5.9 Fuel Economy Rebuild
All Star
Joined: Jan 2009
Posts: 907
Likes: 2
From: Corrales, New Mecico
Why?
I knew this would come up...I have 4.10s for my Ram's Dana 60, I bought them before I towed with it because I read the same advice you just handed out...
I'm not going to tow at 65-70 with the OD ON....With the 3.55 gears and OD OFF, I'm around 2500 RPM at 68 mph. Perfect.
That's why.
I knew this would come up...I have 4.10s for my Ram's Dana 60, I bought them before I towed with it because I read the same advice you just handed out...
I'm not going to tow at 65-70 with the OD ON....With the 3.55 gears and OD OFF, I'm around 2500 RPM at 68 mph. Perfect.
That's why.
All Star
Joined: Jan 2009
Posts: 907
Likes: 2
From: Corrales, New Mecico
I mis-spoke. The spintechs don't come in 1-1/2, instead it's actually only 1-3/4 unless you get the longtube Dakota headers and they'll have clearance issues. Pacesetter is only longtube available in 1-7/8 for the rams.
I have the 2bbl m1, 1.5" JBA shorties, and a 52mm tb and the powerband is strong throughout. Good down low and up high and everywhere in between.
I have the 2bbl m1, 1.5" JBA shorties, and a 52mm tb and the powerband is strong throughout. Good down low and up high and everywhere in between.
FYI...get ready to take it all back to stock if the EPA get's its way this July, vote Republican, I dont care who it is.
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Rookie
Joined: Oct 2013
Posts: 86
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From: Arkansas
Afraid not. It's the old can of beads style catalytic converter that's the killer.
Again, as others have already told you, it depends on your application. I started this thread with the words "fuel economy" in the title. . . that should be your first clue. If I wanted to sacrifice 2-3 mpg just to have an additional 15 horsepower for the 0.05% of the time I have the engine at 3500 rpm, I'd have done a lot of things differently.
This isn't the 1970s where the butt-dyno and Joe-Bob engine builder's secrets to horsepower reign supreme. This is the age of empirical data and scientific testing. Try to catch up.
Thread Starter
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Rookie
Joined: Oct 2013
Posts: 86
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From: Arkansas
Based on what data. . . your gut feelings?? Scroll up to page two and read the link I posted where stock manifolds vs shorties vs longtubes were tested.
Afraid not. It's the old can of beads style catalytic converter that's the killer.
Again, as others have already told you, it depends on your application. I started this thread with the words "fuel economy" in the title. . . that should be your first clue. If I wanted to sacrifice 2-3 mpg just to have an additional 15 horsepower for the 0.05% of the time I have the engine at 3500 rpm, I'd have done a lot of things differently.
This isn't the 1970s where the butt-dyno and Joe-Bob engine builder's secrets to horsepower reign supreme. This is the age of empirical data and scientific testing. Try to catch up.
Afraid not. It's the old can of beads style catalytic converter that's the killer.
Again, as others have already told you, it depends on your application. I started this thread with the words "fuel economy" in the title. . . that should be your first clue. If I wanted to sacrifice 2-3 mpg just to have an additional 15 horsepower for the 0.05% of the time I have the engine at 3500 rpm, I'd have done a lot of things differently.
This isn't the 1970s where the butt-dyno and Joe-Bob engine builder's secrets to horsepower reign supreme. This is the age of empirical data and scientific testing. Try to catch up.
A working unclogged cat has very little detriment on anything short of a race engine.
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Rookie
Joined: Oct 2013
Posts: 86
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From: Arkansas
The gen 2 ram has a first generation catalytic converter which is sometimes referred to as a "can of beads" style cat. It is a large flat canister packed full of platinum-coated BBs located on the Y-pipe just after the merge. This generation of catalytic converters are well known to be extremely restrictive to exhaust flow. If you just remove it, you'll only see small gains because all the other stock exhaust components each act as a bottleneck to flow in their own right. There are studies that show that a well designed and properly tuned exhaust system loses quite a lot of power to this style of catalytic converter versus the newer generation honeycomb style cats which are far less restrictive, and that even the newest, best flowing cats significantly rob power compared to no cats. So if you're going to keep all exhaust components stock, then the cat by itself isn't going to make a huge difference. But even a mild exhaust upgrade will start to show that the cat is a real impediment to flow.
