diesel v. gasoline exhaust.

[JohnnyO]

Bigger is better to a point, but as mentioned, too big and it hurts the exhaust gas velocity. That is more a problem seen with headers but the same effect can happen with the exhaust system. Too little velocity and scavenging will hurt low end power and torque.
Ranger engines simply aren't that big and don't flow the air that a big-block does, so you simply don't NEED a pair of 2.5" pipes with Flowmasters like a 454 Chevy does.

Gibson Exhaust's own data shows more hp and torque with their single system than their dual outlet setup on a Ranger. IIRC, their single system gains 8 hp and dual gains 5 hp.

 

[91rangerxlt]

if you have a semi truck over 4in pipe would work because the motors are pushing out some much cfms of exhaust but the people that dont have have a 400 to 600 cubic inch diesel motor stuffed between the frame rails of their DD only want to go to 4in pipe and thats still pushing it now the tip of the exhaust can big as big as you want and can put on ive seen 8in tips before.

most fords diesels ever made had 400+ cubic inches. the 7.3 was around 455 the 6.0 was around 390 and the newer 6.4 is around 400. i think the chevy diesels are somehwere in the area of 6.5 liter i beleive. not for sure.

 

[BigJohn76]

most fords diesels ever made had 400+ cubic inches. the 7.3 was around 455 the 6.0 was around 390 and the newer 6.4 is around 400. i think the chevy diesels are somehwere in the area of 6.5 liter i beleive. not for sure.

chebbys are 6.5 and are junk. a buddy of mine has 5 in exhaust and a banks programmer, he blows through injectors and all sorts of other crap like nothing. a buddy had a 7.3 with 5 in exhaust and a chip and never had any problems. the best one that a buddy has is an 06 5.9 Cummins with bullydog programmer, 6 in exhaust, new tranny to handle the torque, and pushing 650 horse with the chip up and at least 700 ft lbs. no problems at all.
it all depends on the engine and how it is driven.

 

[JohnnyO]

One of my favorite YouTube videos:
http://www.youtube.com/watch?v=D43mL1p65vg

 

[85_Ranger4x4]

most fords diesels ever made had 400+ cubic inches. the 7.3 was around 455 the 6.0 was around 390 and the newer 6.4 is around 400. i think the chevy diesels are somehwere in the area of 6.5 liter i beleive. not for sure.

400CI is 6.6, which while both the 6.9 and 7.3 are bigger than but still no where close to 600CI.

Chevy has made 6.2 and 6.5 diesels, debates ramble on about their quality but the military still uses them in their humvee's so they must not be all bad. Now they have a 6.6 Duramax built by Izuzu in their trucks.

 

[shadetree]

On a turbo engine, you can run as big of an exhaust as you want and it isnt going to hurt performance. There is a point where it doesnt help, but it aint going to hurt it.


not tryin to start anything but if you put a 5in+ pipe on a turboed superduty you would kill that motor in no time think about it turbos need pressure what do diesels need to run compression when the pipe is to big the turbo cant spool up to power the motor so the computer starts dumping diesel in the motor to make up for the loss of power. so there goes fuel ecomony, now not only will fuel ecomony be your only problem now it will be when you take your foot off the go pedal there will be no pressure keeping the exhaust system from sucking in air so now when you have incoming air and you put your foot on the gas the exhaust valves in the motor are going to become under even more pressure because you are not olny pusing out exhaust but also what got sucked in when you let of the go pedal so now you have to repalce exhaust valves. so now you have to hear your pos truck go down the road popping rattling and all sorts of noise. my point is your statment isnt true you see all these lil punks in their hondas,toyotas and whatever else import they have a small exhaust system to keep the turbos from losing pressure

Because you do not use punctuation and capital letters, it is very hard to read your posts. How does an exhaust system suck in air when it is under pressure, or at any time for that matter??????shady

 

[shadetree]

+1 i want to hear the real def then so i can use it as correctly as possible. didnt think that 2.5 yrs of schooling and 6+ yrs of experience w/ exhausts much less the rest of the systems that ive understood was all wrong. hell ive spent a lot of time self studying and reading up on tuned exhausts and tuned exhaust theory using "backpressure" "flow rates/cfm" along w/ "compression/expansion and sound wave tuning."

