Ebay GT45 Turbo

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Moparturbo

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Hello all,

In the process of putting an Ebay turbo GT45 on a mild 318. Starting off with the 318 to learn some tuning. I was wondering if anyone had a recommendation on what size wastegate to use.
I was thinking of using a 50mm. Probably staying 10 pounds or less.
 
I built a Ford 2.3 turbo engine a few years back and got a similar ebay turbo for it and I just have to ask, why didn't you get a turbo with the waste gate built into it? Mine was and it was fully adjustable. Oil and water cooled with a waste gate. It was just a tic over 200 bucks. I'm rolling around the idea of a slant 6 turbo engine and if I do it, I'll go the same route.
 
RustyRatRod said:
I built a Ford 2.3 turbo engine a few years back and got a similar ebay turbo for it and I just have to ask, why didn't you get a turbo with the waste gate built into it? Mine was and it was fully adjustable. Oil and water cooled with a waste gate. It was just a tic over 200 bucks. I'm rolling around the idea of a slant 6 turbo engine and if I do it, I'll go the same route.
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Everything I have seen with a wastegate is not a big enough turbo unless I decided to do a twin turbo set up. I am also wanting to keep this turbo for the next engine. I have a 340 with a 3.58 stroke crank that I will install at some point once I figure this tuning out. This will be carbureted on E85.
 
Agree 50mm will be plenty, could even drop down to a 38mm. I have twin 46mm on my twin turbo set up. I had a 38mm on my neon SRT with a 60mm turbo and it did just fine, controlled the boost up to 30psi.
 
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50mm wastegate is far more than enough. I run a 60mm single gate on a 700whp big block Chevy. Wastegate priority and placement is much more important.
 
Another point, a gt45 eBay turbo (they’re usually around 70mm if I remember correctly) is about 650-700hp worth of turbo. It will be fairly lazy on a “mild 318”.
 
Just on a search not knowing which one he got but a lot of them say 88-98mm which that's a big turbo for a 318
 
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Kinda funny the first one I pulled up to look at specs on, says 92mm in the title. Most (legit) turbo manufacturers use the compressor inducer to relate to sizing. Therefore, this in my mind is a 69mm turbo. I have no idea where they come up with the 92.
 
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The Maxpeeding gt45 (which I know a lot of people use) is listed as a 98mm in the title. Inducer size? 69mm.
 
Yeah its hard to tell with some, but like you I go off the inducer size. The GT 45 is just all over the place on ebay. Now if the person that made the thread has a 69mm turbo that would work perfect on his 318 I think.
 
69mm gt45 with a 1.25 ar (most of them are) will be soft on 318 inches. Especially a mild 318. I have done a few 5.3 LSs (325 inches) and with 70mm Garrett’s they’re soft down low and they make 100 more hp than a 318 NA.
 
TT5.9mag said:
69mm gt45 with a 1.25 ar (most of them are) will be soft on 318 inches. Especially a mild 318. I have done a few 5.3 LSs (325 inches) and with 70mm Garrett’s they’re soft down low and they make 100 more hp than a 318 NA.
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That could be considered a good thing if he’s crazy enough to run a 7.25“ diff, right? :D
 
TT5.9mag said:
Another point, a gt45 eBay turbo (they’re usually around 70mm if I remember correctly) is about 650-700hp worth of turbo. It will be fairly lazy on a “mild 318”.
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Here are the posted specs
Exhaust Inlet (Turbo Manifold) Flange: T4 Flange
Exhaust Outlet (Downspout) Flange: 3.25 " V-Band Flange
Compressor Trim: 49.6
Compressor Inducer Diameter: 69 mm
Compressor Exducer Diameter: 98 mm
Compressor Air Inlet Size: 107mm
Compressor Air outlet Size: 86.3mm
Compressor A/R: 0.66
Turbine Trim: 77.6
Turbine Inducer Diameter: 88 mm
Turbine Exducer Diameter: 77.5 mm
Turbine A/R: 1.05
 
Okay so you have the 69mm version, that will work good for a 318. Here's a good reference for mounting the waste gate properly.

wastegateplacement.jpg
 
Matts440 said:
Okay so you have the 69mm version, that will work good for a 318.
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I have to respectfully disagree. That’s exactly the size gt45 I was talking about when I said it would be lazy on a mild 318. It’s a 1.05 AR hot side also. @Moparturbo, that will work and it will make boost, eventually, but something in the lower 60 mm range would be much more enjoyable to drive on a mild 318.
 
TT5.9mag said:
I have to respectfully disagree. That’s exactly the size gt45 I was talking about when I said it would be lazy on a mild 318. It’s a 1.05 AR hot side also. @Moparturbo, that will work and it will make boost, eventually, but something in the lower 60 mm range would be much more enjoyable to drive on a mild 318.
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When you say lazy on a mild 318, what RPM would you say it will start making boost? It has the XE268 Comp Cam, 391 gear. Don't have a converter picked out yet for the 904.
 
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