open dumptube vs merge downpipe

[blazen_accord]

When I 1st got my external waistgate an open dumptube I thought it was cool since it make the engine sound meaner with my dual exhaust. But after a while I find it become some troublesome. The exhaust fume smell is all around the car at a red light or when parking the car, I can't have my windows down or fresh air fan on unless i'm on the highway. I did not mind that before but now it just a pain to deal with. I have check with some shop asking them to weld the dumptube and merge to the downpipe like some turbo design, it will make the car more quiter and no more raw exhaust fume smell. The exhaust shop say they have try it on 3 other turbo honda and doing this has reduce power as much 30hp/30tq since it disrupt the exhaust outflow when they merge the dumptube to downpipe.

I'm not sure if they say is all BS or true, and just want to know the other people who has open dumptube( my is about 18" inches long) ran into similar issue as myself? My dumptube might be too short? it bend 90 degree and is next to the AC compressor. beside the smell it also too loud when barely in boost at 1/3 throttle and it open up at 5psi. My exhaust does not get deep and loud till I floor it. Any one try anything like adding lenth and routing it the dumptube elsewhere? or putting something on it to make it more quiter?

[chessboxer]

im running open dump myself, but its with the 272 cam as well, so its really loud all the time, and sounds mean at idle. Mine runs to about the middle of the car and then dumps down at a 45/90 ish degree angle. As for making it quieter, I have heard of people keeping the exhaust short, but putting a muffler under the car and still making the exhaust dump down. It is still semi loud, but supposedly, it keeps it from being as loud as what youve probably got going on right now.
Also, why do you want to go with a dual exhaust? I do not like a dual exhaust on a 4 cyl car personally, and I do not think anything sounds meaner than a cammed turbo car running open dump, making people think youve dropped an lsx in your car. However, this is just my opinion, and if you really want the best of your dual exhaust and open dump, you could run an electric cutout, which gives you the power when you want it, and the quiet when you do not.
Whichever thing you choose, good luck and be careful.

[MRX]

your dumptube would have no effect on the exhaust fume smell in your car at a stop light though. The dump tube only has exhaust flowing through it when the wastegate is open...which is only under boost...which is USUALLY while the car is moving.

You probably just have an exhaust leak. If the dumptube is angled at the ground so that the oncoming air underneath the car is wisking it away then you shouldn't be able to smell anything when you come to a stop.

I never had a problem with my dumptube, all of my exhuast fumes came from exhaust leaks. But to answer your question i'd heard of 10whp loss by routing the dumptube back into the exhaust stream. Thats probably on higher end setups closer to the 350whp+ range though.

[Boost_Lee]

i agree, the dumptube should only function during boost. double check your manifold and turbo connections, as well as your downpipe

btw...where the hell have you three been?!?!

[d112crzy]

The only way routing the dumptube into the dp will make you lose power is if the shop doesn't know how to do it.

You gota put it at least ~14" after the turbo. The further the better. They also gotta do it at the correct angle. Well, there isn't a correct angle, but there is an incorrect angle.

It's about flow, think about it.

[MRX]

you shut your dirty mouth

[MRX]

The only way routing the dumptube into the dp will make you lose power is if the shop doesn't know how to do it.

You gota put it at least ~14" after the turbo. The further the better. They also gotta do it at the correct angle. Well, there isn't a correct angle, but there is an incorrect angle.

It's about flow, think about it.

yea but any disruption will cause turbulence...end result is it'll still lose power...probably no where near what that shop claimed though...not for his application atleast.

[d112crzy]

yea but any disruption will cause turbulence...end result is it'll still lose power...probably no where near what that shop claimed though...not for his application atleast.

yea, I left out "that much" before "power". lol

[zack_odom]

you shut your dirty mouth

LOLOLOL
Okay, so the moral here is, too not run a divorced down pipe?
Just to run an open wastegate dump? Seriously? wow.

[jDmacCordh22a]

x2

[F22HB]

Sooo... good choice or bad??

[MRX]

bad, its actually going INTO the turbo's expeller. Great fitment and cleanliness though. But...why is you oil inlet and outlet not perpendicular to the ground? Do you have some sort of pump thats replacing the effects of gravity?

[F22HB]

Ya, I realised that that is a problem with the oil feed/dump. Thats just the way the turbo came configured. It should be simple to rotate the center 90 degrees though.

[zack_odom]

I could see how your setup, is B.A.D bad.
WOW it puts the dump directly back into the exhaust wheel LOL

[F22HB]

yaaa.... I've been owned by life alot lately... idk what I was thinking. I guess it was just what was easiest at the time. But like I said, I think I just got ownd.

Edit.
Ok, actualy now that I go back to why I did that, it really doesn't point straight at the exit,lol. It has more flow than you can see from the pic. In this pic it looks like it literaly is dumping at the wheel,lol.