Then you have been doing all this since you were 13.5 years old?

I will post this link again, however it is useless unless it is read.

www.veryuseful.com/mustang/tech/engine/

shady

 

[Will]

chebbys are 6.5 and are junk. a buddy of mine has 5 in exhaust and a banks programmer, he blows through injectors and all sorts of other crap like nothing. a buddy had a 7.3 with 5 in exhaust and a chip and never had any problems. the best one that a buddy has is an 06 5.9 Cummins with bullydog programmer, 6 in exhaust, new tranny to handle the torque, and pushing 650 horse with the chip up and at least 700 ft lbs. no problems at all.
it all depends on the engine and how it is driven.

My buddy, which is ME, says 6.5s are good. I don't know how you blow through injectors. Matter of fact, I don't even know what you're talking about. I've had the same setup for 6 years and replaced one water pump and a starter solenoid. I replaced an o-ring on the throttle shaft of my injector pump 4 years ago, and changed the stock box fuel filter/sperator for a screw-on Racor--and added an electric boost pump. I have a Banks turbo and the 3" single exhaust with the Banks school bus muffler on it. It's a reliable 250hp/450ft# motor that makes 12psi boost and rarely exceeds 1,000F. I'm not trying to be a hotrodder with it, but it tows regulaty--up to 9,500#. It's quicker than my 4.0 B2 and gets better mileage too.

And, by the way, the 6.5 is still being manufactured--it's 28 years old still being built in Moraine, Ohio--operations now being done by AMG, manufacturer of the HMMWV. It's available in marine and civilian verions, known as the Optimizer 6500. It can be bought from the factory in a twin turbo 400hp, 600ft# version.

A design doesn't last 3 decades unless it's good. At any point along the way someone could have supplanted this Detroit Diesel design, but it never happened, and other companies tried. Most the problems people have had are because they don't understand the machine they are messing with.

 

[91rangerxlt]

My buddy, which is ME, says 6.5s are good. I don't know how you blow through injectors

if i remember right i think it was the late 90's early 2000's the duramax's did have troubles from the factory with the injecters. not for sure tho ugh

 

[85_Ranger4x4]

if i remember right i think it was the late 90's early 2000's the duramax's did have troubles from the factory with the injecters. not for sure tho ugh

I am no expert, but I don't think the 6.2/6.5 were ever called "Duramax" by GM. The Izuzu 6.6 is called the "Duramax", to try to give it a semi-cool sounding name.

 

[David85]

First of all, diesels and gassers are two different animals and respond to exhaust mods differently. When it comes to a turbocharged diesel engine, you can dump the exhaust that exits the turbocharger directly to the road with virtually no back pressure after the turbo and the engine will will be quite happy especially once you wind it up. NO damage will be done except to your ears.

Naturally aspirated diesels can benefit from a properly sized exhaust tube for the sake of exhaust scavenging, but going to a larger pipe will not have much affect on powerband like in the case of a regular compression throttled gasoline engine. When it comes to peak power against the RPM governor, the bigger pipe you can fit, the better. There is of course a limit after which it becomes hard to measure any gains.

Bottom line is you can put as big an exhaust on your diesel as you want, but after a certain size the cost/benefit ratio gets much worse. It will not however, damage the engine, I don't know where that myth came from.

6.2/6.5 and 6.5 turbo are a completely different engine from the duramax.
Nothing in common what so ever. I wouldn't call the 6.5 the best diesel ever made, but its far from being the worst (we have one). No, it never carried the duramax name.

 

[SSpeeDEMONSS]

You're thinking backwards. A larger diameter tube creates less back pressure and increases flow.

For a forced induction engine, there is no upper limit, shortest largest exhaust the better - hence Ø6"+ hood stacks on pulling trucks/tractors.

