Wastegate Nipple on Hotpipe

[blitz180]

I have a plain Enjuku Hotpipe. I was thinking of buying the BOV flange to weld on before the swap. SR swap sells aluminum hot pipes as well, but advertises that there is not a wastegate nipple on them, but there is on the Stainless ones. I'll be running a Greddy FMIC Vspec. I will not be running a boost controller yet. Here's the question:

Will I have to weld a tube onto the aluminum Hotpipe for wastegate signal? Or is there a tube somewhere on the greddy pipes to send the WG signal too. I'm confused.

[iamwesley]

You can get the wastegate signal from a nipple on the throttle body. Im not sure if greddy has it but my Blitz FMIC kit has a nipple on the pipe that connects to the FMIC and the hotpipe.

[nlzmo400r]

get a picture of the greddy aluminum piping you're talking about and see if theres a westgate bung welded on it. Even if there isnt, any competent welder can do it, its not that big of a deal. But i dont understand why you would have a wastegate on the 'hot'pipe. I think you're meaning BOV, the wastegate is usually best placed near the collector of the manifold.

Is this for an SR or KA-T?

[S14DB]

Best location is after the TB.

[skatanic28]

you could also get the vacuum source off the cold pipe as well, if you are having trouble finding someone to weld onto the alum. isnt it best to have it closer to the compressor for the best response?

hes not mounting the wastegate there, but trying to get the boost source to control the wastegate.

[weirdstyles.net]

sorry I saw something about nipples....

[blitz180]

yes skatanic is right... i need to know where to get my signal from. and thanks so far

[nlzmo400r]

oh, ok. Well then find a good welder who can weld aluminum, and run it on the hotpipe. Im assuming both your hotpipe and coldpipe are both aluminum so it wouldnt matter.

[blitz180]

that's cool... thanks for the help

[Jeff240sx]

you could also get the vacuum source off the cold pipe as well, if you are having trouble finding someone to weld onto the alum. isnt it best to have it closer to the compressor for the best response?

hes not mounting the wastegate there, but trying to get the boost source to control the wastegate.

Skatanic is not right about the compressor. You don't want it close to the compressor, because response doesn't have anything to do with the wastegate. And you'll lose boost. All intercoolers have a pressure drop, and the way around that is to get the wastegate vacuum signal from after the intercooler. The manifold is the best place, that way you know the engine is seeing 8psi. But your turbo probably needs to make 10psi to get those 8 into the motor.
You can tap off the cold pipe, which would be 2nd best I guess. I just tee'd into the brake master cylinder vacuum.
-Jeff

[skatanic28]

Skatanic is not right about the compressor. You don't want it close to the compressor, because response doesn't have anything to do with the wastegate. And you'll lose boost. All intercoolers have a pressure drop, and the way around that is to get the wastegate vacuum signal from after the intercooler. The manifold is the best place, that way you know the engine is seeing 8psi. But your turbo probably needs to make 10psi to get those 8 into the motor.
You can tap off the cold pipe, which would be 2nd best I guess. I just tee'd into the brake master cylinder vacuum.
-Jeff

most people that i know with boosted cars run some sort of boost controller, so the pressure drop is pretty easy to work around.

ive heard that running it off the manifold could lead to small boost spikes when the wastegate is first opening. the signal is somewhat delayed and the wastegate opens a bit later than it would have coming off the comp housing.
not sure how accurate it is, but it makes sense to me.

[Jeff240sx]

We're not talking about sending a signal via an aerated hydraulic line filled with molasses. We're talking about air. In about 4 crank revolutions, the engine can essentially suck the air out of the manifold, intercooler and piping. This "delay" that "causes boost spikes" is .0032 seconds at 7000rpm. I don't buy that reasoning.
-Jeff

[ditosx]

I'm sure the "difference" is negligable, but it is definitely best to keep the wastegate vacuum line as short as possible.

[blitz180]

So where do you guys think I should get boost signal from? The master cylinder line doesn't sound like a bad option... any other suggestions?