Hey what's up guys, I thought I would shoot something across you guys and see what you thought. I have a 2001 Sierra that has a 4.3. I have been looking at LQ4 drivetrains, with maybe a 4L80e trans. The ? that I have is I have been thinking about running two T3/T4 hybrid turbos mounted on a set of truck manifolds that I cut the flanges off for V-band assembley to be welded to I have seen this done before but I would like to run twins with low boost such as 3-4 psi per turbo so I wouldn't have to run an intercooler. Will this work welding on the cast manifolds and them flipped 180 and with out the intercooler such as the Banks twin kit?

 

3-4lbs per turbo is still 3-4lbs total entering the manifold, why such low boost? Can you flip the maniolds? Yes, it's been done alot.

 

Well the way I see it would be like 8psi total two turbos on each bank making 4psi and I know you can flip the manifolds but can I weld v-band flange on the cast manifolds because I cut off the flanges for that reason and then I will use a v-band exhaust inlet instead of the 4 bolt flange. I have seen a few twin kits where they were using that low a boost on each turbo so it was not making alot of heat and the intercooler was not needed.

 

I don't think you can flip those manifolds. The manifolds people are flipping are on V8's, and they have a port pattern that can be flipped. The 4.3 has 2 exhaust ports close together on the front in the drivers side and 2 exhaust ports close together in the rear on the pass side. You might be able to get 350 Chevy manifolds, cut off a port on each manifold and weld a port shut (not sure about this). Cast is a pain to weld anyways. I would leave the manifolds in the stock location, run a pipe to the front, and into a single turbo. Running 2 turbos at 4 PSI will not give you 8 PSI, it will give you 4 PSI. If you really wanted to stay away from an intercooler I would run methanol injection.

 

my bad, :duh: 4.3... and yeah, 4lbs through 4 turbos is still 4lbs

 

He said he was looking at LQ4s...lol c'mon people read

Now what if he wanted to boost 6lbs on one turbo and 3 lbs on the other...what boost would that be??? HAHAAA

 

lol, i had it right the first time

 

See this is why I asked for advice because I wasn't sure, but I understand the boost, I still would like to use the manifolds, it just seems like it would far less complicated and cheaper if you just weld on schedule 40 bends to the cast manifolds to locate the turbos where you want and then just use a turbo with a V-band exhaust inlet, no expensive and hard to find flanges, easier to work as well. I am not going to turbo a 4.3 I said LQ4!

 

Oops sorry buddy, I was thinking 4.3. Lol I hate welding cast, and it seems like it is near impossible to weld a V-band to cast without it warping real bad. I personally never cared for cast. If it were me I would get some cheap shorty headers and cut them up for the easiest build.

 

I've seen a few guys on LS1Tech that have done the Sch40/truck manifolds. It sounds like it's all about finding a welder that has experience welding cast. These photos are from a F-Body build.









Skipping the Intercooler is just plain stupid. Boost creates heat. Even with shitty eBay turbos you'll well over $1500 in parts & materials and your going to try and save $120 on an intercooler? Your already going to have to fab the cold side, just add the intercooler and be done with it.

Rick