How does this setup sound?

[Acepilot1023]

2.9L V6 with true dual straights running through headers and an X-pipe.

Ye, or neigh?

 

[dernst]

It would probably sound cool, but, on a 2.9, I don't feel that duels with a cross over will not buy you any noticible power gains. The extra plumbing is will get in the way, be heavier and more expensive. Besides, do you plan on runing cats?

 

[gaz]

dual "X" VS. 86-87 "H"

"Acepilot1023",

I have made use of the 1987 "H" pipe that is upstream of the cats on both of my trucks. It can be used on later model RBV's also. It will permit duals and facilitate your full dual with "X" concept. My BII has a fully built 2.9l through headers into the "H", then a dual in dual out cat, into a dual in muffler with 2.5" from there. Despite it making great power/torque I am much fonder to the exhaust on my Ranger 2.9l; same headers to the same "H" but then to a 2 to 1 cat, one in/one out muffler and 2.25" from there. The later gets 20% better fuel economy and with the right clutch really puts me in my seat (note use of long sentence).

In summary, I don't recommend your true dual with cross pipe concept. It is an idea I threw around when building these two exhausts and is the reason I took the BII so far back with 2 pipes. I am uncertain what you get for gas mileage but I still believe that low 30's are possible with a manual and the 2.9l. I haven't achieved it yet but haven't given up either. I know that duals any farther than the muffler should help on the very top of the RPM range but I also expect that it will be at great cost in the lower RPM torque and fuel economy.

If you would like more detailed information regarding the exhausts I have put together for this engine, just let me know


.

 

[Acepilot1023]

Nah, I don't plan on running cats, so it should be a little bit louder and deeper. What I usually do is take a cat with a 3" opening and slide it on top of a 2 1/2" pipe and weld it up there. That takes care of the legal issue.

Gaz, thanks for your input. I like the H pipe concept. But mileage isn't a big issue for me. Haha, after a lift kit and bigger tires, I get 12 MPG.

 

[gaz]

Mpg with lift and rubber

Hey Ace,

My BII and Ranger are both lifted with some decent rubber. The BII (auto) has a 4" suspension with 33" rubber; best while towing was 24mpg at 2.5k RPM from Melling Or to Seattle Wa. The Ranger (manual) has a 3" body lift and the 2" Hi-Rider Ford suspension lift (5 inches total) with 33's and gets 28mpg on the highway.

If you are only getting 12mpg, you could double it. When I originally went from stock tires to 30.5x9.5-15's, my mileage dropped from 25mpg highway to 18mpg on a good day. My quest to regain my original mileage after the tire change is the whole reason I still have my Ranger and that it pulls 28mpg with the 5" lift and 33's!

Kevin

 

[dernst]

Those mileage claims are a bit exaggerated. I have JBA headers and everything is match ported. With a brand new engine, fresh injectors and everything working flawlessly, the best mileage I could get was 24 MPG. This is with 31" tires and mostly flat land freeway miles (probably also had a tail wind). I regeared the rear and the odometer/speedometer has been checked using a GPS

Read the threads about mileage. 28 MPG with 33" tire is delusional. There must be an error in the calculation.

 

[gaz]

Improving on the original

"dernst"

I think 24 mpg on 31's with an auto tranny is a significant achievment! You have done well. It has been suggested before that the work Ford did engineering this engine may be hard to improve upon. I am not yet certain that rebuilding anything other than stock will surpass the original's potential... but I am going to continue to attempt it.

Kevin