Jeep 4.0 in 69 Barracuda

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I think I understand what you're saying, but if you mean you plan to run two pipes from the manifolds out to the tail, that still means you'll be buying twice as much pipe (from manifold to back bumper, cuz the pipe comes in 8' sticks...and you typically will need a couple sticks per pipe) compared to if you went single 2.5" from a 2 into 1 just past the manifold...or am I still not thinking clearly here?
 
txstang84 said:
I think I understand what you're saying, but if you mean you plan to run two pipes from the manifolds out to the tail, that still means you'll be buying twice as much pipe (from manifold to back bumper, cuz the pipe comes in 8' sticks...and you typically will need a couple sticks per pipe) compared to if you went single 2.5" from a 2 into 1 just past the manifold...or am I still not thinking clearly here?
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Yeah, that would mean twice as much pipe and 2 mufflers instead of one as compared to a single exhaust system. If I was to go with a single tail pipe, I may as well keep the stock single exhaust manifold. I just dont know if that is the look I am going for. I could still get a dual exhaust look out the tail pipe by using a sideways mount muffler such as whats found in a 80s Camero or Firebird where the pipe from the engine goes in the passenger side, and the 2 smaller pipes come out, one from the driver and the other from the passenger. This would not be a true dual exhaust system. But may be my solution. I am not really happy with the thought of running a single large diameter exhaust system. This is not a truck, but a Muscle car. Even if I am running a in line 6 and not a V8.

John
 
Yeah, that's an option...I think Flowmaster and others make dual in dual out inline mufflers though...Walker comes to mind. I dunno man, it's really whatever floats your boat and blows your hair back...nothing wrong with true duals, but if you're gonna go true and performance, what's stopping you from dual 2"? Lots of people go duals 2 1/4" on a 273, and that's only 4.5 liters...:)
 
I am assuming that 273 is a carburated engine which doesn't care as much about exhuast back pressure. But if you look at stock jeeps with 4.0's, they have a 2.25 from the manifold to the cat, 2.5 inch pipe from cat to muffler, and 2.25 pipe tail pipe. Keep in mind I plan on keeping the Jeep Stock fuel injection.

So going full 2.5 exhaust from head to tail, thats a upgrade. And thats what alot of manufactures are selling for Jeeps. And if I go dual 1.75, thats about the same as a single 2.5 inch exhaust as I expressed in my prior post on page 2.

At this point, its all up in the air as I need to sort out the dual exhaust manifolds and O2 sensors. Cause I may be stuck going single manifold and dual tail pipes.

John
 
So a bit of good news. I had the 2 Cherokee's delivered today. And after getting a chance to further look them over, I found that the 2wd one I was going to use the parts from for the Barracuda is a Manual 5sp. I will know for sure tomorrow, but hopefully a AX-15 (and not the BA-5). So I will not be working with a AW4 Auto tranny.

The other brain storm I may have to settle on, as much as I want true dual exhaust, I may make use of a "X" pipe towards the front of the exhaust and install a single O2 sensor there. This would allow me to make use of the dual manifolds, and still keep a mostly dual exhaust with a single point where a O2 sensor could be. Apparently a "X" is a good way for a dual exhaust system to improve its scavenging. I was really trying to avoid this, but a fellow jeep owner and good friend really thinks I should consider that first before mucking around with different O2s and or reprogrammed ECUs.

So tomorrow, I start tearing down the "Parts Jeeps" and getting the parts moved to my storage unit. Then next week I scrap the jeeps.

BTW: It looks as if the house is ours. Closing has officially been decided on July 27th. So I can say that measurements and decision making will start in Aug on this project. Probably starting the second week.

John
 
I am assuming that 273 is a carburated engine which doesn't care as much about exhuast back pressure.
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Ehh, I wouldn't say that-as a matter of fact, I'd straight out disagree...I've seen it a few times where complete new free flowing exhaust required new jetting, whereas your factory fuel injection system will use adaptive strategies to figure out what fuel injector duty cycle to use based on the exhaust O2 readings under all sorts of different throttle and ambient environmental conditions--EFI is cool that way.

All that being said, again, I'm not trying to convince you one way or the other...just giving some perspective.

X pipes can be a help, and usually smooth out the tone in the exhaust.