For a N/A gasoline engine, exhaust pipe size is actually a tuned parameter based on engine size and RPM range.

correct!

Im not an expert by any means but diesels are choked heavily from the factory thats why the bigger exhaust and intake help drastically but yes after a point the performance should drop down. Believe it or not I saw a truck about a week ago that had twin stacks that were made from 12"(minimum) Chimney pipe on an f250. Not only did it look and sound terrible but I bet its safe to assume its hurting the mileage as well. However I feel you would have to know the extent of engine modifications to truly know or not bigger turbos and other goodies are going to effect the diameter you should go with.

wrong! a larger exhaust will not hurt mileage.

on a diesel you DO NOT want to go over about a 4in pipe and thats with of course a turbo and performance mods like tuners and an bigger intake if you go to big in diesel exhaust you will burn the valves up before you get 5 miles down the road. so yes you can go to big on diesel exhaust. if you have a semi truck over 4in pipe would work because the motors are pushing out some much cfms of exhaust but the people that dont have have a 400 to 600 cubic inch diesel motor stuffed between the frame rails of their DD only want to go to 4in pipe and thats still pushing it now the tip of the exhaust can big as big as you want and can put on ive seen 8in tips before. now to the orgnial poster if your friends think that the bigger the pipe on a diesel the better. well that really shows they never need to work on their trucks. i have seen a diesel with a 6in exhaust and it was so funny i out ran him in my old 1990 toyota 4x4 all he did was blow balck smoke and make alot of racket im sure alot of the black smoke was partly his vavles buring up and god knows what else

you are SOO wrong. stop using your gasser knowledge on diesels. they are not the same.

5"+ tips on a diesel look about as good to me as a fart can on a fwd car, it is just too much.

about as stupid as a little truck that thinks it can actually do something? get out of the way next time my REAL truck is coming down the highway.

Some people may consider that increasing back-pressure. I guess it could be considered pulsed back-pressure. In any case; back-pressure, in any form, is not good for an engine's performance.

true, for a gas motor.

On a turbo engine, you can run as big of an exhaust as you want and it isnt going to hurt performance. There is a point where it doesnt help, but it aint going to hurt it.

correct!

and when an outgoing exhaust pulse collides with a stalled or reverted exhaust pulse, what happens? pressure. the outgoing pulse is slowed. this is knows as "backpressure"

yes, like i said before. on a gas motor. that doesnt apply to a diesel.


Garrett

 

[SSpeeDEMONSS]

On a turbo engine, you can run as big of an exhaust as you want and it isnt going to hurt performance. There is a point where it doesnt help, but it aint going to hurt it. you can make it as large as you want but after a certain point you wont see anymore gains, but it's not going to hurt it.

correct!

Bigger is better to a point, but as mentioned, too big and it hurts the exhaust gas velocity. That is more a problem seen with headers but the same effect can happen with the exhaust system. Too little velocity and scavenging will hurt low end power and torque.
Ranger engines simply aren't that big and don't flow the air that a big-block does, so you simply don't NEED a pair of 2.5" pipes with Flowmasters like a 454 Chevy does.

Gibson Exhaust's own data shows more hp and torque with their single system than their dual outlet setup on a Ranger. IIRC, their single system gains 8 hp and dual gains 5 hp.

correct.

most fords diesels ever made had 400+ cubic inches. the 7.3 was around 455 the 6.0 was around 390 and the newer 6.4 is around 400. i think the chevy diesels are somehwere in the area of 6.5 liter i beleive. not for sure.

the 7.3 international and ford diesel are 444ci. the 6.0 is 365ci. the older chevy diesels were 6.2 then 6.5 and the new duramax is 6.6.

chebbys are 6.5 and are junk. a buddy of mine has 5 in exhaust and a banks programmer, he blows through injectors and all sorts of other crap like nothing. a buddy had a 7.3 with 5 in exhaust and a chip and never had any problems. the best one that a buddy has is an 06 5.9 Cummins with bullydog programmer, 6 in exhaust, new tranny to handle the torque, and pushing 650 horse with the chip up and at least 700 ft lbs. no problems at all.
it all depends on the engine and how it is driven.

