Mileage Mods
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Mileage Mods
I'm thinking of tinkering with my 94 F150 4X4 5.8 to see what kind of mileage improvements I can get out of it. I have a set of Hooker 27in long x 1.5 diameter primary headers with 8 inch collectors. I am thinking of installing them along with header wrap, an Accel ignition kit that provides spark advance control with multi-spark discharge through 20 degrees crankshaft rotation. The exhaust system I am thinking of will consist of 2.5 inch pipes with the left one being routed around the back end of the transmission pan, running into the stock cat which will be modified with a 3 inch outlet. A 50 series flowmaster with a 3 inch single exhoust. Has anyone tried this? Also where should I weld the bung for the O2 sensor? Then lastly, can I route a pipe up from the collector to the EGR or do I need to weld a pipe into the primary?
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Joined: Mar 2006
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From: Venetia, PA
I have a 93 that I put full length headers on and dual exhaust. I ran the drivers side pipe back to the crossmember and then parallel to it until it met the passenger side exhaust pipe which I ran straight back (with a little hoop de do to go under the crossmember. The two pipes then run straight back for a few inches until they go into a flange I made to convert from dual 2 1/4" to dual 3". My cats are two 3" magnaflows. From there on both pipes are identical. 3' of 3" pipe into a 3" turbo muffler to a 3" turn down right before the axel. I put the O2 bung in a short H pipe I put between the 2, 2 1/4" pipes right before the cats. For you, you could to the same before the cats with 2 1/2" pipe, then they make dual 2 1/2" inlet cats with a single 3" outlet, or if you can get your stock cat to work, that should work just fine, with the exception that you loose a little power (not alot) since its not a high flow cat. IMO if your gonna modify your exhaust, splurge on a new cat. Its worth it. From the cat back you can just run a single 3" exhaust and muffler like you said. Good luck with the project!
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Joined: Jun 2006
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From: Ottawa, Ontario
Originally Posted by Hawk180
I'm thinking of tinkering with my 94 F150 4X4 5.8 to see what kind of mileage improvements I can get out of it. I have a set of Hooker 27in long x 1.5 diameter primary headers with 8 inch collectors.
Originally Posted by Hawk180
I am thinking of installing them along with header wrap, an Accel ignition kit that provides spark advance control with multi-spark discharge through 20 degrees crankshaft rotation.
Originally Posted by Hawk180
The exhaust system I am thinking of will consist of 2.5 inch pipes with the left one being routed around the back end of the transmission pan, running into the stock cat which will be modified with a 3 inch outlet. A 50 series flowmaster with a 3 inch single exhaust. Has anyone tried this? Also where should I weld the bung for the O2 sensor?
Originally Posted by Hawk180
Then lastly, can I route a pipe up from the collector to the EGR or do I need to weld a pipe into the primary?
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Conanski, The collector is 2.5" in diameter and 8" long. Sorry, I should have specified. As far as welding a pipe for the egr to the primary, I hate to do that as the headers are ceremic coated. I suppose I could get my local powder coater to repair it once the pipe is welded on. BTW the headers are the Hooker HOK 6912-1hkr part number.
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Joined: Mar 2006
Posts: 590
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From: Venetia, PA
I have my O2 sensor about 2 ft farther back than the stock location, and it doesnt trip the CEL, hurt mileage, make it run rough, rich/lean or blow smoke or do anything wrong for that matter. I see no reason why it cant be located in the crosspipe if thats more convenient.
