Jambbii

I am going to slowly piece together twins for my truck, I am going to use the hybrid I have now and an HT3b. My question is do both turbos need wastgates? I remember something about an external wastegate too. Should I run my 12cm2 housing on the hx 40/35 or a bigger size?

thanks

Mike Holmen

My 3B turbo doesn't have a wastegate. I would just use the wastegate thats on your existing turbo. You might need a pop-off valve to regulate your boost pressure. You should set your pop-off valve at 45-50psi to save your head gasket. You might have to put a bung into your oil pan for the oil drain off the 3B turbo. An ATS manifold is a good idea, as twins turbo are heavy mothers. The biggest deal is getting the exhaust out of your HX-40/35 turbo into your 3B turbo. Twins are pretty easy install, its just all the little pieces that will slow ya down. I did mine the lazy way and just bought a package. My twin package wasn't complete and will some little tweaks here and there. No instructions either.

Rhino

It would be nice if the 3b was wastegated but pop off valves seem to work ok for most. Keep in mind you will need to modify your current wastegate to bypass enough air in a twins setup.

Head studs are pretty much a must if you want to try to keep your OEM HG. Or you can pull the head and O-Ring it.

Stamey

You need a wastegate for the smaller turbo, period. Depending on the size of the housing on the HT3B, you may need a wastegate. I am running a 26cm exhaust housing and can't put enough fuel through the engine to overspool the HT3B. This is a good thing.

The 12cm housing on the HX35 should be fine if you have it wastegated properly. I am running a 14cm now, but may go back to a 12cm to make spool up a little faster. This will limit your air and may cause EGT problems at higher RPM. I can't give exact numbers because I have not run a 12cm housing since I installed my twins.

You will want to look into a pretty big external wastegate, 42mm or larger, if you run an external. I wanted to run my stock wastegate on my HX35 but found that when the exhaust housing was oriented correctly for clearance of the HT3B the WG assembly would interfere with the HT3B outlet, so my stock WG got welded shut.

Chris

Jambbii

So how much are "pop off valves" and where do I get them? So there might be a chance that my wg on my 12cm housing might not clear everything? I know head studs will be a must. Say my
wastegate clears on my current setup, what mods do I need to do to it? What is a good size for the ht3b exhaust housing? I am not going to be pushing too much fuel through the setup right now with my 160 pump.

Thanks