I have been able to keep my boost regulated until now with my modded internal wastegate on my 12cm2 housing. I am going to have my pump modded and going to push a lot more fuel than my 160 pump did.

I am wondering if I add an external wg and dump the bypass on the hot-pipe (like so many do) will I still be pushing the 12cm2 housing on my 35/40 still? I am under the notion that since I am bypassing the small turbo after a certain amount of boost is built up that I am decreasing the flow of exhaust through small turbo and therefore I dont have to worry about the lack of flow through the small housing. Or am I out of my mine and do I need to upgrade the housing on my hx35/40 to a larger unit?

Thanks for the input!

 

Even if your turbine housing is modded so that the WG acts on all 6 cylinders, I think you'd find that the 35/40 is out of it league if you going to "push a lot more fuel" as you say.

I wouldn't go though the hassle of external WG just for anti-explosion protection for an undersized turbo. Rather, just regulate the boost on your 35/40 with an MBC or such.

If you can't regulate the boost down to safe levels with the MBC, you seriously need a bigger turbo...

jmo

 

I'm guessing that you are trying to controll max boost on your Twins??? by just using the one wastegate on the small turbo you can controll the amount of pressure being created by that turbo.. but when the gate open you are still sending exhaust to the big charger.. and if you add more fuel you will see an increase in pressure... how much will depend on the amount of fuel you add and the size of the exhaust housing you are using on the big charger.. you maybe able to still controll max boost with the small gate.. but it tends to take away how efficient the twins are working.. best setup is to have to two gates.. either one on the big charger.. or bypassing both...
Good Luck,
Bryan

 

I am planning on controlling max boost with the wastegates and my fuel plate. I am more concerned about egts with the small top turbo housing.

 

have you seen-thought of this?
40 mm internal w/g mod

i am about to have the same twin setup as you have...soon, hopefully. what other fueling mods are you going to install?

what boost do you see with your current setup?

 

That internal mod is pretty neat. My old setup was boosting about 60lbs and the headgasket let go and I broke the flex plate. Everything is torn apart so I am getting the head oringed and the pump is going to worked over. Not sure exactly what is going to be done to the pump because I have had a hard time getting in touch with the shop.

I like the 40mm wastegate idea but I dont have a big head actuator and much access to a lathe. I figure putting an external one is easier for me to fab up.

 

twas just an idea...

you made 60 psi, with just the stock wastegate? and a milled out divider?
do you have any dyno nuymbers? 1/4 mile numbers?
whats the flex plate? you broke...

 

Ran a 14.01 in the quarter with 40" bias ply tires in 95 degree heat. Next day cooled off to low 80 and broke the output shaft. I did have the divider drilled out too. Look in my gallery for a broken flex plate.