Single 3" with a v8?

[deathbypsi]

I keep seeing everyone here posting about "upgrading" from the single exhaust to duals but my questions is has anyone just upgraded the single system?

I picked up a stripped 83 Tbird and Im going to drop in a Explorer 5.0 but with the dual fuel pump arrangement taking the space where one muffler would go and Im assuming like on all older single exhaust Mustangs the brake line on the axle is in the way wouldn't it just be easier to make a simple 2.5" Y-pipe merged to a single 3" system? I assume somebody like Stinger must make a 3" single system for the TC.

My old daily was a 70 Torino wagon with a 89 5.0 and I build the same kind of system and loved the mellow sound and it performed great.

[PaceFever79]

Hi, here is what I have read (but never tested for myself on a dyno). A single 3" exhaust is about equal in flow to a 2.25" dual exhaust (like came on later 5.0 HO's). The single 3" exhaust compared to a dual 2.5" exhaust, will make more torque but a little less peak HP than the dual 2.5" exhaust. So on a mild 5.0 (say under 325HP@5500) there should be very little difference. But the more horsepower, the more RPM and flow, the more that top end HP difference will show itself.

[PaceFever79]

Also, sound wise, the single 3" should be deeper in tone, more deep rumble, less rasp and crackle on top end, and overall not as loud (DB) as the dual exhaust.

[JACook]

3rd and 4th-Gen Camaros all came from the factory with a large single exhaust. Just sayin'...

A lot of this is just about packaging, tone, and NVH. There is nothing inherently bad about either single or
dual exhausts, if the pipes are properly sized. Single does add the question of proper merges and/or splits,
but done well, it'll work well.

[deathbypsi]

Hi, here is what I have read (but never tested for myself on a dyno). A single 3" exhaust is about equal in flow to a 2.25" dual exhaust (like came on later 5.0 HO's). The single 3" exhaust compared to a dual 2.5" exhaust, will make more torque but a little less peak HP than the dual 2.5" exhaust.

I dont think that theory holds water.

My other toy is my 88 Ranger with a 2.3t motor which has a full 3" single exhaust. It ran 11.20s and put 382hp to the wheels thru a c4 and loose converter so there is close to 450hp being made. An open downpipe showed no gains.

I think alot of people confuse exhaust "flow" with exhaust pulses. Its not like water thru a garden hose.

So in my mind if my Ranger can make that kind of power using a single 3" I would almost bet a single 3" on a 250-300hp 5.0 would perform better due to stronger scavenging.

[PaceFever79]

Fair enough. Since we are both estimating.

[great white]

I dont think that theory holds water.

My other toy is my 88 Ranger with a 2.3t motor which has a full 3" single exhaust. It ran 11.20s and put 382hp to the wheels thru a c4 and loose converter so there is close to 450hp being made. An open downpipe showed no gains.

I think alot of people confuse exhaust "flow" with exhaust pulses. Its not like water thru a garden hose.

So in my mind if my Ranger can make that kind of power using a single 3" I would almost bet a single 3" on a 250-300hp 5.0 would perform better due to stronger scavenging.

The only issue when talking scavenging is your 2.3 was a single exhaust manifold and the 302 is two separate manifolds.

It being a turbo changes it up again, but I'll stick with a NA 2.3 to make the discussion a little simpler.

(low 11's on a 2.3 turbo ranger is pretty impressive by the way!)

On a single manifold, scavenging is easier to achieve as the collector design and header length mostly determine it. As it all terminates on one collector, design is (relatively) simple to achieve strong scavenging properties.

Doing a single on a V and getting scavenging right is a little more difficult as you're joining the flow from two banks into a single exhaust. especially if you want to get the last 10 10ths out of your setup. If each bank produces a firing order that makes scavenging strong in the one manifold, then the Y pipe becomes less of an issue. if you need opposite banks to work together for strong scavenging, it becomes a bit more difficult to get it right.

I'm not saying it can't be done, but it's a bit more than just deciding between single or dual.

If using the stock log style cast iron manifolds, we might as well stop talking scavenging and just pick the rest of the exhaust on what the OP likes/fits instead of performance. OEMs put little more thought into cast iron logs than it had to hold the exhaust until it hits the tailpipe, it has to last past warranty and it has to be cheap and easy to produce.

If someone just wants to decide between sound, it doesn't matter a whole bunch either way either. Go for what you like.

For what it's worth, I went with a 3" single on my old 89 Chev silverado with a 350 and 700R4. Never bother to strap it to a dyno, but it would regularly pull on my buds with similar trucks and it would seem to have more "grunt" in the mud and on the trail. Worked for me.

Sounded better too, although that's' pretty subjective:

[never]

I made this for my 85 LTD LX...longtube headers to 2.5" into single 3".





https://youtu.be/-tu_dB1Q7Og

Just a guess but it seemed like too much exhaust for the mild roller 302 that was choked with CFI. Had issues with the car but the engine now has a carb and is going into a Marquis wagon, along with the exhaust.

[deathbypsi]

Thats what Im talkin bout. Nice setup

[gmatt]

So, are any of the exhaust companies making a 3" single? Or is this strictly a 'custom' deal.

