[Nabush]

Guys,

Strange....

I put my MSD Intake manifold this WE.

Before I had an AFE CAI and American Racing headers LT / X pipe with cats.

With this setup I had to add 5% more fuel at WOT to have a Lambda at 0.85-0.87. (12-12.2 AFR for E10 all pumps have so 14.1 stochio not 14.7)

I kept the same tune with the MSD....then I was running very rich (Lambda at 0.79 = 11.1 AFR for E10)

I had to go back to stock fuel trims to run back in the Lambda = 0.87 range...

I'm kind of surprised, I would have thought this IM would suck more air and then make the engine run leaner.... But when I look at my MAF mass air flow value i definitely see higher air volume through the rev range....

Can someone explain to me that ?

I'm new to tuning but this doesn't seem to make sense to me...

Thanks

[Juiced1]

The MSD intake has more Volume. So you're pushing more air through but there is less pressure. Make sure you check your manifold pressure.

[Nabush]

Originally Posted by Juiced1

The MSD intake has more Volume. So you're pushing more air through but there is less pressure. Make sure you check your manifold pressure.

Barometric pressure and manifold absolute pressure are the same both before and now with the MSD when I look my datalogging

The MSD has more volume and less drag/more flow (like less backpressure if we can say). I don't get what you say about pressure, pressure will stay the same inside the intake manifold or be a little higher/compared to stock inside the intake manifold since there is less resistance for the air to go through....