Downpipe Loss Measurement?
Thread Starter
|
Laughing Gas
Joined: Feb 2014
Posts: 774
Likes: 25
From: Reno, Nevada
Downpipe Loss Measurement?
The previous owner had a problem with the egpbv sticking closed and I'll be deleting it soon. The darn downpipe just looks inefficient and I know it's pretty much a standard upgrade when working on the backpressure valve system.
I know that everything that looks bad isn't always necessarily bad. Has anyone measured the actual pressure drop across that downpipe? Any real numbers for the loss, like in psi or inches of water? I'm sure not trying to second guess the conventional wisdom, but I'd like to see some numbers. If no one has done it I have a pressure transducer, I can tap a couple of ports and I'll give it a try.
Thanks,
Bob
I know that everything that looks bad isn't always necessarily bad. Has anyone measured the actual pressure drop across that downpipe? Any real numbers for the loss, like in psi or inches of water? I'm sure not trying to second guess the conventional wisdom, but I'd like to see some numbers. If no one has done it I have a pressure transducer, I can tap a couple of ports and I'll give it a try.
Thanks,
Bob
Thread Starter
|
Laughing Gas
Joined: Feb 2014
Posts: 774
Likes: 25
From: Reno, Nevada
Yeah, I think it will be interesting. I didn't want to re-invent the wheel, but if it looks like no one else has done it, I'll get after it.
Has to be done sorta scientifically because I think low pressure measurements are tricky and I don't want to be spreading false numbers around.
Bob
Has to be done sorta scientifically because I think low pressure measurements are tricky and I don't want to be spreading false numbers around.
Bob
Post Fiend
Joined: Dec 2010
Posts: 10,121
Likes: 3
From: Orrville, Ohio
I don't know that anybody has done actual measurements in the past, but it would be cool to see it done! I just cut my old stock piece out a couple nights ago so if it would help for any measurements, etc let me know and I'll get you some numbers. IIRC when I have measured them in the past I have found the stock DP to be approximately 1x4" and clearly the 3" would be 3" diameter. just comparing those two from area alone is pretty telling. Clearly a 1x4 pipe has an internal are of 4 in/sq whereas a 3" round pipe has an area of 7.065 in/sq. That's a pretty sizable difference. I know that's just a rough guesstimate but you get the idea.
Hotshot
Joined: Dec 2006
Posts: 14,069
Likes: 17
From: Melbourne, Ky
While size isn't everything (where have we heard that before) the flow dynamics also needs to be taken into account. Just looking at the factory downpipe to me, looks very inefficient. Some actual flow numbers would be interesting!
Welcome to FTE!!
Welcome to FTE!!
Fleet Owner
Joined: Aug 2004
Posts: 20,419
Likes: 197
From: AZ
Trending Topics
Thread Starter
|
Laughing Gas
Joined: Feb 2014
Posts: 774
Likes: 25
From: Reno, Nevada
The truck is a '96 and as far as I know is completely stock. My initial plan is to install a port somewhere on the egbpv housing, after the valve is deleted. Then measure the exhaust pressure of the complete exhaust system at say 2500 RPM. Then remove the muffler and repeat the measurements. Then remove the cat and repeat again, which should show just the backpressure on the downpipe. Then install one of the round aftermarket downpipes and repeat the measurement. I want to take several measurements at each point to make sure they are all within a reasonable range.
I'm not sure what to expect as far as backpressure on just the downpipe. I have a Fluke PV350 digital pressure measurement sensor but it's +/- 0.3 psi accuracy. If it reads 0.5 psi then the actual pressure could be from .2 to .7 psi and I'd like to do be more precise than that. I ordered a 0 to 3 psi analog dial gauge to back up the Fluke.
The above is just my initial poorly thought out plan and I'd appreciate any comments or suggestions.
Bob
I'm not sure what to expect as far as backpressure on just the downpipe. I have a Fluke PV350 digital pressure measurement sensor but it's +/- 0.3 psi accuracy. If it reads 0.5 psi then the actual pressure could be from .2 to .7 psi and I'd like to do be more precise than that. I ordered a 0 to 3 psi analog dial gauge to back up the Fluke.
The above is just my initial poorly thought out plan and I'd appreciate any comments or suggestions.
Bob
FTE Stories
Ford Trucks for Ford Truck Enthusiasts
Top 10 Most Expensive Ford Trucks Ever Sold on Bring a Trailer
Joe Kucinski
2027 Ford Super Duty Buyer's Guide (Every Model, Engine, & Package)
Brett Foote
Top 10 Ford Truck Tragedies
Joe Kucinski
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
Post Fiend
Joined: Dec 2010
Posts: 10,121
Likes: 3
From: Orrville, Ohio
I think it sounds like a good plan. If you intend to put the port in the EBPV housing, you may consider drilling and tapping the freeze plug that you install to block off the hole in the housing for the shaft. The thing I'm not sure of though is how you would be best to install the port so the gasses flowing past it don't create a Venturi effect and skew you readings.
Thread
Thread Starter
Forum
Replies
Last Post
TheTowingCowboy
1994.5 - 1997 7.3L Power Stroke Diesel
7
Jul 31, 2009 08:32 AM