried a different boost gauge? Does the boost go straight to 25 and stay there? (hope you're running some good gas!) or does it creep higher and higher? I'd also try hooking a pressure hose to the actuator with a tire pump (or low-pressure 30psi or less from a compressor) to see if you can visually see the actuator arm doing it's job. Lastly, not sure if you cut a smooth radius on the backside of the hole or not, but that is very helpful. No sharp corners in there.