What can an exhaust system do?

Most car and truck manufacturers leave room for improvement when it comes to horsepower and torque. Not to say that these vehicles are poorly made, but many companies use less expensive alternatives when producing items such as exhaust systems for their vehicles.

A performance exhaust can free some of the power in your engine. These aftermarket systems allow for a quicker, more efficient path for exhaust gases to escape. This means your engine "breathes" better, so spent fuel and air exit the combustion chambers faster and new fuel and air can be burned to create more power.

There are several other pluses to adding an aftermarket exhaust system. One of the most noticeable advantages is a more aggressive exhaust note. Depending on the system, you'll get the more aggressive, deeper rumble that is found on most high-end sports cars. Many of the better systems are only slightly louder than your stock exhaust, and deepen to a low "growl" as your RPMs rise during acceleration.

The way the pipes are bent also affects the exhaust flow, and there are two types of bends used in making exhaust systems. The typical factory-made systems, as well as some aftermarket systems, use a "crush-bend" technique. This type of process creates a crinkled area in the pipes, decreasing the diameter and slowing exhaust gases. A mandrel bend is smooth, and does not affect gas flow. The pipe is a constant diameter through the bend, yielding less resistance for a more efficient and better performing exhaust.


A crush bend causes the exhaust pipe to become more restrictive in certain areas.



Mandrel bends, like the ones in this Borla system, yield the best performance and sound gains.

Another factor to consider is the material used to make the system. Most factory exhaust systems are made of mild steel, meaning they have a tendency to deteriorate over time. Better aftermarket systems are constructed of aluminized steel or stainless steel. Aluminized steel offers slightly better longevity over stock systems, while stainless systems are designed to last much longer, usually for the life of the car or truck.

When exploring further differences in exhaust systems, it becomes more important to factor in how you use your vehicle. Most aftermarket systems add to your car or truck's appearance, with larger tips and highly polished mufflers for a more refined, aggressive look. There are many aftermarket systems that allow you to retain a stock appearance, while still seeing performance gains. The diameter of the pipes used in the system is also dependent on how you use your car, as well as whether or not you are adding further aftermarket performance parts. Most cars and trucks benefit from slightly larger piping, but if you go too big, you can actually hurt your vehicle's performance. On the other hand, if you are adding forced induction to your vehicle, such as a turbocharger or supercharger, you will want to go much larger than your stock exhaust.



The polished tips on this Borla system for the Honda Accord give the car a more refined look.

No matter what direction you choose, an aftermarket exhaust is sure to add to your car or truck's performance, appearance, and sound. Take into consideration what direction you want to go with your vehicle, whether it be performance, show, or simply an improvement over stock. The right exhaust system can dramatically change your car or truck for the better.




info taken from http://www.crutchfield.com/S-M7PVOFEyTTw/learn/learningcenter/car/performance_parts/exhaust_benefits.html

To add to this, be careful with pipe size. Bigger is not always better.

merlin5577 wrote:

To add to this, be careful with pipe size. Bigger is not always better.

should post that on a honda site lol..


also, galvanized fence post is not a good idea.. it'll rust away from the heat exposure faster than the OEM mild steel

One more thing; the above post really lends itself toward gasoline engines, Diesels are a complete different story. Still, its a good read. Thanks Junior.

Yeah very nice little artical jr... Good mind man!!

Of course, you could always just run it straight out of the manifolds....



Thanks for the tip!



How much HP/Torque gain would I possible gain if I ran a dual pipe system in my GMC with the 5.0? It currently has the single exhaust, and I'm not liking that.

