Looking to see what other are running for timing at around 25 lbs of boost. Engine is a 5.3 at about 8.8 on compression and has a good air to water intercooler where iats never get over 70 degrees after 1/4 pass and it's running on e85. Has an S475 w/ t6 flange and we're maxed out at 24-25 lbs of boost and looking to squeeze some more power out of it...currently sitting at 19 degrees at 24 lbs of boost. Just looking for suggestions

 

Did it pick up power going to 19*? Where did you start out on timing at 25psi?

 

x2, if it keeps picking up 20+whp a degree then leave it in there, if it doesn't take it out.

S475 should have more life past 25PSI on a 5.3L, turn it up if you want more power.

Also what's your current A/F?

 

I run 19* also at 24psi and 11.6 AFR with E85.

 

19* is pretty much where its always been...never had the car on a dyno only track. This is straight race car no street driving. The way it sits its been 8.83 @ 152 in a 3100lb car @ 23.9 lbs of boost. That's with the waste gate pinned shut. Gonna try and pressure test the system and make sure it has no boost leaks. Car does have 4" piping from the turbo to the intercooler where the rear seat would be then to throttle body. Its blowing a 7.5 AFR at 24lbs...car runs on Holley Dominator also

 

that afr is costing you power but id drop timing a little first then add it back with a leaner afr.

is that on a gas scale wideband. ?

 

no e85 scale...its about 11.4 on gas scale

 

Sounds like the turbo is done if you don't have any leaks. I always tune off the plugs and iirc at 24psi it could maybe take another degree or two but not much more.

 

I've seen that term from time to time, "...waste gate pinned shut...". How does one do that?

 

CO2 dome control.

 

While you can use CO2 or washers instead of a spring, I literally deleted the wastegate and used a blockoff plate:

 

Damn! That'll do it! Thanks for the tip.

 

Plugs


CR and chamber play a huge roll in what timing it will want

 

Do you have a 96mm turbine?