As for the house-congrats!
 
Inline and smaller V8 engines generally perform best with some sort of HP single exhaust.
 
txstang84 said:
Ehh, I wouldn't say that-as a matter of fact, I'd straight out disagree...I've seen it a few times where complete new free flowing exhaust required new jetting, whereas your factory fuel injection system will use adaptive strategies to figure out what fuel injector duty cycle to use based on the exhaust O2 readings under all sorts of different throttle and ambient environmental conditions--EFI is cool that way.

All that being said, again, I'm not trying to convince you one way or the other...just giving some perspective.

X pipes can be a help, and usually smooth out the tone in the exhaust.

As for the house-congrats!
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I would agree with your EFI thought if I was running ODB2 out of a TJ or newer (97+), or if I was to run a MegaSquirt which does self learn and computer programmable, but the ECU I am planning on running is a ODB1, has no re-programmability, and does not learn. It adjusts based on tight pre-set variations.

I appreciate your providing perspective. I worked at a couple of local Brake and Muffler shops for just under 10 yrs in my late teens thru 20s while I was working out my life and trying to make college a priority. Your perspective is the same thought I am battling myself with how best to build this car. At this time, I dont think there is much I can do till I start dropping the engine in and taking measurements.

RustyRatRod said:
Inline and smaller V8 engines generally perform best with some sort of HP single exhaust.
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vntned said:
Single 3" would be the way to go!
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At this point, I know that I can always goto a Single 2.5 inch Flowmaster setup which would result in great power and a even better tone. Many the Cherokee's, Grand Cherokee's, and Wranglers have ran this setup. If I can make a dual setup work, I am going to attempt it. Which if I do end up attempting will make for some great reading (and YouTube video's) to be posted to this thread.

Thanks to everyone for the great insight. These conversations make for a good platform for learning. I am getting more excited on starting this project and seeing what it come out like.
John :D
 
I would agree with your EFI thought if I was running ODB2 out of a TJ or newer (97+), or if I was to run a MegaSquirt which does self learn and computer programmable, but the ECU I am planning on running is a ODB1, has no re-programmability, and does not learn. It adjusts based on tight pre-set variations.
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I'm not trying to argue with you here, but I'm about 99% positive that statement is inaccurate. Ford EEC-IV systems from '84 to '95, for example, were OBD1 and they did self-learn, and the multipliers in the programming allowed a good deal more adjustability than I think you're giving credit for...and we're talking changes as big as cams, heads, intakes, exhaust--all on the stock computer (trust me-thousands of people myself included have done it--and I had a completely different induction, cam, and exhaust). Did you have to do some other tweaking (fuel pressure adjustment, timing, idle throttle setting, etc) sometimes? Yes, but unless you were putting on nitrous or forced induction or running a cam that significantly changed the intake flow signature, the stock or even an aftermarket MAF, would make it's own adjustments. Now, granted that's a Ford system, and not a Pentastar or GM, but by the time the EEC-IV came out in 1984 or '85 (can't recall clearly right now), all the big three and every other make were utilizing similar technologies which could account for a decent amount of variability. If you're talking about a multiport system from the late 80s, I'm all but completely positive your computer can account for some modest performance upgrades to include a free flowing exhaust without having to remap your computer programming.
 
txstang84 said:
I'm not trying to argue with you here, but I'm about 99% positive that statement is inaccurate. Ford EEC-IV systems from '84 to '95, for example, were OBD1 and they did self-learn, and the multipliers in the programming allowed a good deal more adjustability than I think you're giving credit for...and we're talking changes as big as cams, heads, intakes, exhaust--all on the stock computer (trust me-thousands of people myself included have done it--and I had a completely different induction, cam, and exhaust). Did you have to do some other tweaking (fuel pressure adjustment, timing, idle throttle setting, etc) sometimes? Yes, but unless you were putting on nitrous or forced induction or running a cam that significantly changed the intake flow signature, the stock or even an aftermarket MAF, would make it's own adjustments. Now, granted that's a Ford system, and not a Pentastar or GM, but by the time the EEC-IV came out in 1984 or '85 (can't recall clearly right now), all the big three and every other make were utilizing similar technologies which could account for a decent amount of variability. If you're talking about a multiport system from the late 80s, I'm all but completely positive your computer can account for some modest performance upgrades to include a free flowing exhaust without having to remap your computer programming.
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txstang, please understand that I am in no way offended by your explaining your stance. I do agree, not wanting to Argue. I am listening and in many cases having to go back and google search things based on whats being said. Hence it may take some time to respond as I want to make sure what I am trying to explain of my thoughts is clear. I do thank you for taking the time to talk this out. I believe this to be a very productive conversation for the project which will be coming around the corner really soon. Thanks for taking the time and interest to discuss this with me.

