KevinEF7

General broad question. On a turbo honda, running about 20psi, 350whp estimate ballpark.

How much power could I expect to lose going from a 3" open downpipe that 90's off the turbo and under the oil pan VS a straight 3" exhaust with no restrictions, at most a 3" flexpipe but running the exit all the way to the back of the car

Trying to get an estimate if its worth it to go loud and untamed and smelly for my dd, vs probably a little bit quieter and more tolerable of a DD

Im aware of the cutout route, and thats an option But Im just curious of an estimated power loss at this point

Turbo-LS

iTrader: (4)

350 whp is 350 whp it can be done on open DP also with full exhaust or just a straight pipe back like your talking about. You will see a Ho increase on the same boost level from exhaust to open DP but it's not nessesary at that power level.

TheShodan

iTrader: (14)

It can't be calculated or guessed until you're back on the dyno. there are a lot of variables for it, including backpressure from the exhaust housing / exhaust wheel combination, boost control, duty cycle, etc.

If you want to for sure get pulled over more, and get headaches from fumes under the floor pan go open downpipe. If you want to at least reduce the likelihood of getting pulled over, just get a good exhaust. You'll thank yourself later for doing it.

KevinEF7

I was thinking there could be as much as a 50whp difference from just open dp VS piping routed to the back

TheShodan

iTrader: (14)

If that makes your feel better, fine.. Just telling you the factors so that you can go to a dyno and test.

LightningTeg

I like my full exhaust. Doesn't seem to be a restriction at my power level yet.

Turbo-LS

iTrader: (4)

Although your making good power if you went open dp It will absolutely free up more hp but the downfall is smell headache and noise in a street car

TheShodan

iTrader: (14)

I guess not, huh??? 567whp on a stock LS head.

EsotericImage

iTrader: (8)

Wouldnt the exhaust heat up the oil pan thus heating up the oil which isnt a good thing.

Just throwing my fart in the wind

Ash J. Williams

there is finesse to doing things that is lost on some people.

Wobbz

Caught wind of your fart.........

Wouldn't make a significant difference in oil tempiture.

v8killaz

you may gain a tiny bit of hp which to most is not worth it,
i got my dp cut like 6 inches off the turbo going straight down. never smell any fumes and its quiet. barely hear it when cruising

K7-1Ktrevor

I love my 3" straight pipe. somewhat queit when cruising, you don't have to smell the car and sounds roudy as all hell >)

Silent_Bob69

bumper exit downpipe for me. windows up: quieter than the skunk2 mega power I had before, windows down: it's about the same(unless I'm beside something and I get the echo). WOT is a whole other ball park lol.

LightningTeg

I would imagine 10-15whp but it would make drivability lower, more noise, more "racecar" and that's exactly what I dont want lol.

GEN2 LS

iTrader: (3)

What about running the downpipe through the hood? Or side exit?

LightningTeg

What about it? Cutouts are really nice BTW:

https://www.youtube.com/watch?v=Zcow_AsTQBs

I was just too lazy to do it again on this car. And it sits kinda low if you dont weld it real tight against the chasis

kbouchard1092

Save yourself the fumes and Harrasment from police. It would just be a headache in either case literally.

If its a street car 100% do the full exhaust. if its for the track only you wont need to worry about it....It is not going to be 50 more hp at the same boost level no way! not at a 350whp power level. You should see a difference but it shouldnt be much with a proper Exhaust. If youre that worried about power loss turn the boost up to make uo for the difference

92redhatch

With the hood exit I'm always worried about it raining. If it was a dd I would no question have a full exit. It's just less headache.

A BeastyDC4

at 515whp the only thing i noticed from my crush bent 3" exhaust to open downpipe was spool time and powerband about 1,000 rpms sooner, that was definitely worth it to me.

KevinEF7

Yes thats a significant improvement

I think I will start off with the open downpipe and then if it bothers me I will order the 3" kteller piping kit and possibly get creative with a manual opened throttle body cutout

Turbo-LS

iTrader: (4)

If you exit the open dp to the side of the car it wont be as loud and wont smell so bad

GEN2 LS

iTrader: (3)

i've had both on my old integra, the power difference doesn't constitute the amount of noise and headache:p not worth it, if your worried about not making enough power just turn the boost up more. At 350whp it won't be substantially noticeable honestly.

LS AzZkIkr

From my experience open dp under the pan would be more quiet than a straight pipe out the back of the car with no muffler. There is nothing wrong with a nice mandrel bent 3" exhaust on a Honda with the right mufflers. Hell I'm about to recirculate the dump tube and add another muffler!

KevinEF7

Open downpipe ending under the oil pan, was QUIETER than a full length exhaust ???