I installed a snorkel 2 1/4 exhaust pipe. Then installed a Thorley header with no cat and generic flowmaster with 2 1/2 pipe all the way back. It seems like I lost power. Do I need to have a muffler on it to create some backpressure to get my power back? Oh yeah 1.6 16v

Should put the size motor         but yes the lack of back press can rob power

2 inch for these engines, but you could try putting on a 1-3/4 or 2"
after your muffler and see if it creates a torque tube affect that they
are doing on the new trucks, the only problem might be I think they
are tuned lengths for the displacement of the engines.

This works like an expansion chamber on a 2 stroke motorcycle

Wild

How is your snorkle filtered? through the airbox, or did you just put a filter on the end?

Yes its filtered throught the airbox with a K&N Filter.

got any pics of how you did the snorkel? is it a kit or did you make it?

Here's one I made for my samy that's filtered through the original air box.

Granted, My engine is turbocharged, but I also run a snorkle, through the airbox with a K+N filter, the downpipe from the turbo is 2.5 ", NO cat, and 2.5 " tubing through a turbo style muffler and out through a 2.5" tailpipe. Mine is no stump puller down low, but it sure didn't lose any power when I built the 2.5" system. Maybe 2.5" IS too big for a stock engine, your just not moving enough air to utilize that big of diameter. IMO, I'd probably go back to a 2" system all the way on a stock engine.

Yeah I'm going back to 2". 2 1/2" is just too much for a stock engine.

The turbo provides all the back pressure you need, so the better the exit
exhaust flow is the more potential for power.

Wild

So maybe I should keep the exhaust and get a turbo!!! hahahah  I think that may be a little over my head right now.  All the broken and seized bolts are keeping me busy enough with my Calmini 3" install and widening mod. Unless someone has a complete turbo set up they would want to get rid of

Smife,
I put a header on my 16v kick and it seemed to lose torque in a big way. I'm running 2.5" pipe with cat and homemade muffler. Straight through. I'm thinking about getting rid of the header!
Kj

It's not the header, it's too big of pipe.

Yep, you need a 2" pipe instead, don't take any lessons
from Rice Rockets, those are patterned after racecars
with turbo setups

Bentparts,
You think a 2" tailpipe would help? May try that first!
Thanks,
Kj