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What to do with Exhaust

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peeeot
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What to do with Exhaust

Post #1 by peeeot » Thu Oct 25, 2018 9:01 am

I need some insight from you folks with practical experience. My objective is to maximize efficiency and performance up to 4000 rpm; seat-of-pants feel is about as important as actual performance.

My current exhaust is a single 1.75” pipe off the stock manifold. After about 2-3 feet it steps up to 2” all the way to the stock-style muffler at the rear of the car.

I have been considering a few things:
1. Just step the first bit up to 2” to match the rest
2. Step the whole system up to 2.25”—manifold outlet is only 2” so would have to step up just after the flange
3. Split the manifold old-school style, either 4/2 or 2/2/2 and probably join the pipes into a single outlet after several feet or possibly leave separate (very curious as to what 2/2/2 would sound like out of 3 exits!!)

Which of these possibilities would work best for my objective? I’m not interested in Cliffords headers, which are the only header option I’m aware of for a car application.

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bubba22349
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Re: What to do with Exhaust

Post #2 by bubba22349 » Thu Oct 25, 2018 8:33 pm

I would go with a 2 1/4 inch system for a single exhaust or you want a duel system then a pair of 1 3/4 to 2 inch would be good. You could port the exhaust manifold to get it closer to 2 inch or you could make a tappered transition piece to help flow, also if you can find a big truck 223 or 262 (F500 or up) exhaust manifold it should have a lager outlet too. A nice mandrel bend system with a free flowing muffler or mufflers (Turbo's, Magnaflow ect.) should get you that seat of the pants feel you want. On the manafold split a 2 /'4 is the easiest better is a 3 / 3 see below link on stock manafold s that were split. And the other link showing an older post of mine with pictures of the best cast iron 223 exhaust manifold these was made by Fenton. Good luck on your 223. :thumbup: :nod:



Splitting a 223 exhaust manifold.
https://www.jalopyjournal.com/forum/thr ... ld.272374/

Fenton duel exhaust manifold
viewtopic.php?t=72780
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

peeeot
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Re: What to do with Exhaust

Post #3 by peeeot » Wed Nov 14, 2018 8:54 pm

Those Fenton manifolds are ideal, but seem to be rather scarce these days. To bad they aren’t reproduced!

I am planning to go with your suggestion of a mandrel-bend 2.25” single, at least to start with. I may have to dimple the pipe at the flange to accommodate the nuts.

I found an article from Hotrod.com where they put a 2.5” single on a 225 slant six that had previously had a 1.75” to 2” pipe almost exactly like mine, and it gained 9 hp with just the pipe change. Granted, it’s not the same manifold and it has a true 2.25” outlet, but it supports the idea that it’s possible to make a noticeable improvement even while retaining a 6-into-1 cast manifold. Here’s the link: https://www.hotrod.com/articles/making-slant-six-sense/ it’s interesting to me because other articles (horsing around, soup that chev, slant sickness) all show a 10 hp increase from swapping to dual outlet headers/manifolds. I would have guessed that a big single on a stock manifold would not have made so similar a gain to the dual outlet headers. I suppose peak numbers only tell part of the story. Or maybe it’s because the slant started with a 1.75” pipe.

About the larger outlet on the truck manifolds: are you sure? I found an eBay listing for a heavy truck manifold with the right casting number (c3te-9430-c) and contacted the seller to get outlet measurements. The numbers he gave matched my current manifold.

Thanks for your help!

peeeot
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Re: What to do with Exhaust

Post #4 by peeeot » Sun Jun 23, 2019 10:49 pm

I finally bought a 2.25" mandrel j-bend, some pipe and a new flange to replace my 1.75" head pipe. The inside diameter of the manifold, flange, and pipe are all 2-1/8", so it all fits together perfectly. At present, I am just replacing the undersized section of pipe, so I will clamp on a reducer to connect the 2.25" to the existing 2".

Looking forward, what would be the best way to complete the system if I want a drone-free but audible, unrestrictive exhaust? Seems like 2.25" would not be needed all the way to the bumper since exhaust cools and contracts as it moves away from the engine. Is the muffler's stock placement at the very rear of the car desirable, or would the system perform better if the muffler were located closer to the engine?

