LLY twins? Or bigger VGT?

[NevadaLLY]

I’m looking for experience from those that have upgraded the lly turbo or put in twins. What did you see?

My use will be 80% heavy towing (20k toy hauler) and I live at 4500ft. All indications point to doing an sdp or hsp twin kit with s475. What did you go with? How were towing egt’s?

On the compound turbo, which is better to have over stock? Does billet vs cast make much difference?

Thanks!

 

[Chevy1925]

how much searching have you done because that is a shit ton of info on exactly what you are looking for.

475 over stock is best. EGT's will drop to the point you are pushing power up and will run into coolant temp and oil temp issues. buy an external oil cooler setup.

unless you are going for all out power, the wheel wont make that big of a difference but a billet wheel 475 will make more power.

once tuning is done correctly for the twins, you will notice 0 difference in spool up but way more torque and power with much cooler egts (like 2-300 degrees or more)

 

[NevadaLLY]

Actually I’ve searched most of the forums and come up a bit empty. Many people are sled pulling or dragging. I’m looking for tow performance to pull the 7% grade for 8-12 minutes sustained without egts/coolant/etc getting out of hand. I regularly go over the Sierras and always have issue on 70deg+ days.

I’ll use Kory to update the tune, and oil cooler/twin would be the plan at the same time. Was mostly looking for some real world results. Would an upgraded vgt get me close to that as well or are twins really the best/only way to go?

 

[Chevy1925]

Actually I’ve searched most of the forums and come up a bit empty. Many people are sled pulling or dragging. I’m looking for tow performance to pull the 7% grade for 8-12 minutes sustained without egts/coolant/etc getting out of hand. I regularly go over the Sierras and always have issue on 70deg+ days.

I’ll use Kory to update the tune, and oil cooler/twin would be the plan at the same time. Was mostly looking for some real world results. Would an upgraded vgt get me close to that as well or are twins really the best/only way to go?

twins will be your only route to get what you want.

look harder on here or search my posts. i have a ton of indepth work on making high HP while towing heavy in high temps here in az.

 

[2004LB7]

If you want to do what James does then you are going to need to do what James did. There aren't too many [reliable] paths to get what you want.

Otherwise if you are overheating pulling those grades then the other option is to slow down

 

[NevadaLLY]

With everything I have modded, pedal to the floor, the truck slows down for me and temps begin rising. Not that I won’t slow down, but last trip I blew up the lower intake boot on 22psi while doing 45mph up grants pass. One of my wirelooms melted on the hot side IC pipe. My best guess is turbo just can’t handle the airflow at that rate. Egts were about 1300 all the way up so I don’t think that was too high.

With twins, I want to have the “option” to slow down but not have to.

Btw, the boot was new. Also blew a banks hot side IC boot the trip before that. Temps are definitely out of hand on the hot side.

 

[gmduramax]

How much power are you towing with and how large are your tires?

 

[S Phinney]

Compounds is definitely what you are looking for. A billet wheeled 475 with a 87 turbine and 1.32 housing it vband 1.3 housing is what I would do. If you have enough fuel you can make 800 rwhp and tie the crap out if anything you want.


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[Burn Down]

I have raced and towed heavy all of my setups, stock/75mm, 68vvt/75mm, 68vvt/82mm blue truck on stock fuel. 65vvt/75mm, 65vvt/80mm white 05 with built engine and 12mm pump and 30 overs. Hands down best was stock with the 75 or the 65 75 setup. Instant spool and the least egts towing. I was using gt4202’s but I feel the Borg is a better setup with the larger turbine.

 

[NevadaLLY]

How much power are you towing with and how large are your tires?

Kory tow tune. I think it’s 30hp. I’m running 35’s.

When I blew the banks tube, I had the banks 6gun which I since pulled as it just wasn’t performing well.

