Hi guys. I just plunged back into the game, for the final big power build of my life. It's a turbo LSx conversion, in a '97 Firebird original V6 car, that will be 1000whp capable on ethanol. Today starts my first foundational decisions, about where the money should be spent, and why.

#1 is which K-Member to work with, considering the consequences of that decision. Specifically, how it impacts my options on routing a 4" downpipe.

Hooker has released their motor mounts for converting a 4th gen V6 car to LS, using the stock V6 K-Member. They're $273. Which sounds very tempting at first thought.. to potentially save money and time on the initial build, by not having to spring for the BMR/UMI/Midwest tubular piece, and not having to take the front end apart(initially). It's these: https://www.hawksmotorsports.com/93-...ackets-hooker/

My question and concern, is whether the V6 K-Member will offer more, less, or equal clearance for the downpipe, as the stock LS1 piece does. Several members I see have been successful getting a 4" to clear with the stock LS1 K-member with various methods, but I can't see that anyone has tried this option with the V6 K and the Hooker conversion mounts.

I appreciate any thoughts! Here is a side-by-side of the stock V6 and stock LS1 pieces.

 

I'd ask myself, how much am I going to drive this on the street? Reason being, I have seen numerous threads on tubular K members failing with street use. I'm sure people have had great experiences with them as well, but I'm staying stock because of that. Granted, I'm only going to be running a 3" downpipe on my setup, but when I eventually go 4", I'm just going to run a dump pipe with a cutout and merge it into the 3" exhaust. You're just going to choke the turbo running a full exhaust anyway, may as well dump it up front and have a 3" exhaust to keep things quiet when you're street driving. I'd have it set up with an electric cutout that opens based on exhaust pressure post turbo. I'm assuming you plan on the full exhaust if you have a need to route the downpipe through the K member. Most people just run dump pipes when they're running a 4" outlet turbo. It looks to me like the V6 K member *might* have more clearance once mounts are installed, but I have no idea, I've never messed with one.

 

Bite the bullet an buy a turbo specific K-Member.
It will save weight, open up lots of space for access and making routing the down pipe vastly easier.

 

Thanks guys, it's my first turbo build, and I hadn't thought about the full exhaust robbing that much power when you're in high boost / race gas / kill mode.. or the dual route cutout. Guess it's a better big picture plan to do all the tubular pieces upfront. and just be done with the subframe assembly. Appreciate the replies.

 

This.

I had to use a BMR turbo k member with my kit and it's amazing how much more room there is for activities.