67 billet wheel boost control

[MikeL.]

With any of the CEA billet wheel turbos, Q-trim (6768, 6765, 6466), has anyone here successfully managed boost with an internal gate like a THDP, or is that a pipe dream?

 

[bison]

Plenty of control can be had if your engine can swallow 80lbs/min or more of mass flow. So on a 231ci like 27-28psi/5900rpm with a 67cea. That's with race ported heads and enough cam to make the power. If you have average heads and small cam you will need a lot more boost to get over 80lbs/min. If you plan on running less than 25psi and have less than 218*@.050 you are over turboed.

 

[KevinB]

I was able to go anywhere from 18-30+.

 

[jasjamz]

ATR 3" Stainless downpipe and a RJC Mega Puck installed by TurboBuRick. 22-23 pis with minor porting of the wastegate hole. No radius on the hole and a HD wastegate. 6765 billet.

 

[818GN]

. That's with race ported heads and enough cam to make the power.

Can you race port Champion irons like you can with GN1's?

 

[bison]

Can you race port Champion irons like you can with GN1's?

No

 

[SloGN]

See Sig for build info. I have internal gate using a stock springed wastegate rod and I can run 15 Psi with very little creep of maybe 1 Psi or I can run 21 Psi with the.same creep . It normally only creepers by a half a Psi per the fast xfi . Thdp stock puck and on Hell of a radauis on the turbine housing .

 

[northerngn]

I was able to go anywhere from 18-30+.

same here,but only after i opened the hole in the turbo, ported it and added a rjc big puck...

 

[mzunino]

Don't want to hijack the thread but I have a 6766 with the standard waste gate. Ported the hole but still can't get below 22 psi. Have rjc type controller closed totally. Had to grind the flange a little with standard puck, no idea how I would fit a bigger one. Am I SOL?

 

[mzunino]

The idea is to get the boost down to around 16-18 psi. Not sure of total engine displacement long stroker bored .20. Want to run it on street without alky or race gas if possible. Are external gates worth the $$$?

 

[toomanymodz]

Try eliminating the RJC controller so that you're just running straight hose from the turbo to the actuator. That will give the lowest possible boost. If that doesn't do it, then you'll have to re-visit the WG hole. Be sure to radius the opening, putting the carbide cutter down in and giving it nice smooth curves, just like you're porting a cylinder head. The diameter of the hole should be around 1 inch to 1.1 inches. With my old 6765 I could lower the boost down to 12 psi if I wanted to.

I just read your sig "midly ported heads". If that's true, then a 6766 is too much turbo in my opinion. A 6266 would of been my choice.

 

[turboc87gn]

I know i sound like an idiot but what do you mean by radius the opening? I just bought a 6266 and i have a stock motor and an internal gate Thdp.....Im gonna use this now and on my new buildup later on i already have ported irons and a bare block...Id like to use it now at like 18-20 psi and under till i build my new bullet..

 

[toomanymodz]

If you stick your finger into the waste gate hole, you'll feel some sharp corners, especially if you grind the hole bigger. You need to round off those sharp edges in there.

 

[turboc87gn]

Is it necessary to remove the exhaust housing when porting the hole,and or a particular bit that works the best for the job?

 

[toomanymodz]

Use a carbide bit. Preferably one shaped like a football (versus a cylinder, or round ball). Stuff rags up into the exhaust housing and put tape over the inlet and outlets to keep debris out.