Can they be used together, or will the wastegate bleed off the back pressure?

 

your waste gate is electronically activated, it wont open while coasting which the only time the e brake activates. mine doesnt bleed off, it works great and wont tow with it again.

 

Sorry about that, I meant an External wastegate, plumbed onto the exhaust manifold,

 

I would email BD and ask them. Why not just go with a blow off valve instead and put it on the intake side?

 

What I plan on doing is fab up a set of towing twins, using the stock turbo as the secondary, but still using the bd turbo mount brake on the stock hy.

The external wastegate would be plumbed in before the stock turbo and then the bypass would go around the brake, into the ht3b.

If I made this setup will the external wastegate open up when the exhaust brake is on, letting all the back pressure made between the brake and the ext wastegate, back out the wastegate into the ht3b? Does this make sense

 

I see what you are doing now. That's a good question. Logically it would escape out of the wastegate since that is it's function but I can't say for sure. I do know that when I installed my Pac brake I used the ECM for control. It watches rail pressure, accelerator input and must also control the waste gate to some extent. 04.5 and up are electronic waste gate so I think I got lucky.

 

Assuming you are using a 38mm external w/g, then you will just need to size the spring so that it keeps the plug on its seat with 60psi backpressure. The diaphram is about 4x the area of the plug on a Tial 38mm w/g, so that means you would need a 15psi spring.

 

So if I use the 15 psi spring, to get the 60 lbs of back pressure needed to use the brake, It also wont open up to 60 lbs of boost if drive pressures are 1-1 etc, far out the hy-9s working range right?

 

If you use a 15psi spring, it will take 15psi boost pressure plumbed to the bottom side of the diaphram to start opening the w/g. Because the surface area of the plug is about 1/4 the size of the diaphram, it will take 60psi drive/backpressure to open it, so you should be fine.

 

If the wastegate is set to open at 60psi of exhaust pressure, to use the exhaust brake properly, it also has to open at 60psi of drive pressure, ruining the idea of the hy-9 working in its effiency range. Or am I still a$$ backwards?

Id like it to open at 15-17 psi, then dumping the rest of the exhaust into the ht3b. Total air pressure would aroung 50psi.

Im thinking I'll have to get a 5'' Pacbrake and mount it on the ht3b.

 

With a 15psi spring, the w/g is set to open with 15psi boost being plumbed to the bottom side of the diaphram. The diaphram on a Tial 38mm is about 3" diameter which makes it about 7 sq-in total area. 15psi x 7 sq-in = 105 lbs of total force needed to open the w/g with a 15psi spring. Since the plug is 38mm (1.5") diameter, the total area of the plug is only ~1.75 sq-in (about 4x smaller than the diaphram) which means that 105 lbs force / 1.75 sq-in = 60psi needed on the plug to open the w/g. Clear as mud?

With a 15psi spring, the w/g will open with 15psi boost, or 60psi drive pressure.

FWIW, I have a 5" pacbrake after my twins in the exhaust, so I don't have to worry about this issue

 

OK, I think I figured out how the Tial works,

It gets its 15psi reading from the compressor outlet of the secondary turbo, theres a line running form there to the spring housing,

then it pushes the valve open, releases excess exhaust out and around the hy-9/e brake into the ht3b, right

So when the e brake is on it will push the exhaust inlet valve(of the Tial) back closed, not letting the exhaust through, I think

So it should work?

 

Slowly but surely we are getting there

You are going to have a boost pressure line coming from your intake horn (its cooler than off the turbo) to the bottom fitting on the w/g. When that pressure gets above 15psi, it is going to start to open the w/g.

The exhaust brake will NOT try to close the w/g when engaged. The exhaust brake will increase backpressure in the manifold up to 60psi, and that pressure will be exerted on the plug (trying to push it open) of the w/g. Since we sized the spring (15psi) to require a minimum of 60psi on the plug to start opening the w/g, you have ensured that the w/g will not open when the exhaust brake is engaged.

 

It took a little while but I think figured it out,
I first thought that it ran solely on the exhaust pressure,

so the brake should work up to the 60psi limit,

Where did u get your twins, and the Tial wastegate, I think Poole uses ksb turbos, or are they a homebrew.

 

sounds like you got it now!

I got my twins from Power by Poole. He uses the B1/B2 line of turbos, and now also has HTT turbos as well. His kit includes a Tial 38mm wastegate.

While I waited the 9 months for my current setup, I made my own twins using the stock turbo and a B2/S400 and a Tial w/g. I just sold all the parts a couple days ago which is too bad since you live so close! Send me a PM sometime and I can point you in the right direction for all the parts/pieces needed to build your own twins

Jeff