how much boost?

[flguy1215]

how much psi will i be seeing with a 100 performance and 120 race tunes? i have a turbo master waste gate actuator so i can dial in as needed. i just got rid of my diablosport predator programmer. on the 110 setting i could pin 27 psi or so. i know 25 psi is kinda the guideline for these stock turbos, i'm just wondering what the new tunes will be cranking out. also, i am reading that a boost fooler is recommended? how hard is that to install?? thanks

[cleatus12r]

The boost fooler is a piece of cake.

You likely will not see any more or any less boost with Bill's tunes.

The truck will definitely run better than it did with the programmer.


Remember, higher boost DOES NOT equal more power.

[flguy1215]

more boost does not mean more power?? ok... i kinda get it but could use a little more explanation there. I mean, i know there is only so much fuel the injectors are gonna throw in there. So, more forced air isn't gonna help without enough fuel? Is that close?? I really hope the truck runs like everyone says it will!! I have always been impressed with the way my truck runs. I have a friend that has the same year same body style truck as me and his felt like it was running about a cylinder down compared to mine. Someone once suggested that I may have a flash programmer on my truck from a previous owner. I have no idea... If there is a flash programmer still on my truck when I install a tuner, will that affect it at all?

[907DAVE]

More boost = more backpressure.

You turbo is designed to operate within a specific "range", get out of that range and backpressure increases, and the air coming out of the turbo is beat up and way to hot.

Cooler, more dense air with low backpressure is what makes power.

As far as stacking tuners..........dont do it!

Buuuut......a chip will override a tuner anyways.

[cleatus12r]

To elaborate a bit......

The stock turbocharger turbine housing (exhaust side) is very restrictive -- especially on the SD trucks from 99-03. It makes decent boost from a low RPM. This comes at a price though and that price is high RPM flow. If you can't get the exhaust out, then you can't get as much air in. On the other hand, the compressor (intake side) is out of it's efficiency range at anything near 24-26 PSI of boost. Anything beyond that does NOTHING for flow and everything for super heating the air that your engine takes in.

Take this example for instance:
When the stock turbocharger is creating about 25 PSI of boost, the drive pressure (exhaust backpressure between the exhaust manifold and the turbine housing inlet) is just above 50 PSI. Mine ran 52 PSI of drive pressure at 24 PSI of boost before changing turbochargers. I could easily break 30 PSI all day (but I never did it more than twice). The difference in drive pressure and boost causes a severe axial (side to side) load on the turbocharger shaft.....this kills the thrust bushing and causes turbo failure.

Any one of the aftermarket solutions (even including a larger, less restrictive turbine housing) will cause less strain on the thrust bushing and allow a higher volume of flow so the drive pressure remains closer to the boost pressure. This will allow the engine to breathe better and make more power....even on less boost.

If your PCM already has an aftermarket program flashed in it's memory, the Phoenix chip will override it anyway.

[flguy1215]

OK awesome thanks for the schooling!!! that was very helpful!

[907DAVE]

*quietly goes back into the corner*

[flguy1215]

ok, a couple more questions. first, how does anyone feel about turbo housing mods? my truck is my daily driver family hauler. it sees very little towing and when it does it may be a boat or a small pull behind camper. so would turbo housing be more to my benifit vs. say a gtp38r? for future mods i may put some stage 1 injectors in but thats about it.

and second question, i already ordered a phoenix ( can't wait!!!!) i was wondering if i can upgrade to an FU? Basicly, just pay the difference for the burner? thanks again for the knowledge!!