Can anyone speak about performance on a 4.6L with the new magnaflow same-side exit? How much would this eliminate backpressure as compared to a rear exit? As this exhaust is forward of the rear tire, would this be a better choice as far as off-road clearance? The cost is the same so that plays no part. Suggestions?

Regards,
C.

 

Well, even though the piping is mandrel bent, avoiding the over-the-axle bends will improve your exhaust flow. I have a Flowmaster 40 series muffler that is dumped before the rear axle, and I noticed some definite performance increases that I can't completely credit the Flowmaster with. I understand that removing the piping over the axle improved my exhaust flow.

 

Hey 4.6,
Is your Flow a SISO or SIDO? I haven't seen a SIDO forward o/t rear tire on anything except custom or magnaflow. Also, have you noticed any oxidation on the rims from the exhaust? Thanks for the imput. Much obliged.

Regards,
C.

 

Actually, I don't have any pipes after the muffler. The Flow is SI/SO and then I just have it dump out on the ground (under the truck). I was looking at the Magnaflow kit that exits before the rear tire and it looks sweet. If Magnaflows are superior to Flows I'd be tempted to get that kit. By the way, you can expect your rim to get very dirty.

 

I figured the rims are going to get oxidized a bit. I've seen a few trucks that have been slammed and the exhaust comes out of a riveted hole o/t body. That looks good for a slammed truck, but I always wondered about the "soot" build-up.

Magnaflow's does look pretty sick exiting in front o/t tire, but it all goes back to performance. As in, the least amount of backpressure, etc. I'm also concerned about too little backpressure on the "smaller" 4.6, on the shorter pipe. Have you run into any issues when you switched up from OEM?

I also have the possibility of getting an exhaust done through Gibson free of charge, if I drive out to Corona. That would be a SIDO exit in the rear. Decisions, decisions....

 

BUMP

 

Nice pics Noir,
Too bad they didn't show in the forum. Is that a 3" or 2 1/2" pipe? The SS looks very clean--almost too clean--you gotta get some mud on that truck quick!

 

c0ckac0la, no loss in low end whatsoever. I have gained a lot at higher RPMs and have picked up about 2 MPGs as well. I was told by my muffler guy (good friend, I trust his advice) just to run a single exhaust rather than true duals (two pipes from manifold back) because I would lose low end on the 4.6. With SI/DO mufflers you gain less than with a SI/SO muffler just because the velocity of the exiting gasses are split. However, you're going to see decent gains no matter what you run as soon as you get rid of that massive stock muffler. I would only run true duals if I supercharged my truck, because I would gain more from increased exhaust flow than I would lose in torque. However, plenty of guys on here have run true duals on the 4.6 with considerable success.

 

It's been muddy...about 7 years ago. I just take it to dunes know. When I replaced the spark plugs last weekend, every single sparkboot and chamber STILL had mud in it from 7 years ago.

Here's the photos:






More are in My gallery

 

Noir - looks good - I just ordered the Magnaflow SIDO to the rear and can't wait to get them installed.....yours looks sweet - is that the stock Magnaflow dual to the rear kit, i.e., what I can expect?

 

Noir,
Good choice on the mods. Are you happy with the AF1 intake? I haven't decided who to go with, but I know granatelli offers a performance MAF sensor that reconfig's the computer to draw in more air, couple that on to their CAI or another, and that could have some great gains. I read a mag article where they strapped their MAF onto a '99 lightning and had better gains than with a superchip alone. They combined the two and got about 50 HP to the wheels. That mod will come after I free up the exhaust. Hence, the reason for the 20?'s RE side vs. rear.

4.6,
My original question about the exhaust, regarding SIDO, was with the intention of getting a MAF and CAI as well. What would your friend advise with that in mind?

PS~I had no intention of running true duals on the 4.6, unless supercharged and/or headers.

 

With those mods the exhaust is only going to help you. You'll gain plenty - I believe the loss in a SI/DO system is negligable over a SI/SO. I'm also planning on an Air Force 1 myself when my funds allow. Please educate me on the MAF sensor. I'm totally clueless, but it sounds like a must-have from what was said earlier. Of course, if I'm taking that much more air in, I may have to put headers and true duals on too - what a shame!

 

4.6,
I did a bit more research about MAF upgrades. Check out this thread to understand more. https://www.f150online.com/forums/showthread.php?t=155174&highlight=MAF+upgrade . I can say that it has changed my opinion a bit about granatelli vs. another brand. The one thing I can say is that with a new MAF sensor and a CAI such as AF1, you really should have the engine tuned well. The upside I had seen to granatelli--previous to the threads--was that they claim not to require an aftermarket tune. They claim to have a custom tune done pre-ship. It is a little unclear if that is the case or not. For the money, I'm going to look into just flat out upgrading the size to the 90mm from a Lightening ED. Check out granatelli if you want for a play-by-play of MAF sensors and how they work. http://www.granatellimotorsports.com/fordmaftruck.htm

To NE1,
Does AF1 whipple the intake pipe on their CAI? Supposedly this also reduces the turbulence in the intake as the wider, less restrictive MAF should.

 

Sorry, did that backwards... :o
MAF thread

Granatelli MAF info