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bubba22349
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Re: What to do with Exhaust

Post #5 by bubba22349 » Sat Jun 29, 2019 2:31 pm

I have no Enginering Education to speak of only an A & P license and training, most of this I learned the hard way by trail and error experiments, lots of time, investing some money, self study, talking to a long time friend of my Dad's that owned and ran a muffler company, and also examining many systems at car shows and the drag races. In the 1960's was using the Glass Pack mufflers they were inexpensive, had a good sound, better performance, and an increase in MPG. In 1970's started going with the Turbo style mufflers, reasonable cost, good sound, better performance yet, and an increase in MPG. My conclusion was that mufflers were a big part in the cars performance or lack there of. Later on Hot Rod did an article on muffler flow called the Great Muffler Shoot Out, where they tested the flow of a group of mufflers, if you can find the article it is quite interesting. After that the sales of the wining muffler a Cyclone Turbo style muffler went through the roof. Since then there have been even more improvements in muffler design, so picking a muffler is the most important part of your system.

Next I experimented with pipe size, lengths, and flow, found that with fewer bends and shorter pipe lengths performance also increased, as with a tail pipe out the side ending in front of the rear wheels or dumping in front of rear axle that I personally don't care for. As the better mandrel bends became available flow again increased for better performance. I use the same pipe size from the start of system to the tail pipe end. Experimented building some headers and with collector lengths for my drag cars performance increased as I found what the car liked. Yes placing the muffler forward may help in performance I found that there is a certain collector lenght off of the headers that gives the best torque so placing the muffler near there will probably be of help. I also found like many others back then that though my street cars performed well, but with an open exhaust at the drags the performance was still much better. In the 1980's David Visard wrote an article on building a Zero Loss System that was within 1 % of an open exhaust, this was ground breaking and has increased knowledge of exhaust system performance. This is link on article based on his experiences well worth the read. https://www.musclecardiy.com/performanc ... ail-pipes/

Hope this helps you finish your design! Though in my experiences a good exhaust system design has almost no down sides with better performance, better MPG, the sound can be personalized too. Some people experience a drone with some types of mufflers and if it's in the cars normal cruising RPM it can be annoying, a Helmholtz tube or resonator can probably take care of that. Or a small Glass Pack install just before the tail pipe. http://dirtydeedsindustries.com/product ... resonator/
Good luck :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

peeeot
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Re: What to do with Exhaust

Post #6 by peeeot » Tue Jul 02, 2019 4:27 pm

So your experience was that the turbo-style mufflers performed better than glasspacks overall?

I read the article by Vizard and found some data from a muffler shootout published in Car Craft (https://www.bangshift.com/forum/forum/b ... -test-info). One thing I find over and over with researching this stuff is that the articles are all focused on v8s with headers. It’s hard for me to tell how much of it applies to a straight six with a manifold. For example, the importance of secondary length is stressed—but the flow characteristics of a cast manifold are totally different from headers, so does exhaust pulse tuning even work? If so, do the same rules apply?

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bubba22349
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Re: What to do with Exhaust

Post #7 by bubba22349 » Tue Jul 02, 2019 9:12 pm

Yes over all the Turbo's I used performed better than the older style Glass packs. There are some cases were I still prefer the sound of a glass pack though as in a few vintage applications such as a member ldle built up late 1930 to 1953 flathead Ford V8's they just sound great on them. The first Turbo mufflers were made by GM for their Corvair (Turbo charged) flat six engines, later this design was copied and adapted for other uses such as the much bigger Street Hemi version.

