[Chevy71]

Originally Posted by Joe's_cool_1le

My AEM gauge shows me at 14.7 at idle and goes down to around 11.2 at WOT. Does that mean I can get more out of her? I do know I have to change to headers and 2nd cat delete to get more air coming out too (going to do that soon) but wondering if my ATF being 11.2 is on the conservative side too?

That's a matter of opinion it seems lol. I would say your leaving horsepower at that AFR, and most hot rod tuners would push it a little further.

[jwdominick]

Originally Posted by JANNETTYRACING

Each tuner has his or her own preference and I respect that.

.86 is 12.65 AFR.

That is a lot leaner than I would like to see and explains why you could stretch the fuel so far with your set up.

On the dyno .85 is where they seem to make the most power but we run them at .78-.80 for cooling on pump gas especially on long pulls past 1/8 mile.

I have no trouble running them at .85 on Race Gas.

You have a very nice set up Congrats, and enjoy.

My experience with di engines is that you can go closer to stoich than traditional efi. My last boosted vehicle was the tt bmw n54 we ran much closer to perfect stoich with minimal detonation correction. Then again that was also on high ethanol content mixes.

[ProCharger]

Originally Posted by Hyper SS

12.65 is almost a N/A tune. We would shoot for 13-13.3 when I had my dyno. F/I cars were 10.0-11.0 max AFR. So Ted has a very valid point. 12.65 is way to lean for F/I car.

DI motors are very different.


Important factors of why GDI engines are different.

- The way fuel mixes in the combustion chamber.
- The amount of time to get fuel into the combustion chamber.
- The duration of injector pulse time
- The amount of fuel used to remove heat from the chamber.
- The amount of fuel used for actual combustion


Overly rich conditions will lead to....

- improper combustion,
- raised emissions output, (by alot)
- hard to detect "rich" misfires (bad bad bad for cats)
- overall poor performance,
- extra stress on the fuel system.
- oil film stripped from the combustion chamber walls.
- raw fuel sent out the exhaust (poor kitty cats again)


The nice thing about DI motors is that it has taken a LOAD of the hassle out to tuning for all the different brands of port injectors and all their issues. Sizes, data, spray patterns, wall-wetting, etc. So at least that's nice.

[JANNETTYRACING]

Originally Posted by ProCharger

DI motors are very different.


Important factors of why GDI engines are different.

- The way fuel mixes in the combustion chamber.
- The amount of time to get fuel into the combustion chamber.
- The duration of injector pulse time
- The amount of fuel used to remove heat from the chamber.
- The amount of fuel used for actual combustion


Overly rich conditions will lead to....

- improper combustion,
- raised emissions output, (by alot)
- hard to detect "rich" misfires (bad bad bad for cats)
- overall poor performance,
- extra stress on the fuel system.
- oil film stripped from the combustion chamber walls.
- raw fuel sent out the exhaust (poor kitty cats again)


The nice thing about DI motors is that it has taken a LOAD of the hassle out to tuning for all the different brands of port injectors and all their issues. Sizes, data, spray patterns, wall-wetting, etc. So at least that's nice.

Great thread, What Lambda do you prefer with your superchargers.

Ted.

[Hyper SS]

Originally Posted by ProCharger

DI motors


Important factors of why GDI engines are different.

- The way fuel mixes in the combustion chamber.
- The amount of time to get fuel into the combustion chamber.
- The duration of injector pulse time
- The amount of fuel used to remove heat from the chamber.
- The amount of fuel used for actual combustion


Overly rich conditions will lead to....

- improper combustion,
- raised emissions output, (by alot)
- hard to detect "rich" misfires (bad bad bad for cats)
- overall poor performance,
- extra stress on the fuel system.
- oil film stripped from the combustion chamber walls.
- raw fuel sent out the exhaust (poor kitty cats again)


The nice thing about DI motors is that it has taken a LOAD of the hassle out to tuning for all the different brands of port injectors and all their issues. Sizes, data, spray patterns, wall-wetting, etc. So at least that's nice.

Thanks for clearing that up. I owned a dyno 15 years ago....lol

[Chevy71]

I'm already looking for more power. I'm looking at possibly getting set up to do forged bottom end, but definitely want more boost. So I'm thinking about going with a D1X head unit. My P1S may be up for sale shortly. It has roughly 13,000 miles on it as of now. What is the thoughts on dropping forged rods and pistons in my engine, or doing the 416 bottom end by Texas Speed? I feel like if I go more boost and power I will need to improve bottom end strength and probably fuel.

[Clin5910]

If you go d1 are you going to get a whole new kit and sell a complete p1 kit, or just buy the d1 head unit and sell the p1 head unit?

[Chevy71]

Originally Posted by Clin5910

If you go d1 are you going to get a whole new kit and sell a complete p1 kit, or just buy the d1 head unit and sell the p1 head unit?

Only the head unit. I went with the larger intercooler when I got my set up, so there is no reason to change anything else with th other components in my pro charger set up.