GT3076R-WG - Want to convert to external WG.

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Qemyst
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GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

So, as the title suggests, I want to (at least I think I *should*) convert my internally gated GT3076R to an external WG.
It's a T2 flanged turbo. .86 ar. Currently mounted on a Isis V2 bottom mount manifold (came with the buy so I'm just using it. No issues so far)

Basically, this Spring i'd like to get it to the dyno and get a tune that pushes roughly 300hp. It's Nistune so things should be fairly smooth. The motor is totally stock but was recently rebuilt, just...with OEM parts. I know it can handle it so no worries there.

I just want to add a bit of reliability in the form of an external WG, but am unsure if I -NEED- to go to an external WG for my turbo spec/power goals. I've seen people shying away from the GT3076R internally gated because of boost creep due to the WG. I want to avoid that problem by going external if necessary.

So yeah... Should I convert to external? If so, does anyone know of any fairly inexpensive bottom mount T2 flanged manifolds out there with WG flange? Can the Isis V2 bottom mount have a wastegate flange welded on?
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Re: GT3076R-WG - Want to convert to external WG.

Post by shift_down »

I think the real question is, why do you want to use a t2 turbo to make 300hp?

Anyways, just weld the flapper shut and weld a wastegate flange on your manifold. Good to go.
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

It was a great buy on the turbo and many people have told me that turbo is great for the KA. Numerous people have said .86 ar T2 flanged is perfect. I talked to 8-bit on the phone a while back regarding Nistune and he said it was a very good turbo for the KA for my power goals.

But yeah.. so it's that simple. weld flapper, weld flange to manifold.
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Re: GT3076R-WG - Want to convert to external WG.

Post by neverlift »

go for a jog and note your breathing effort, now go for run a while breathing through a straw and note your breathing effort.


Most t2 setups make massive trq down low that tappers off(some cases drastically) which will reduce the HP output. If you make peak trq later you generally make more hp. Someone recently posted a dyno IIRC it was a ca t25 made good trq but hardly an hp.
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

The guy running it before me was making pretty mean numbers with a lot of room to grow on a similar setup. A .86 ar T2 flanged turbo flows very similarly to a T3 flanged .63. There should be no issues whatsoever for the turbo to do 300. I'm happy with the turbo for my goals (many others have agreed), i'm just curious about the WG situation.

Just wondering if converting to external WG is *recommended* for my power goals or if stock internal WG would be reliable (ie. not cause boost creep). I read about the internal WG ports being physically unable to move enough volume and got a little concerned. I'm just wondering if you run into internal WG problems at like... REALLY high power output or if it is something that can be an issue even at lower levels of power (like my 300hp). Basically, when is is recommended to use external WG to avoid boost creep?

If it's recommended to convert to external i'll get a 38mm flange welded onto my manifold and run a Tial. If my setup will be fine/reliable with a stock internal WG I will just leave it alone.
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Re: GT3076R-WG - Want to convert to external WG.

Post by shift_down »

I'm running a t3 at 7psi and only making 230 hp/tq, that should put things in perspective.
You will need to run very high boost to make 300 hp which will be way out of the t2s efficiency range. It will also cost you more money because you have to buy a flange and have it welded.

If you really are sticking to the t2, then yes you will need an external wastegate. No doubt about it.
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

Ahhh, yeah. I'm not too worried about the cost of having the flange welded and the flange itself isn't terribly expensive. Just gotta figure out where on the manifold would be the best place to weld on the WG. As close to the turbo flange as possible I would imagine.

Is a MBC ok for external WG or is EBC pretty much the way to go?
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Re: GT3076R-WG - Want to convert to external WG.

Post by neverlift »

I honest could care less what the turbo can flow I am speaking specifically of the flange and it has been proven the t3 flows more. If a t2 could flow the air a t3 can then at some point the t3 would be fazed out or never designed.

Its like saying a 2.5"pipe flows the same as a 3", it does not.

I am not knocking your friggin turbo man take a pill, I'm on an ebay t3/t4 for crying out loud....

any boost controller will work if installed correctly.

I'd toss it close to the turbo flange.
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

Ease up slugger, I wasn't saying you were "knocking" anything. I was just saying for my needs a T2 .86 ar 3076r is fine so as to keep on the topic of the wastegate question instead of discussing turbo airflow.