As much as I believe that there are manufactures which built a Programmable adaptive ODB1 such as the Ford you explained. It is my belief that Chry/Jeep did not. In example, if you build too big of a Jeep inline 6 Stroker (much pass 4.9L) with to many changes, the ECU will never run it correctly and a new ECU is required. Especially if you consider the 5.2L with the custom offset grind crank. Yes it will run, but not correctly. Many threads on this topic have been posted on JeepForum. As such, its in my belief that the by going with a 94 Jeep Wrangler ODB1 ecu (though convenient) does mean I have to remain with in certain criteria. And to what started this conversation off being about Exhaust systems. I do believe that I need to look at what aftermarket suppliers are providing for solutions, but keep with in the realm of what their researchers have found to be the best solution for performance and driveabiltiy. Now yes I am being somewhat adaptive because I have the space to consider a dual 1.75 setup vs sticking to a single exhaust. And that should flow almost as well as a full 2.5 inch exhaust which is still bigger than the stock which is mostly 2.25.
 
JohnFM3 said:
txstang, please understand that I am in no way offended by your explaining your stance. I do agree, not wanting to Argue. I am listening and in many cases having to go back and google search things based on whats being said. Hence it may take some time to respond as I want to make sure what I am trying to explain of my thoughts is clear. I do thank you for taking the time to talk this out. I believe this to be a very productive conversation for the project which will be coming around the corner really soon. Thanks for taking the time and interest to discuss this with me.
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Excellent--too many times, even up to recently, I was dumb enough to engage a fruitless argument...not trying to do that here.

As much as I believe that there are manufactures which built a Programmable adaptive ODB1 such as the Ford you explained. It is my belief that Chry/Jeep did not. In example, if you build too big of a Jeep inline 6 Stroker (much pass 4.9L) with to many changes, the ECU will never run it correctly and a new ECU is required. Especially if you consider the 5.2L with the custom offset grind crank. Yes it will run, but not correctly. Many threads on this topic have been posted on JeepForum.
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It just seems counterintuitive to me that one manufacturer would use that readily accepted variability within the technology, and another wouldn't...but we are talking about an auto industry seemingly run by bean counters...sigh...but, if you've seen it on Jeep forums where people have taken this route modifying their engines and been sorely disappointed or required a new EFI system, then you're already ahead of me there...but you are talking about stroking it...I was only talking about the exhaust part...more on that below...

As such, its in my belief that the by going with a 94 Jeep Wrangler ODB1 ecu (though convenient) does mean I have to remain with in certain criteria. And to what started this conversation off being about Exhaust systems. I do believe that I need to look at what aftermarket suppliers are providing for solutions, but keep with in the realm of what their researchers have found to be the best solution for performance and driveabiltiy. Now yes I am being somewhat adaptive because I have the space to consider a dual 1.75 setup vs sticking to a single exhaust. And that should flow almost as well as a full 2.5 inch exhaust which is still bigger than the stock which is mostly 2.25.
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Now, the exhaust bit though--I still believe that if you opened up the exhaust to a modest system where you have your two head pipes into a single 2.5" or even a 3", the computer can compensate for that change. In the big picture, changing it only uncorks the resistance, which *may* create a felt difference somewhere in the low or midrange, but the engine is still only going to function within its own intrinsic capabilities...the induction will still only allow so much air in, the cam and valvetrain will still limit your top end to about 5K RPM...it'll just breathe a little better throughout that range.
 
