HKS Downpipe Review!

[gryphon]

Originally posted by Verdugo


It may well easily be my crappy TurboXS ABC that's causing the spiking. What do you use for boost control, Gryphon?

I just use a $5 MBC from Home Depot. Bleeder type. I'm not getting spiking but I got 1.2 MPa in 4rd after I installed it so I readjusted it and got 1.0 which I'm ok with for now. It wasn't a spike... just a peak and hold... (until ECU dropoff of course)

I really don't see why one would be spiking and not the other... I got spikes WITHOUT any boost control in 5th gear WOT. I'm not too worried about it... just set boost at a reasonable level (16psi or so) and any spikes should be relatively minor (0.5-1 psi) and settle quickly. No biggie. I'm waiting for the DeltaDash logs to reveal any spikes that aren't apparent to the naked eye (laptop's battery and AC cord are dead at the moment).

[206WRX_GDA]

Great reviews everyone! But all the 'spiking talk' is scaring me..hehe, maybe I should have went all motor? Heh....keep us posted on the CE lights!

B

[Verdugo]

I should note that my spiking isn't holding the boost that high...it goes up for a split second and then comes back down to where it should be. I just notice it more now since I didn't turn down my boost when I should've. I drove around A LOT yesterday and it didn't spike or overboost whatsoever.

[gqzboy]

Will this HKS DP fit the godspeed uppipe? Im moving back to california and right now i'm equipped with HKS Ti cat back exhuast, uppipe is going in in about 1 wk, that will leave the 2 cat from downpipe, i know i won't pass the smog test 1st of all, plus i was told if you get pull over by the pigs, they will give thousand dallor ticket for driving without a cat.. anyone???

[WRXin']

Originally posted by gqzboy
Will this HKS DP fit the godspeed uppipe? Im moving back to california and right now i'm equipped with HKS Ti cat back exhuast, uppipe is going in in about 1 wk, that will leave the 2 cat from downpipe, i know i won't pass the smog test 1st of all, plus i was told if you get pull over by the pigs, they will give thousand dallor ticket for driving without a cat.. anyone???

The uppipe fits between one end of the turbo and the manifold, and the downpipe fits on the other end of the turbo. So you see, the up and downpipes are not connected. So to answer your question: yes, it will fit just fine.

[Baluchitherium4]

I have an ATR downpipe on my car and it is a flat plate design also. I don't think it really makes a difference on the stock turbo.

I know exactly what I'm going to do when I upgrade the turbo though. Weld in a divider to separate the wastegate from the exhaust side of the turbo. Cut a hole in the flange for the wastegate and weld on a 1" mandrel bent pipe pointed directly at the ground.

For me, it's not that big of deal because I have the tools and know-how to do this. It will be a "screamer" though.

Later,

Dale

[MisterX]

I have an ATR downpipe on my car and it is a flat plate design also. I don't think it really makes a difference on the stock turbo.

You're gonna set your car ablaze like that. If the noise and the fumes don't kill you first.

russ

[gryphon]

Originally posted by russ


You're gonna set your car ablaze like that. If the noise and the fumes don't kill you first.

russ

Do you have firsthand knowledge of this or are you just speculating?

[Verdugo]

Originally posted by russ


You're gonna set your car ablaze like that. If the noise and the fumes don't kill you first.

russ

Yeah ummm...my car hasn't caught fire yet...especially since the OEM downpipe has the exact same flange design

[gryphon]

I think he's talking about the wastegate dump tube... but I could be wrong...

[Baluchitherium4]

The wastegate dump tube is exactly what I'm talking about. This is not an uncommon thing on turbo cars. I've seen it on DSM's, WRX's, hell, almost any car with an external wastegate. Russ obviously is confused or doesn't know a lot about turbo cars.

Either way, it won't set your car on fire and it's very unlikely fumes will make their way into the cabin due to the fact the dump tube will only be active when under boost. You're going fast enough under boost that the fumes will be carried away from the cabin.

Later,

Dale

[206WRX_GDA]

I thought we have INTERNAL wastegates?

Originally posted by Baluchitherium4
The wastegate dump tube is exactly what I'm talking about. This is not an uncommon thing on turbo cars. I've seen it on DSM's, WRX's, hell, almost any car with an external wastegate. Russ obviously is confused or doesn't know a lot about turbo cars.

Either way, it won't set your car on fire and it's very unlikely fumes will make their way into the cabin due to the fact the dump tube will only be active when under boost. You're going fast enough under boost that the fumes will be carried away from the cabin.

Later,

Dale

[Baluchitherium4]

We do have an INTERNAL wastegate. I wasn't saying we had an EXTERNAL wastegate.

It can be done on INTERNAL or EXTERNAL wastegates on most cars. I've seen it on BOTH with no ill effects.

Maybe I should draw a PICTURE or perhaps FLASHCARDS would work.

[206WRX_GDA]

Thanks for clarifying...I guess.

[gryphon]

The wastegate is internal to the turbo. The HKS (and OEM) downpipe have a flat flange exactly where the wastegate opens, forcing the wastegate exhaust and turbine exhaust to tumble violently when the wastegate is open.

When the exhaust gas pressure at the turbine/wastegate is less than the rest of the exhaust pressure downstream (i.e. too much backpressure), the results will be that the gases at the turbo might lead to pushing the wastegate closed some (i.e. boost spiking) until the backpressure is overcome. (At least I think this is what happens, feel free to correct me).

What Bal is suggesting is a hole drilled into the downpipe flange with a bend that points straight down. Also, welding in an exhaust divorce plate that effectively forces the turbine gasses into the downpipe while forcing the wastegate gasses through the dumptube.

An external wastegate (from what I understand) is outside of the turbo and can simply vent the wastegate exhaust to atmosphere.
While no turbo car that I can think of in any kind of reasonable price range comes STOCK with an external wastegate, they are generally considered more reliable and are often necessary for particular turbos.

Russ is contending that this could start a fire. I don't really see this happening although my knowldge on the subject could be less than his so I asked if his knowledge was genuine (i.e. firsthand) or simply rumor.

For more info on separate wastegate dump tubes, see the BPM downpipe, which utilizes a separate dump tube which joins back in with the normal exhaust farther downstream.

Or was you "Thanks for clarifying... I guess" merely a sarcastic thank you and not conveying confusion?