Thanks for the info regarding boost controller and flange location though. Typically a short pipe would have to be welded to the manifold and then the wastegate flange to the pipe, correct?

Also, does the following flange essentially replace the need to weld flapper shut? Or do you still need to weld flapper shut AND use that flange?

http://www.enjukuracing.com/products/5- ... egate.html
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

Alright, so I got a pretty big wastegate. Precision turbo 46mm. This is because numerous people have said that because of my turbo and probably running low boost (12-14psi) I'd need a big wastegate to evacuate excess exhaust gasses.

I've had people say a 38mm Tial (or 39mm Precision Turbo) would be fine and i've had others say they get boost creep on those with similar setups...So I went big. it will be dumping to atmosphere so I won't have quite as much back pressure to worry about, but we'll see I guess.
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Re: GT3076R-WG - Want to convert to external WG.

Post by cleantune »

.
hey if you have not installed this already, make sure to have the pipe for the WG coming out of the exhaust slightly angled with the exhaust flow too; if you have not done so already:

Image
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

Yeah, I was actually curious about that. I've read from multiple sources that 90 degree tube is not good, and others who have said 90 is fine. I haven't actually welded the tube for the WG onto the mani yet and am planning to try to angle it as much as possible. I don't know how much of an angle I will be able to get though as I will be attaching it as close to the turbo flange as possible, where the 4 exhaust pipes converge.

I've seen multiple turbo manifolds, such as the doc race top mount and the xcessive top mounts that have the pre welded wastegate tubes and they seem to be coming off at damn near a 90 degree angle...though I guess it could be a slight angle more, as pics don't always give an accurate picture.

Cheers man
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Re: GT3076R-WG - Want to convert to external WG.

Post by cleantune »

yeah supposedly 90 degree is acceptable, less than 90 is not, and between 90 and symmetrical is highly recommended. You should be good with a 90, but I was just thinking, If you're going to custom fab one up, why not make it better?

The reason both 90 degree and symmetrical work and even the highly Unrecommended <90 to some extent, is because of the gas pressure (flow through path of least resistance). The symmetrical design (and angles close to it) work so well because they allow for equal flow to both the WG and the turbo; which results in a more responsive WG and less chance of overboosting.
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Re: GT3076R-WG - Want to convert to external WG.

Post by jmhalder »

I'd mention that if you are trying to hit 300hp on this turbo, and you're close to the actual efficiency of it, you won't creep. I've always hated having a external gate, I liked my internal, nice and simple.
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Qemyst
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

Yeah, I don't really *want* to go external, but want things to be reliable. I'm definitely going to replace my MBC with the Greddy Profec B Spec II ebc I have though.

I'm actually going to run internally at first and see if it creeps before I weld and convert to external....because I like money and time.

I believe the internal gate is set at 7psi, so it may be fine.

Thanks!
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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

I'm curious as to what the best place to weld on this wastegate will be, if it comes down to it.

Here's a pic of the manifold

Image

Is it ok to weld on the pipe for the WG on the side of the manifold closest to the cabin where I put the arrow in the pic?

The runners aren't divided, and the tube will be coming off where all 4 runners converge closest to the turbo. There's room to get everything on if I were to attach it there.

Ideally I would want it to come off towards the driver side wheel well, but there really isn't any room to do it there.

Any thoughts?
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Re: GT3076R-WG - Want to convert to external WG.

Post by cleantune »

Maybe something like this:Image

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Re: GT3076R-WG - Want to convert to external WG.

Post by Qemyst »

I'll have to get a pic of my setup on tuesday, but I'm not sure I'll have enough room to come off the manifold towards the strut tower like that, but maybe with a really tight 90 degree bend like that it could work.

Is there a good place you know of to order exhaust piping like that? I'd need a 1-3/4" inch pipe on the discharge side and a 1-7/8" pipe on the inlet. So, a tight 90 degree 1-7/8" might do the trick, i'm just not sure where to get a tight 90 like that.
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Re: GT3076R-WG - Want to convert to external WG.

Post by cleantune »

Summit Racing should have what you're looking for. Vibrant performance makes a lot of pre-bent and straight custom tubing. Here's a link:
http://www.summitracing.com/search/depa ... ing&page=2

Maybe pick up something like this and then cut it to the length and cut the ends to what ever angles you need:
Image



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