txstang84 said:
It just seems counterintuitive to me that one manufacturer would use that readily accepted variability within the technology, and another wouldn't...but we are talking about an auto industry seemingly run by bean counters...sigh...but, if you've seen it on Jeep forums where people have taken this route modifying their engines and been sorely disappointed or required a new EFI system, then you're already ahead of me there...but you are talking about stroking it...I was only talking about the exhaust part...more on that below...
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Final thoughts.
Keep in mind we are talking about Jeep. With a very picky and demanding group of owners. Jeep Wrangler was the LAST to implement a fuel injection. Owners wanted to keep the tried and tested 4.2L (aka the 258 inline 6) with the Webber carb. Even though Jeep had a very sound fuel injection system in a 1986 Cherokee and Comanche, Jeep didnt run a fuel injected Wrangler till 1992 in the First Year that the H.O. (High Output) was produced.

We are talking about the same group of people who complained about the car like ride characteristics of the 1997 TJ as it was the first to implement a 4 corner coil and link suspension. Even though straight axles were still being used as other manufactures were going to IFS (Smart Move to stick with Full front axle). When the TJ came out, everyone griped and wanted Leaf Springs cause thats what Jeep have had since the begining. Why mess with what works. Keep in mind, Jeeps till recently are still running Full front axles. If jeeps were to have followed industry, IFS would have been the norm 10+ years ago.

Shoot look how much crap the YJ gets being called the Barbie Jeep with its square headlights. Now the wrangler is possibly going to reduce the slots from 7 (which has been a time honored tradition) down to 5, and people cried out saying Jeep shouldnt do that. The 7 slots is iconic to the Wrangler. Keep in mind that the TJ went back to 7 inch Round Head lights.

So I can totally believe Jeep would not embrace new tech as thats not what the consumer they are dealing with want. They want something very utilitarian, and easy to work on. Lift. Known reliable tech even after modifying. What you would call counter-intuitive, totally explains the normal Jeep owner. Not the Fan Boys or the Mall Crawlers. But those who really know and want to drive Jeeps for what they are, and not how fancy they can be. Cause a jeep is not fancy, its not a comfortable drive. Its iconic with the top off and the doors off. And thats why we own and drive them. And will continue for as long as Jeep will produce them.

We really gota feel bad for those reading this thread now an into the future. As they go thru 2 plus pages of a discussion/debate over automotive historical knowledge and opinions. This is no different than the ongoing Chevy vs Ford debates.... lol I gota say Thank You for it. And I apologize to those who had to read thru it.... lol Well, maybe not sorry :eek:ops:

Just My 2 cents



BTW: I just got great news. We have to contact the Home Insurance company to complete the application and have it sent to the Lender. Looks like we are going thru Pre Underwriting. Thing with the house seem to be going faster than expected.
 
Touche!

I see your point, and I've shared company with many a Jeep enthusiast over the past almost 25 years-I harbor no ill will toward any of them, and fully respect them for being hard headed or even contrary...it goes with the territory. I can't recall how many times I bled on friends' Jeeps trying to keep them in running condition (or modifying them) and ready for the next off road adventure; and no, not mall crawlers--buried over the axles in mud muck and unidentifiables flowing around your feet hoping you didn't just suck water, dragging others out of the same said muck, navigating places where angels fear to tread, spending hours cleaning and reservicing axles, t-cases, and zerk fittings to make sure you didn't ruin something (learned the hard way)

Don't feel bad about it--there are at least a dozen other resto threads more than 30 pages long that have 2-3 page stints where the content goes off topic...besides, if they don't like it, mice have scrollers for a reason.

OK-now that that's out--great news on the house, always a good feeling when you start signing papers and seeing stuff with your name on it!
 
txstang84 said:
I can't recall how many times I bled on friends' Jeeps trying to keep them in running condition (or modifying them) and ready for the next off road adventure; and no, not mall crawlers--buried over the axles in mud muck and unidentifiables flowing around your feet hoping you didn't just suck water, dragging others out of the same said muck, navigating places where angels fear to tread, spending hours cleaning and reservicing axles, t-cases, and zerk fittings to make sure you didn't ruin something (learned the hard way)
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I have a game I play for that... Its the Game I play every trip home from wheeling. I call it "Name that Noise"... lol Its where I spend the entire trip home trying to determine what the new noise is I am hearing and determining what I should look at and how much it is going to cost to be ready for the following weekend trip... lol

I have a friend who believes 4wd is for getting you into places you have no business being at in the first place... Which is why his roll bar sticker says "My idea of a good vacation would be considered your worst nightmare". Personally, I keep it simple. "Dont follow me, you wont make it".
 
