Cstmg8

I've decided to take my Callaway a bit further. Nothing too extreme yet, but probably close to the limits of fuel and transmission.
My plan for the first round of mods is:
e85
Throttle body
Smaller pulley
Headers
Dyno tune
My Callaway blower is based off of the tvs 2300 rotor pack, and currently has about a 3.5" pulley on it. The C7 SC757 runs the same blower with a 2.6ish pulley on their 6.2, so I should have room to grow. I need to learn the major differences between the L86 and LT4.
I would appreciate any advice or opinions as this is my first venture into modding the DI engines.
Am I going to require fuel mods with this plan, or will the stock system. Support this level?

Cstmg8

Pic of my truck:

gat0r

is your truck flex fuel? i am thinking not.

that will require some fuel mods. someone will be along to give better idea on what.
(at a min. a flex fuel sensor){i think cjtunes sell a kit}


12# boost is the "rule of thumb" max boost before you might be on borrowed time... that is when its time to think about upgrading the pistons & the powdered metal rods.



you should be about 6# now based on how my burb came from them. though i only have the 5.3 & 1900 (came w/ a 3.4 pulley)
... if so, a 3.0 pulley should be in 11# neighborhood. then LT headers should drop you down ~2# so back to 9-9.5#

*look at the rear lip of your pulley for the part # & size.


hopefully your tuner is good... as that is what will help your trans last longer.



* you will also want to think about an upgraded driveshaft

gat0r

boost #s above are for pump gas (93).


oh & good looking truck

good to see they got you the quality rims
vs the ones i got


eta:
you may need to think about injectors too

not to mention 1 step colder spark plugs
while you are here, might as well change out plug wires & add sleeves to protect from LTs

& look at pinning the crank pulley

Cstmg8

Thanks! I did order the flex fuel parts, they arrived last week. Pretty simple addition, then it will need turned on in the tune, of course.
Awesome to hear that you have a Callaway as well, I never run into anyone else.
I'm not excited to hear that the bottom end gets weak at 12#, what average rwhp would that be on these motors?
I am curious about the fuel system though. E85 may require upgrades for volume, but I know the current tune is pig rich.

gat0r

my chevy dealer sold quite a few tahoes but only the 1 burb that i know of.
everyone seems to want the shorter wheelbase lol

its expensive, but keeps the warranty mine sat on lot for a year, so i got a sweet discount


like i said that the rule of thumb.... i think some peeps here are running maybe 14#
a lot of it is in the tuning

i want to say that will be in the 650-700ish rwhp neighborhood

gat0r

i have read peeps talking about using LT4 or {LT4+30%} injectors & LT4 hpfp
tie that in w/ a cam that has a larger fuel lobe

next weak links will be torque converter & diff

Jonblarc7

LT4 have bigger injectors and a bigger HPFP. I would think just from what I read on here is your would need a cam with a 32% over fuel lobe and LT4 injectors to run E85. Some will say you need both of those plus LT4 HPFP.

https://www.performancetrucks.net/fo...denali-556039/


https://www.performancetrucks.net/fo...harger-554074/

https://www.performancetrucks.net/fo...-555840/page2/

Here are some other threads to look over.

ZO6Ted

Hey gat0r I'm 90 % sure the crank is keyed on LT's. That's what I came up with few years ago but have never actually seen.

OP I've seen a couple L86's go into the high 600's but they backed off because of ring lands to 600-620 for longevity. After pretty exhaustive research in the past week I'm comfortable that the LT4 injectors, pump and fuel lobe will manage 700 np on E85 with blower ~ 100 more with turbo with an upgraded low side (800- $1000). If you want more fuel than that it's either meth or port injection kit for $4900. Lt1 Hpfp would be good for ~ 600 on E85. If you're doing the cam there are drop in piston/rod combos that will do 1000whp np. Nice build!

Jonblarc7

The crank is keyed, it was on mine.