i currently have a dual 3" tip exhaust on my accord and is looking to add another twin exhaust on the other side, i know it will be loud , but will i actually gain any horsepower??? oh, yeah, the exhaust i have now is Ractive

 

no, you will probably lose hp. you'd also just be adding weight, which is a bad thing.


[Modified by carolinaACCORD, 3:21 PM 10/15/2002]

 

if you don't want to lose any HP, you can just custom hang the extra non-working muffler w/ little piping that isn't connected to the actual pipe. yeah the weight will be added to your ride but it will function good.

 

No.

 

for extra good stunnaness try 5 inch tips!

-chris B

 

Can someone explain to me why being able to breath better would cause a loss of hp? I thought less backpressure was a good thing?

 

i did it to my car...i have what no other car has...i like to call it "quad" exhaust...yeah thats right...2 straight out the back and then to others coming from underneath my doors...gawd it sounds awesome!! you should try it out...i got all my piping from KTeller8...PM him...good guy.

 

wahahah.. oh my...

without going into fluid/air dynamics losing back pressure IS ok.. but:

"Any properly designed exhaust system will have back pressure, in an acceptable range. When modifying/ changing your exhaust, you want the lowest back pressure you can get away with [allows the engine to breath, zero load rev speed increases, and so does heavy load rev speed], while keeping exhaust velocity optimized for the RPM range you're looking to make power."

PS i didnt write that, thats an old post/remark from a guy called 1stGenCRXer i think is his handle. I don't think i could have explained it better... so thats why I use him.

PSS the first kid i catch in town with exhaust coming out the side and the rear ala gets a shoe in the crotch


[Modified by GimpyAccord, 2:23 AM 10/16/2002]

 

Accords need back pressure. Just Fact!
You have no back pressure the car loses HP, and also makes your car look like ARROZ

$0.2

 

Em...adding silencers=back presure?
until today the mystery of g4y back pressure myth continues...

 

Who said that dual exhausts (Y-pipe design) on a 4-cylinder car will decrease backpressure at all? The idea is just stupid.

 

Too many myths...

Lets settle this.

Lets clear up what backpressure is. Back pressure is the resistance to motion of the piston and it basically increases the inefficiency of the motor as a big air pump.

This is not good for air flow.

Backpressure will also cause exhaust gases to linger in the combustion chamber and screw up the A/F and that will also kill power. Exhaust back pressure tries to reduce the pressure difference between the cylinder and the exhaust. This hurts flow.

Get it?

This hurts the engines efficiency ALOT. The ideal situation is a header and exhaust that flows so well that it acts like a vacuum and sucks the air right out of the combustion chamber and out through the muffler.

Exhaust gases will flow if each section of the exhaust, 1) coming out of the cylinders, 2) through the header, and finally 3) the exhaust, have different pressures of gas being forced through them at any point in time. The difference in the pressure is what makes exhaust gases flow. A fresh batch of exhaust gases coming out of the cylinders will want to replace the spot of the gases leaving to travel down the primaries of the header.

This is why sometimes an open header is much more likely the kill the energy of the gases leaving the header and fail to produce the vacuum to suck the gases out of the combustion chamber. This is why race cars run turn down short exhausts and not a straight open header. The scavenging effect has to be kept intact. A typical OE muffler will have like 20psi of backpressure. A Greddy for example may have 5 or so. And a race car around 1.

A "dual" is exhaust could theoretically be designed to flow very well. The question always comes back to WHY? The R&D involved would be probably not be worth the effort to get it work as well as even a decent single exhaust.

1 bank of cylinders

1 header

1 exhaust pipe

Maximum horespower


This is what I have learned during my 645 days on H-T about exhausts and back pressure. Someone please correct me if I gave any incorrect information.

Nick- Who hopes this helps and who rarely writes such lengthy tech posts unless he gets annoyed enough with misinformation

 

to summarize.. 1stgen is wrong .. or maybe not wrong but incomplete in his summary????? you went off on a slightly different tangent so im trying to get the BS flag up or down on what... i thought made sense. his logic did apply to me in a street car sense.

people you see running 502 chevys arent too worried about a lil bottomend gone and of course do run straight dump


[Modified by GimpyAccord, 5:37 AM 10/16/2002]

 

Nick is absolutely right.

While I was running my exhaust with no catalytic converter, I had better high end power than I do now with the cat on. It's a noticable difference, and when I design my next exhaust I'm taking that into consideration.

 

Just do it if you want it. You won't feel any difference either way. About that extra weight... Do you guys make your girlfriend walk to save weight too? He's not drag racing. I ran my car with an open header before and it was definitely quicker.

 

yeah the weight **** doesn't make one bit of difference to a daily driver.............

 

no backpressure is only good for turbo motors not n/a motors, plus the motor is not in the state of tune where it will push so many cfm's to take advantage of the total exhaust volume to use its efficieny to where there would be a powergain

 

you guys arent even mentioning the heat loss that a dual exhaust setup would inevitably encounter. doubling the flow path of the exhaust will also double the area of piping that the heat could be lost through. and we all know that would be bad. heat needs to stay inside the piping.

of course, i dont guess any of what has been said in this post matters to a non-competition daily driver, except to me.


[Modified by carolinaACCORD, 9:39 AM 10/16/2002]

 

cool avatar Beach Accord

 

oops i knew i left somethign out temp loss = flow momentum/speed loss

 

for extra good stunnaness try 8 inch tips with some 20s

 

I run no cat too.. not by choice, but I wasnt about to pay 200 to replace it. I will say I noticed a little bottom fall out, but on the top it does run harder. The proof of this to me is: I've casually raced 3-4 different 4th gens around town and none of them can pull my car.

Whatever I cant wait to be turbo than all this non-sense will be behind me

I know how to build engines, not exhausts.


[Modified by GimpyAccord, 8:10 AM 10/16/2002]

 

i am planning to run a 60 nitrous express kit over the next month or so, and i already bought the exhaust, i just havent welded it yet. should i just not put the exhaust on? and would it help me out with Nos if i do install it?
Is this just a lose, lose situation??????????????

 

and what about twin factory exhausts? dual tip of course

 

When I took out my catalytic converter I gained more high end power too. As far as losing heat/exhaust velocity due to the dual exhausts, my mufflers both get very hot (since the converter is gone). I don't really care much about the low end of the power band being that 4 cylinder engines make power in the high end revving. This is where I like to see my gains. If I don't need to go fast, I still have plenty of power to move the car. When I need to go fast I step on the gas harder and rev the engine higher. I don't know of any races that people stay in the low RPM range. When you need to go, you put the pedal to the floor. High end power is what I focus on and if I lose some low end torque in the process oh well. My .02