Downpipe question.

mk3_chris

New Member
Jul 31, 2007
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I've read about the hp gain from ddp as compared to just a regular dp, but how would they compare if you were just running an open dp.
 

Poodles

I play with fire
Jul 22, 2006
16,757
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Fort Worth, TX
Open stock downpipe is still restrictive as hell. Sounds pretty crappy and is a hazard. Exhaust can get in the cabin, undercoating catching on fire, ect...

The Type-A race cars run DDP's that exited behind the front wheel. It would solve the issues of exhaust getting in and all the heat under the car, but it's not street legal (it WILL shoot flames).
 

mk3_chris

New Member
Jul 31, 2007
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Like suppose you have a 3 inch ddp and a 3 inch dp. If you ran then open how would they compare?
 

Poodles

I play with fire
Jul 22, 2006
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Fort Worth, TX
3" DDP is pretty close to a 4" DP flow wise not to mention the benefits of removing the turbulance (you usually get more boost with a DDP because of this).
 

FernandoDLT

New Member
Apr 13, 2007
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Texas
My brother was having problems with his exhaust so we took it off. He ran the open dp for 2 months(his car has a HKS knockoff dp). Sounded really mean at WOT lol. Nothing bad happened (exhaust in cabin, fire, etc.). He drives his car pretty hard so if anything was gonna happen it would have...

It did have its draw backs. Talking on the phone was next to impossible with all the noise. He was seeing more boost(may be a bad thing with a weak motor).

Fernando
 

Davismj711

PA Mountain Supra
Fernando

Both you and your brother were simply lucky. More than one member on here has in fact had a fire from the exact procedure you described.

Because you had no problems does not at all make it either safe, or right. I would prefer to say that someone was watching over you.
 

Supra28

Supramanian
Aug 17, 2006
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Columbus, OH/Kansas
My bro ran an open DP on his car and the undercaoting was started to wear out, not worth it. It sounded alright, sounds just like a diesel.

As for the DDP, I've noticed that some are going with the recirculated ones, why is that? (maybe a stupid question, sorry). I'm thinking about getting a DDP soon, but a lil' unsure about the recirculated ones.
 

Supra469

New Member
Apr 20, 2007
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Maryland
Davismj711;1429546 said:
Because you had no problems does not at all make it either safe, or right. I would prefer to say that someone was watching over you.

That's a very nice way of putting it! ;)
 

mv520

New Member
Mar 18, 2007
37
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Midwest
Ive been running open downpipe for about 2 years. gets annoying after a while now. anyone get a custom exhaust made from a local muffler shop? how much did it run you guys.
 

mk3_chris

New Member
Jul 31, 2007
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I've known quite a few people to run open downpipe with no problem. shit i've seen a ws6 trans am run basically enough pipe off the header, to dump right behind the front tire with no problem.
 

Poodles

I play with fire
Jul 22, 2006
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Fort Worth, TX
Rubber under coating + insane EGT's from a turbo car = potential fire :3d_frown:

If you've ever seen tires burn, you'll know rubber does NOT like to stop burning. If you have any oil leak of any kind, you're only going to compound the issue...
 

mkiiibro

New Member
Sep 25, 2009
26
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Detroit
you really should attach something to the downpipe, especially if the car is a DD because the droning on and on gets to you fairly quickly, aside from all of the aforementioned issues that you will encounter

~phil
 

funky_monkey58

Closing in on 200+MPH
Apr 3, 2006
1,307
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St.cloud MN
If you do a DDP make sure it is rerouted back into the exhaust. As much fun as a loud car is it is even more fun when someone says something like this.
A//// Guy;308646 said:
That was a sick car. At first when it did a pull, it was so quiet I was like, yea maybe 200hp. LOL boy was I wrong.


Taken off a local forum in regards to one of our cars we ran on the dyno.
 

88t

HATE EM, BUT LOVE THEM
Oct 13, 2008
94
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Juneau, Alaska 99801
i have my stock exhaust cut off rite after the cat due to rust and it sucks!! The noise is unbearable on the high way. it attracks way to much attention. Just my opinion
 

rustfarmer

New Member
Jul 20, 2009
127
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Centerville, TN
Many books have been written on exhaust design. Pipe size, length and back-pressure can be used to make your car both quicker and faster, not to mention a lot more fun to drive. At age 18 I loved headers and fuck the cops but I find I now drive much faster and draw little heat with a mild exhaust note. Used to be I was all "Look at me!". Now its more get the fuck out of my way.
 

dragracer

GearHead
Oct 31, 2005
221
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Churubusco
Why exactly would you want to run an open dp on a street car?

Maybe its just me because I am older. But it doesnt sound cool.

Not to mention carbon monoxide poisoning. You do realize that?

Just my 2 cents worth
Rich
 

dusthead

C-C-C-C-COMBO BREAKERRRRR
Aug 10, 2009
100
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New London, CT
my exhaust thats in my future will include the recirculated DDP. i'm just not interested in the noise...let it all go where it's supposed to: through the cat(or test pipe) and out the muffler.