PPI Typhoon

iTrader: (1)

So I decided to start the fabbing up of the turbo setup for the GTM. I want to get the project started for now, but will be running the stock LS1 until after tax time. Once I get through Mr. IRS, I want to up the cubes to something like an LS3. The current motor is a stock LS1, circa 2001.

I did do a search and the reason for this question is that I have seen twin TC series on even 5.3's, but haven't seen any posts on results.

My goals for now are only 450-500'ish on the stock motor, but later on, I'd like to get around the 1k mark with a forged motor upgrade and would rather not buy a pair of turbos now just to buy bigger ones down the road. I'm just wondering if I'd even be able to spool a pair of these. Is an a/r lower than 0.81 an option on these? If there was something around a 0.68, would I be able to spin them up then?

This is a daily driven car, not a track/trailer car.

I know I can go pick up a pair of BW S200's, but I know with the bigger motor down the road, those might prove to be a bit small.

Thanks ahead of time for any help you can provide.

mrstepheneades

I would get twins that will work ideal for your future cubes and not worry that much about the lag now especially if you gonna swap out soon. Unless you like buying 4 turbos lol. As for keeping the power low as in 450-500, turn that ls1 up!!!. Mine is holding strong at 20psi and I made 755 at 17psi. Who knows what it puts down now. Keep fat afrs and keep timing low it will last a while. I would probably go with s366's if I were doing twins. Borgs are good units for sure.

PPI Typhoon

iTrader: (1)

Thanks for the feedback. I would turn it up, but the Porsche transaxle currently in the car is only good for up to about 500hp. I'm eventually going to a Lamborghini/Audi unit, but that's another $21k and a year or two down the road.

There is one guy doing over 1k through a Ricardo transaxle (from the Ford GT), but those are pretty hard to find.

I'm just wondering if they'd even spool, or just be aesthetic until I upped the cubes.

mrstepheneades

They will spool. Maybe not till 4000rpm but they will. I still have junky 10bolt and stock trans. Stay on street tires lol. Saves a weak drive train.

JAX04

iTrader: (17)

yes....

crazyelf

iTrader: (21)

Twin tc78 would be to much turbo

PPI Typhoon

iTrader: (1)

Would a pair of TC66 be a better fit?

I'm just not sure of the T3 vs the T4.

Mike@Diablosport

iTrader: (2)

Whats your final power goal once the built motor is in there?

TC76's will support a ton of power, seems like overkill to me.

A agree that keeping the power down to 500 rwhp is going to be tough, you'll need some really good wastegates/boost control with all that turbo

skinnies

iTrader: (33)

I can tell you this, precision 46mm gates will control them down to 1.5lbs no problem.

Mike@Diablosport

iTrader: (2)

We fought a pair of tial 38s on a 346 with a lumpy cam and twin PT67s, couldn't get it to hold less than 10 psi down low, and then it would creep to 11-12 up top. No fun

It has Tial 44s currently, and they seem to be doing fine.
In reality, he's gonna need to keep it to about 3-4 psi to make just 450-500 rwhp I would think.

mrstepheneades

I agree. With twins of any sizes stated above it will make 500 on hardly any boost. I made over 500 on just 8psi with my single s475 on my cam only ls1. With twins the power will be around there with a lot less boost.

qqwqeqwrqwqtq

If you want something fun to drive get something in the twin 58-61 range. Twin 76TCS will be all lag during normal driving.

(you can either have boost as you roll onto the throttle to pass someone or it can come into boost by about the time you've already passed them).

PPI Typhoon

iTrader: (1)

Am I correct though that the TC series actually flow less than an equivalent size T series?

I know the pair may be overkill, but with the car, I'm also planning on things being a bit over the top, but still functional. I've only had the experience with single turbos before with my Typhoons, not dealt with the twins ever.

I was speaking with the guys over at AGP Turbo and they advised in-flow placement of the WG to help control the boost at the low levels, where if I have it off at 90 degrees, it's going to take a lot bigger gate just to get the consistent control.

So yeah I admit that part of the goal is aesthetics. I almost bought a pair of S256's last night, but while they may be perfect for my HP goals, I was hoping for something with a little larger physical size. If they were hugging the block, they'd be perfect, but they'll be hanging out the in the back, so I have a bit more room.

qqwqeqwrqwqtq

The physical size of the TC units is pretty tiny actually. IMO there is nothing good about a TC76 either in twin or single form. The turbine is too small to efficiently drive that much compressor.

Even if you wanted to go overkill there are much better options.