I have an 03 ranger sohc 4.0 does running headers on these motors cause you to loose torque? Due to too much flow. My exhaust is 2 quarter from the cats back. And I'm running a 40 serious flow master. THANKS!

 

I'm no expert on headers on a 4.0, but the stockers actually look pretty decent.

 

ive never heard of it loosing tourqe... but it doesnt increase that much either...

 

Thanks for the input guys!

 

SOHC stock headers flow well compared to the OHV that do not. You won't get much improvement to the SOHC. The last cat has a 2 1/2" diam tube that reduces down to 2 1/4". You should see better inprovement if you get rid of the reducing flange and run full 2 1/2" from cat to and from muffler.

 

So the combo of larger Cat Back exhaust and Headers gives a decent return?

 

Well, my '07 has a cat on each side after the manifold then a 3rd larger cat @ the Y-pipe union. I went with the Dynomax 2-1/2" cat-back kit to get a better sound and flow. I noticed a little top end improvement and better sound but no other real changes. On mine, the Y-pipe has some significant factory kinks in it for clearance that appears to be more of a potential flow problem than the factory manifolds on the 4.0 SOHC.

For less than $200 delivered, the cat-back system acheived what I was looking for. I have doubts regarding the cost of headers-vs-effectiveness without addressing the Y-pipe & the factory cats. When you add those to the equation that is a lot of $$$ for what the potential gain would be on a stock engine. That's my opinion.

 

I port and polished my 97 b4000 header than removed a cat and ran the exhaust out the side to keep the 3 inch pipe from the flow master increased power by like 20 hp maybe helps it get to 107mph a little faster still sucks off the line

 

Read and understand.
CobbTuning.com - Exhaust Design

 

20 hp?

Says who? Your butt dyno?

 

Interesting. I can barely tell the difference on 50-60whp after actually measuring it myself. Sounds like a bunch of tom-foolery to me.