Open Exhaust?
Thread Starter
|
Senior User
Joined: Jun 2015
Posts: 114
Likes: 0
Open Exhaust?
Hello my fellow Ford Enthusiasts! I have a quick question. I've heard through the grape vines that running straight headers, or an open exhaust will harm your engine and cause exhaust valves to crack, but I 've also heard this is an old wives tale. So I have an 89 Ford F-150 XLT Lariat Longbed Pick-Up truck with the Fuel Injected 5.8 Liter 351 Windsor. I can't afford headers at the moment so I cut off the exhaust right before where the two pipes from each exhaust manifold connected together. There is no muffler, or cat on it. All there is is maybe three foot of piping coming from one exhaust manifold and about a foot and a half from other. My question is will this hurt anything? I drive it daily and I never hear any backfiring, or anything. The only reason I did this is because I love sound of open exhaust. I live in South Carolina where it gets up to 115 degrees in the Summer and down to 18 degrees in the Winter.
Thread Starter
|
Senior User
Joined: Jun 2015
Posts: 114
Likes: 0
I mean its not like it's straight exhaust manifolds. There is a decent amount of pipe afterwards. I don't think it will hurt anything I just want a second opinion. Also, my oil pressure gauge fluctuates between the "M" in the NORMAL section to nothing at all and the red "Engine" light comes on. Do you think it's he oil pressure sender/sensor?
Thread Starter
|
Senior User
Joined: Jun 2015
Posts: 114
Likes: 0
Well I plan on keeping the pipes connected to the manifolds anyways. I wouldn't run straight manifolds anyways. Is it ok for long trips? Like 200 mile trips? What do you think about the oil pressure? The truck only has 169,400 miles on it. I doubt the oil pump bad ya know.
Posting Guru
Joined: Sep 2013
Posts: 1,033
Likes: 0
If its fine for warm up and idling around its fine for a long trip like that. At that mileage I recommend having a real oil pressure gauge to get good readings. I seen some engines have great pressure at that mileage and soon that barely hold two psi.
Thread Starter
|
Senior User
Joined: Jun 2015
Posts: 114
Likes: 0
Trending Topics
Posting Guru
Joined: Sep 2013
Posts: 1,033
Likes: 0
I recommend doing so. you can either rig up a T with some pipe fittings or just run strictly the mechanical gauge and deal with the dash gauge not working. its an idiot light anyways.
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
AEV FXL Super Duty - the Super Duty Raptor Ford Doesn't Make
Brett Foote
Lobo Vs Lobo: Proof the F-150 Lobo Should Be Even Lower!
Michael S. Palmer
Ford's 2001 Explorer Sportsman Concept Looks For a New Home
Verdad Gallardo
10 Best Ford Truck Engines We Miss the Most!
Joe Kucinski
2026 Shelby F-150 Off-Road: Better Than a Raptor R?
Brett Foote
2027 Super Duty Carhartt Package First Look: 12 Things You NEED to Know!
Michael S. Palmer
10 Most Surprising 2026 Ford Truck Features!
Joe Kucinski
Top 10 Ford Trucks Coming to Mecum Indy 2026
Brett Foote
5 Best / 5 Worst Ford Truck Wheels of All Time
Joe Kucinski
Posting Guru
Joined: Sep 2004
Posts: 1,556
Likes: 5
The gauge fluctuation is likely a corroded wire connection at the sensor or a bad sensor. Like said, its basically an on/ off switch, if you have the least acceptable oil psi, it will show good, if not, itll show zero, no in between.
Running your exhaust as described wont necessarily hurt anything but without modifying the tune, itll affect low end power, even if its not obvious.
Experienced the differences many times running open exhaust to the muffler shop, to realize it got its ***** back once the exhaust was put on.
Running your exhaust as described wont necessarily hurt anything but without modifying the tune, itll affect low end power, even if its not obvious.
Experienced the differences many times running open exhaust to the muffler shop, to realize it got its ***** back once the exhaust was put on.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
If the motor had a carb on it then you could expect the motor to run lean and possibly burn valves or melt a piston with the exhaust all chopped off because a carb has no way to adjust itself, but EFI self adjusts constantly so it can work and not result in any engine damage. However it sounds like you cut off the part of the exhaust with the O2 sensor in it and if so that will have a negative effect on fuel consumption and engine life and it would be best for both of you put at least a couple feet of tubing on each side and reinstalled the O2.
Thread Starter
|
Senior User
Joined: Jun 2015
Posts: 114
Likes: 0
Actually whenever I bought the truck the exhaust system consisted of a pipe running from each exhaust manifold and them two pipes running into one pipe and connected to a "Thrush" 31-Inch Glasspack. It had no cat, or anything. I only seen one O2 sensor and it was located right where both of the two pipes connected together, so I cut the exhaust off right after that sensor.
FTE Legend
Joined: Jun 2006
Posts: 31,930
Likes: 1,499
From: Ottawa, Ontario
The truck should only have one O2 sensor but it's not good for it to be right at the end of the exhaust it should have at least a few feet behind it to prevent fresh air back washing the sensor and totally messing up the readings.
