LQ4 into a 3rd Gen/1972 Nova by frojoe

4 minute(s) of a 891 minute read

Up here in BC we have a 3-day long weekend coming up in a couple days, I have a full tank of Argon, and on Thursday I'll FINALLY be picking up the Precision T3 flanges and downpipe clamps/flanges.. so I could very well have the hotside and a decent amount of the donwpipes finalized this weekend.

Also, I'll just post this here for posterity:

2-10-2018

Received the Precision turbine outlet flanges and the T3 inlet flanges. Inlet flanges fit the turbine housing profile much better, slight discrepancy but I'm not going to lose sleep over it.. much better fit than the generic Ace Race Parts T3 flanges which had almost a 3/16" step difference between the T3 flange and the T3 inlet profile on the turbine housing.

Ordered some extra misc M10 flange hex head for various accessory drive stuff, including some SS316 nuts to finish off the stainless turbo mounting hardware.

Turned down the flange OD on the ARP bolts (modified on left, untouched on right) just to have a bit more clearance to the radius on the turbine housing.

Started on the downpipe fabrication, started on the passenger side because the design is much more felxible and I was a bit too hungover to think hard haha.  

Downpipes will be 3.0" from the turbo to the subframe rail, then 3.5" under the floorpan back to the rear bumper. This is because the downpipe routing is so tight on the driver side around the steering box that I just didn't want to push it with 3.5" OD and the required increase in centerline bend raidus of the 3.5" 90* bends I have.

I figure that if I am pushing the setup hard enough for the 3.5" dual exhaust to be a significant benefit over full 3.0", then surely having the majority of the exhaust be 3.5" should be enough. The turbo outlets are 3.0" vband but the actual ID of the turbine outlet was something like 2.7" I think when I measured it with calipers.. so 3.0" downpipes for first ~24" shouldn't be a huge deal.

Sure I could've made the passenger downpipe out of minimal bends and a long straight, but I added some style to it because it will be much more visible than the driver side. I tried to make the very front bend mimic the bend of the pre-turbo hot piping, and then make the rest of the downpipe parallel to the slant in the CTS-V manifold. Then have the bend going down to the framerail mimic the bend at the back of the exhaust manifold.. kindof making the downpipe look like a nested duplicate shape of the manifold+hotpiping.