Yes by far all the articles written are based on results with V8's still we can learn a lot by reading between the lines. Visard's testing of his zero loss exhaust system idea's actually began on a tiny 1500 CC Mini Copper inline 4 so the principles are still relevant. The Muffler flow is directly adaptable as well as pipe size and flow. Also Ideally if we were trying to build a max performance Six a set of headers are a major part in the of this exhaust system and the first bottle neck. So does that mean there isn't away to make an exhaust (log) manifold perform better? Well the answer is yes it can and the secondary lenght of the head pipe could be found out with math and or testing. Yes the flow characteristics of an exhaust manifold are different and t can be improved by porting. Yes the exhaust pulse tuning dose work and most of the rules will still apply. What is a bit different between a V8 and a Six is the dergees during rotation which is 90 degrees (out of the 720 degrees of rotation to fire all 8 cyclinders) for the V8, and 120 degrees for the six out of the 720 degrees. This so is the pluse differance we need to work with. The other major difference is the RPM operating range of most V8's compared to a six. What an inline engine has over the V8 is that the six can build torque from idle too. Good luck :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

peeeot
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Joined: Thu Feb 07, 2008 5:07 pm

Re: What to do with Exhaust

Post #8 by peeeot » Wed Jul 10, 2019 11:41 pm

Thank you for another informative response.

Without readily available guidelines for optimizing a manifolded in-line six with single pipe, I am prepared to just leave some power on the table and keep the exhaust design simple. Constructing and altering the exhaust to try different setups is too time consuming for me to pursue a trial-and-error approach at this point. The farthest I may go is to bring the 2.25” all the way to the rear bumper and use a turbo muffler or glass pack mounted at the rear. For now, it’ll be 2.25” to the car’s midpoint, then 2” out the back with a stock muffler.

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Re: What to do with Exhaust

Post #9 by bubba22349 » Mon Jul 15, 2019 12:52 am

Not a bad plan 2 1/4 inch up to the muffler when it ts time to replace muffler and then going with 2 1/4 inch pipe up to bumper. It's all depends how good the muffler you have flows as to how much more improvement can be made. The 2 inch tail pipe isn't likely so bad if you need to wait for awhile. Good luck :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

Charlie Cheap
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Re: What to do with Exhaust

Post #10 by Charlie Cheap » Mon Aug 12, 2019 9:05 am

One thing I often see with six cylinder guys, is way too much carb and way too much exhaust for street use. Ford engineers designed our 6 for economy as the main objective. We want more power with out the loss of MPG, so we need to look at the total package. A 2 barrel works great if not too big. A hotter ignition always helps if timed properly. Getting the exhaust out needs to be balanced with the increase in the intake. For street use a header greatly increases under hood heat for little if any gain in street power in the 2,000 to 4000 RPM range. Stay with a good cast manifold feeding bigger tubing. I sand blasted my exhaust manifold inside/out before painting. If the cast exhaust has a 2" opening, increase the tubing from 1.75" to 2" for a better match. Do not forget VELOCITY as related to intake and exhaust! There is NO GAIN on the street with big valves. Yep, big valves are wonderful above 4 to 5 thousand RPM all the way up to 7,000. On the street, torque is hurt...not helped. Small valves give better velocity causing better swirl in the chamber. A large 2-barrel also hurts torque while a smaller one helps. Keep things matched. A bigger than stock carb is a good way to add HP, but don't go crazy. Vintage Inlines has great info to read, about building a proper street car...or racer, if that is what you want. Three carbs look cool, but can hurt performance. Electronic ignitions are great, but don't expect ANY GAIN on the street. Those claims about better MPG, and quicker starting is a myth. Points or Pertronix works fine up to 5,000 RPM and my engine starts before I get my hand off the key. A hotter coil, lower resistance ignition resistor, solid copper wires kept as short as possible, and platinum plugs will give a good increase in spark. That allows a .038" to .040" gap. Getting the dizzy recurved is a good idea. A mild street cam helps, a good valve job, hotter ignition, and better exhaust help on the street. If you are a weekend racer, headers make lots of good sense, if coupled with other mods like a cam, and even hotter ignition. USE THE FORMULAS AVAILABLE TO FIND CARB SIZE and EXHAUST FLOW. Info seen on-line is often wrong if from individuals...like me. I am an ASE Certified engine builder, spent over a decade as a city shop superintendent for emergency vehicles (Cop cars, ambulances, and fire trucks), spent 50 years building street rods as a hobby and business, and my 65 Mustang 6 makes about 150 HP (old method) and gets 25 MPG, and it runs great on long trips.

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