Just ordered an FIS S478 96/87 1.10 T4. On a forged 6.2 with 11.2 compression and 216/228 .600 112 cam do you see an issue lighting it off?

2009 Avalanche 4.10 gears with truetrac and zl1 converter in built 6l80.

boost will be between 10-15#. Wanted something to light off decently quick and almost jumped on a gen 3 7875 but everyone told me that there would be back pressure issues.

I planned to run an on3 3” downpipe to 3.5” exhaust. I would need to run a 4-3” reducer and looking at the size of the turbo I’m not sure I have the room for the reducer. I might be cutting the DP and welding it in place.

 

That turbo will do very good.
And yes the 78/75 would start choking out up top.
And you can fit a 4" downpipe. But a 3.5" downpipe into some 4" exhaust would be easier and flow plenty for 800hp.

 

I shift at 6300 and would be happy with 650-700whp max. Running 80# Deka so 92ish lbs at 58psi.

if only run 12# should I stick with a 7875 for more midrange boost? Wife drives a 3.5 eco with a 10 speed and and I love the low end boost. Makes me want to go 7875 .96 and easily run the on speed 3” DP. Worry about back pressure but at 12# it might be fine.

 

That compression is a little on the high side to try and get a bunch of low end torque.
You running LS3 heads?
id rather not choke it out up top where its really going to shine. Trans tuning can make it more responsive.

Her 3.5 is direct injected and the 10sp has low gears so thats not too good of a comparison.

 

Also for 700rwhp max you could go down on the compressor side to help with spool time. No point in "oversizing" the turbo.
What fuel are you going to be running? E85?

 

I’m going to run 93. Only one e85 station within 30 miles of me and it’ll be a daily driver.

just don’t want it to be super laggy and I plan to still tow play toys with the truck. I won’t be out racing it all the time. I see people have good luck with the gen 3 7875. With only 12# boost max esp with the higher compression I don’t want to go too large of a turbo. FIS recommend the 93 wheel but I found the 96 for a few hundred cheaper and figured it would be near the same. So 78/87 wheels roughly. Jose at FIS said the 7875 had popped head gaskets due to back pressure on 6.2.

 

Hopefully you have a good tuner.
Id go with what Jose says or atleast stay as close to the size he suggest.
Going with a larger turbine will help the most but don't expect a twin screw blower type of response.

 

I’m not overly happy with my NA tune and the trans tunes leaves something to be desired. I’m looking for a new tuner on the gulf coast. I’ve heard decent things from boosted innovations. Not sure how good remote tuning would be. I’m also debating on getting HP Tuners. I will be running an electronic boost controller and AFR wide band. Either 50-60mm wastegate with trick manifold and crossover.

 

You in AL or MS?
I know some guys remote tune that are better than certain in person tuning haha.

 

I’m down in AL between mobile and Pensacola.