Dumps

[Super Shredder]

been thinking of the cheapest exhaust i can think of to get done at a shop and i want to ask everyones opinion on:

a 3inch dump pipe maybe 2 feet long from the cat, so its basically a muffler delete, but keeps both cats and a 1-2 foot pipe bent downward. besides noise, what would be BAD about this?

then again how much louder would it be, traveling into the ground as opposed to out the back of the car like a muffler delete single catback from cpe? i figure the longer the trumpet the louder the noise, so is all that pipework even neccissary?

 

[jville]

Bad... worst enemy would probably be heat. Also the smell of exhaust fumes more likely to enter cabin at redlights and such.

 

[Blendercloud]

I believe the reduction in backpressure would probably screw with your tuning.

 

[Atreyu3388]

You could always just buy a test pipe, and hack off the stock mufflers and weld in some "delete pipes." This probably isn't the prettiest route, but cheapest...yup.

 

[jville]

I believe the reduction in backpressure would probably screw with your tuning.

Turbo vehicles get backpressure from the turbo itself. Now our turbo seals are a totally different issue, Depending on which batch of the K04 you got ur seals might start leaking with less backpressure.

 

[Super Shredder]

if my turbo seals go kapoot at 45000 miles i will take a bow, apologize to my car for running in boost most of the time, back up behind the curtain, giggle, and go get a PG K04.

 

[Blendercloud]

if my turbo seals go kapoot at 45000 miles i will take a bow, apologize to my car for running in boost most of the time, back up behind the curtain, giggle, and go get a PG K04.

+1!!! Haha

 

[Super Shredder]

but also thank you for that info because i will correlate the two. my only thought was, i figured when you get a test pipe and remove a cat, thats when you see the smoke that was already there because of the cats doing their jobs, but i would be keeping both cats and dumping to the gravel 1-2 feet afterwards. maybe if i put a small resonator before it could solve this? does the length of the exhaust determine backpressure?

 

[Blendercloud]

The way I relate exhaust and backpressure is imagining your exhaust pipes as plumbing. Essentially, in plumbing you're going to maintain pressure as long as you have the same diameter piping. If you increase the diameter of the pipe, you will lose pressure/backpressure. If you apply restrictions (sharp bends, mufflers, resonators, catalytic converters) you will increase the pressure by reducing the volume permitted.

Essentially, the length of the exhaust will not 'determine' your back pressure. It will only hold that backpressure that the restrictions force upon it.

If you get long enough with piping that has an atmospheric outlet (way longer than a car) you will begin to see pressure drop per foot depending on starting pressure and atmospheric pressure that you're venting to. On a car, you don't need to worry about that really for the size of pipe that exhaust is made of.

 

[lynnriderm6]

but wait if he gets the dump valve exhause isnt it just a button that opens it up and closes back up because i have a friend that has a 300z and he has it where its normal exhaust or the dump

 

[TX Speed 6]

but wait if he gets the dump valve exhause isnt it just a button that opens it up and closes back up because i have a friend that has a 300z and he has it where its normal exhaust or the dump

That sounds more like an exhaust cut out, not quite what hes talking about here

 

[zinger002]

get stacks!!! lol.

 

[kylefire5]

Great post on back pressure and turboed cars.

Check it out... http://www.msprotege.com/forum/showthread.php?t=67805

 

[Blendercloud]

Great post on back pressure and turboed cars.

Check it out... http://www.msprotege.com/forum/showthread.php?t=67805

That is an awesome find. For the MS6, it sounds almost like Corksport's downpipe is probably the best way to go because of the divorced design. Thanks for the post. That was quite an education for me. I am very familiar with NA exhaust but turbo exhaust is new to me.

 

[Super Shredder]

so that article basically enforces that backpreassure is kept in the header/manifold and turbo however my idea of a bent dump which wouldnt be perpendicular or straight wouldnt work well.