6.5s are good motors and can be reliable when near stock horsepower levels. and 06 cummins with a bullydog will NOT make 650hp. and if it did, it would make more like 1200-1300lb-ft of torque.

400CI is 6.6, which while both the 6.9 and 7.3 are bigger than but still no where close to 600CI.

Chevy has made 6.2 and 6.5 diesels, debates ramble on about their quality but the military still uses them in their humvee's so they must not be all bad. Now they have a 6.6 Duramax built by Izuzu in their trucks.

First of all, diesels and gassers are two different animals and respond to exhaust mods differently. When it comes to a turbocharged diesel engine, you can dump the exhaust that exits the turbocharger directly to the road with virtually no back pressure after the turbo and the engine will will be quite happy especially once you wind it up. NO damage will be done except to your ears.

Naturally aspirated diesels can benefit from a properly sized exhaust tube for the sake of exhaust scavenging, but going to a larger pipe will not have much affect on powerband like in the case of a regular compression throttled gasoline engine. When it comes to peak power against the RPM governor, the bigger pipe you can fit, the better. There is of course a limit after which it becomes hard to measure any gains.

Bottom line is you can put as big an exhaust on your diesel as you want, but after a certain size the cost/benefit ratio gets much worse. It will not however, damage the engine, I don't know where that myth came from.

6.2/6.5 and 6.5 turbo are a completely different engine from the duramax.
Nothing in common what so ever. I wouldn't call the 6.5 the best diesel ever made, but its far from being the worst (we have one). No, it never carried the duramax name.

thank you!

My buddy, which is ME, says 6.5s are good. I don't know how you blow through injectors. Matter of fact, I don't even know what you're talking about. I've had the same setup for 6 years and replaced one water pump and a starter solenoid. I replaced an o-ring on the throttle shaft of my injector pump 4 years ago, and changed the stock box fuel filter/sperator for a screw-on Racor--and added an electric boost pump. I have a Banks turbo and the 3" single exhaust with the Banks school bus muffler on it. It's a reliable 250hp/450ft# motor that makes 12psi boost and rarely exceeds 1,000F. I'm not trying to be a hotrodder with it, but it tows regulaty--up to 9,500#. It's quicker than my 4.0 B2 and gets better mileage too.

And, by the way, the 6.5 is still being manufactured--it's 28 years old still being built in Moraine, Ohio--operations now being done by AMG, manufacturer of the HMMWV. It's available in marine and civilian verions, known as the Optimizer 6500. It can be bought from the factory in a twin turbo 400hp, 600ft# version.

A design doesn't last 3 decades unless it's good. At any point along the way someone could have supplanted this Detroit Diesel design, but it never happened, and other companies tried. Most the problems people have had are because they don't understand the machine they are messing with.

if i remember right i think it was the late 90's early 2000's the duramax's did have troubles from the factory with the injecters. not for sure tho ugh

so what year did the duramax come out? late 90s? early 2000s?

2001 was the first year of the duramax, LB7 engine.




to everybody else who thinks they know something about an engine, keep it to yourself. a turbocharged diesel engine functions nothing like a gas engine.

Garrett

 

[fastpakr]

to everybody else who thinks they know something about an engine, keep it to yourself. a turbocharged diesel engine functions nothing like a gas engine.

Garrett

You're making great strides towards winning friends and influencing people.

 

[SSpeeDEMONSS]

You're making great strides towards winning friends and influencing people.

i understand that. i dont like coming onto a site and causing problems but some of the people that have posted in this thread really DO NOT know what they are talking about. then they talk about it like they know what they are talking about and further spread the ignorance.

their thoughts of BP on a gas engine are totally correct, i give them that. but they cant apply that to a turbocharged diesel engine, they are two totally different animals.

Garrett