Yet another Lq4 turbo build
11-17-2016, 07:43 PM
#1
Teching In
Thread Starter
iTrader: (1)
Join Date: Mar 2014
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
Yet another Lq4 turbo build
So I have been building my obs truck for about 2 years. Mainly parts collecting
. I bought a 02 2500hd with 130k on it and pulled engine, trans, and Ecu and parted out the rest of the truck pretty much breaking even on cost. So my initial intent was a mild n/a build and so I bought 243 heads and had them Milled .030 to bump compression. I also did the trunion upgrade and Vinci dual valve springs. I pieced this together with new hardened push rods,ls7 lifters and a Vinci trucker cam with the thought of torque and power below the curve. Well I got bit by the turbo bug and had to rethink some things but I'm looking for a little direction for the turbo sizing. My thoughts on this part of the build were to buy On3s hot and cold side kit and put a bws475t4 on it. My concern is the fact that I bumped my compression up to somewhere like 10:8:1 ish. Also I don't want to have a laggy turbo or have to much back pressure with a small one. So thoughts please.
. I bought a 02 2500hd with 130k on it and pulled engine, trans, and Ecu and parted out the rest of the truck pretty much breaking even on cost. So my initial intent was a mild n/a build and so I bought 243 heads and had them Milled .030 to bump compression. I also did the trunion upgrade and Vinci dual valve springs. I pieced this together with new hardened push rods,ls7 lifters and a Vinci trucker cam with the thought of torque and power below the curve. Well I got bit by the turbo bug and had to rethink some things but I'm looking for a little direction for the turbo sizing. My thoughts on this part of the build were to buy On3s hot and cold side kit and put a bws475t4 on it. My concern is the fact that I bumped my compression up to somewhere like 10:8:1 ish. Also I don't want to have a laggy turbo or have to much back pressure with a small one. So thoughts please.
11-17-2016, 08:13 PM
#2
TECH Junkie
Definitely would need meth or E85 to run much timing. As you probably already know 9-9.5 is usually preferred. 317s would be better and sell your 243s.
11-18-2016, 04:55 PM
#5
Teching In
Thread Starter
iTrader: (1)
Join Date: Mar 2014
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
I was planning on cutting the wastegate off and moving it to the other side to clear my ac compressor. Are you talking about the t3 flange? I think I could get the bw in a t3 flange. When does your truck start to spool?
11-18-2016, 05:54 PM
#6
The BW's are 1/2" taller on the t4 pedestal with a 4" v-band where the on3 turbo is shorter on the pedestal and only a 3" vband. You will have to at min cut up the down pipe and re work it to a 4" vband and accommodate it for the taller pedestal to be able to use it.
My truck starts making noise around 2-2200 rpm and is in full boost by 3500 or so, just depends on how it's loaded. I don't consider it laggy at all.
My truck starts making noise around 2-2200 rpm and is in full boost by 3500 or so, just depends on how it's loaded. I don't consider it laggy at all.
Trending Topics
11-19-2016, 06:09 AM
#10
Teching In
Thread Starter
iTrader: (1)
Join Date: Mar 2014
Posts: 42
Likes: 0
Received 0 Likes
on
0 Posts
Do you see any issue with cutting the T4 flange off and welding a t6 on. Are the up pipes going to be big enough? Also is a 3.5" down pipe going to be big enough? My concern is flow not fitment.