Don Terrill’s Speed-Talk

Thank you mt-engines. I do have some tootsies

Getting closer on getting the Lq4 together. Filing the Rings supplied with the wiseco pistons has taken me a while. I've read some info on break in oils. Is a break in oil necessary since the Lq4 has a roller cam? Another question as far as ring seating, should I drive it to break in the Rings before going to the dyno? The tune I have on my ecm is for a L59(flex fuel 5.3), so it would be running on that tune. I will have 42lb injectors in the Lq4. The L59 had 35ish lb stock injectors. My thought is the bigger injectors with the 5.3 tune on the Lq4 will keep it from running lean for long enough to break in the Rings before going to the dyno. But wanted to get opinions from others on this first.

Gibbs BR30 oil.

The dyno is great for seating in the rings, and the tune can be monitored so you don’t overfuel and wash down the bores.

I was looking at that break in oil earlier. Thanks for verification that its good to use. For my top ring gap with my 4.030 bore I chose .018 on the top ring and .20 on the 2nd. Does this seem right for a truck that will be towing up mountain passes from time to time in Colorado? I noticed in the chevy book stock ring gap for the top ring gap is supposed to be between .012 and .020 for the lq4 and lq9 as a reference. I would think I would be fine since lots of people seem to add some boost with that kind of gap, although stock pistons and rings are a bit different than what I got.

This is the ring gap chart that came with my wiseco pistons.
http://www.wiseco.com/PDFs/Manuals/RingEndGap.pdf

This is the rings I got:
https://www.summitracing.com/parts/wis-4035hf

With a proper tune you should be fine, plus the gap will increase during the break in process anyways. Good luck!

I ordered up a set of comp cams trunnions. I noticed years past a lot of people complaining about them. Some say they have been redesigned since. Should I return them? Are they total junk?

We’ve used a few sets, I can’t recall any issues.

I did a similar build on my 2002 2500hd 2 years ago and im very happy with it. I tuned it with HP tuners myself and I feel like I have a lot of area to improve at full throttle from a dead stop, but it runs much better than stock. I went with stock LQ4 pistons and 5.3 heads with the 6.0 valves. measures right at 10:1. 216 216 @ .050 .500 .500 cam 113 lobe sep. I read the whole thread and maybe I missed it, but I went with the NNBS intake and it seems to work well.

Pulling around 7500# coming out of Denver heading west on I-70 I had to drop over into the shame lane could only hold 35-40 mph on the steep pass. Pretty much the top of 2nd gear the whole way up. I am sure a better tune would help, but it got me there and back.

Thanks for the input. I am going to run the gen 3 truck intake. I looked into the gen4 intake and it did make more power up top. But the gen 3 makes more torque below 3k rpm so I kept the gen 3. I'm guessing the smaller throttle body gives more velocity at lower rpms. Here is the link...
https://m.facebook.com/bdturnkeyengines ... _tn__=EH-R

Hi im back, hope your all doing well. Ive had my lq4 on the road for a while now. It does decent but i still want more power for towing below 3500 rpm. So if I could have like 6lbs of boost at like 2500 rpm i think that would do it. Someone else that put a turbo on a lq4 for towing said they were happy with a single S475/83 1.10A/R T4 turbo. However I have more room for twin turbos, a single would be pretty tough to package. So how do i find what 2 turbos would equal the spool of a single S475/83 1.10A/R T4?

There's a fair amount of math that i don't know about, but in general I'd go with the smallest pair that can support your target power level and boost (rule of thumb if you're not sure, double your n/a power and look at the 2:1 pressure ratio line on the compressor map. Remember there's two though). Come to think of it, you could directly compare them to the s475 map and make sure they flow about half.

If you've got the room, go twin scroll take cylinder pairs at 270/540 degrees firing separation into each scroll. Avoiding blowdown interference will be your friend at low rpm, not just for torque, but also for detonation resistance

I'm having difficulty finding manifolds to fit a twin turbo setup for the room I have. I have not seen any twin scroll manifolds at all for LS motors. I'd be happy with around 650hp max at the crank. So 325hp per bank. The armageddon manifolds look like they would fit really well in my engine bay.