 

[baggedLB7]

I love my set up. 475 over stock.
Towed great then I put a billet wheel in the 475 and got a little quicker spool which also made it easier to stay on top of the chargers while towing up hills.
Then I ported, polished, and put a batmo wheel in my ihi and it made a big difference in spool up and now staying on top of the chargers while rolling slow on the hills is like nothing. I dont think I could be talked into another route for towing on my lb7 with out driving it first.

 

[NevadaLLY]

I love my set up. 475 over stock.
Towed great then I put a billet wheel in the 475 and got a little quicker spool which also made it easier to stay on top of the chargers while towing up hills.
Then I ported, polished, and put a batmo wheel in my ihi and it made a big difference in spool up and now staying on top of the chargers while rolling slow on the hills is like nothing. I dont think I could be talked into another route for towing on my lb7 with out driving it first.

Is the port polish on the stock turbo? Where did you have it done? I’m also not convinced the VGT is changing vane position correctly. Your LB7 has a std turbo though.

 

[TheBac]

Moved over to Turbo Talk.

 

[baggedLB7]

Is the port polish on the stock turbo? Where did you have it done? I’m also not convinced the VGT is changing vane position correctly. Your LB7 has a std turbo though.

Yes stock charger. I did the work myself but look up yellowchevy on here he has some good write ups on how to do it and he also offers the service to do it for you. He is a vendor here.
I am about to do it to an lly charger on an 05 I picked up. Yellow has some threads on the vet turbos also.

 

[Bdsankey]

Kory tow tune. I think it’s 30hp. I’m running 35’s.

When I blew the banks tube, I had the banks 6gun which I since pulled as it just wasn’t performing well.

I am doing the same thing on my LB7 (building it for a "tow anything" rig) and am going with a cast S475/96/1.10 T6 over the stock LB7 IHI turbo and a 2020 oil cooler with an external remote cooler. I feel that either a 475/87/1.15 or 475/96/1.10 are ideal over the stock turbo on a tow rig.


Is Kory still updating tuning? Your truck would technically be non-emissions compliant with all of the aftermarket twin kits unless you fabricate your own to use the factory y-bridge. There are many many quality kits out there, pick what ever one fits your budget and needs/wants (underhood battery vs frame mount etc) and go for it.

 

[Dozerboy]

Is this for recreational use? Do you have daily driver or do you depend on this truck every day?


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[NevadaLLY]

Is this for recreational use? Do you have daily driver or do you depend on this truck every day?

Not a daily driver - tow rig and bad weather. SOME occasional driving just for taking toys out or grabbing hardware at the hardware store.

 

[NevadaLLY]

I am doing the same thing on my LB7 (building it for a "tow anything" rig) and am going with a cast S475/96/1.10 T6 over the stock LB7 IHI turbo and a 2020 oil cooler with an external remote cooler. I feel that either a 475/87/1.15 or 475/96/1.10 are ideal over the stock turbo on a tow rig.


Is Kory still updating tuning? Your truck would technically be non-emissions compliant with all of the aftermarket twin kits unless you fabricate your own to use the factory y-bridge. There are many many quality kits out there, pick what ever one fits your budget and needs/wants (underhood battery vs frame mount etc) and go for it.

According to his website, the tune updates for turbo, injectors, etc. are all still available. I should give him a call to double check.

Also, where are you getting the 2020 oil cooler? Anyone have data on it or the benefit? I'd be interested.

 

[NevadaLLY]

So it looks like tuning will be an issue. What are you guys doing to get around EGR delete? Can I keep the EGR in place? What if I only leave the valve plugged in and remove all the hardware? EGR would be “functional” and I have the fingerstick so it’s covered operationally.

 

[Bdsankey]

According to his website, the tune updates for turbo, injectors, etc. are all still available. I should give him a call to double check.

Also, where are you getting the 2020 oil cooler? Anyone have data on it or the benefit? I'd be interested.

Do a quick search and you’ll find a ~80+ page thread. Title is called “Oil Cooling”. I got mine straight from the dealership. 01-16 cooler is 10 plates, 17-19 is 14 plates, 2020 cooler is 20 plates and not a super costly upgrade.