ATR headers -4bolt

4 bolt needs external gate and usually comes off under the turbo mounting ..whether your intentions are to dump the gate to atmosphere or tie back into downpipe means your pretty much in need of custom fabricating , not something you can buy off the shelf.

back in the day you could get a downpipe for the atr 4 bolt oncenter setup as those were the main turbos available back then with a 4 bolt housing .. i have a setup like this on the shelf with turbonetics racegate that returns to the downpipe and a 72mm turbonetic oncenter turbo ..not sure how much of it was customized but doesn't matter you cant call and order from atr anymore

atr4.jpg

now a days the 4 bolt turbos are tangenital with a vband flange for the exhaust and needs a vband downpipe .. so once you go 4 bolt you're pretty much in need of a custom fabbed downpipe . gn1perf sells a vband downpipe 3.5" diameter which clears headers by a mile and then a few feet more than that .. but their vband is 3.5" and most 4 bolt vband turbos are only 3".. so its not quite a buy it and bolt it up deal ..still needs some costum fabbing
heres my 4 bolt (ta headers ) with 71hpq tangenital 81 4bolt housing and the gn1 3.5" pipe . i cut off the 3" vband ring edge from the turbine housing and welded a 3.5 flange , or you could modify the pipe and weld on a 3" vband flange . i ran the gate down to atmosphere ..with that downpipe theres lots of room for whatever header you want but it required trimming the wheelhouse plastic and might even limit turns with a wide front tire
atco 9.73 trap picture.jpg

if you want bolt on you can get a fabricator to build one for you that should be able to bolt on once you get the parts back but youll more than likely have to send your header turbo and wastegate to the fabricator to build the downpipe .. try jack cotton or bison .
 
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