It all depends on how you decide to run the dual exhaust... You have the same model truckas I so it is impossible torun dual straight pipes on your truck because of the gas tank... I personally can't put a number on how much power you'll make because pipe size and route take part muffler choice has alot to do with it as does whether or not you run a cat and probably one of the biggest factors is if you continue to run the stock manifold's which are severly restrictive or if you upgrade to headers and even then if you decide to run stock length hugger headers or run mid length headers or if you go all out and modify your motor mounts and go full length tube headers... If you run a free flowing exhaust like glasspack and no cat then you'll notice a powerband around 3000 rpms and around 3500 your exhaust is gonna resonate so voilently it is gonna be loud raspy but if you run the infamous Flowmaster you'll notice a larger torque curve thoughtout the whole rpm range and you'll get a more even low harsh tone that resonates only at high rpms... So unless you know exactly what your gonna do it's hard to predict power gains from adding daul exhaust to your truck... IMO

I partly diasgree. Removing the cat does not always improve power. Modern (ie comptuter controlled) vehicles rely on the cat to be there when controlling the engine. If its removed, more then likely you will trip a check engine light, which will lower performace. Also, the cat does add some backpressure, which gas engines need to run correctly.

True I was refering to me and 93 early 90's series... I don't have a cat on my truck and there are no codes for it and I noticed a power gain and slight fuel mileage drop from removing mine...

No CEL/SES from removing the cat on a TBI motor? That's odd.

You really won't find any increase between a slightly larger single exhaust with mandrel-bent pipe with the right muffler as compared to running equivalent duals. The only thing I ever noticed change was the price and sound.

Be very careful when anyone that is considering this goes with a big Flowmaster. I personally love a good droan. I put the S40 with 3" straight out the back on my '02 gasser and even I was a bit irritated at the droan while on the highway. The 80 would have been a better choice or maybe putting a resonator in there, but the resonator defeats the purpose of the 40 and bigger, mandrel bent pipe. We pulled the cat and ran a single with an 80 on a '98 5.7 and it threw codes and CEL. We also lost a lot of torque in the usable RPM range. On the newer LS V-8s you will see your torque move even further up the RPM band.

The one truth in exhaust I can verify is that you should buy your pipe according to your weather. The pipe that a local shop has in-stock may be a great deal but up north it will only last a few seasons. Even my 304 polished stainless got pretty dull and spotty in a Michigan winter.

You almost had me for a second Robert. Although I will say going 5" straight back on Chum was probably not beneficial. It does sound great though. My 6" stack kit came in yesterday!!

Its possible. His truck is an OBDI and they tend to be more "lax" with regards to tripping an CEL. On a OBD II truck, guaranteed to trip the light.

My old '89 did not know what to make of it after we did that. It didn't really help or hurt on that truck.

It has been a long time since I had to mess with an OBDI system. That is what I learned on, though.

BombDocDiesel wrote:

It has been a long time since I had to mess with an OBDI system. That is what I learned on, though.

Cost of getting CEL looked at at a shop,



$105.00

Cost of doing it yourself with the proper tools,



$59.95+tax.

Cost of doing it free,





Priceless.

Good one!! I don't even remember which pins to jump anymore.

I think top left and bottom right.

Good guess 93 but alittle off... top far right and top 2nd far right

d'uh.

I actually tried running true duals on my 95 Gmc 1500, with the 5.0...... and like said, the gas tank becomes and issue...... I had a good exhaust man do mine and I actually lost some low end power..... could be I went to big on pipe size....... anyway, I ditched that, Took my cats out, and ran a single 3" pipe out into a single in/dual out flowmaster, with 2 1/2 inch pipe dual out the back turned behind the rear tires........ I gained power, and response, and it sounds really good.... I started getting in trouble with the law for excesive exhaust noise, and had a 3" through the center glass pack(magnaflow) in before the flowmaster, and it quieted it down, still giving a good tone and respectable power.....

93, Duals with Flowmaster 40's and 2 in. pipe. It will roar.

This is exhaust can be a chock block if you don't have a parking brake.

That's 5" straight with 7" Magnaflow tip.
It is free, just come get it.

hmm.. wonder what it'd make my half blown 2.8 sound like

like a full blown pos.. lol..

Here's what a 6" Grand Rock can do.