HydroStream6

iTrader: (16)

I'm working on my dump tube now and with the way I have everything run, it would be MUCH easier just to route the wastegate back into the downpipe rather than snaking a dump tube all the way through where it needs to go. My question is though, will I be losing power by not doing an atmospheric dump?

To me it seems like the atmospheric dump would just be additional exhaust flow, therefore less backpressure and more power.

Thoughts? I want to finish my hot side tonight...

Downpipe is 3" by the way...

Old Geezer

iTrader: (3)

If it's a street car, I doubt you want to listen to an atmos dump barking at you. [The cops probably won't like it, either.]
Race only?? Dump it out to atmos.
Done correctly, there's not alot of loss w/ return to downpipe.

HydroStream6

iTrader: (16)

I had an open dump with my old setup and it was no big deal. Returning it to the downpipe is just easier this time around. I just don't want it to hurt me. I'm looking to make 750-800 rwhp. Dynoed 650rwhp with the old setup.

ninetres

iTrader: (35)

WG do not add power. They control boost. I would think dumping it in the atmosphere would be more effective at bleeding off excess ex. gasses on low boost. If you are running low boost with a long dump pipe of so sort it would seem to be "harder" for the WG to vacate a large amount of gasses.

HydroStream6

iTrader: (16)

Do you really think I don't know what a waste gate does? Even at high boost you are now creating more exhaust than on low boost; the waste gate is still open under high boost. I would think it would have to be a benefit to have it dumped, but no one really seems to be able to say yes or no.

HUNTER02SS

iTrader: (24)

I think if you merge your dump in with your exhaust , and you have a poor exhaust setup, you may get backpressure issues and this may effect your wastegate opening. Just dump it to atmosphere and be done with it if you can.
Will it make more power?? Havnt done comparison, but this way the gate will open when it is supposed to without any adverse effects from another exhaust source.

cracker

iTrader: (1)

Depends on a lot of factors.

Turbo size, dowpipe size, how they recirculate.

I have personally seen 35 rwhp lost by recirculating on a 302ci 2v Modmotor with 2.5" DP's. Same boost, timing, etc.

Ask just about any import guy, especially common thought amongst the EVO crowd, most agree recirculation kills power.

I personally think downpipe size and manner the gas is recirculated plays a large role in power. However, I would rather give up 35 rwhp on a 750-800 hp car than run open WG's. It just sounds ridiculous.

-W

Phil99vette

iTrader: (11)

dumping it makes more power. period.

Mike454SS

iTrader: (4)

Dumping the wastegate absolutely makes the exhaust more efficient, and thus the hot side isn't working as hard to turn the cold side to create the same boost pressure...and as a result, that same boost pressure is more airflow through the overall system (less resistance on the outlet means more flow @ the same intake pressure) and that is more power...but it's up to you dude, if you can tolerate the sound, AND plumb the open dump somewhere that won't melt things (I've seen an open dump melt a strap on an AWD dyno with a DSM on it)...go for it...but I think on a 370 you can make that power anyways...as long as the turbo's are up to the airflow you need with the WG's plumbed into the exhaust, and as long as your engine is up to a little more heat generated by a slightly less efficient system shooting for the same output goal.

Edit: reading my own post kinda sounds like I'm trying to call you on knowledge...and I'm not, I'm not questioning you at all, just offering my opinion...hope you don't take what I'm saying as me being a d-bag.

HydroStream6

iTrader: (16)

Awesome, these are the kind of responses I was looking for. It made sense to me also that it should flow better overall dumped, but I wasn't sure what to do. I will take the extra time and just make an ornate dump tube. Thanks everyone

Mike454SS

iTrader: (4)

Just curious...what does your car weigh?...and is the 4L80E built?

HydroStream6

iTrader: (16)

A little over 2 ton... she's a porker. I'm going to try to get it below 4000lbs this season. I'm 280lbs as well so a driver swap would help! Haha.

My two buddies and I built the 4L80e ourselves with the HD rebuild kit and a Stage 2 shift kit. Only hard parts that were replaced was what was worn out.

Mike454SS

iTrader: (4)

Thats cool...I'm building a really similar 370 for my 95 Caprice...which used to weigh in at 4200 with an iron head LT1...so I'm hoping with the iron block and AL heads...and all the turbo related goodies...to be right around 4200 pounds again...I want to keep it a stick car (it currently is, I converted it YEARS ago when it was just a bolt on's LT1 car)...but realistically a 4L80E would probably be a better choice for me/the car.

I'd be happy to run your car and let you see what it does with a 140lb driver behind the wheel if you want (half kidding, I'd probably never take someone elses car down the track unless it was stock)...do you run the car at LVD?

HydroStream6

iTrader: (16)

That sounds like a pretty cool project! I'll let you know how the 80 holds up this season, so far so good though!