Nice--sounds about right too, on both parts of the discussion. Either way, man, you need to get some pics up to break up this tangent so we can marvel how at home that engine will look in there
 
txstang84 said:
Nice--sounds about right too, on both parts of the discussion. Either way, man, you need to get some pics up to break up this tangent so we can marvel how at home that engine will look in there
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Good point. Let me get on that. Note that I now have a Avatar. I am kind of thinking of that concept for my barracuda logo on the car.
 
Pictures are going to take a bit of time. I really dont want to start another account with another service. And Cardomain has really screwed things up when they changed to more of a FB feel. Which means i need to download my images and close my account. The problem is I need to decide on a new location to store all my pictures. I have plenty of room on my hotmail Onedrive, but thats not shareable as far as I can tell. Which kind of stinks. Pictures on the way. Keep everyone posted.
 
We're good--have you seen some of the build threads here? They span over yeeeeeeeears.
 
txstang84 said:
We're good--have you seen some of the build threads here? They span over yeeeeeeeears.
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Yeah, same with my old cardomain. Which you probably know is a absolute disaster. The problem is I have no way to post pictures. I used to keep my cardomain updated, then copy the URL and use that to provide pictures to JeepForum and of sites such as this. Now I will need to see what it takes to save pictures to ForABodiesOnly.
 
To elaborate more, Prior to the cardomain change, I had several cars on my profile including a 72 Duster, 72 Datsun 510, 80 VW Rabbit Convertible, 88 Jeep Cherokee, and a 92 Jeep Wrangler. And this was where I kept all my cars updated as well has my own journal of things the family did involving those vehicles. This site is great for my Barracuda, but that still leaves both my Jeeps, my Mk4 Jetta, my Mk6 Jetta (new car) and the Datsun 510. It would be nice to have one place in a old style cardomain format where I can show case all my cars.

John
 
JohnFM3 said:
So not to get too geeky here, but the Surface Area of a 2.5 inch exhaust system is 4.9 inches. The Surface Area of a single 1.75 inch exhaust system is 2.4 inches. So a Siamese dual 1.75 inch system would be just a hair off of what a single 2.5 inch exhaust system at 4.8 inches. The presentation of of a Siamese system would absolutely killer, and the main benefit would probably be clearance.
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Sorry,but that is inaccurate,allow me to to explain.First up,You are confusing surface
area w/ CROSS-SECTIONAL area,which is the dimension you stated.Secondly,the
inside dimensions are the ones you need to calculate for,which is approx. 1/8"less
for 90% of std. bendable exh. tubing and available in up to at least 12'sticks.
2.5"/ 1.75"x(2) / 1.125"x(6)

area) 4.43"sq./ 4.148"sq./ 4.71"sq.

circum.) 7.47" / 10.2" / 18.85"

surf.area/ 89.64"sq./ 122.4"sq./ 226.2"sq.
lin.ft.

It should be obvious the frictional area goes up w/multiple piping,even when the
cross-sectional area is the same,which I illustrated w/the 6 -1 1/8" pipe numbers.
This doesn't take into account frictional factors based on boundary layer shear &
tumble,which will remain constant on the surface regardless of pipe dia.This effect
will "shrink"the usable area of the pipe by approx. the same dimension,obviously
having a much more detrimental impact on smaller pipes than larger ones,which
have the mass fluid flow moving more freely in the center.
If ground clearance is an issue,you mite investigate Burns oval tubing as a much
better compromise,not cheap tho'.I like the center exh. exit concept,and you can
dual tip or Y-split two pipes out back if you use a single but like the "dual look".
Going to be a tite bit of work w/ the spare well there w/o it hanging low.Good luck
w/ the new place & let us know where you're at with this,I'm sure you know about
the factory offered pieces for that eng.,incl. a ported head etc., and FI means no
carb. air filter and the flexibility of something like pictured above, so hood issue
isn't as bad as it could be, Have fun!!!:coffee2:
 
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