I just did a L with stock exhaust. Went to a maggy cat-back, Dynateh LTs and no cats with an 8# bottom pulley. L was making almost 16#s with a 6# bottom. Just drove it with new setup and now its only making 11#s with an 8# bottom pulley. I never seen this kind of a boost drop. Truck has a JDM chip and a lot less bottom end power than it previously had. We are letting it cycle 10 times as per JDM so it can reprogram itself to new mods and chip while adapting a strategy. Im thinking of trying the 12# lower pulley next week. What do you guys think?

 

suavy was selling a 16# lower..
give that a try

 

They make pulleys that big?

 

Guess they do.

 

Stock Eaton? I saw a 1-2 lb drop in boost with longtubes and high flow cats....That loss does seem excessive though...

 

Something is bad wrong; the is no way you will lose boost that much.

 

yeah ... just give it time to reprogram and see what happends

 

Does a chip affect your max boost numbers?I mean as long as you are seeing 5400 or so rpm... ..

 

DP...sorry

 

Im thinking a severely clogged intercooler could also be the culprit in the boost drop.....

 

Where the heck do you buy lower pulleys that freaking huge?

 

yeah... after the day had cooled down my boost went up some but not much

 

Boost does NOT mean everything.

If your engine is breathing better... because of better heads or exhaust etc......you just have the better airflow ...this may lower your boost, but not decrease your performance. Having lower boost at the same airflow is a good thing. It just gives you more overhead to add more boost. Airflow is power, NOT boost.

An engine is just an airpump...more air in and out = more power.

 

More backpressure = more boost. You dumped your backpressure when you dropped the cats. You truck is probably making great power. You just can't see that on a gauge.

 

Grimace,
You said it better. What he has is a good thing.