Last edited by Big Green 360; Feb 27, 2016 at 11:36 AM.
All Star
Joined: Jan 2009
Posts: 907
Likes: 2
From: Corrales, New Mecico
Based on what data. . . your gut feelings?? Scroll up to page two and read the link I posted where stock manifolds vs shorties vs longtubes were tested.
Afraid not. It's the old can of beads style catalytic converter that's the killer.
Again, as others have already told you, it depends on your application. I started this thread with the words "fuel economy" in the title. . . that should be your first clue. If I wanted to sacrifice 2-3 mpg just to have an additional 15 horsepower for the 0.05% of the time I have the engine at 3500 rpm, I'd have done a lot of things differently.
This isn't the 1970s where the butt-dyno and Joe-Bob engine builder's secrets to horsepower reign supreme. This is the age of empirical data and scientific testing. Try to catch up.
Afraid not. It's the old can of beads style catalytic converter that's the killer.
Again, as others have already told you, it depends on your application. I started this thread with the words "fuel economy" in the title. . . that should be your first clue. If I wanted to sacrifice 2-3 mpg just to have an additional 15 horsepower for the 0.05% of the time I have the engine at 3500 rpm, I'd have done a lot of things differently.
This isn't the 1970s where the butt-dyno and Joe-Bob engine builder's secrets to horsepower reign supreme. This is the age of empirical data and scientific testing. Try to catch up.
I'll just race my low 11 second NA Dodge Dakota at 7000' DA, because I don't know what the **** I'm doing.
All Star
Joined: Jan 2009
Posts: 907
Likes: 2
From: Corrales, New Mecico
The entire exhaust system on the gen 2 ram is terrible. Manifolds are terrible, Y-pipe is terrible, the catalytic converter is terrible, crush bent tubing is terrible, the gigantic muffler is terrible, location of each of these components to each other is terrible, etc. Each of these acts as a bottleneck to flow, and thus power. I haven't seen the specific dyno charts you mentioned. I'd be interested to see them if you could post a link.
This just isn't accurate. The gen 2 ram has a first generation catalytic converter which is sometimes referred to as a "can of beads" style cat. It is a large flat canister packed full of platinum-coated BBs located on the Y-pipe just after the merge. This generation of catalytic converters are well known to be extremely restrictive to exhaust flow. If you just remove it, you'll only see small gains because all the other stock exhaust components each act as a bottleneck to flow in their own right. There are studies that show that a well designed and properly tuned exhaust system loses quite a lot of power to this style of catalytic converter versus the newer generation honeycomb style cats which are far less restrictive, and that even the newest, best flowing cats significantly rob power compared to no cats. So if you're going to keep all exhaust components stock, then the cat by itself isn't going to make a huge difference. But even a mild exhaust upgrade will start to show that the cat is a real impediment to flow.
This just isn't accurate. The gen 2 ram has a first generation catalytic converter which is sometimes referred to as a "can of beads" style cat. It is a large flat canister packed full of platinum-coated BBs located on the Y-pipe just after the merge. This generation of catalytic converters are well known to be extremely restrictive to exhaust flow. If you just remove it, you'll only see small gains because all the other stock exhaust components each act as a bottleneck to flow in their own right. There are studies that show that a well designed and properly tuned exhaust system loses quite a lot of power to this style of catalytic converter versus the newer generation honeycomb style cats which are far less restrictive, and that even the newest, best flowing cats significantly rob power compared to no cats. So if you're going to keep all exhaust components stock, then the cat by itself isn't going to make a huge difference. But even a mild exhaust upgrade will start to show that the cat is a real impediment to flow.
Record Breaker
Joined: Sep 2015
Posts: 1,552
Likes: 4
Sorry to interrupt the "discussion" but why is that huge 55gal drum of a muffler bad? To me, it looks like there should be little restriction in that thing. And, would a thrush hush power do much for my stock system then?
