Head scratcher

[cougar]

Once again my 91 proves its weirdness.
I recently installed a Diamond Eye 4" exhaust in an effort to lower my EGTs and perhaps gain some power in the process. No other changes.
Well I obtained my initial goals, but in the process acquired a new problem that makes no sense. I now have a huge turbo lag similar to when I still had the 21cm2 turbo housing. With that lag also comes a huge black (very black) fart cloud. It clears once the turbo spools.
1st I tried the star wheel adjustment. No change at all.
2nd I installed a home made AFC spacer to give the fuel pin more up travel (.110"). Helped some with the smoke but nada on the lag.
3rd I pulled the DP and intake hose to check the turbo for condition and for any visible restrictions. Spins free, no damage, and no restrictions.

Any ideas?

[dvst8r]

Did you take the turbo off the truck when you were doing this?

[cougar]

Did you take the turbo off the truck when you were doing this?

No. I had the front drive shaft out so it went in from the bottom.

[dvst8r]

Coincidental boost leak?

I am assuming 4 inch downpipe? If so how soon does it flare to 4"?

[cougar]

Coincidental boost leak?

I am assuming 4 inch downpipe? If so how soon does it flare to 4"?

If there is a boost leak, can't be much. I'm burying my boost gage now with it.
There is just enough room for the clamp before it goes to 4" on the DP.
I'm beginning to think I need a smaller turbo housing and/or a bigger turbo with a smaller housing.