[PaceFever79]

Stinger makes a 3" turbo coupe exhaust

You can order it minus the downpipe for the 2.3 turbo

[deathbypsi]

I think Im goin to talk to Stinger bout buyin parts from him to build mine. I building a sweet 2.3t XR7 for a buddy right now and it came with a Stinger kit for me to install and it looks real nice

[deathbypsi]

Well I picked up a set of BBK long tube headers, some 3" to 2.5" ball fitting collectors/reducers, some 2.5" SS J bends, Flowmaster SS dual 2.5" to single 3" y-pipe,SS Magnaflow 3" muffler and a Stinger SS 3" TC tailpipe kit.

[Dogster]

My old roommate back in the 80s worked at a well known east coast speed shop that also built cars and installed superchargers and turbos. I helped him build a 67 Camaro convertible with a 70's 350 LT1 (350-350 stock hp) with a turbo running 12+ lbs. of boost. He ran a single 3" exhaust because their experience was that it out performed dual 2.5" exhaust, especially with a turbo. The thing would suck you back in the seat and hold you there till he let off. Just sayin'... People would look at it and the look on their face was huh, single exhaust? Made for a great sleeper. But duals still look cool.

[PaceFever79]

N/A and Turbo exhausts are 2 different things. Turbo responds better to a single exhaust. But on a mild street motor the single 3" should perform just fine.

[gry84GT]

3rd and 4th-Gen Camaros all came from the factory with a large single exhaust. Just sayin'...

A lot of this is just about packaging, tone, and NVH. There is nothing inherently bad about either single or
dual exhausts, if the pipes are properly sized. Single does add the question of proper merges and/or splits,
but done well, it'll work well.

I agree...I changed my merge approach using flowmaster 2:1 with sufficient merge pipe length before 3" muffler....
It change sound completely from what I had. It reminds me a bit of my 01 bullitt albeit a bit louder.
As well this system has less vibration and no usual drone associated with some true duals I've had.

[deathbypsi]

Well Im almost ready to drop my motor in so I should be hearing mine soon.

[deathbypsi]

Just to follow up on this my system is finished and I couldn't be happier. Car sounds killer but not to loud.



https://www.youtube.com/watch?v=n7uK9Vqu1D0

[GLXGeorge]

Hello, i am not sure that a reply is the best way to present a question but didn't necessarily want to start a new thread and I am a newbie. I have a 83 GLX w/ 5.0. It had bad muffler, tailpipe and convertor on its last legs. Purchased a new muffler and tailpipe which is 2.5" and then most of the parts for a dual system. Looking at this thread I think a new set of headers, my new MAC H-pipe and some universal bullet style cats could run to a 2 into 1 after the H-pipe with the 1 being the muffler end. This would avoid having to change the brake line location. There would still be a performance gain going from 2.25 to 2.5 and replacement of the cast iron headers would account for the biggest gain. Am I missing anything? Thanks.

[GLXGeorge]

Thanks for sharing your experience and the photos. Sorry about the second post, I am clueless.

[deathbypsi]

Hello, i am not sure that a reply is the best way to present a question but didn't necessarily want to start a new thread and I am a newbie. I have a 83 GLX w/ 5.0. It had bad muffler, tailpipe and convertor on its last legs. Purchased a new muffler and tailpipe which is 2.5" and then most of the parts for a dual system. Looking at this thread I think a new set of headers, my new MAC H-pipe and some universal bullet style cats could run to a 2 into 1 after the H-pipe with the 1 being the muffler end. This would avoid having to change the brake line location. There would still be a performance gain going from 2.25 to 2.5 and replacement of the cast iron headers would account for the biggest gain. Am I missing anything? Thanks.

If its a stock 83 5.0 Im sure a single 2.5" wont hurt it ,but personally I would have used 3" for the single portion.

[BTD]

If its a stock 83 5.0 Im sure a single 2.5" wont hurt it ,but personally I would have used 3" for the single portion.

Are you required to use the CAT converter where you live ? If not, take the damn thing off. That's what I did on my 83 GT - Shorty heads to 3 inch all the way to the muffler - 2 straight pipes , 2 J Bends, 2 Mufflers and I was set. Let your baby roar I say.

[GLXGeorge]

Yes, I agree that the 3" would be the way to go, but the muffler and tailpipe are relatively new. I guess my goal is to make the necessary repairs which there are plenty and try to build in some modest upgrades while I am at it. I inherited the car so I haven't invested too much, tires and used wheels, brake lines and now the exhaust. I don't mind working on the car but I am getting itchy to have more road time. It's a convertible with a 4 speed. I am the second owner. Maybe I am just lazy and put off by possibly changing the newer brake lines. Mufflers are Dynomax. I thought that the dual system was a sure kick in the seat but I have been reading conflicting info which makes me open to other options. I do like the straightforward single exhaust approach. Sorry if I said too much, its like going to the optometrist, "is this better than the other one?" Also your system looks really good, deathbypsi. The Stinger components are nice looking, smooth.

[GLXGeorge]

If the 5.0 is stock could the going to the larger exhaust (3") have a negative effect due to the loss of backpressure? Have you experienced this?

[GLXGeorge]

Are you required to use the CAT converter where you live ? If not, take the damn thing off. That's what I did on my 83 GT - Shorty heads to 3 inch all the way to the muffler - 2 straight pipes , 2 J Bends, 2 Mufflers and I was set. Let your baby roar I say.

I am in Ohio, we used to have emissions monitoring here but it's been gone for a while. I suspect that the cats have to be replaced but I am not certain...need to check it out rather than make assumptions. Not sure if this baby is ready to roar yet, of late it has been more like a whimper! Stay on target, right?